Development and Field Testing of Multiple Deployment Model Pile (MDMP)
Alternative Text
Also – Note that standard FHWA report style is to provide metric and English measurements consistently throughout the report, or only provide metric. Because this report has already been printed, however, we provided measurements as they were provided in the report.
Figure 1. The Dual Piezo Friction Cone Penetrometer (De Ruiter,1982). Drawing. A line drawing illustrates the dimensions and technical specifications of a Type F7.5CKE2W/V piezocone penetrometer with a standard filter element. A second drawing to the side of the complete schematic
shows only the cone with the filter element in an alternative location. The drawing of the entire penetrometer, which depicts the filter element 50 millimeters above the cone tip, has the following dimensions: (A) total length of shaft is 440 millimeters (B) length of the 60-degree point-angle cone is 34 millimeters topped with an additional 18 millimeters straight section, (C) a 2.5 millimeters O-ring is between the shaft and the cone's straight section, (D) thickness of the filter element is 8 millimeters where the top is 2 millimeters below the O-ring; (E) diameter of the friction sleeve is 43.9 millimeters; (F) diameter of the shaft is 43.8 millimeters; (G) diameter of the cone is 43.7 millimeters. The second drawing of the cone shows that the filter element can be in an alternative location, in this case, within the 60-degree cone where the filter top is located 24.5mm from the cone tip. The following dimensions are shown on the second drawing: (A) length of the 60-degree cone is 34 millimeters; topped with an additional 5 millimeters straight section, (B) a 2.5 millimeters O-ring is between the shaft and the cone's straight section, (C) thickness of the filter element is 7 millimeters where the top is 14.5 millimeters below the O-ring. Detailed specifications and notes for the instrument are listed, alongside the schematic, in tabular format.
Figure 2. Typical Locations of Pore Pressure Measurements for Piezocone Penetrometers. Drawing. In the absence of a standard, the pore pressure transducer can be located in one or more different areas of the penetrometer. This line drawing of four penetrometers illustrates that the pore pressure transducer can be located (1) in the tip of the cone (U subscript 1), (2) immediately behind the tip of the cone (U subscript 2), (3) just above the friction sleeve (U subscript 3), and (4) in all three of these locations. Two dimensions are shown on the figure. The cone tip projected area is 10 square centimeters and the surface area of the friction sleeve is 150 square centimeters.
Figure 3. The Piezo-Lateral Stress (PLS) Cell (Morrison, 1984). Drawing. Components and dimensions for the PLS cell are shown in two line drawings. The first drawing (not to scale) identifies the major parts of the instrument and includes, from top to the bottom tip, the AW rod, which is 44.45 millimeters in diameter; the housing, which is 38.35 millimeters in diameter; the tip extension; and the 60-degree tip. At a location "L" distance away from the tip are the measurements for pore pressure (u), horizontal stress (sigma-sub h), and axial (vertical) stress (sigma-sub a). This measurement section is 2.85 inches (72.39 millimeters) in length, and 2.67 inches (67.82 millimeters) below the AW Rod. The second drawing is a magnification of the instrument inside of the housing. It identifies the components and some related dimensions. Shown, from top to bottom, are the AW rod, housing, load cell, axial load device, water film, solid stem, hollow core, membrane, porous stone, and cone tip extension. The diameter of the housing is 38.35 millimeters. Immediately below the AW rod, the load cell and axial load device are contained in a section of housing that is 195.6 millimeters long. Below that is the lateral stress cell, 46.99 millimeters in diameter and containing the water film, solid stem, hollow core, and membrane. This is followed by the pore pressure detection element, which contains porous stone and is 25.4 millimeters long, just above the cone tip extension.
Figure 4. Detailed Cross-Section of the Piezo-Lateral Stress (PLS) Cell (Morrison, 1984). Drawing. This figure illustrates, in detail, the components of the piezo-lateral stress (PLS) cell and some dimensions, which are the same as shown in the magnification in figure 3. The PLS cell is divided into the (A) steel housing, which contains the transducer and is located over the head of the PLS cell, (B) lateral stress cell, which is comprised of, outside to inside, a steel outer membrane, the water film, a solid steel core, and the pore pressure transducer; and (C) pore pressure sensing element, which is comprised of, top to bottom, the upper block, porous ring, lower block, and assembly screws. Below these three main components is the cone tip extension, which is approximately 27 times its diameter in length and separates the PLS cell from the cone tip.
Figure 5. Details of the Axial Load Cell in the Piezo-Lateral Stress (PLS) Cell (Morrison, 1984). Drawing. Shown in this figure are the components of the axial load cell found in a PLS cell. Inside the steel housing, the load cell is divided into an upper section, which measures 91.4 millimeters in length, and a lower section, which measures 94 millimeters in length. The upper and lower sections are sealed together by an O-ring. The lateral stress cell is located just below the load cell assembly.
Figure 6. The Grosch and Reese (G and R) Instrumented Model Pile (Grosch and Reese, 1980). Drawing. This figure illustrates the components and dimensions of the G&R model pile. The instrument is a close-ended aluminum tube with a solid aluminum plug, 25.4 millimeters thick. The aluminum tubing is 254 millimeters in diameter and 889 millimeters total length (top and bottom sections). At the top of the model pile are the instrumentation wires, which are routed through a flexible garden hose. Immediately following is the connector assembly, measuring 76.2 millimeters in length. The connector is attached by screws to a 50.8-millimeter-diameter galvanized pipe. Below the connector unit is a 25.4-millimeter-thick pile cap containing valves. The outer diameter of the pile cap is 50.8 millimeters. Below the pile cap are two unequal lengths of 6061 aluminum tubing, 25.4 millimeters in diameter and separated by a porous plug, also 25.4 millimeters in diameter. The upper
section of aluminum tubing is 508 millimeters long and the section below the porous plug is 254 millimeters long. Within each of the two sections of aluminum tubing are two diametrically opposed 120-ohm strain gages, located 127 millimeters from (above and below) the porous plug.
Figure 7. The Norwegian Geotechnical Institute (NGI) Instrumented Test Pile (after Karlsrud and Haugen, 1985). Drawing. Shown in this figure are the components of the NGI test pile. The instrument is 5.15 meters in length and 154.4 millimeters in diameter, with a wall thickness of 4.5 millimeters. Located at the top of the pile are a load cell and a displacement transducer. Six strain gages are distributed along the length of the pile at approximately 0.5, 1, 2, 3.5, 4.5, and 5 meters from the top of the unit. Four earth pressure cells and four pore pressure cells are located at intervals about 0.5, 2, 3.5, and 5 meters from the top.
Figure 8. The 7.62-centimeter (3.0-inch) Instrumented Model Pile (Bogard and Matlock, 1985) Drawing. Components of the 7.62-centimeter instrumented model pile are shown, along with schematic magnifications of these components. Shown from top to bottom of the unit are the load cell, total and pore-pressure transducers, a second load cell, the direct-current linear-variable displacement transducer (DC-LVDT) housing, and the cutting shoe near the bottom. Magnification of the load cell illustrates the strain gages within a sleeve that is welded to the ends of the load cell. Enlargement of the transducers shows the total pressure load cell located above the pore-pressure cell with its porous element. Below the second load cell is a magnification of the DC-LVDT housing.
Figure 9. The X-Probe (Bogard and Matlock, 1985). Drawing. The figure is a simple line drawing of the X-probe, identifying the major components. Shown, from top to bottom, are the instrument cable, standard cone rod connection, load cell, total pressure cell, pore pressure cell, displacement transducer, and soil anchor.
Figure 10. Details of 7.62-centimeter (3-inch) Model Pile Axial Load Cells (after Patent Number 5,259,240). Drawing. Shown in figure 10 are two line drawings of axial load cells. One shows a cross section, identifying the strain gages, which are mounted in a Wheatstone bridge formation, the load cell cover, and two accelerometers. The second drawing shows the load cell cover, which protects the strain gages in the instrumented section of the load cell.
Figure 11. Details of 7.62-centimeter (3-inch) Model Pile Pressure Instruments (after Patent Number 5,259,240). Drawing. This figure shows two cross section line drawings of a pressure instrument used in a model pile. The drawings illustrate two different views of the total pressure transducer and pore pressure transducer located between two load cells.
Figure 12. Configuration and Instrumentation of the In Situ Model Pile (IMP) (after Lehane, 1992). Drawings. This figure is a set of four drawings representing the IMP and its components. One diagram shows the overall configuration of the IMP, which consists of two concentric cylinders attached to a common pile head. The relative locations of the sensors in these cylinders are also depicted. Shown, from top to bottom, are the drill string; pile head; the following instrument cluster, comprised of an axial load cell, a radial pressure sensor, and a pore pressure sensor; the leading instrument cluster, comprised of a radial pressure sensor and a pore pressure sensor sandwiched between two axial load cells; tip of pore pressure sensor; and tip of instrument. The total length of the configuration from the bottom of the head to the upper tip is 1135 millimeters. The diameter of the unit is 80 millimeters. A second drawing is a cross section of the radial stress sensor illustrating the following components: the stainless steel loading platen, location of the platen attachment to the base, O-ring seal, and strain gauged encastré beam. The third drawing is a cross section of the pore pressure sensor with the Druck semiconductor transducer. It shows the PDCR 81 transducer in relation to the ceramic filter, the epoxy/sand filter, and the pile shaft. The last drawing is a simple cross section of the pore pressure sensor with a strain-gauged diaphragm, showing the strain-gauged diaphragm, filter, brass holder, and rubber ends.
Figure 13. The Imperial College Instrumented Model Pile (Bond and Jardine, 1991). Drawing. This figure is a simple diagram illustrating the components of the Imperial College instrumented model pile. This close-ended instrument is 7 meters long and contains three clusters of instruments, spaced 1 meter apart. Each cluster contains an axial load cell, a surface stress transducer with temperature sensor, and a pore pressure unit containing two probes. The pile tip is a 60-degree cone. At the top of the instrument is a set of three displacement transducers and an axial load cell.
Figure 14. Typical Imperial College Model Pile Instrument Cluster (Bond et al., 1991). Photograph and Drawing. This figure includes a black-and-white photograph and corresponding line drawing of the instrument cluster used in the Imperial College model pile. From left to right, the drawing identifies the axial load cell, with its rubber O-ring (water seal) and thinned wall housing the strain gauges. In the middle of the cluster is the pore pressure unit, which contains a "Nu-lip" rubber O-ring (soil seal), the pore pressure block, and a port-hole for the pore pressure block. At the right end of the instrument cluster is the surface stress transducer showing the Cambridge earth pressure cell, the window frame, and the windowpane.
Figure 15. The Surface Stress Transducer (Bond et al., 1991). Drawing. This break-apart figure illustrates the details of a surface stress transducer (SST) contained in the instrument clusters of the Imperial College model pile. The main cable duct is shown on the main housing, which has a raised platform and stiffener around the cable hole and a rubber O-ring surrounding the window frame. The window frame contains the Cambridge earth pressure cell, which is sealed to the windowpane with hot-bonded rubber. A rubber O-ring is also located at the cable duct end of the unit where it is attached to the pore pressure unit (see figure 16).
Figure 16. The Combined Axial Load Cell and Pore Pressure Unit (Bond et al., 1991). Drawing. This figure illustrates the details of an axial load cell and an adjacent pore pressure unit contained in the instrument clusters of the Imperial College model pile. Shown on the drawing of the axial load cell are two O-ring grooves and the thinned wall area of the cell. Illustrated on the drawing of the pore pressure unit are the ledge for the "Nu-lip" rubber O-ring, protective sleeve of the unit, its porthole, and an O-ring groove on the end attached to the surface stress transducer (see figure 15).
Figure 17. Typical Configuration of the Modular MDMP. Drawing. This simplified line drawing illustrates the components of a typical MDMP and some related dimensions. The 2.87-meter-long and 76.2-millimeter-diameter unit contains three load cell assemblies. Shown, from top to bottom, are the N-rod adaptor, connector housing, upper extension, top load cell assembly, upper coupling, transducer housing (containing the pore pressure transducer and radial stress cell), lower coupling, middle load cell assembly, slip joint assembly, lower extension, bottom load cell assembly, and 60-degree point angle tip segment.
Figure 18. Tip Configuration of the MDMP. Drawing. This figure includes a simplified drawing of the MDMP and three different tip configurations: (A) the "short pile" (lead cell plus tip); (B) the "long open-ended pile" (load cell plus cutting shoe); and (C) the "long close-ended pile" (an extension plus load cell plus tip).
Figure 19. Typical Soil Profile for the Boston Area. Graph. This figure is comprised of two charts. One illustrates vertical effective stress (sigma subscript VO on the X-axis) as a function of soil layer and depth (feet on the Y-axis) for typical subsurface conditions found in the Boston area. Soil layers and depths identified on the Y-axis are fill material between the surface and 30 feet; medium Boston blue clay (BBC) between 30 and 70 feet, and soft BBC between 70 and 120 feet. Labeled on the X-axis is sigma subscript VO between 0 and 700 in kilopascals. The graph serves to illustrate that different soil types found at various subsurface depths can present varying levels of soil resistance to load cells when a model pile instrument is deployed. The second chart illustrates undrained shear strength (s sub u) as a function of soil layer and depth. The Y-axis shows depth from surface to 35 meters, and the X-axis shows undrained shear strength (S subscript U) in kilopascals (0 to 100) and in ton-per-square-foot (0 to 1.0).
Figure 20. Hypothetical Soil Profile of Dense Sand. Graph. This figure is a chart that displays vertical effective stress as a function of depth (surface to 36 meters and surface to 120 feet) for dense sand. The chart illustrates the upper limit of soil resistance that may be encountered by the load cell when a model pile is deployed in dense sand. The X-axis shows sigma subscript VO in kilopascals (0 to 750) and in ton-per-square-foot (TSF) (0 to 8). Depth in the sand column is shown on the Y-axis in meters (0 to 35) and feet (0 to 120). The chart shows that effective stress and total stress begin at 0 near the surface of the soil and increase with depth. With depth, there is a greater increase in total stress than in effective stress. At about 35 meters (118 feet), effective stress is about 450 kilopascals (4.5 TSF) and total stress is about 750 kilopascals (7.8 TSF).
Figure 21. Drop Hammer Configuration Modeled in the Wave Equation Analyses. Drawing. This line drawing illustrates the drop hammer driving system used in the wave equation analyses to evaluate dynamic loads and accelerations during driving. Some values used in the analyses are listed along the drawing. Shown from, top to bottom above the surface of the ground, are the ram, ram guide rod, donut striker plate, stroke distance, anvil, and drill rod adapter. From the ground surface to the bottom, the following components are illustrated: N-rod, cased hole, length of rods, model pile (76.2 millimeters in diameter), length of pile, penetration depth, end bearing, and skin friction distribution points.
Figure 22. Photograph of the MDMP Load Cell With Sleeve. Photograph. The figure is a black-and-white photograph of a load cell with the load cell sleeve.
Figure 23. Photograph of the Transducer Housing With the Pore Pressure Transducer and the Total Radial Stress Cell. Photograph. The figure is a black-and-white photograph of a disassembled transducer housing showing the total radial stress cell and pore pressure transducer.
Figure 24. Photograph of the Slip Joint With DCDT. Photograph. The figure is a black-and-white photograph of a disassembled slip joint showing the upper and lower components, and the DC-LVDT with its mount.
Figure 25A. Schematic of the Calibration Frame for the MDMP. Drawing. Companion to photograph in figure 25B. This figure illustrates the components of calibration frame used for the MDMP load cell calibration. The reaction frame, which measures 1.1 meters in width and 3.5 meters in height, consists of one horizontal W6-by-15 section and two vertical W6-by-15 sections. The frame has a base support. Within the frame are, from top to bottom, the upper loading plate, 50,000-pound load cell, drill rod adapter, model pile with wire adapter, movement-free connection, hydraulic ram, bearing plate, and bottom reaction.
Figure 25B. Photograph of the Calibration Frame for the MDMP. Photograph. Companion to drawing in figure 25A. The figure is a black-and-white photograph of the calibration frame used for the MDMP load cell calibration (as described in the figure 25A schematic).
Figure 26. Pressure Instrumentation Calibration Setup. Drawing. This figure is a line drawing that shows the layout for calibration of the pore pressure transducer. The pore pressure cell is enclosed in a cylindrical calibration chamber, which is suspended horizontally from supports by steel wires and circular clamps. A cable connects the internal accelerometers and load cells to a connection box and a Hewlett Packard data acquisition system (HP DAS). A PID control pressure transducer is shown in the line between the PID circuit and piston (used to apply pressure to the fluid in the calibration chamber) and the pressure chamber.
