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| Earth and Rock Works | Earth Retaining Structures | Geotechnical Hazards | Ground Improvement | Structural Foundations | Subsurface Investigation |
| FHWA > Engineering > Geotechnical > Geotechnical Hazards > Mines |
| Subject | From | Posted |
|---|---|---|
| Cost Estimate | Matthew Trainum | 07/19/2004 12:15PM |
| RE: Cost Estimate | Priscilla Duskin | 07/20/2004 04:25PM |
| RE: Cost Estimate | Matthew Trainum | 07/21/2004 09:30AM |
| RE: Cost Estimate | Rick Ruegsegger | 07/23/2004 09:39AM |
Messages posted for Cost Estimate
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Subject: Cost Estimate From: Matthew Trainum Date: 07/19/2004 | ||
| I am looking for a general cost for mobilization, investigation, processing, etc (as well as a time frame for both site visit and setup) for a geophysical imaging beneath a highway (resistivity or seismic). Some apparent sinkholes have developed adjacent to a major highway here in Iowa. Currently we are drilling to get better subsurface information. Due to the high clay content of embankment fill and natural ground (glacial clay) we will be limiting ground penetrating radar to immediately below the pavement, for which we have already started making inquiries. I can answer any questions to help with estimating cost. Please pass on any contacts that you would recommend. If possible please call me at the number below Matthew Trainum, Geologist III Office of Design, Soils Design Section Iowa Department of Transportation 800 Lincoln Way Ames, Iowa 50010 515-239-1476
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Subject: RE: Cost Estimate From: Priscilla Duskin Date: 07/20/2004 | ||
| What is the lateral extent of this survey? Is this a two lane, four lane, or six lane road? And who is responsible for maintenance and protection of traffic for lane closures, the contractor or the DOT? Here at NYSDOT, we do the seismic investigations ourselves, but contract out the GPR surveys. Tony Alongi at Penetradar can give you a ballpark figure over the phone for shallow, high frequency GPR surveys over driving lanes. We have had good results from him at finding voids immediately below pavement--they use air-coupled antennnae mounted on a van and don't require lane closures. His phone # is (716) 731-4369. | ||
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Subject: RE: Cost Estimate From: Matthew Trainum Date: 07/21/2004 | ||
| This is a 4 lane, rural, freeway. Traffic control would be done by DOT. We have a "on-call" geotech lined up for GPR. I have received many helpful phone calls and emails suppling contacts and have summitted a list, with recommendations, to my