Figure 27A. Photograph of the Dynamic Instrumentation Testing Setup. Photograph. Companion to drawing in figure 27B. This figure is a black-and-white photograph of a custom-designed system used to support the MDMP under dynamic loading and also for its associated loading equipment.
Figure 27B. Schematic of the Dynamic Instrumentation Testing System. Drawing. Companion to photograph in figure 27A. This figure is a line drawing that shows the custom-designed support system used to support the MDMP under dynamic loading. It shows a horizontal MDMP suspended from supports by steel wires and circular clamps. A steel ram, supported in the same manner, is used as a hammer. Between the steel ram and the pile is a one-eighth-inch-thick piece of plastic or a one-half-inch-thick piece of plywood, which serves as a cushion. Varying lengths of drill rods, connected to a surface accelerometer and a strain gage, may be used to measure force and acceleration applied to the rods.
Figure 28. Schematic of the MDMP Data Acquisition System. Drawing. This figure is a line drawing of the MDMP and the elaborate system for collecting data from its various sensors. Shown are the MDMP with all of its cables routed through a connection box, the PDA, and DCDTs. The PDA and the HP DAS are also schematically shown.
Figure 29. Hewlett Packard Data Acquisition System (HP DAS). Photograph. This figure is a black-and-white photograph of the data acquisition system used with the MDMP. It shows the two basic components of the system: an HP-75000 Series-B cage VXI bus data acquisition system, which is comprised of a mainframe HP-E1301A with several modular components, and an IBM-compatible 486 PC.
Figure 30. Pile-Driving Analyzer (PDA) Data Acquisition System. Photograph. The figure is a black-and-white photograph of a Pile Dynamics, Inc. (PDI) portable PDA used with the MDMP.
Figure 31. Connection Box, Back Faceplate. Drawing. This figure is a simplified line drawing of the back faceplate of the custom-designed connection box used with the MDMP DAS. The rectangular plate shows three cable input jacks on the left side and three cable output jacks on the right side. The two circular input connections on the left are for the dynamic ground-surface inputs (upper) and the static ground-surface inputs (lower). To the right of these is a rectangular down-hole input for the cable containing all instrumentation wires from the MDMP. Next on the right are two circular dynamic output jacks. One is for the connection to the piezoresistive accelerometer (upper) and the other is for the connection to the two piezoelectric accelerometers and their associated strain gages (lower). Furthest right is the large jack for the static output.
Figure 32. Connection Box, Front Faceplate. Drawing. This figure is a simplified line drawing of the front faceplate of the custom-designed connection box used with the MDMP. The rectangular plate shows three switches across the front labeled, from left to right, "top load cell," "middle load cell," and "lower load cell." Each switch has "dynamic" and "static" setting, which allows data collection from the three MDMP load cells to toggle between dynamic and static modes. Above the switches are three jacks for connection to a dual DC external power supply. Below the switches are jacks for three DC voltages: two for plus-5 volts, three for plus-15 and minus-15 volts, and two for plus-18 volts.
Figure 33A. Schematic of the MDMP Static Load Frame. Drawing. Companion to photograph in figure 33B. This line drawing illustrates the static loading system and its component parts. The load frame consists of an upper and lower steel plate connected by turnbuckle-threaded support rods. It is stabilized on the ground by subsurface anchors and is equipped with blocks to level the unit. At the top, displacement transducers are located on a disk attached to the upper plate of the hydraulic ram, which is secured to the upper plate of the load frame. The load from the hydraulic ram is transferred down to the drill rods by a loading rod, which contains the load cell. An instrument cable transfers signals from the instruments to a connection box. Below the ground under the drill rods is a casing containing the MDMP.
Figure 33B. Photograph of the MDMP Static Load Frame. Photograph. Companion to drawing in figure 33A. The figure is a black-and-white photograph of the MDMP static loading system deployed in the field. The photo shows the static load frame, hydraulic ram, cables, and frame anchors.
Figure 34. Newbury Site Locus Plan. Map. This figure presents two maps. The upper map is the state of Massachusetts, identifying the site locus, which is in the extreme northeastern part of the state. Below the state map is a more detailed map of Newbury, Massachusetts, showing the location and boundaries of the project site.
Figure 35. Newbury MDMP Site Plan. Drawing. This figure is a line-drawn map (scale is 1 inch equals 60 feet) of the test site, illustrating site elevations, locations of historical borings, and locations of the MDMP tests.
Figure 36. Representative Soil Stratigraphy at the Newbury MDMP Test Site (Chen, 1997). Drawing. The figure depicts a 30-meter- (98-feet-) deep soil column identifying 10 general strata developed from pre-test borings and some historical borings. Various geotechnical properties of each strata are also included in the drawing. The strata, identified from the surface down, are miscellaneous fill to 2.5 meters (8 feet), organic matter to approximately 2.75 meters (9 feet), overconsolidated clay to 5.5 meters (18 feet), soft, normally consolidated clay to 11.5 meters (38 feet), normally consolidated clay to 16.5 meters (54 feet), interbedded silt, sand, and clay to about 19.25 meters (63.5 feet), silty sand to about 21.75 meters (71.5 feet), interbedded silt, sand, and clay to 24 meters (79 feet), fine to medium sand to 26.5 meters (87 feet), and fine to coarse gravel/till to 30 meters (98 feet).
Figure 37. Soil Profile of the Newbury Test Site (South-North). Drawing. The figure shows a soil profile based on four borings (BB7, NB1, NB4, and W5U) made from south to north along the center line of the proposed construction site. The horizontal scale is 1 millimeter equals 20 meters and the vertical scale is 1 millimeter equals 15 meters. The profile roughly corresponds to the soil stratigraphy identified in figure 36, with only minor variation in the depths of the strata horizontally along the boring line. The composition is primarily clay above 10 meters, followed by several layers of interbedded sand, silt, and clay to about 22 meters, and ending with a 2.5-meter till layer above the bedrock.
Figure 38. Groundwater Elevations at the Newbury Test Site. Chart. This figure is a chart that shows the levels of groundwater, measured in four monitoring wells, over a period of about 6 months (March 1996 to September 1996). Elevation in meters (1.6 to 6) and in feet (5 to 20) is shown on the Y-axis. Measurement dates, in approximate one-month intervals, are shown across the X-axis. Although the range of groundwater elevation for all the wells was 3 to 4.5 meters (10 to 15 feet), most measurements were between 3.7 and 3.9 meters (12 and 13 feet). Over the 6-month monitoring period, groundwater levels generally rose slightly nearer to the surface.
Figure 39. Profiles of Vertical Effective Stress, Maximum Past Pressure, and OCR at the Newbury Site (Chen, 1997). Chart. This figure presents a depth profile plot of stress and maximum past pressure, and a profile plot of the OCR for the clay strata at six of the Newbury site bore locations. On the first chart, the X-axis shows maximum past pressure between 0 to 600 kilopascals (0 and 6 Ton-per-Square-Foot (TSF)). The Y-axis shows depth between the surface and 30 meters (98 feet). Changes with depth are shown for vertical effective stress with embankment and without embankment. Measured and calculated undrained shear strength is shown plotted against depth in the clay layer at each of the six monitoring sites. The plot shows that, at most test locations, little change in the maximum past pressure was detected with depth. On the second chart, the X-axis is OCR ranging between 0 and 7.5, and the Y-axis is depth between the surface and 30 meters (98 feet). The approximate range for OCR in the overconsolidated region is 1 to 7. Higher ratios occur nearer the surface; for example, ratios between 2.5 and 7 occur between 10 and 25 feet. Below 30 feet, OCR drops to unity.
Figure 40. Profiles of Vertical Effective Stress, and Calculated and Measured Undrained Shear Strength at the Newbury Site (Chen, 1997). Chart. The figure is a depth profile plot of vertical effective stress, and calculated undrained shear strength of the clay component at the Newbury test site. The X-axis is undrained shear strength between 0 to 200 kilopascals (0 to 2 TSF). The Y-axis shows depth from the surface to 30 meters (98 feet). Changes with depth are shown for vertical effective stress with embankment and without embankment. Measured and calculated undrained shear strength is shown plotted against depth in the clay layer at each of the six monitoring sites. The plot shows that, at most test locations, little change in the undrained shear strength was detected with depth.
Figure 41. Initial Excess Pore Pressure Distribution (only OCR readings between 1 and 10 included) (Paikowsky et al., 1995). Chart. This figure is a chart that that shows the excess pore pressure distribution for both historical data, and data from the NB2 and NB3 study locations. All data are plotted logarithmically. Only soils having an OCR ratio between 1 and 10 are shown. The X-axis is the normalized radius (small r over capital R) (1 to 100) and the Y-axis shows normalized excess pore pressure (delta u divided by sigma prime sub v), which is the ratio of average initial excess pore pressure (delta u) to vertical effective stress (sigma prime sub v) from 0 to 5. The generalized trend appears to be an inverse relationship between normalized radius and normalized excess pore pressure.
Figure 42. Effects of OCR on Normalized Excess Pore Pressure Along the Shaft (h over r greater than or equal to 17, which means a distance of 17 radii or more from the pile tip tip) for Small R over Capital R (normalized radius) Equals 1 (Piakowsky et al., 1995). Chart. This figure is a chart showing the relationship between normalized excess pore pressure and clay soil OCR. Both historical data and data from the NB2 and NB3 study locations are shown. The data have been normalized and plotted logarithmically. The X-axis is the soil OCR (1 to 15) and the Y-axis is normalized excess pore pressure ratio (negative 2.5 to positive 20). All data are plotted logarithmically. The generalized trend appears to be a slight increase in excess pore pressure with an increase in soil OCR.
Figure 43. Predicted Pore Pressure Dissipation and Capacity Gain for the MDMP at the Newbury Site. Chart. This figure is a chart that illustrates the changes in the pore pressure dissipation ratio and the capacity gain ratio with time after driving. Data are plotted logarithmically. The X-axis is time in hours (0.01 to 100) after driving. The left Y-axis is the pore pressure dissipation ratio (0 to 1) and the right Y-axis is the capacity gain ratio (0 to 1). A high, average, and low ratio is plotted for both the pore pressure dissipation and for the capacity gain. The high, average, and low pore pressure dissipation ratios decrease consistently with time after driving. The high, average, and low capacity gain ratios increase consistently with time after driving.
Figure 44. Site Layout During MDMP Tests at the Newbury Site: (A) Initial Setup, (B) During Snowstorm, and (C) Static Load Test. Photograph. This figure consists of three black-and-white photographs taken at the Newbury test site. The top photo (A) shows two personnel at the roadside test site, which is covered in snow. An Army tent, which housed personnel and equipment during the study, is also shown. The second photo (B) shows a drill rig set up at the test site during a snowstorm. The third photo (C) shows five engineering personnel at the test site displaying a sign, which identifies them as from the Department of Civil Engineering at the University of Massachusetts in Lowell. The static load frame is also shown in place at the test site.
Figure 45. Steps for Installation and Testing of the MDMP at the Newbury Site. Drawing. This figure is a series of six line drawings that illustrate the steps involved in a typical MDMP installation and testing performed at the Newbury site. The first drawing represents a water-filled cased hole. The second drawing shows the MDMP attached to drill rods and located at the bottom of the cased hole. The third drawing in the series depicts the 140-pound SPT hammer used to drive the MDMP. The strain gages and accelerometers, used for monitoring dynamic response, are also shown. In the fourth drawing, the surface load cell is shown attached to the unit in preparation for conduct of the initial load test using the drill rig. The fifth drawing depicts the static load frame installed over the hole in preparation for the static load test. The last drawing shows the MDMP with attached strain gages and accelerometers in preparation for restrike with the STP hammer.
Figure 46. (A) MDMP Being Driven and (B) Static Load Frame Assembled. Photographs. The figure is comprised of two black-and-white photographs. The photo on the left (A) shows an engineer driving the MDMP at the test site. On the right side (B) is a photo of the assembled static load frame at the test site.
Figure 47. Pore Pressure Build-Up and Dissipation With Time (Log Scale) for Model Pile Test NB2. Chart. Companion to table 25. This figure is a chart that illustrates changes in pore pressure over a logarithmic time scale measured at the NB2 test location. The X-axis is time in hours (0.01 to 100) after the start of installation. The Y-axis is pore pressure in kilopascals (0 to 200) and PSI (negative 5 to positive 35). Pore pressure is shown as a continuous trace over the duration of a four-day test sequence, beginning with the model pile in a cased borehole and ending near the completion of the series of load tests. From the starting pressure, which approximates the pressure head in the casing (about 45 kilopascals or 6.5 PSI), a rapid increase in pore pressure is shown at the point when the pore pressure cell penetrates the soil and the pile is being driven. The pressure continues to rise until slightly after driving stops. The pressure then reaches a plateau at around 200 kilopascals (30 PSI) until the start of the load test, when it dips slightly and is then followed by a small but rapid increase to about 220 kilopascals (32 PSI). During the following series of load tests using the static load frame, the pore pressure declines gradually until the end of the testing, when it approximates the hydrostatic pressure in the clay (about 50 to 55 kilopascals or 7 to 8 PSI).
Figure 48. Pore Pressure Build-Up and Dissipation With Time (Linear Scale) for Model Pile Test NB2. Chart. Companion to table 25. This figure is a chart that illustrates changes in pore pressure over a linear time scale measured at the NB2 test location. The X-axis is time in hours (0 to 140) after the start of installation. The Y-axis is pore pressure in kilopascals (0 to 200) and in PSI (negative 5 to positive 35). Pore pressure is shown as a continuous trace over the 140-hour duration of the test sequence, beginning with the first load test, and ending with a restrike and removal of the pile. From the starting pressure of about 210 kilopascals (31 PSI), which corresponds to the first load test, the pore pressure decreases inversely with time through the completion of the load test sequence until it approximates the hydrostatic pressure in the clay (about 50 to 55 kilopascals or 7 to 8 PSI).
Figure 49. Pore Pressure Build-Up and Dissipation With Time (Log Scale) for Model Pile Test NB3. Chart. Companion to table 26. This figure is a chart that illustrates changes in pore pressure over a logarithmic time scale measured at the NB3 test location. The X-axis is time in hours (0.01 to 100) after the start of installation. The Y-axis is pore pressure in kilopascals (0 to 250) and in PSI (0 to 40). Pore pressure is shown as a continuous trace over the duration of a four-day test sequence, beginning with the model pile in a cased borehole and ending near the completion of the series of load tests. From the starting pressure, which approximates the pressure head in the casing (about 80 kilopascals or 12 PSI), a rapid increase in pore pressure is shown at the point in time when the pore pressure cell penetrates the soil and the pile is being driven. The pore pressure continues to rise until the driving stops. The pressure then reaches a plateau at around 220 kilopascals (32 PSI) until the start of the load testing with the static load frame, when the pore pressure begins a gradual decline. At the end of the testing, the pore pressure approximates the hydrostatic pressure in the clay (about 92 kilopascals or 13 PSI).
Figure 50. Pore Pressure Build-Up and Dissipation With Time (Linear Scale) for Model Pile Test NB3. Chart. Companion to table 26. This figure is a chart that illustrates changes in pore pressure over a linear time scale measured at the NB3 test location. The X-axis is time in hours (0 to 120) after the start of installation. The Y-axis is pore pressure in kilopascals (0 to 250) and in PSI (0 to 40). Pore pressure is shown as a continuous trace over the 120-hour duration of the test sequence, beginning with the first load test, and ending with a restrike and removal of the pile. From the starting pressure of about 220 kilopascals (32 PSI), which corresponds to the first load test, the pore pressure decreases inversely with time through the completion of the load test sequence until it approximates the hydrostatic pressure in the clay (about 88 kilopascals or 12.5 PSI).
Figure 51A. Changes in Total Radial Stress With Time (0 to 100 Hours log Scale), MDMP Test NB2. Chart. Companion to table 25. This figure is a chart that illustrates changes in total radial stress over a logarithmic time scale measured at the NB2 test location. The X-axis is time (in hours) after the start of installation. The Y-axis is total radial stress in kilopascals (negative 100 to positive 200) and in PSI (negative 15 to positive 35). Total radial stress is shown as a continuous trace over the duration of a four-day test sequence, beginning with the model pile in a cased borehole and ending near the completion of the series of load tests. The initial total pressure on this chart is negative 52 kilopascals (7.5 PSI), which does not correspond to the pressure head in the casing (about 45 kilopascals or 6.5 PSI). The chart shows that, as the pore pressure cell penetrates the soil and the pile is being driven, the total radial stress increases rapidly. The pressure continues to rise just after driving stops. The pressure then reaches a plateau at around 180 to 185 kilopascals (27 to 28 PSI). During the series of load tests with the static load frame, the total radial stress declines gradually to about 100 kilopascals (15 PSI) and then rises sharply to about 200 kilopascals (30 PSI) during the last few load tests.
Figure 51B. Changes in Total Radial Stress With Time (0 to 100 Hours log Scale), MDMP Test NB2. Unadjusted and Adjusted Data. Chart. Companion to table 25. This figure, which is similar figure 51A, is a chart that illustrates changes in total radial stress over a logarithmic time scale measured at the NB2 test location. It shows both an unadjusted data set and a data set adjusted so that the initial pressure approximates the pressure in the water-filled borehole. The X-axis is time (in hours) after the start of installation. The Y-axis is total radial stress in kilopascals (negative 100 to positive 250) and in PSI (negative 15 to positive 40). Total radial stress is shown as a continuous trace over the duration of a four-day test sequence, beginning with the model pile in a cased borehole and ending near the completion of the series of load tests. The unadjusted initial pressure is negative 52 kilopascals (negative 7.5 PSI). The adjusted initial pressure is about 45 kilopascals (7 PSI). On both unadjusted and adjusted data tracings, this is follow by a rapid increase in radial stress at the point when the pore pressure cell penetrates the soil and the pile is being driven. The radial stress continues to rise until just after driving stops, when it reaches a plateau at 180 to 185 kilopascals (27 to 28 PSI). During the series of load tests with the static load frame, the total radial stress declines gradually and then rises sharply during the last few load tests. Unadjusted total radial stress ends at about 240 kilopascals (35 PSI). Adjusted total radial stress ends at about 200 kilopascals (30 PSI).
Figure 52A. Changes in Total Radial Stress With Time (0 to 140 Hours linear Scale), MDMP Test NB2. Chart. Companion to table 25. This figure is a chart that illustrates changes in total radial stress over a linear time scale measured at the NB2 test location. The X-axis is time (in hours) after the start of installation. The Y-axis is total radial stress in kilopascals (negative 100 to positive 200) and in PSI (negative 15 to positive 35). Total radial stress is shown as a continuous trace over the duration of a 4-day test sequence, beginning with the second load test, and ending with the restrike and removal of the MDMP. At the beginning of the second load test, the total radial stress is about 200 kilopascals (29 PSI). This is followed by a decline to a short plateau, representing the time between load tests number 5 and number 8. There is a sharp increase in radial stress during load test number 9, plateauing at 190 to 205 kilopascals (28 to 30 PSI), and continuing until restrike and removal of the pile.
Figure 52B. Changes in Total Radial Stress With Time (0 to 140 Hours linear Scale), MDMP Test NB2. Unadjusted and Adjusted Data. Chart. Companion to table 25. This figure, which is similar figure 52A, is a chart that illustrates changes in total radial stress over a linear time scale measured at the NB2 test location. It shows both an unadjusted data set and a data set adjusted so that the initial pressure approximated the pressure in the water-filled borehole. The X-axis is time (in hours) after the start of installation. The Y-axis is total radial stress in kilopascals (negative 100 to 250) and in PSI (negative 15 to 40). Total radial stress is shown as a continuous trace over the duration of a four-day test sequence, beginning with the second load test and ending near the completion of the series of load tests. At the beginning of the second load test, the unadjusted total radial stress is about 200 kilopascals (29 PSI) and adjusted total radial stress is about 240 kilopascals (35 PSI). This is followed by a decline to a short plateau, representing the time between load tests number 5 and number 8. There is a sharp increase in total radial stress during load test number 9, plateauing at 190 to 205 kilopascals (28 to 30 PSI) for the unadjusted data set, and between 240 to 250 kilopascals (34 to 36 PSI) for the adjusted data set. The plateau continues until restrike and removal of the pile.
Figure 53A. Changes in Effective Radial Stress With Time (0 to 100 Hours log Scale), MDMP Test NB2. Chart. This figure, which is similar to figure 53B, is a chart that illustrates changes in effective stress over a logarithmic time scale measured at the NB2 test location. The X-axis is time (in hours) after the start of installation. The Y-axis is effective radial stress in kilopascals (negative 100 to positive 200) and in PSI (negative 20 to positive 35). The effective radial stress is shown as an interrupted trace over the duration of the four-day test sequence. Between the start and the first 0.15 hours after installation, the chart shows a series of sharp spikes, ranging between negative 130 to 0 kilopascals (negative 20 and 0 PSI), followed by a break in the line. The effective radial stress then increases gradually, with several embedded spikes, to about 35 kilopascals (5 PSI) at about 40 hours after installation, followed by another break in the line. Between 40 and 70 hours after installation, the pressure increases rapidly to about 140 kilopascals (20 PSI). After 70 hours, the effective stress levels off until the end of testing.
Figure 53B. Changes in Effective Radial Stress With Time (0 to 100 Hours log Scale), MDMP Test NB2. Unadjusted and Adjusted Data. Chart. This figure, which is similar to figure 53A, is a chart that illustrates changes in effective stress over a logarithmic time scale measured at the NB2 test location. The X-axis is time (in hours) after the start of installation. The Y-axis is effective radial stress in kilopascals (negative 100 to positive 200) and in PSI (negative 20 to positive 35). The unadjusted and adjusted effective radial stress are shown as interrupted traces over the duration of the 4-day test sequence. Between the start and the first 0.15 hours after installation, the chart shows a series of sharp spikes, ranging between negative 130 to 0 kilopascals (negative 20 and 0 PSI) for the unadjusted data, and between negative 20 and positive 100 kilopascals (negative 3 and positive 14 PSI) for the adjusted data, followed by a break in the line. The unadjusted effective radial stress then increases gradually, with some embedded spikes, to about 35 kilopascals (5 PSI) and the adjusted effective radial stress increases to about 80 kilopascals (12 PSI) at about 40 hours after installation, followed by another break in the line. Between 40 and 70 hours after installation, the unadjusted pressure increases rapidly to about 140 kilopascals (21 PSI) and the adjusted pressure reaches 190 kilopascals (27 PSI). After 70 hours, the effective stress levels off until the end of testing.
Figure 54A. Changes in Effective Radial Stress With Time (0 to 140 Hours linear Scale), MDMP Test NB2. Chart. This figure, which is similar to figure 54B, is a chart that illustrates changes in effective stress over a linear time scale measured at the NB2 test location. The X-axis is time (in hours) after the start of installation. The Y-axis is effective radial stress in kilopascals (negative 100 to positive 200) and in PSI (negative 20 to positive 35). The effective radial stress is shown as an interrupted trace over the duration of the 4-day test sequence. Between the start and 40 hours after installation, the chart shows a series of irregular spikes, increasing gradually from negative 20 kilopascals (negative 3 PSI) to positive 35 kilopascals (positive 5 PSI), followed by a break in the line. At about 42 hours following installation, the effective radial stress increases rapidly to about 140 kilopascals (21 PSI) at about 70 hours after installation, followed by another break in the line. Between 87 and 125 hours after pile installation, the pressure is depicted as a plateau at about 140 kilopascals (21 PSI). Between 132 hours and the end of the testing, the effective radial stress dips from 140 kilopascals (21 PSI) to 125 kilopascals (18 PSI) and goes back up to 170 kilopascals (24 PSI).
Figure 54B. Changes in Effective Radial Stress With Time(0 to 140 Hours linear Scale), MDMP Test NB2. Unadjusted and Adjusted Data. Chart. This figure, which is similar to figure 54A, is a chart that illustrates changes in effective stress over a linear time scale measured at the NB2 test location. The X-axis is time (in hours) after the start of installation. The Y-axis is effective radial stress in kilopascals (negative 100 to positive 200) and in PSI (negative 20 to positive 35). The unadjusted and the adjusted effective radial stress are shown as interrupted traces over the duration of the 4-day test sequence. Between the start and 40 hours after installation, the chart shows a series of irregular spikes, increasing gradually from negative 20 to positive 35 kilopascals (negative 3 to positive 5 PSI) for the unadjusted data, and from 30 to 80 kilopascals (4 to12 PSI) for the adjusted data, followed by a break in the line. Between 40 and 70 hours following installation, the unadjusted effective radial stress increases rapidly to about 140 kilopascals (21 PSI) and the adjusted effective radial stress increases to about 190 kilopascals (27 PSI), followed by another break in the line. Between 87 and 125 hours after pile installation, the pressure is depicted as a plateau at about 140 kilopascals (21 PSI) for the unadjusted data and at about 190 kilopascals (27 PSI) for the adjusted data. Between 132 hours and the end of the testing, the unadjusted effective radial stress dips from 140 kilopascals (21 PSI) to 125 kilopascals (18 PSI) and goes back up to 170 kilopascals (24 PSI). The adjusted effective radial stress during the last time interval dips from 190 kilopascals (27 PSI) to 170 kilopascals (25 PSI) and goes back up to 215 kilopascals (31 PSI).
Figure 55. Force Measurements in Top and Middle MDMP Load Cells for Test NB2. (A) Unadjusted records based on initial readings before driving and (B) Adjusted records based on zero loads assumed prior to the initial load test. Charts. Companion to table 27. The two charts in this figure present the temporal changes in force measurements in the top and middle load cells of the MDMP. Unadjusted data are shown as a continuous trace in the top chart (A) and adjusted data are shown in the bottom chart (B). The X-axis of both charts shows time in hours (0.35 to 0.5) and in minutes (22.50 to 30) after the start of installation. The Y-axis on both charts shows the axial load in kilonewtons (negative 2 to positive 2) and in pounds (negative 500 to positive 500). Between 0.35 and 0.42 hours after installation, the unadjusted axial load from the middle cell is constant at about 0.2 kilonewtons (25 pounds). At 0.42 hours after the start, the unadjusted load from the middle cell increases sharply to about 1.3 kilonewtons (300 pounds), followed by a short plateau and gradual decline to about 0.75 kilonewtons (200 pounds) at 0.44 hours after the start. The unadjusted axial load then declines rapidly to a narrow range between 0.75 to 1.25 kilonewtons (200 and 300 pounds) between 0.44 and 0.5 hours after the start of the test. The trace pattern for the unadjusted axial load from the top cell parallels the trace from the middle cell, but is consistently lower by 0.5 to 1 kilonewtons (100 to 200 pounds). The bottom chart (B) presents the adjusted data for both the middle and top load cells. The traces of adjusted axial load over time are similar to the unadjusted traces, but the difference between the top and middle cells is a narrower range over time.
Figure 56. Internal Load Measurements, MDMP Test NB2. Charts. Two charts are presented that illustrate the changes in axial force recorded by three different load cells during the testing period at the NB2 location. The top chart is an expanded graph of the data during the initial two hours after the start of installation. The X-axis is time in hours (0 to 2) after the installation. The Y-axis shows axial force in kilonewtons (negative 2 to positive 2) and in pounds (negative 500 to positive 500). The expanded chart shows all three load cells beginning at zero, gradually separating into relatively parallel traces, with embedded spikes, until just after 1 hour following installation. Between 1 and 2 hours the trace from the top load cell separates, and is well below the traces from the middle and bottom cells by approximately 0.75 to 100 kilonewtons (300 to 350 pounds). The bottom chart shows the changes in axial loads from all three cells over the entire test period. The X-axis is time in hours (0 to 140) after the start of installation. The Y-axis is axial force in kilonewtons (negative 12 to positive 2) and in pounds (negative 3000 to 0). The changes in axial force measured by the three load cells are shown as interrupted traces. The trend over time for the top and middle cells is essentially a continuation of the expanded 2-hour view in the top chart, showing relatively parallel traces over the duration of the test, but becoming increasingly divergent with time after the start of the installation. The output from the top and middle cells is separated by about 4 kilonewtons (800 to 1000 pounds). From about 10 hours to the end of the test, the output from the bottom load cell is shown as a continuously decreasing trace, not parallel with the other two cells.
Figure 57. Adjustments to Internal Load Measurements, MDMP Test NB2. Chart. This figure presents a chart illustrating temporal changes in unadjusted and adjusted axial force recorded by the top and middle load cells during testing at the NB2 location. The X-axis is time in hours (0 to 2.25) and in minutes (50 to 140) after the start of installation. The Y-axis shows axial force in kilonewtons (negative 2.5 to positive 2.5) and in pounds (negative 600 to positive 600). Traces of the output are shown for each cell. The chart also shows a shaded area between 1 and 1.25 hours that illustrates a number of large spikes in the traces. This shaded area represents disturbances that were recorded during connection to the model pile. Between 1.25 and 1.75 hours, unadjusted data from the top load cell decreases from about negative 0.6 kilonewtons (negative 125 pounds) to about negative 1 kilonewton (negative 225 pounds). During this same time period, force measured by the middle cell declines from about 0.6 to 0.3 kilonewtons (125 to 75 pounds). From 1.75 hours following installation to the end of the test, the load data are shown corrected. Output from the top cell was adjusted by increasing the force and output from the middle cell was adjusted by decreasing the force. Between 1.75 hours and the end of the test, the corrected data remain relatively flat and parallel at about negative 1.3 kilonewtons (negative 300 pounds) and negative 1.7 kilonewtons (negative 375 pounds) for the middle and top load cells, respectively.
Figure 58. Frictional Forces Along the Friction Sleeve for MDMP Test NB2. Chart. The figure is a chart that illustrates details of the frictional force during initial displacement recorded for 11 load tests, and the extension and compression of the initial load test at the NB2 test location. Displacement is shown on the X-axis in millimeters (0 to negative 6) and in inches (0 to negative 0.25). Frictional forces along the frictional sleeve are shown on the Y-axis in kilonewtons (0 to negative 6) and in pounds (0 to negative 1500). The overall trend shows that data from all the load tests are generally parallel across the X-axis (displacement). The amount of friction measured along the sleeve increases with each subsequent load test. The lowest friction is associated with the initial load test compression and extension. Just above these traces are the friction data for load test number 1, flat at about negative 0.5 kilonewtons (negative 125 pounds). The highest friction, negative 5.5 kilonewtons (negative 1250 pounds), is associated with the last load test at NB2, test number 11.
Figure 59. Shear Transfer Along the Friction Sleeve for MDMP Test NB2. Chart. The figure is a chart that illustrates details of the shear transfer during initial displacement calculated for 11 load tests, and the extension and compression of the initial load test at the NB2 test location. Displacement is shown in millimeters (0 to negative 6) in millimeters (0 to negative 6) and in inches (0 to negative 0.25) on the X-axis. Shear transfer along the frictional sleeve is shown on the Y-axis in kilopascals (0 to negative 30) and in PSI (0 to negative 4.5). The overall trend shows that data from all load tests are generally parallel across the X-axis (displacement). The amount of shear transfer along the sleeve increases with each subsequent load test. The lowest pressures are associated with the initial load test compression and extension. Just above these traces is the shear transfer calculated for load test number 1, basically flat at about negative 3 kilopascals (negative 0.4 PSI). The highest pressure, negative 27.5 kilopascals (negative 4 PSI), is associated with the last load test at NB2, test number 11.
Figure 60. Internal Load Measurements, MDMP Test NB3. Charts. Two charts are presented that illustrate the changes in axial force recorded by the top and middle load cells, above and below the friction sleeve, during testing at the NB3 location. The top chart is an expanded graph of the data during the initial 1.25 hours after the start of installation. The X-axis is time in hours (0 to 1.2) after the installation. The Y-axis shows axial force in kilonewtons (negative 2 to positive 2) and in pounds (negative 500 to positive 500). The expanded chart shows a very similar trace for both load cells during the first hour after installation. No internal load is detected until about 0.35 hours, when a spike jumps to 1.4 kilonewtons (300 pounds) and then drops back to near 0. The measured load from both cells is generally unchanged until the end of the test. The bottom chart shows the changes in axial loads from both cells over the entire test period. The X-axis is time in hours (0 to 120) after the start of installation. The Y-axis is axial force in kilonewtons (negative 12 to positive 2) and in pounds (negative 3000 to 0). The changes in axial force measured by the top and middle load cells are shown as interrupted traces. Over the test period, the two load traces remain parallel, but become increasingly divergent as time after the start of installation increases. By the midpoint of the test, the output from the top and middle cells is separated by about 4 to 5 kilonewtons (600 to 700 pounds).
Figure 61. Frictional Forces Along the Frictional Sleeve for MDMP Test NB3. Chart.
The figure is a chart that illustrates details of the frictional force during initial displacement recorded for nine load tests and the initial load test compression at the NB3 test location. Displacement is shown on the X-axis in millimeters (0 to negative 6) and in inches (0 to negative 0.25). Frictional forces along the frictional sleeve are shown on the Y-axis in kilonewtons (0 to negative 5) and in pounds (0 to negative 1250). The overall trend indicates that data from all the load tests are generally parallel across the X-axis (displacement). The amount of friction measured along the sleeve, with one exception, increases with each sequential load test. The lowest friction, negative 0.2 kilonewtons (negative 50 pounds) was associated with the initial load test compression. Just above this trace are the data for load test number 1, basically flat at about negative 0.4 kilonewtons (negative 100 pounds). The highest friction, about negative 4 kilonewtons (negative 900 pounds), is associated with the load test at NB3, test number 8. The trace of frictional force recorded during load test number 9 falls between the traces for load tests number 7 and number 8.
Figure 62. Shear Transfer Along the Frictional Sleeve for MDMP Test NB3. Chart. The figure is a chart that illustrates details of the shear transfer during initial displacement calculated for nine load tests and the initial load test compression at the NB3 test location. Displacement is shown on the X-axis in millimeters (0 to negative 6) and in inches (0 to negative 0.25). Shear transfer along the frictional sleeve is shown on the Y-axis in kilopascals (0 to negative 25) and in PSI (0 to negative 4). The overall trend shows that data from all the load tests are generally parallel across the X-axis (displacement). With one exception, the amount of shear transfer along the sleeve increases with each subsequent load test. The lowest pressure, between negative 0.5 to negative 1 kilopascals (negative 0.1 and negative 0.2 PSI), was associated with the initial load test compression. Just above this trace are the data for load test number 1, flat at about negative 2.3 kilopascals (negative 0.4 PSI). The highest pressure, generally about negative 20 kilopascals (negative 3 PSI), was calculated for load test at NB2, test number 8. The trace of shear transfer calculated for load test number 9 falls between the traces for load tests number 7 and number 8.
Figure 63. Force and Displacement Measurements Following the MDMP Installation of Test NB2, Including Heave Effect and Initial Load Test. Charts. Shown in this figure are two charts displaying the temporal changes in force measurements and the corresponding displacement after the start of installation. The top chart displays the axial load measured in the surface cell, and in the internal top and middle load cells following installation of the MDMP. The X-axis is time in hours (0.35 to 0.5) and in minutes (22.5 to 30) after the start of installation. The Y-axis is the axial load in kilonewtons (negative 2 to positive 10) and in pounds (negative 500 to positive 2500). Traces of the load, measured by all three cells, remain at 0 until about 0.39 hours after installation, when the surface cell records a sharp increase in compressive load to 9 kilonewtons (2000 pounds). After a short plateau, load data from the surface cell drop sharply at about 0.44 hours after installation to about 7 kilonewtons (1600 pounds). The traces for both internal cells are very similar. No activity is recorded until about 0.425 hours after installation, when both cells show a rapid increase in load to about 1.0 kilonewton (250 pounds). After a short plateau at this level, the load drops to the negative range, leveling off at about negative 1.5 kilonewtons (negative 275 pounds). The lower chart illustrates the change in displacement with time after the start of installation. Time after the start of installation is shown on the X-axis in hours (0.35 to 0.5) and in minutes (22.5 to 30). Displacement is shown on the Y-axis in centimeters (negative 10 to positive 10) and in inches (negative 4 to positive 4). The tracing of displacement is related to the load chart just above it. Shown is zero displacement until about 0.425 hours after installation. At that point in time, coinciding with pile movement, displacement rises to 5 centimeters (2 inches). It then follows the short plateau recorded for the load from the surface load cell in the top chart. Displacement then gradually declines to a low of negative 7.5 centimeters (negative 3 inches).
Figure 64. Force and Displacement Measurements Following the MDMP Installation of Test NB2, Adjusted for Heave Prior to the Initial Load Test. Charts. This figure presents the same two charts shown in figure 63, but with load data adjusted for the initial load test and heave effect, so that the surface load cell data are comparable to data from the two internal load cells. Shown in this figure are two charts displaying the temporal changes in force measurements and the corresponding displacement after the start of installation. The top chart displays the adjusted axial load measured in the surface cell, and in the internal top and middle load cells following installation of the MDMP. The X-axis is time in hours (0.35 to 0.5) and in minutes (22.5 to 30) after the start of installation. The Y-axis is the axial load in kilonewtons (negative 2 to positive 2) and in pounds (negative 500 to positive 500). Traces of the load from all three cells are similar over the time period of the test, but differ in magnitude of the load. Traces of the load, measured by all three cells, essentially remain at 0 until about 0.43 hours (25 minutes) after installation when, coinciding with pile movement, all three cells record a sharp increase in compressive load. The surface cell records an increase to about 2 kilonewtons (450 pounds), the top load cell records about 1.25 kilonewtons (300 pounds), and the middle load cell records about 1.1 kilonewtons (250 pounds). After a short plateau, load data from all cells drop sharply at about 0.44 hours after installation to around negative 0.25 kilonewtons (negative 50 pounds) for the surface cell, negative 1.2 kilonewtons (negative 250 pounds) for the middle load cell, and to around negative 1.5 kilonewtons (negative 350 pounds) for the top load cell. Thereafter, the recorded loads show smaller spikes and plateaus that correspond with pile top movement. Data from the surface load cell alternate slightly above and below the zero point. Data from the top and middle load cells drop to the negative area, leveling off between negative 1.2 kilonewtons (negative 250 pounds) and negative 1.4 kilonewtons (negative 325 pounds) for the middle load cell, and between negative 1.5 kilonewtons (negative 350 pounds) and negative 1.75 kilonewtons (negative 400 pounds) for the top load cell. The lower chart illustrates the change in displacement with time after the start of installation. Time after the start of installation is shown in hours (0.35 to 0.5) and in minutes (22.5 to 30) on the X-axis. Displacement is shown in centimeters (negative 10 to positive 10) and in inches (negative 4 to positive 4) on the Y-axis. The tracing of displacement is related to the adjusted load chart just above it. Shown is zero displacement until about 0.425 hours after installation. At that point in time, coinciding with pile movement, displacement rises to 5 centimeters (2 inches). It then follows the short plateau and gradually declines to a low of negative 7.5 centimeters (negative 3 inches).
Figure 65. Comparison Between the Surface and the Internal Load Cell Measurements for MDMP Test NB2. Charts. Two charts are presented that compare the temporal changes in axial force, recorded by the three MDMP internal load cells, with the force recorded by the surface load cell during the testing period at the NB2 location. The top chart is an expanded interrupted trace of the load data during the initial 2 hours after the start of installation. The X-axis is time in hours (0 to 2) after the installation. The Y-axis shows axial force in kilonewtons (negative 2 to positive 2) and in pounds (negative 500 to positive 500). The expanded chart shows all four load cells beginning at zero, gradually separating into relatively parallel traces, with embedded spikes. Within the first 2 hours, the highest force recorded was about 1 kilonewton (250 pounds) by the middle load cell. The lowest axial load recorded within the first 2 hours, negative 2 kilonewtons (negative 500 pounds), is associated with the internal top load cell. Measurements from the internal bottom cell and from the surface are similar in magnitude over the 2-hour period, and follow the same trace pattern shown by the top and middle internal cells. The bottom chart shows the changes in axial loads from all four cells over the entire test period. The X-axis is time in hours (0 to 140) after the start of installation. The Y-axis is axial force in kilonewtons (negative 12 to positive 2) and in pounds (negative 3000 to 0). The changes in axial force measured by the four load cells are shown as interrupted traces. Trace patterns from the surface cell, and the top and middle internal cells are similar, but vary in magnitude. The trace from the bottom load cell shows a steady decline to negative 13 kilonewtons (negative 3000 pounds) over the period of the test. Data from the top, middle, and surface cells result in relatively parallel traces with several spikes, plateaus, and declines shown, all in the negative range, over the duration of the test. The output from the top and middle cells is separated by about 4 kilonewtons (800 pounds).
Figure 66. Comparison Between the Surface and the Internal Load Cell Measurements for MDMP Test NB3. Charts. Two charts are presented that compare the temporal changes in axial force recorded by two MDMP internal load cells with the force recorded by the surface load cell during the testing period at the NB3 location. The top chart is an expanded interrupted trace of the load data during the initial 1.2 hours after the start of installation. The X-axis is time in hours (0 to 1.2) after the installation. The Y-axis shows axial force in kilonewtons (negative 2 to positive 2) and in pounds (negative 500 to positive 500). The expanded chart shows an interrupted trace similar in pattern and magnitude for all three load cells. Within the first 2 hours, the highest force recorded was about 1.1 kilonewtons (260 pounds) and the lowest axial load recorded was negative 1 kilonewton (negative 250 pounds). The bottom chart shows the changes in axial loads from all three load cells over the entire test period. The X-axis is time in hours (0 to 120) after the start of installation. The Y-axis is axial force in kilonewtons (negative 12 to positive 2) and in pounds (negative 3000 to 0). The changes in axial force measured by the three load cells are shown as interrupted traces. The trace patterns from all the cells are similar. Axial force recorded by the surface cell and the middle internal cell is also similar in magnitude. The trace from the top load cell is lower in magnitude than the data from the other two cells. The output from the surface and middle cells is separated from the output from the top load cell by about by about 4 kilonewtons (800 pounds).
Figure 67. Static-Cyclic Load Test Results for MDMP Test NB2: (A) Load cell measurements versus time, (B) Displacement measurements versus time, and (C) Pore pressure measurements versus time. Charts. Three charts comprise this figure. They describe the load, displacement, and pore pressure measured at the surface, and at the top and middle load cells during several cycles of loading and unloading at the NB2 test location. The top chart displays the temporal changes in load during this cycle over time following the start of installation. The X-axis is time in hours (137.8 to 138.6) and in minutes (8270 to 8320) after the start of installation. The Y-axis shows the axial load in kilonewtons (0 to 8) and in pounds (0 to 2000). Load traces from all three cells are similar in pattern but vary in magnitude. The axial load measurements increase during the loading portion of the cycle and decrease during the time period that the pile was held with no displacement. The highest load was consistently recorded by the surface cell. The middle chart records displacement during the same time period. The lower X-axis is time in hours (137.8 to 138.6) and in minutes (8270 to 8320) after the start of installation. Displacement is shown on the Y-axis in millimeters (0 to 150) and in inches (0 to 6). The chart records a trace of the surface displacement and slip joint displacement over the time interval following start of installation. The surface displacement increases from 0 to 150 millimeters (0 to 6 inches) over the time period following installation. Slip joint displacement begins at 100 millimeters (4 inches) and decreases to about 50 millimeters (2 inches) at the point where its trace intersects the trace of the surface displacement, which occurs at about 137.83 hours (8270 minutes) after start of installation. The last chart in the sequence displays the temporal change in pore pressure following the start of installation. The X-axis is time in hours (137.8 to 138.6) and in minutes (8270 to 8320) after the start of installation. Pore pressure is displayed on the Y-axis in kilopascals (50 to 70) and in PSI (6 to 11). Over the time period following the start of installation, the pore pressure remains relatively constant at around 66 kilopascals (10 PSI).
Figure 68. Static-Cyclic Load Test Results for MDMP Test NB3: (A) Load cell measurements versus time, (B) Displacement measurements versus time, and (C) Pore pressure measurements versus time. Charts. Three charts comprise this figure. They describe the load, displacement, and pore pressure measured at the surface, and at the top and middle load cells during several cycles of loading and unloading at the NB3 test location. The top chart displays the temporal changes in load during this cycle over time following the start of installation. The X-axis is time in hours (119.4 to 120.2) and in minutes (7160 to7210) after the start of installation. The Y-axis shows the axial load in kilonewtons (0 to 8) and in pounds (0 to 2000). Load traces from all three cells are similar in pattern but vary slightly in magnitude. The axial load measurements increase during the loading portion of the cycle and decrease during the time period that the pile is held with no displacement. The highest load was consistently recorded by the surface cell. The middle chart records displacement during the same time period. The X-axis is time in hours (119.4 to 120.2) and in minutes (7160 to7210) after the start of installation. Displacement is shown on the Y-axis in millimeters (0 to 150) and in inches (0 to 6). The chart records a trace of the surface displacement and slip joint displacement over the time interval following start of installation. The surface displacement increases from 0 to 140 millimeters (0 to about 5.5 inches) over the time period following installation. Slip joint displacement begins at 100 millimeters (4 inches) and decreases to about 50 millimeters (2 inches) at the point where its trace intersects the trace of the surface displacement, which occurs at about 119.45 hours (7168 minutes) after start of installation. The last chart in the sequence displays the temporal change in pore pressure over the time period following the start of installation. The X-axis is time in hours (119.4 to 120.2) and in minutes (7160 to7210) after the start of installation. Pore pressure is displayed on the Y-axis in kilopascals (70 to 100) and in PSI (10 to 15). Over the time period following the start of installation, the trace of the pore pressure is essentially opposite that of the axial load. Pore pressure increases to about 98 kilopascals (14.5 PSI) during the time that the pile is held with no displacement and the pressure drops to about 90 kilopascals (13 PSI) during the cycle of loading.
Figure 69A. Load-Displacement Relationship for Static-Cyclic Final Load Test for MDMP Test NB2. Chart. This figure is a chart that displays the relationship between displacement and load measured by the surface load cell and two internal load cells during cycles of loading and unloading at the NB2 test location. Axial load is shown in kilonewtons (0 to 8) and in pounds (0 to 2000) on the X-axis. Displacement appears on the Y-axis in millimeters (0 to 160) and in inches (0 to 7). The chart illustrates that the surface load cell measurement is greater than that measured by the top load cell, which is, in turn, greater than that measured by the middle load cell. A large increase in axial load is shown for each of the load cells at a displacement of about 50 millimeters (2 inches). For the middle load cell, an increase to about 5 kilonewtons (1100 pounds) is shown. For the top and surface cells, the increase is to about 6.7 and 7 kilonewtons (1500 and 1600 pounds), respectively. Similar increases are shown with increased displacement. A trace of frictional forces along the friction sleeve (2 kilonewtons or about 400 to 500 pounds) parallels the increases in axial load detected by the load cells during the loading and unloading cycles.
Figure 69B. Shear Resistance-Displacement Relationship Along the Friction Sleeve During Static-Cyclic Final Load Test for MDMP Test NB2. Chart. This figure is an enlarged presentation of the frictional force trace shown in figure 69A. It displays the relationship between displacement and shear resistance along the friction sleeve during the final load test at the NB2 location. Shear resistance is shown on the X-axis in kilopascals (0 to 12) and in PSI (0 to 1.8). Displacement appears on the Y-axis in millimeters (0 to 160) and in inches (0 to 7). A large increase in axial load is shown for each of the load cells at a displacement of about 50 millimeters (2 inches). For the middle load cell, an increase to about 5 kilopascals (1100 pounds) is shown. For the top and surface cells, the increase is to about 6.7 and 7 kilonewtons (1500 and 1600 pounds), respectively. Similar increases are shown with increased displacement. The trace of the frictional forces parallels the increases in axial load detected by the load cells during the loading and unloading cycles shown in figure 69A.
Figure 70A. Load-Displacement Relationship for Static-Cyclic Final Load Test for MDMP Test NB3. Chart. This figure is a chart that displays the relationship between displacement and load measured by the surface load cell and two internal load cells during cycles of loading and unloading at the NB3 test location. Axial load is shown in kilonewtons (0 to 8) and in pounds (0 to 2000) on the X-axis. Displacement appears on the Y-axis in millimeters (0 to 150) and in inches (0 to 6). The chart illustrates that the surface load cell measurement is greater than that measured by the top load cell, which is, in turn, greater than that measured by the middle load cell. A large increase in axial load is shown for each of the load cells at a displacement of about 50 millimeters (2 inches). For the middle load cell, the increase is shown at about 5.75 kilonewtons (1400 pounds). The increase for the top and surface cells is at about 6.7 and 7 kilonewtons (1500 and 1600 pounds), respectively. Similar increases are shown with increased displacement. A trace of frictional forces along the friction sleeve (1 kilonewton or 200 to 250 pounds) is also shown.
Figure 70B. Shear Resistance-Displacement Relationship Along the Friction Sleeve During Static-Cyclic Final Load Test for MDMP Test NB3. Chart. This figure is an enlarged presentation of the frictional force trace shown in figure 70A. It displays the relationship between displacement and shear resistance along the friction sleeve during the final load test at the NB3 location. Shear resistance is shown in on the X-axis in kilopascals (0 to 6) and in PSI (0 to 0.8). Displacement appears on the Y-axis in millimeters (0 to 150) and in inches (0 to 6). A large increase in axial load is shown for each of the load cells at a displacement of about 50 millimeters (2 inches). For the middle load cell, the increase is shown at about 5.75 kilopascals (1400 pounds). The increase for the top and surface cells is at about 6.7 and 7 kilonewtons (1500 and 1600 pounds), respectively. Similar increases are shown with increased displacement. The trace of the frictional forces parallels the increases in axial load detected by the load cells during the loading and unloading cycles shown in figure 70A.
Figure 71. Blow Count and Energy Delivered Versus Penetration Depth for the Installation of MDMP Test NB2. Charts and Diagrams. The figure is comprised of five components illustrating a soil column at the NB2 test location, pile location before and after installation, chart of energy delivered as a function of depth, and blow count as a function of depth. Before installation, the pile is shown at a depth of approximately 6 meters (20 feet), which is identified as Boston blue clay in the soil column. After installation, the pile is shown at 9 meters (30 feet) in the soil column, also Boston blue clay. The amount of energy delivered during driving of the pile is shown on the energy chart. The X-axis displays depth in meters (6 to 9) and feet (20 to 30). Energy in joules (0 to 125) is on the Y-axis, and varies irregularly from about 36 joules at 6.5 meters (21.5 feet) to 75 to 85 joules at greater depths. A chart of blow count (0 to 20) for the same depths is also presented in this figure. Blow count, recorded as number of blows per 100 millimeters of soil depth, varies irregularly between 5 and 12 with increased depth.
Figure 72A. PDA Dynamic Measurements During the Installation of MDMP Test NB2: Surface Force and Velocity Records Over 25 MS. Chart. Results are plotted from the PDI Pile Driving Analyzer NB2RODIN. The charts display the force and velocity times impedance signals (in units of force, kips from 0 to 20) measured with time (0 to 25ms). There are 3 charts displayed, the bottom two are the measurements taken from different locations at the top of the pile, while the first one is the average of the two.
Figure 72B. PDA Dynamic Measurements During the Installation of MDMP Test NB2: Surface Force and Velocity Records Over 5 MS. Chart. Results are plotted from the PDI Pile Driving Analyzer NB2RODIN. The charts display the force and velocity times impedance signals (in units of force, kips from 0 to 20) measured with time (0 to 5ms). There are 3 charts displayed, the bottom two are the measurements taken from different locations at the top of the pile, while the first one is the average of the two.
Figure 72C. PDA Dynamic Measurements During the Installation of MDMP Test NB2: Internal Force and Velocity Records Over 25 MS. Chart. Results are plotted from the PDI Pile Driving Analyzer NB2RODIN. The charts display the force and velocity times impedance signals (in units of force, kips from 0 to 20) measured with time (0 to 25ms). There are 3 charts displayed, the bottom two are the measurements taken from different locations at the top of the pile, while the first one is the average of the two.
Figure 72D. PDA Dynamic Measurements During the Installation of MDMP Test NB2: Internal Force and Velocity Records Over 5 MS. Chart. Results are plotted from the PDI Pile Driving Analyzer NB2RODIN. The charts display the force and velocity times impedance signals (in units of force, kips from 0 to 20) measured with time (0 to 5ms). There are 3 charts displayed, the bottom two are the measurements taken from different locations at the top of the pile, while the first one is the average of the two.
Figure 73A. PDA Dynamic Measurements During the Installation of MDMP Test NB2: Surface Force and Velocity Records Over 25 MS. Chart. Results are plotted from the PDI Pile Driving Analyzer NB2RODIN. The charts display the force and velocity times impedance signals (in units of force, kips from 0 to 20) measured with time (0 to 25ms). There are 3 charts displayed, the bottom two are the measurements taken from different locations at the top of the pile, while the first one is the average of the two.
Figure 73B. PDA Dynamic Measurements During the Installation of MDMP Test NB2: Surface Force and Velocity Records Over 5 MS. Chart. Results are plotted from the PDI Pile Driving Analyzer NB2RODIN. The charts display the force and velocity times impedance signals (in units of force, kips from 0 to 20) measured with time (0 to 5ms). There are 3 charts displayed, the bottom two are the measurements taken from different locations at the top of the pile, while the first one is the average of the two.
Figure 73C. PDA Dynamic Measurements During the Installation of MDMP Test NB2: Internal Force and Velocity Records Over 25 MS. Chart. Results are plotted from the PDI Pile Driving Analyzer NB2RODIN. The charts display the force and velocity times impedance signals (in units of force, kips from 0 to 20) measured with time (0 to 25ms). There are 3 charts displayed, the bottom two are the measurements taken from different locations at the top of the pile, while the first one is the average of the two.
Figure 73D. PDA Dynamic Measurements During the Installation of MDMP Test NB2: Internal Force and Velocity Records Over 5 MS. Chart. Results are plotted from the PDI Pile Driving Analyzer NB2RODIN. The charts display the force and velocity times impedance signals (in units of force, kips from 0 to 20) measured with time (0 to 5ms). There are 3 charts displayed, the bottom two are the measurements taken from different locations at the top of the pile, while the first one is the average of the two.
Figure 74. Blow Count and Energy Delivered Versus Penetration Depth for the Restrike of MDMP Test NB2. Charts and Diagrams. The figure is comprised of five components illustrating a soil column at the NB2 test location, pile location before and after restrike, chart of energy delivered as a function of depth, and blow count as a function of depth. Before restrike, the pile is shown at a depth of approximately 9 meters (30 feet), which is identified as Boston blue clay in the soil column. After restrike, the pile is shown just beyond this mark, at approximately 10 meters (32 feet) in the soil column. The amount of energy delivered during driving of the pile is shown on the energy chart. The X-axis displays depth in meters (9.2 to 9.6) and in feet (30 to 32). Energy is shown in joules (100 to 125) on the Y-axis. Between approximately 9.3 meters (30.6 feet) and 9.45 meters (30.95 feet), the energy delivered to the pile is constant at about 110 joules. Energy to the pile increases to about 122 joules between 9.45 meters (30.95 feet) and 9.52 meters (31.3 feet). Between this point and the end (about 9.68 meters or 31.8 feet), the energy delivered remains constant at about 122 joules. A chart of blow count (20 to 40) for the same depths is also presented in this figure. Blow count, recorded as number of blows per 100 millimeters of soil depth, is 22 at about 9.3 meters (30.6 feet), near 40 at about 9.36 meters (30.8 feet), and 22 at 9.6 meters (31.6 feet).
Figure 75A. PDA Dynamic Measurements During the Restrike of MDMP Test NB2: Surface Force and Velocity Records Over 50 MS. Charts. Results are plotted from the PDI Pile Driving Analyzer NB2RODIN. The charts display the force and velocity times impedance signals (in units of force, kips from 0 to 20) measured with time (0 to 50ms). There are 3 charts displayed, the bottom two are the measurements taken from different locations at the top of the pile, while the first one is the average of the two.
Figure 75B. PDA Dynamic Measurements During the Restrike of MDMP Test NB2: Surface Force and Velocity Records Over 20 MS. Charts. Results are plotted from the PDI Pile Driving Analyzer NB2RODIN. The charts display the force and velocity times impedance signals (in units of force, kips from 0 to 20) measured with time (0 to 20ms). There are 3 charts displayed, the bottom two are the measurements taken from different locations at the top of the pile, while the first one is the average of the two.
Figure 75C. PDA Dynamic Measurements During the Restrike of MDMP Test NB2: Internal Force and Velocity Records Over 50 MS. Charts. Results are plotted from the PDI Pile Driving Analyzer NB2RODIN. The charts display the force and velocity times impedance signals (in units of force, kips from 0 to 40) measured with time (0 to 50ms). There are 3 charts displayed, the bottom two are the measurements taken from different locations at the top of the pile, while the first one is the average of the two.
Figure 75D. PDA Dynamic Measurements During the Restrike of MDMP Test NB2: Internal Force and Velocity Records Over 20 MS. Charts. Results are plotted from the PDI Pile Driving Analyzer NB2RODIN. The charts display the force and velocity times impedance signals (in units of force, kips from 0 to 40) measured with time (0 to 20ms). There are 3 charts displayed, the bottom two are the measurements taken from different locations at the top of the pile, while the first one is the average of the two.
Figure 76. Blow Count and Energy Delivered Versus Penetration Depth for the Installation of MDMP Test NB3. Charts and Diagrams. The figure is comprised of five components illustrating a soil column at the NB3 test location, pile location before and after installation, chart of energy delivered as a function of depth, and blow count as a function of depth. Before installation, the pile is shown at a depth of approximately 9.6 meters (32 feet), which is identified as Boston blue clay in the soil column. After installation, the pile is shown at about 12 meters (40 feet) in the soil column, also Boston blue clay. The amount of energy delivered during driving of the pile is shown on the energy chart as output from both upper and lower gages. The X-axis displays depth in meters (10 to 12) and in feet (30 to 40). Energy in joules (0 to 500) is on the Y-axis. At the start of driving, the output from the upper gages shows that the energy delivered to the pile increases from about 350 joules at approximately 9.85 meters (32.15 feet) to about 475 joules at 9.9 meters (32.25 feet). At 10 meters (32.5 feet), the surface gage output indicates that the energy delivered to the pile decreases to 100 joules. Between 10.4 meters (34 feet) and 10.7 meters (34.55 feet), another small increase to 250 joules was recorded by the surface gage. Output from the lower gages indicates that energy delivered to the pile is constant with depth at about 100 joules. A chart of blow count (0 to 8) for the same depths is also presented in this figure. Blow count, recorded as number of blows per 100 millimeters of soil depth, varies irregularly between 2.5 and 5 over the total depth.
Figure 77A. PDA Dynamic Measurements During the Installation of MDMP Test NB3: Surface Force and Velocity Records Over 25 MS (at the upper location). Charts. Results are plotted from the PDI Pile Driving Analyzer NB2RODIN. The charts display the force and velocity times impedance signals (in units of force, kips) measured with time (0 to 25ms). There are 3 charts displayed, the bottom two are the measurements taken from different locations at the top of the pile, while the first one is the average of the two.
Figure 77B. PDA Dynamic Measurements During the Installation of MDMP Test NB3: Surface Force and Velocity Records Over 5 MS (at the upper location). Charts. Results are plotted from the PDI Pile Driving Analyzer NB2RODIN. The charts display the force and velocity times impedance signals (in units of force, kips) measured with time (0 to 5ms). There are 3 charts displayed, the bottom two are the measurements taken from different locations at the top of the pile, while the first one is the average of the two.
Figure 77C. PDA Dynamic Measurements During the Installation of MDMP Test NB3: Surface Force and Velocity Records Over 25 MS (at the lower location). Charts. Results are plotted from the PDI Pile Driving Analyzer NB2RODIN. The charts display the force and velocity times impedance signals (in units of force, kips) measured with time (0 to 25ms). There are 3 charts displayed, the bottom two are the measurements taken from different locations at the top of the pile, while the first one is the average of the two.
Figure 77D. PDA Dynamic Measurements During the Installation of MDMP Test NB3: Surface Force and Velocity Records Over 5 MS (at the lower location). Charts. Results are plotted from the PDI Pile Driving Analyzer NB2RODIN. The charts display the force and velocity times impedance signals (in units of force, kips) measured with time (0 to 5ms). There are 3 charts displayed, the bottom two are the measurements taken from different locations at the top of the pile, while the first one is the average of the two.
Figure 77E. PDA Dynamic Measurements During the Installation of MDMP Test NB3: Internal Force and Velocity Records Over 25 MS. Charts. Results are plotted from the PDI Pile Driving Analyzer NB2RODIN. The charts display the force and velocity times impedance signals (in units of force, kips from 0 to 40) measured with time (0 to 25ms). There are 3 charts displayed, the bottom two are the measurements taken from different locations at the top of the pile, while the first one is the average of the two.
Figure 77F. PDA Dynamic Measurements During the Installation of MDMP Test NB3: Internal Force and Velocity Records Over 5 MS. Charts. Results are plotted from the PDI Pile Driving Analyzer NB2RODIN. The charts display the force and velocity times impedance signals (in units of force, kips from 0 to 40) measured with time (0 to 5ms). There are 3 charts displayed, the bottom two are the measurements taken from different locations at the top of the pile, while the first one is the average of the two.
Figure 78. Blow Count and Energy Delivered Versus Penetration Depth for the Restrike of MDMP Test NB3. Charts and Diagrams. The figure is comprised of five components illustrating a soil column at the NB3 test location, pile location before and after restrike, chart of energy delivered as a function of depth, and blow count as a function of depth. Before restrike, the pile is shown at a depth of approximately 12 meters (40 feet), which is identified as Boston blue clay in the soil column. After restrike, the pile is shown at approximately 13.5 meters (44 feet) in the soil column, also Boston blue clay. The amount of energy delivered during driving of the pile is shown on the energy chart. The X-axis displays depth in meters (12.2 to 13.6) and in feet (40 to 45). Energy in joules (125 to 150) is on the Y-axis. Between approximately 12.42 meters (40.75 feet) and 12.5 meters (41.5 feet), the energy delivered to the pile fluctuates between 150 and 136 joules. At around 12.8 meters (42 feet), energy to the pile decreases to about 120 joules, and then remains constant at about 136 joules with increasing depth. A chart of blow count (20 to 40) for the same depths is also presented in this figure. Blow count, recorded as number of blows per 100 millimeters of soil depth, fluctuates irregularly between approximately 35 and 25 with depth in the soil column.
Figure 79A. PDA Dynamic Measurements During the Restrike of MDMP Test NB3: Surface Force and Velocity Records Over 50 MS. Charts. Results are plotted from the PDI Pile Driving Analyzer NB2RODIN. The charts display the force and velocity times impedance signals (in units of force, kips from 0 to 20) measured with time (0 to 50 milliseconds). There are 3 charts displayed, the bottom two are the measurements taken from different locations at the top of the pile, while the first one is the average of the two.
Figure 79B. PDA Dynamic Measurements During the Restrike of MDMP Test NB3: Surface Force and Velocity Records Over 12 MS. Charts. Results are plotted from the PDI Pile Driving Analyzer NB2RODIN. The charts display the force and velocity times impedance signals (in units of force, kips from 0 to 20) measured with time (0 to 12 milliseconds). There are 3 charts displayed, the bottom two are the measurements taken from different locations at the top of the pile, while the first one is the average of the two.
Figure 79C. PDA Dynamic Measurements During the Restrike of MDMP Test NB3: Internal Force and Velocity Records Over 50 MS. Charts. Results are plotted from the PDI Pile Driving Analyzer NB2RODIN. The charts display the force and velocity times impedance signals (in units of force, kips from 0 to 40) measured with time (0 to 50 milliseconds). There are 3 charts displayed, the bottom two are the measurements taken from different locations at the top of the pile, while the first one is the average of the two.
Figure 79D. PDA Dynamic Measurements During the Restrike of MDMP Test NB3: Internal Force and Velocity Records Over 12 MS. Charts. Results are plotted from the PDI Pile Driving Analyzer NB2RODIN. The charts display the force and velocity times impedance signals (in units of force, kips from 0 to 40) measured with time (0 to 12 milliseconds). There are 3 charts displayed, the bottom two are the measurements taken from different locations at the top of the pile, while the first one is the average of the two.
Figure 80. Maximum Dynamic Forces Measured During Installation of MDMP Test NB2. Chart. This figure is a chart that presents the temporal change in maximum force recorded for each blow by the surface, and the top and middle load cells during installation of the MDMP at the NB2 test location. The lower X-axis displays time after start of driving in seconds (0 to 500) and the upper X-axis shows the approximate penetration depth in meters (6.5 to 8.97). Maximum force is shown on the Y-axis in kilonewtons (40 to 110) and in KIPS (10 to 25). The chart shows that the peak forces recorded by the surface and middle load cell are similar in magnitude, and that the majority of blows range between 55 to 80 kilonewtons (12 and 18 KIPS). The top load cell recorded a higher range of peak forces, with the majority of blows between 80 to 98 kilonewtons (18 and 22 KIPS). These force ranges appear to be generally constant over time and depth.
Figure 81. Maximum Dynamic Forces Measured During Restrike of the MDMP Test NB2. Chart. This figure is a chart that presents the temporal change in maximum force recorded for each blow by the surface, and the top and middle load cells during restrike of the MDMP at the NB2 test location. The lower X-axis displays time after start of driving in seconds (0 to 250) and the upper X-axis shows the approximate penetration depth in meters (9.28 to 9.68). Maximum force is shown on the Y-axis in kilonewtons (50 to 130) and in KIPS (10 to 30). The chart indicates that the peak forces recorded by the surface and middle load cell are similar in magnitude, and that the majority of blows during the restrike range between 70 to 85 kilonewtons (16 and 20 KIPS). The top load cell recorded a higher range of peak forces, with the majority of blows between 98 to 115 kilonewtons (22 and 26 KIPS). Over time and depth, the range of the force measurements does not change much. Compared to the figure 80, where the data represent installation, the force range recorded for restrike is much tighter around each cell (top) or cell group (surface and middle).
Figure 82. Maximum Dynamic Forces Measured During Installation of MDMP Test NB3. Chart. This figure is a chart that presents temporal change in maximum force recorded for each blow by the surface, and the top and middle load cells during installation of the MDMP at the NB3 test location. Data from the surface include a piezoelectric and a piezoresistive measurement. The lower X-axis displays time after start of driving in seconds (0 to 500) and the upper X-axis shows the approximate penetration depth in meters (9.67 to 11.96). Maximum force is shown on the Y-axis in kilonewtons (70 to 130) and in KIPS (15 to 30). The chart indicates that the peak forces recorded by the middle load cell and the piezoresistive location of the surface cell are similar in magnitude, and that the majority of blows range between 85 to 95 kilonewtons (19 and 21 KIPS). The top load cell and the piezoelectric location of the surface cell recorded similar forces, but in a higher range than the data from the middle cell and the piezoresistive surface cell. The majority of blows range between 98 to 110 kilonewtons (22 and 25 KIPS). The range of measured forces appears to be generally constant over time and depth for both groups.
Figure 83. Maximum Dynamic Forces Measured During Restrike of the MDMP Test NB3. Chart. This figure is a chart that presents temporal change in maximum force recorded for each blow by the surface, and the top and middle load cells during restrike of the MDMP at the NB3 test location. The lower X-axis displays time after start of driving in seconds (0 to 500) and the upper X-axis shows the approximate penetration depth in meters (12.37 to 13.58). Maximum force is shown on the Y-axis in kilonewtons (50 to 130) and in KIPS (10 to 30). The chart indicates that the peak forces recorded by the surface and middle load cell are similar in magnitude, and that the majority of blows during the restrike range between 75 to 85 kilonewtons (17 and 20 KIPS). The top load cell recorded a higher range of peak forces, with the majority of blows between 102 to 115 kilonewtons (23 and 26 KIPS). Over time and depth, the range of the force measurements appears to decrease, with force measurements within a tighter range for each cell group.
Figure 84. Maximum Dynamic Velocities Measured During Installation of MDMP Test NB2. Chart. This figure is a chart that presents temporal change in maximum velocity recorded for each blow by the surface, and the top and middle load cells during installation of the MDMP at the NB2 test location. The lower X-axis displays time after start of driving in seconds (0 to 500) and the upper X-axis shows the approximate penetration depth in meters (6.5 to 8.97). Maximum velocity is shown on the Y-axis in meters per second (0.5 to 2) and in feet per second (1 to 7). The chart shows that the peak velocities recorded by the top and middle load cell are somewhat similar in magnitude, and that the majority of blows range between 0.9 to 1.4 meters per second (3 and 4.5 feet per second). A higher range of peak velocities is shown for the surface cell, with the majority of blows between 1.2 to 1.8 meters per second (4 to 6 feet per second). The velocity ranges appear to be somewhat tighter near the beginning and end of driving, and generally broader midway through the test (200 to 350 seconds after the start of driving).
Figure 85. Maximum Dynamic Velocities Measured During Restrike of MDMP Test NB2. Chart. This figure is a chart that presents temporal change in maximum velocity recorded for each blow by the surface, and the top and middle load cells during restrike of the MDMP at the NB2 test location. The lower X-axis displays time after start of driving in seconds (0 to 250) and the upper X-axis shows the approximate penetration depth in meters (9.28 to 9.68). Maximum velocity is shown on the Y-axis in meters per second (1 to 2) and in feet per second (2 to 8). Only velocities between 0.305 and 2.438 meters per second (1 and 8 feet per second) are plotted on this chart. The chart shows peak velocities recorded at the surface generally ranging between 1.45 to 2 meters per second (5.5 and 6.5 feet per second). Velocity data from the top and middle load cells are inconsistent and irregular over the duration of the test. Over time and depth, the velocity measurements do not appear to change.
Figure 86. Maximum Dynamic Velocities Measured During Installation of MDMP Test NB3. Chart. This figure is a chart that presents temporal change in maximum velocity recorded for each blow by the surface, and the top and middle load cells during installation of the MDMP at the NB3 test location. Data from the surface include a piezoelectric and a piezoresistive measurement. The lower X-axis displays time after start of driving in seconds (0 to 500) and the upper X-axis shows the approximate penetration depth in meters (9.67 to 11.96). Maximum velocity is shown on the Y-axis in meters per second (0.5 to 2.5) and in feet per second (2 to 9). Only velocities between 0.305 and 2.743 meters per second (1 and 9 feet per second) are plotted on this chart. The chart shows that, within the first 100 seconds after the start of driving, the surface piezoelectric and piezoresistive measurement locations resulted in two distinct data groups, with velocities ranging between 2.25 and 2.7 meters per second (7.25 and 9 feet per second) for the piezoelectric measurement, and between 1.75 and 2.2 meters per second (5.75 and 7 feet per second) for the piezoresistive measurement. The peak velocities recorded by the top and middle load cell are inconsistent and irregular during this initial time interval. From 175 seconds after the start of driving, no velocity data are available from the surface. Between 175 and 300 seconds, maximum velocities measured by the top and middle load cell are shown on the chart. Peak velocities recorded by the top and middle load cell are similar in magnitude, and the majority of blows range between 1.26 to 1.6 meters per second (4.25 and 5.25 feet per second).
Figure 87. Maximum Dynamic Velocities Measured During Restrike of MDMP Test NB3. Chart. This figure is a chart that presents temporal change in maximum velocity recorded for each blow by the surface, and the top and middle load cells during restrike of the MDMP at the NB3 test location. The lower X-axis displays time after start of driving in seconds (0 to 500) and the upper X-axis shows the approximate penetration depth in meters (12.37 to 13.58). Maximum velocity is shown on the Y-axis in meters per second (0.5 to 2.5) and in feet per second (1 to 9). Only velocities between 0.305 and 2.743 meters per second (1 and 9 feet per second) are plotted on this chart. Data from the top load cell are sparse and irregular. The chart shows that the range of maximum velocities recorded at the surface during restrike is distinct in magnitude from the range of velocities recorded by the middle load cell. For most of the blows, peak velocities recorded at the surface generally vary from 2 to 2.25 meters per second (6.5 to 7.5 feet per second), and the range becomes somewhat tighter with time and depth. Maximum velocities recorded by the middle load cell during restrike range between 1.25 and 1.6 meters per second (4.25 and 5.25 feet per second), with the range clearly becoming tighter with time and depth.
Figure 88. Normalized Excess Pore Pressure and Shear Transfer Gain, Model Pile Test NB2. Chart. This chart displays the temporal change in normalized excess pore pressure and the shear transfer gain after driving the model pile at the NB2 test location. All data are plotted logarithmically. The X-axis is time in hours (0 to 100) after driving. The left Y-axis is normalized excess pore pressure in UNITS (0 to 1) and the right Y-axis shows the ratio of shear transfer to maximum shear transfer (0 to 1). The chart shows that peak shear transfer and residual shear transfer are inversely related to normalized excess pore pressure.
Figure 89. Normalized Excess Pore Pressure and Shear Transfer Gain, Model Pile Test NB3. Chart. This chart displays the temporal change in normalized excess pore pressure and the shear transfer gain after driving the model pile at the NB3 test location. All data are plotted logarithmically. The X-axis is time in hours (0 to 100) after driving. The left Y-axis is normalized excess pore pressure , which is the ratio of pore pressure (delta u) divided by the maximum/initial excess pore pressure (delta u sub i) (0 to 1) and the right Y-axis shows the ratio of shear transfer to maximum shear transfer (0 to 1). The chart shows that peak shear transfer and residual shear transfer are inversely related to normalized excess pore pressure.
Figure 90. Initial Excess Pore Pressure Distribution for Soils With OCR Greater Than 1 But Less Than 10, Including the MDMP Data (based on Paikowsky et al., 1995). Chart. This chart shows the excess pore pressure distribution for both historical data and data from locations NB2 and NB3 in this study. All data are plotted logarithmically. Only soils having an OCR ratio between 1 and 10 are shown. The X-axis is the normalized radius (1 to 100) and the Y-axis shows normalized excess pore pressure, the ratio of pore pressure (delta u) divided by the maximum/initial excess pore pressure (delta u sub i) (0 to 5). The generalized trend appears to be an inverse relationship between normalized radius and normalized excess pore pressure.
Figure 91. Effects of OCR on Normalized Excess Pore Pressure Along the Shaft (small H over small R greater than or equal to 17) for small R over capital R equals 1 with MDMP Data Included (based on Paikowsky et al., 1995). Chart. This figure is a chart showing the effect of the soil OCR on normalized excess pore pressure. Both historical data and data from locations NB2 and NB3 in this study are shown. The X-axis is the soil OCR (1 to 10) and the Y-axis is normalized excess pore pressure, the ratio of pore pressure (delta u) divided by the maximum/initial excess pore pressure (delta u sub i) (negative 2.5 to positive 20). All data are plotted logarithmically. The generalized trend appears to be a slight increase in excess pore pressure with an increase in soil OCR.
Figure 92. Measured Pore Pressure Dissipation and Capacity Gain for MDMP Tests at the Newbury Site With Predicted Ranges. Chart. This figure is a chart displaying the distribution of the predicted pore pressure dissipation ratio and the capacity gain ratio, and the measured relationships of these parameters based on data collected at the NB2 and NB3 study locations. The X-axis is time in hours (0.01 to 100) after driving. The left Y-axis is the pore pressure dissipation ratio (0 to 1) and the right Y-axis is the capacity gain ratio (0 to 1). All data are plotted logarithmically. The increasing negative slopes of the measured pore pressure for both the NB2 and NB3 tests suggest that the measured pore pressure dissipation rate is faster than the predicted rate. Similarly, the increasing positive slopes of the measured capacity gain for both the NB2 and NB3 tests indicate that the capacity gain rate is faster than the predicted rate.
Figure 93. Effect of Pile Radius on T subscript 50 (Time for 50 Percent Excess Pore Pressure Dissipation) for NC Clays (OCR Equals 1 to 2), Including MDMP Data (based on Paikowsky et al., 1995). Chart. This figure is a chart that displays the relationship of pile radius on the time for 50 percent of the excess pore pressure to dissipate, as applied to clay soil having an OCR between 1 and 2. Both historical data and data from locations NB2 and NB3 in this study are shown. The bottom X-axis shows the time for 50 percent of the pore pressure to dissipate or T subscript 50. The top X-axis is time from 5 minutes to 1 week. The left Y-axis is pile radius in millimeters (5 to 10; 2 to 100; and 2 to 4) and the right Y-axis is pile diameter in inches (4 to 10; 2 to 10; and 20 to 30). All data are plotted logarithmically. The chart shows that the time for 50 percent of the excess pore pressure to dissipate is a direct function of the pile radius and pile diameter. The plot illustrates that the data collected from the NB2 and NB3 study locations are in line with this relationship.
Figure 94. Changes in Pore Pressure, and Total and Effective Radial Stresses: (A) Log Time Scale and (B) Linear Time Scale. Charts. This figure is comprised of two charts that illustrate the changes in pore pressure, total radial stress, and effective radial stress over a log time scale (A) and a linear time scale (B). On both charts, the Y-axis is stress in kilopascals (0 to 250) and in PSI (0 to 40). On the log plot, time after the start of installation ranges from 0.1 to 100 hours. On the linear plot, the time scale is 0 to 140 hours after the start of installation. Pore pressure, total radial stress, and effective radial stress are each shown as interrupted traces over time. On the logarithmic chart, pore pressure and total radial stress are similar in pattern and magnitude for most of the time sequence, and are somewhat inversely related to the effective radial stress. This relationship is not as obvious when the data are plotted on the linear time scale. Over the log time scale, pore pressure and total radial stress increase rapidly from around 50 kilopascals (5 PSI) to about 250 kilopascals (32 PSI), and then pore pressure gradually decreases to the starting pressure at about 100 hours after the start of installation. Near the end of the test, the trace of total radial stress shows a very rapid increase to 250 kilopascals (35 PSI). On the same log scale, effective radial stress increases very gradually from around 0 to a maximum of 75 kilopascals (10 PSI) near the end of the test, and then increases very rapidly to 175 kilopascals (28 PSI) at the end of the test.
Figure 95. Relationship Between Shaft Friction, Radial Stress, and Vertical Stress for MDMP Test NB2. Charts. This figure is comprised of three charts, which summarize three parameters that affect the shear resistance along the MDMP. The upper chart illustrates the temporal change in friction along the friction sleeve. The second chart displays the temporal changes in vertical effective stress, both with and without an embankment. The bottom chart shows the temporal changes in peak friction and in radial friction. The X-axis on all three charts is time in hours (0 to 120) after installation. On the uppermost chart, the Y-axis is friction in kilopascals (0 to 30) and in PSI (0 to 5). The chart shows that, over the 120-hour time scale, the peak friction and the residual friction increase from near zero to 25 to 28 kilopascals (3.5 to 4 PSI). On the next chart, the Y-axis is a ratio of the radial effective stress to the vertical effective stress. This chart shows that vertical effective stress, both with and without an embankment, increases from near zero to about 2.5 with time after the installation. The ratio for stress without the embankment is slightly greater than the ratio considering stress with the embankment. The Y-axis on the last chart is the ratio of frictional stress to radial effective stress. The ratios for both peak friction and residual friction values increase to about 0.15 to 0.2 within the first 20 hours after installation, and then decrease gradually to about 0.1 for the remainder of the test period.
Figure 96. Final Load Test for MDMP Test NB2. Chart. This figure is a chart that displays the relationship between displacement and load measured by the surface load cell and two internal load cells during cycles of loading and unloading at the NB2 test location. Axial load is shown in kilonewtons (0 to 8) and in pounds (0 to 2000) on the X-axis. Displacement appears on the Y-axis in centimeters (0 to 17.5) and in inches (0 to 7). The chart illustrates that the surface load cell measurement is greater than that measured by the top load cell, which is, in turn, greater than that measured by the middle load cell. A large increase in axial load is shown for each of the load cells at a displacement of about 5 centimeters (2 inches). For the middle load cell, an increase to about 5 kilopascals (1100 pounds) is shown. For the top and surface cells, the increase is to 6.7 and 7 kilonewtons (1500 and 1600 pounds), respectively. Similar increases are shown with increased displacement. The trace of the frictional forces (1.5 to 2.5 kilonewtons or 300 to 600 pounds) parallels the increases in axial load detected by the load cells during the loading and unloading cycles.
Figure 97. Final Load Test for MDMP Test NB3. Chart. This figure is a chart that displays the relationship between displacement and load measured by the surface load cell and two internal load cells during cycles of loading and unloading at the NB3 test location. Axial load is shown in kilonewtons (0 to 8) and in pounds (0 to 2000) on the X-axis. Displacement appears on the Y-axis in centimeters (0 to 15) and in inches (0 to 6). The chart illustrates that the surface load cell measurement is greater than that measured by the top load cell, which is, in turn, greater than that measured by the middle load cell. A large increase in axial load is shown for each of the load cells at a displacement of about 5 centimeters (2 inches). For the middle load cell, an increase to about 5.75 kilopascals (1300 pounds) is shown. For the top and surface cells, the increase is to 6.75 and 7 kilonewtons (1500 and 1550 pounds), respectively. Similar increases are shown with increased displacement. The trace of the frictional forces (0.75 to 1.2 kilonewtons or 125 to 250 pounds) parallels the increases in axial load detected by the load cells during the loading and unloading cycles.
Figure 98. Shear Transfer Along the Friction Sleeve for MDMP Test NB2. Chart. The figure is a chart that presents details of the shear transfer during initial displacement calculated for 11 load tests, and the extension and compression of the initial load test at NB2. Displacement in millimeters (0 to negative 6) and in inches (0 to negative 0.25) is shown on the X-axis. Shear transfer along the frictional sleeve is shown in kilopascals (0 to negative 30) and in PSI (0 to negative 4.5) on the Y-axis. The overall trend shows that data from all the load tests are generally parallel across the X-axis (displacement), and that the amount of shear transfer along the sleeve increases cumulatively over time with each subsequent load. The lowest pressures are associated with the initial load test compression and extension. Just above these traces is the shear transfer calculated for load test number 1, basically flat at about negative 3 kilopascals (negative 0.4 PSI). The highest pressure, negative 27.5 kilopascals (negative 4 PSI), was calculated for the last load test at NB2, test number 11.
Figure 99. Shear Transfer Along the Friction Sleeve for MDMP Test NB3. Chart. The figure is a chart that presents details of the shear transfer during initial displacement calculated for nine load tests, and the extension and compression of the initial load test at NB3. Displacement in millimeters (0 to negative 6) and in inches (0 to negative 0.25) is shown on the X-axis. Shear transfer along the frictional sleeve is shown in kilopascals (0 to negative 25) and in PSI (0 to negative 4) on the Y-axis. The overall trend indicates that data from all the load tests are generally parallel across the X-axis (displacement), and that the amount of shear transfer along the sleeve increases cumulatively over time with each subsequent load. The lowest pressures are associated with the initial load test compression. Just above these traces is the shear transfer calculated for load test number 1, basically flat at about negative 2 kilopascals (negative 0.3 PSI). The highest pressure, negative 23.5 kilopascals (negative 3.4 PSI), was calculated for the last load test at NB3, test number 9.
Figure 100. Shear Transfer Along the Friction Sleeve as a Function of the Degree of Consolidation for MDMP Test NB2. Chart. The figure is a chart that illustrates the variation in the peak and residual shear transfer parameters as a function of the degree of consolidation for the NB2 test location. The X-axis is consolidation in percent (0 to 100). The left Y-axis is shear transfer in kilopascals (0 to 30) and the right Y-axis is the ratio of shear transfer to undrained shear strength (0 to 1.2). In general, the chart shows that, for both peak friction and residual friction values, shear transfer increases as consolidation increases. At about 10 percent consolidation, shear transfer for peak and residual friction is near 4 kilopascals. At 100 percent consolidation, shear transfer for peak friction is about 21 kilopascals and for residual friction it is slightly lower at about 19 kilopascals.
Figure 101. Shear Transfer Along the Friction Sleeve as a Function of the Degree of Consolidation for MDMP Test NB3. Chart. The figure is a chart that illustrates the variation in the peak and residual shear transfer parameters as a function of the degree of consolidation for the NB3 test location. The X-axis is consolidation in percent (0 to 100). The left Y-axis is shear transfer in kilopascals (0 to 30) and the right Y-axis is the ratio of shear transfer to undrained shear strength (0 to 1.2). In general, the chart shows that, for both peak friction and residual friction values, shear transfer increases as consolidation increases. At about 10 percent consolidation, shear transfer for peak and residual friction is near 3 kilopascals. At 100 percent consolidation, shear transfer for peak friction is about 22 kilopascals and for residual friction it is slightly lower at about 19.5 kilopascals.
Figure 102. Undrained Shear Strength of the BBC at the Newbury Test Site: (A) Variation With Depth Along With Results of Different Testing and (B) Details of CPT and SHANSEP Parameters Between the Depths of 6.1 and 13.7 Meters (20 to 45 Feet) (based on Paikowsky and Chen, 1998). Chart. This figure displays two charts with historical data illustrating the variation in undrained shear strength with depth. One chart displays historical data from various tests and studies. The second chart illustrates only the CPT and SHANSEPT parameters. The figures are depth profiles plots of undrained shear strength of clay. The X-axis of the first chart is undrained shear strength in kilopascals (0 to 150) and in ton-per-square-foot (TSF) (0 to 2). The left Y-axis shows elevation from positive 10 feet to negative 80 feet. The right Y-axis is depth in feet (0 to 90). Undrained shear strength is shown plotted against depth in the clay layer at each of the test sites from various studies. The plot shows that, below a depth of about 18 feet, little change in the undrained shear strength can be detected at most study locations. Vertical effective stress, with and without embankment, is also shown for several locations and increases with depth in the clay. The second chart compares the changes in undrained shear strength with depth between 20 and 45 feet in the soil measured by the CPT and the values proposed by SHANSEPT. The X-axis is undrained shear strength in kilopascals (0 to 40) and in TSF (0 to 0.5). The depth, shown on the left Y-axis, is from about 6 to 14 meters (20 to 45 feet). The chart indicates that the shear strength data obtained by the CPT are similar to and slightly higher than the values proposed by SHANSEP for the 6- to 13-meter (20- to 45-feet) depth interval.
Figure 103. Details of the Various Segments That Make Up the MDMP (from the point of surface measurements to the upper inner load cell). Drawing. This figure is a simple diagram of the upper portion of the MDMP, illustrating its various segments and some of their dimensions. Near the top is the N-rod connection, 2 to 7 centimeters long and 20.66 square centimeters in area. The drill rod, which can vary in length for each test, is shown 1.52 meters long in the diagram and with an area of 8.33 square centimeters. The N-rod adaptor is shown 21.59 centimeters long and with an area of 27.50 square centimeters. Just below this is the connector housing, 10.24 centimeters long and with an area of 27.88 square centimeters. The upper extension, the next component, is 31.67 centimeters long with an area of 23.89 square centimeters. Below the upper extension is the top load cell assembly, 7.3 centimeters long and with an area of 10.28 square centimeters.
Figure 104. The Relationship Between the Pile Impedance and Measured Signals (modified after Rausche, 1981). Drawing. This figure, a simplified representation of the MDMP during driving, illustrates the influence of the variation in impedance on the traveling force and velocity waves. The figure illustrates the relationship of the force and velocity of impact, and the force and velocity of the MDMP on the pile impedance. The diagram relates to the set of equations described in the text and numbered 7.3 through 7.7.
Figure 105. Surface Force and Velocity Records of the MDMP Test NB2 Restrike, Blow 1. Chart. The chart presents a continuous trace of the temporal changes in surface force and velocity, determined by CAPWAP analyses, for blow number 1 of the MDMP restrike at the NB2 test location. The X-axis is time in milliseconds (0 to 5) and the Y-axis is force in KIPS (negative 10 to positive 20). Maximum force for both parameters is about 15 KIPS and occurs at time zero. Velocity and force are generally similar until about 1 millisecond, when velocity decreases simultaneously with an increase in force. Near the end of the 5-millisecond interval, both parameters return to near zero.
Figure 106. Test NB2 Restrike CAPWAP Modeling of MDMP Case (1): (A) best Match Between Measured and Calculated Force at Top and (B) Drill Rods and Pile Geometry Modeling. Chart and Diagram. Companion to table 41. The figure is comprised of a chart presenting the best match between measured and calculated force, and a diagram of drill rod and pile geometry used for modeling. The chart presents a continuous trace of the temporal changes in calculated (CAPWAP) and measured (CPT) forces during the restrike at the NB2 test location, assuming that the pile is 9.88 meters long and continuous (case number 1). The X-axis shows time in milliseconds (0 to 10); length over wave speed (capital L over small C); and soil segments 1 through 10 (depth). The Y-axis is force in KIPS (negative 10 to positive 20). The calculated and measured forces agree reasonably well for the first 4 milliseconds, through soil segment 3. Thereafter, the differences between measured and calculated force increase. The accompanying diagram illustrates the different geometries of the drill rods and pile used in the modeling analyses, including a rough or jagged configuration, a uniformly smooth surface with an elastic modulus, a uniformly smooth surface with a specific weight, and a smooth surface with a flared bottom.
Figure 107. Test NB2 Restrike CAPWAP Modeling of MDMP Case (2): (A) best Match Between Measured and Calculated Force at Top and (B) Drill Rods and Pile Geometry Modeling. Chart and Diagram. Companion to table 42. The figure is comprised of a chart presenting the best match between measured and calculated force, and a diagram of drill rod and pile geometry used for modeling. The chart presents a continuous trace of the temporal changes in calculated (CAPWAP) and measured (CPT) forces during the restrike at the NB2 test location, assuming that the pile is 9.88 meters long, with a 0.381-millimeter compression slack, 25-percent effectiveness, and a 50.8-millimeter tension slack (case number 2). The X-axis shows time in milliseconds (0 to 10); length over wave speed (capital L over small C); and soil segments 1 through 10 (depth). The Y-axis is force in KIPS (negative 10 to positive 20). The calculated and measured forces agree reasonably well for the first 4 milliseconds, through soil segment 3. Thereafter, the differences between measured and calculated force increase. The accompanying diagram illustrates the different geometries of the drill rods and pile used in the modeling analyses, including a rough or jagged configuration, a uniformly smooth surface with an elastic modulus, a uniformly smooth surface with a specific weight, and a smooth surface with a flared bottom.
Figure 108. Test NB2 Restrike CAPWAP Modeling of MDMP Case (3): (A) best Match Between Measured and Calculated Force at Top and (B) Drill Rods and Pile Geometry Modeling. Chart and Diagram. Companion to table 43. The figure is comprised of a chart presenting the best match between measured and calculated force, and a diagram of drill rod and pile geometry used for modeling. The chart presents a continuous trace of the temporal changes in calculated (CAPWAP) and measured (CPT) forces during the restrike at the NB2 location, assuming the pile is 8.72 meters long and that the slip joint area is the end of the pile (case number 3). The X-axis shows time in milliseconds (0 to 10); length over wave speed (capital L over small C); and soil segments 1 through 7 (depth). The Y-axis is force in KIPS (negative 10 to positive 20). The calculated and measured forces agree reasonably well for the first 4 milliseconds, through soil segment 3. Thereafter, the differences between measured and calculated force increase. The accompanying diagram illustrates the different geometries of the drill rods and pile used in the modeling analyses, including a rough or jagged configuration, a uniformly smooth surface with an elastic modulus, a uniformly smooth surface with a specific weight, and a smooth surface with a flared bottom.
Figure 109. Modeling of Case (1), Calculated and Measured Forces at the Internal Load Cell Locations for the MDMP Test NB2 Restrike Blow 1 (analysis based on a force match at the surface measurement location only). Charts. The figure is comprised of three charts comparing temporal changes in the measured and calculated forces associated with the three internal load cells during blow number 1 of restrike at the NB2 test location. The results are based on case number 1 modeling assumptions (a continuous pile 9.88 meters long). On all three charts, the X-axis is time in milliseconds (0 to 30), and the Y-axis is force in kilonewtons (negative 40 to positive 80) and in KIPS (negative 10 to positive 20). In general, the three charts indicate that, within the first 22 milliseconds, measured and calculated force agrees well for data from the top and middle load cells. Thereafter, the agreement is of little significance.
Figure 110. Modeling of Case (2), Calculated and Measured Forces at the Internal Load Cell Locations for the MDMP Test NB2 Restrike Blow 1 (analysis based on a force match at the surface measurement location only). Charts. The figure is comprised of three charts comparing temporal changes in the measured and calculated forces associated with the three internal load cells during blow number 1 of restrike at the NB2 test location. The results are based on case number 2 modeling assumptions (the pile is 9.88 meters long with a 0.381-millimeter compression slack, 25-percent effectiveness, and a 50.8-millimeter tension slack). On all three charts, the X-axis is time in milliseconds (0 to 30), and the Y-axis is force in kilonewtons (negative 40 to positive 80) and in KIPS (negative 10 to positive 20). In general, the three charts indicate that, within the first 22 milliseconds, measured and calculated force agrees well for data from the top and middle load cells. Thereafter, the agreement is of little significance.
Figure 111. Modeling of Case (3), Calculated and Measured Forces at the Internal Load Cell Locations for the MDMP Test NB2 Restrike Blow 1 (analysis based on a force match at the surface measurement location only). Charts. The figure is comprised of three charts comparing temporal changes in the measured and calculated forces associated with the three internal load cells during blow number 1 of restrike at the NB2 test location. The results are based on case number 3 modeling assumptions (the pile is 8.72 meters long and the slip joint area is the end of the pile). On all three charts, the X-axis is time in milliseconds (0 to 30), and the Y-axis is force in kilonewtons (negative 40 to positive 80) and in KIPS (negative 10 to positive 20). In general, the three charts indicate that, within the first 22 milliseconds, measured and calculated force follow the same trend for data from the top and middle load cells, but not as well as in cases 1 and 2. Thereafter, the agreement is of little significance.
Figure 112. Surface Force and Velocity Records for MDMP Test NB3 Restrike, Blow 2. Chart. The chart presents a continuous trace of the temporal changes in surface force and velocity, determined by CAPWAP analyses, for blow number 2 of the MDMP restrike at the NB3 test location. The X-axis is time in milliseconds (0 to 10) and the Y-axis is force in KIPS (negative 10 to positive 20). Maximum force for both parameters is about 18 KIPS and occurs at time zero. Velocity and force are generally similar until about 6 milliseconds, when velocity decreases simultaneously with an increase in force. Between 9 and 10 milliseconds, the force increases from the negative area to near zero, but the velocity remains at about 5 KIPS.
Figure 113. Test NB3 Restrike CAPWAP Modeling of MDMP Case (1): (A) best Match Between Measured and Calculated Force at Top and (B) Drill Rods and Pile Geometry Modeling. Chart and Diagram. Companion to table 44. The figure is comprised of a chart presenting the best match between measured and calculated force, and a diagram of drill rod and pile geometry used for modeling. The chart presents a continuous trace of temporal changes in calculated (CAPWAP) and measured (CPT) forces for during restrike at the NB3 test location, assuming that the pile is 13.84 meters long with a 50.8-millimeter tension slack (case number 1). The X-axis shows time in milliseconds (0 to 10); length over wave speed (capital L over small C); and soil segments 1 through 10 (depth). The Y-axis is force in KIPS (negative 10 to positive 20). The calculated and measured forces agree reasonably well over the 10-millisecond time interval (soil segment 9). At approximately 8 milliseconds, the force values for both cases drop below 0 and into the negative zone, then return to a range of 0 to positive 5 KIPS. The accompanying diagram illustrates the different geometries of the drill rods and pile used in the modeling analyses, including a rough or jagged configuration, a uniformly smooth surface with an elastic modulus, a uniformly smooth surface with a specific weight, and a smooth surface with a flared bottom.
Figure 114. Test NB3 Restrike CAPWAP Modeling of MDMP Case (2): (A) best Match Between Measured and Calculated Force at Top and (B) Drill Rods and Pile Geometry Modeling. Chart and Diagram. Companion to table 45. The figure is comprised of a chart presenting the best match between measured and calculated force, and a diagram of drill rod and pile geometry used for modeling. The chart presents a continuous trace of temporal changes in calculated (CAPWAP) and measured (CPT) forces for during restrike at the NB3 test location, assuming that the pile is 12.68 meters long and the slip joint is the end of the pile (case number 2). The X-axis shows time in milliseconds (0 to 10); length over wave speed (capital L over small C); and soil segments 1 through 6 (depth). The Y-axis is force in KIPS (negative 10 to positive 20). The calculated and measured forces agree reasonably well over the 10-millisecond time interval (soil segment 6). At approximately 7 milliseconds, the measured force values (CPT) drop below 0 and into the negative zone, then return to a range of 0 to positive 5 KIPS. The calculated force drops into the negative zone at about 8 milliseconds, then rises to near zero at the end of the time interval. The accompanying diagram illustrates the different geometries of the drill rods and pile used in the modeling analyses, including a rough or jagged configuration, a uniformly smooth surface with an elastic modulus, a uniformly smooth surface with a specific weight, and a smooth surface with a flared bottom.
Figure 115. Modeling of Case (1), Calculated and Measured Forces at the Internal Load Cell Locations for the MDMP Test NB3 Restrike Blow 2 (analysis based on a force match at the surface measurement location only). Charts. The figure is comprised of three charts comparing temporal changes in the measured and calculated forces associated with the three internal load cells during blow number 2 of restrike at the NB3 test location. The results are based on case number 1 modeling assumptions (a pile 13.84 meters long with a 50.8-millimeter tension slack). On all three charts, the X-axis is time in milliseconds (0 to 20), and the Y-axis is force in kilonewtons (negative 40 to positive 80) and in KIPS (negative 10 to positive 20). In general, the charts indicate that, the measured and calculated forces agree fairly well for data from the top and middle load cells. No data were collected from the bottom load cell.
Figure 116. Modeling of Case (2), Calculated and Measured Forces at the Internal Load Cell Locations for the MDMP Test NB3 Restrike Blow 2 (analysis based on a force match at the surface measurement location only). Charts. The figure is comprised of three charts comparing temporal changes in the measured and calculated forces associated with the three internal load cells during blow number 2 of the restrike at the NB3 test location. The results are based on case number 2 modeling assumptions (a pile 12.68 meters long and the slip joint is the end of the pile). On all three charts, the X-axis is time in milliseconds (0 to 20), and the Y-axis is force in kilonewtons (negative 40 to positive 80) and in KIPS (negative 10 to positive 20). In general, the charts indicate that the measured and calculated forces agree fairly well for data from the top and middle load cells. No data were collected from the bottom load cell.
Figure 117. Predicted Pile Capacity for the Installation of MDMP Test NB2 (Cases 1 and 2) based on the Energy Approach Method and the Case Method With Varying J subscript C Values (assuming pile length is 9.88 meters (32.4 feet)). Chart. This figure presents a chart profiling pile capacity with depth for data predicted by five approaches: the energy approach; RTL method, RMX method using a damping coefficient of 0.3, RMX method using a damping coefficient of 0.6, and RMX method using a damping coefficient of 0.9. Pile capacity is shown on the X-axis in kilonewtons (0 to 80) and in KIPS (0 to 20). Depth is shown on the Y-axis in meters (6 to 9) and in feet (18 to 30). The chart indicates that values of pile capacity progressively increase with the following methods used for their prediction: energy approach, RMX with damping coefficient of 0.9, RMX with damping coefficient of 0.6, RMX with damping coefficient of 0.3, and RTL. The lowest predicted pile capacity is obtained by the energy approach, yielding values of about 5 kilonewtons (1.25 KIPS) consistently similar with depth. The highest pile capacity, ranging from about 38 to 55 kilonewtons (8.5 to 12.5 KIPS), is predicted by the RTL method. The values increase slightly with depth between 6.6 and 7 meters (22 and 23 feet), and then are fairly constant. The greatest variation in pile capacity with depth is shown in the data predicted by the RMX method using a damping coefficient of 0.9. The values range from about 8 to 21 kilonewtons (2 to 5 KIPS), alternately increasing and decreasing with every 0.3 or 0.6 meters (1 or 2 feet) of depth.
Figure 118. Predicted Pile Capacity for the Restrike of MDMP Test NB2 (Cases 1 and 2) based on the Energy Approach Method and the Case Method With Varying J subscript C Values (assuming pile length is 9.88 meters (32.4 feet)). Chart. This figure presents a chart profiling pile capacity with depth for data predicted by five approaches: the energy approach; RTL method, RMX method using a damping coefficient of 0.3, RMX method using a damping coefficient of 0.6, and the RMX method using a damping coefficient of 0.9. Pile capacity is shown on the X-axis in kilonewtons (0 to 80) and in KIPS (0 to 20). Depth is shown on the Y-axis in meters (9 to 9.6) and in feet (29 to 32). The chart indicates that values of pile capacity progressively increase with the following methods used for their prediction: energy approach, RMX with damping coefficient of 0.9, RMX with damping coefficient of 0.6, RMX with damping coefficient of 0.3, and RTL. The lowest predicted pile capacity is obtained by the energy approach, yielding values of about 10 kilonewtons (2.5 KIPS) consistently similar with depth. The highest pile capacity, ranging from about 70 to 75 kilonewtons (16 to 17 KIPS), is predicted by the RTL method. Capacity values predicted by all methods appear consistently similar with depth, except for the last measurement at the greatest depth, where some irregularities are visible.
Figure 119. Predicted Pile Capacity for the Installation of MDMP Test NB2 (Case 3) based on the Energy Approach Method and the Case Method With Varying J subscript C Values (assuming pile length is 8.72 meters (28.6 feet)). Chart. This figure presents a chart profiling pile capacity with depth for data predicted by five approaches: the energy approach; RTL method, RMX method using a damping coefficient of 0.3, RMX method using a damping coefficient of 0.6, and RMX method using a damping coefficient of 0.9. Pile capacity is shown on the X-axis in kilonewtons (0 to 80) and in KIPS (0 to 20). Depth is shown on the Y-axis in meters (6 to 9) and in feet (18 to 30). The chart indicates that values of pile capacity progressively increase with the following methods used for their prediction: energy approach, RMX with damping coefficient of 0.9, RMX with damping coefficient of 0.6, RMX with damping coefficient of 0.3, and RTL. The lowest predicted pile capacity is obtained by the energy approach, yielding values of about 5 kilonewtons (1.25 KIPS) consistently similar with depth. The highest pile capacity, ranging from about 38 to 60 kilonewtons (8.5 to 13.5 KIPS), is predicted by the RTL method. Pile capacities predicted by the other three methods show little variation with depth.
Figure 120. Predicted Pile Capacity for the Restrike of MDMP Test NB2 (Case 3) based on the Energy Approach Method and the Case Method With Varying J subscript C Values (assuming pile length is 8.72 meters (28.6 feet)). Chart. This figure presents a chart profiling pile capacity with depth for data predicted by five approaches: the energy approach; RTL method, RMX method using a damping coefficient of 0.3, RMX method using a damping coefficient of 0.6, and RMX method using a damping coefficient of 0.9. Pile capacity is shown on the X-axis in kilonewtons (0 to 80) and in KIPS (0 to 20). Depth is shown on the Y-axis in meters (9 to 9.6) and in feet (29 to 32). The chart indicates that values of pile capacity progressively increase with the following methods used for their prediction: energy approach, RMX with damping coefficient of 0.9, RMX with damping coefficient of 0.6, RMX with damping coefficient of 0.3, and RTL. The lowest predicted pile capacity is obtained by the energy approach, yielding values of about 10 kilonewtons (2.5 KIPS) consistently similar with depth. The highest pile capacity, ranging from about 70 to 75 kilonewtons (16.5 to 17 KIPS), is predicted by the RTL method. Capacity values predicted by all methods appear consistently similar with depth, except for the last measurement at the greatest depth, where some irregularities are visible.
Figure 121. Predicted Pile Capacity for the Installation of MDMP Test NB3 (Case 1) based on the Energy Approach Method and the Case Method With Varying J subscript C Values (assuming pile length is 13.84 meters (45.4 feet)). Chart. This figure presents a chart profiling pile capacity with depth for data predicted by five approaches: the energy approach; RTL method, RMX method using a damping coefficient of 0.3, RMX method using a damping coefficient of 0.6, and RMX method using a damping coefficient of 0.9. Pile capacity is shown on the X-axis in kilonewtons (0 to 80) and in KIPS (0 to 20). Depth is shown on the Y-axis in meters (9.5 to 10.5) and in feet (30 to 36). The chart indicates that the lowest predicted pile capacity is obtained by the energy approach, yielding values of about 5 kilonewtons (1.25 KIPS) consistently similar with depth. The highest pile capacity, ranging from about 38 to 55 kilonewtons (8.5 to 12 KIPS), is predicted by the RTL method. Capacity values predicted by the other three methods are similar in magnitude and variation with depth. These values range from about 12 to 28 kilonewtons (3 to 6.5 KIPS. All methods provide data that are generally consistently similar with depth.
Figure 122. Predicted Pile Capacity for the Restrike of MDMP Test NB3 (Case 1) based on the Energy Approach Method and the Case Method With Varying J subscript C Values (assuming pile length is 13.84 meters (45.4 feet)). Chart. This figure presents a chart profiling pile capacity with depth for data predicted by five approaches: the energy approach; RTL method, RMX method using a damping coefficient of 0.3, RMX method using a damping coefficient of 0.6, and RMX method using a damping coefficient of 0.9. Pile capacity is shown on the X-axis in kilonewtons (0 to 80) and in KIPS (0 to 20). Depth is shown on the Y-axis in meters (12.5 to 14) and in feet (40 to 46). The chart indicates that values of pile capacity progressively increase with the following methods used for their prediction: energy approach, RMX with damping coefficient of 0.9, RMX with damping coefficient of 0.6, RMX with damping coefficient of 0.3, and RTL. The lowest predicted pile capacity is obtained by the energy approach, yielding values of about 10 kilonewtons (2.5 KIPS) consistently similar with depth. The highest pile capacity, ranging from about 70 to 80 kilonewtons (16.5 to 18 KIPS), is predicted by the RTL method. Pile capacities predicted by the other three methods show little variation with depth.
Figure 123. Predicted Pile Capacity for the Installation of MDMP Test NB3 (Case 2) based on the Energy Approach Method and the Case Method With Varying J subscript C Values (assuming pile length is 12.68 meters (41.6 feet)). Chart. This figure presents a chart profiling pile capacity with depth for data predicted by five approaches: the energy approach; RTL method, RMX method using a damping coefficient of 0.3, RMX method using a damping coefficient of 0.6, and RMX method using a damping coefficient of 0.9. Pile capacity is shown on the X-axis in kilonewtons (0 to 80) and in KIPS (0 to 20). Depth is shown on the Y-axis in meters (9.5 to 10.5) and in feet (30 to 36). The chart indicates that, in general, values of pile capacity progressively increase with the following methods used for their prediction: energy approach, RMX with damping coefficient of 0.9, RMX with damping coefficient of 0.6, RMX with damping coefficient of 0.3, and RTL. The lowest predicted pile capacity is obtained by the energy approach, yielding values of about 5 kilonewtons (1.25 KIPS) consistently similar with depth. The highest pile capacity, ranging from about 56 to 75 kilonewtons (13 to 16.5 KIPS), is predicted by the RTL method. Pile capacities predicted by the other three methods show little variation with depth, except for the RMX method using a damping coefficient of 0.9, which produced detectable variation in pile capacity with depth.
Figure 124. Predicted Pile Capacity for the Restrike of MDMP Test NB3 (Case 2) based on the Energy Approach Method and the Case Method With Varying J subscript C Values (assuming pile length is 12.68 meters (41.6 feet)). Chart. This figure presents a chart profiling pile capacity with depth for data predicted by five approaches: the energy approach; RTL method, RMX method using a damping coefficient of 0.3, RMX method using a damping coefficient of 0.6, and RMX method using a damping coefficient of 0.9. Pile capacity is shown on the X-axis in kilonewtons (0 to 80) and in KIPS (0 to 20). Depth is shown on the Y-axis in meters (12.5 to 14) and in feet (40 to 46). The chart indicates that values of pile capacity progressively increase with the following methods used for their prediction: energy approach, RMX with damping coefficient of 0.9, RMX with damping coefficient of 0.6, RMX with damping coefficient of 0.3, and RTL. The lowest predicted pile capacity is obtained by the energy approach, yielding values of about 10 kilonewtons (2.5 KIPS) consistently similar with depth. The highest pile capacity, ranging from about 70 to 85 kilonewtons (16.5 to 18.5 KIPS), is predicted by the RTL method. Pile capacities predicted by the other three methods show little variation with depth.
Figure 125. Comparison Between the Measured Static Capacity for MDMP Test NB2 and Predictions Based on the Dynamic Measurements Utilizing Various Methods of Analysis. Chart. This figure is a chart comparing the measured static capacity for the MDMP at the NB2 location with predictions based on four methods of analysis: the energy approach, CAPWAP for restrike, Case method using EOD, and Case method for restrike. The X-axis is final measured total static capacity in kilonewtons (0 to 20) and in KIPS (0 to 6). The Y-axis shows the predicted capacity in kilonewtons (0 to 20) and in KIPS (0 to 6). The chart shows that the energy approach and the CAPWAP restrike methods provide the best prediction for capacity. The two different Case methods both underestimate the measured capacity.
Figure 126. Comparison Between the Measured Static Capacity for MDMP Test NB3 and Predictions Based on the Dynamic Measurements Utilizing Various Methods of Analysis. Chart. This figure is a chart comparing the measured static capacity for the MDMP at the NB3 location with predictions based on four methods of analysis: the energy approach, CAPWAP for restrike, Case method using EOD, and Case method for restrike. The X-axis is final measured total static capacity in kilonewtons (0 to 20) and in KIPS (0 to 6). The Y-axis shows the predicted capacity in kilonewtons (0 to 20) and in KIPS (0 to 6). The chart shows that the energy approach and the CAPWAP restrike methods provide the best prediction for capacity. The two different Case methods both underestimate the measured capacity.
Figure 127. Typical Configuration of the Modular MDMP. Drawing. This simplified line drawing illustrates the components of a typical MDMP and some related dimensions. The 2.87-meter-long and 76.2-millimeter-diameter unit contains three load cell assemblies. Shown, from top to bottom, are the N-rod adaptor, connector housing, upper extension, top load cell assembly, upper coupling, transducer housing (containing the pore pressure transducer and radial stress cell), lower coupling, middle load cell assembly, slip joint assembly, lower extension, bottom load cell assembly, and 60-degree point angle tip segment.
Equations
Equation 5.1. S subscript U divided by sigma prime subscript V equals 0.162 multiplied by the over consolidation ration, OCR, raised to the 0.72 power.
Equation 5.2. S subscript U divided by sigma prime subscript V equals 0.184 multiplied by OCR raised to the 0.72 power.
Equation 5.3. S subscript U divided by sigma prime subscript V equals 0.20 plus or minus 0.01 multiplied by OCR raised to the 0.72 plus or minus 0.05 power.
Equation 5.4. Initial excess pore pressure, delta U subscript I, divided by sigma prime subscript V equals 2.29 plus or minus 0.57.
Equation 5.5. Delta U subscript I divided by sigma prime subscript V equals 1.90 plus the product of 0.154 multiplied by OCR.
Equation 5.6. Excess pore pressure at any time, delta U, divided by delta U subscript I equals the negative horizontal pore pressure dissipation parameter, H subscript UT, which is, multiplied by the log subscript 10 of the time after pile driving in seconds, T.
Equation 5.7. The elapsed time since driving adjusted to a standardized pile size, T subscript 1, divided by the actual time since driving for a known pile, T subscript 2, equals the quotient, squared, of the radius of standardized pile, R subscript 1, divided by the radius of a known pile, R subscript 2.
Equation 5.8. T subscript PLS equals the quotient, squared, of R subscript
PLS divided by R subscript MDMP, multiplied by T subscript MDMP, which equals
the quotient, squared, of 19.177 millimeters divided by 38.1 millimeters,
multiplied by T subscript MDMP, which equals 0.253 multiplied by T subscript
MDMP.
Equation 5.9. The pile shaft capacity at any time after driving, R
subscript S parentheses T, divided by the maximum pile shaft capacity, R subscript
S max, equals the parameter representing the rate at which the pile gains
capacity, C subscript GT, multiplied by the log subscript 10 of T.
Equation 5.10. T subscript 30.48 centimeters equals the quotient,
squared, of R subscript 30.48 centimeters divided by R subscript MDMP, multiplied by T subscript MDMP, which equals the quotient, squared, of 152.4 millimeters
divided by 38.1 millimeters, multiplied by T subscript MDMP, which equals 16 multiplied by T subscript MDMP.
Equation 7.1. U subscript Z equals 1 minus the quotient of delta U divided by delta U subscript I.
Equation 7.2. The radial coefficient of consolidation, C subscript H, equals the quotient of product of the time factor associated with 50 percent radial consolidation, T subscript 50 parentheses H, multiplied the piles radius, R, squared, divided by the time for 50 percent excess pore pressure dissipation, T subscript 50.
Equation 7.3. F subscript MDMP equals F subscript Impact multiplied by the quotient of 2 multiplied by I subscript MDMP divided by the sum of I subscript rods plus I subscript MDMP.
Equation 7.4. V subscript MDMP equals V subscript Impact multiplied by the quotient of 2 multiplied by I subscript rods divided by the sum of I subscript rods plus I subscript MDMP.
Equation 7.5. F subscript MDMP divided by F subscript Impact equals 1.44.
Equation 7.6. V subscript MDMP divided by V subscript Impact equals 0.56.
Equation 7.7. The measured forces above the friction sleeve, Force subscript top, minus the measured force below the friction sleeve, Force subscript middle, equals 0.5 multiplied by Resisting Force.
Equation 7.8. R subscript U equals the energy delivered to the pile, E, divided by the sum of the permanent displacement or set, S, plus the quotient of the maximum displacement, D subscript max, minus S, divided by 2.
Equation 7.9. The total soil resistance, RTL, equals the sum of the measured force at time T1, F parentheses T1, plus F parentheses T1 plus the quotient 2L divided by C, all of which is divided by 2, plus the sum of the measured velocity at the time T1, V parentheses T1, minus V parentheses T1 plus the quotient of 2L divided by C, multiplied by the quotient of MC, where M is the mass of the pile, divided by 2L.
Equation 7.10. T1 equals the time of the impact peak, TP, plus lowercase delta, which is the time delay.
Equation 7.11. RTL equals the static resistance, S, plus the dynamic resistance, D.
Equation 7.12. D equals a damping constant, J, multiplied by the velocity at the pile toe, V subscript toe.
Equation 7.13. V subscript toe equals 2 multiplied by the velocity at pile top, V subscript top, minus the product of the following: the quotient of the pile length, L, divided by the product of pile mass, M, multiplied by wave speed of the pile material C, all multiplied by RTL.
Equation 7.14. J equals the dimensionless Case damping coefficient, J subscript C, multiplied by the quotient of the product of the elastic modulus of the pile material, E, multiplied by the pile cross-sectional area, A, divided by C.
Equation 7.15. RSP equals RTL minus the product of J multiplied
by the quotient of MC divided by L, multiplied by V subscript toe.
|
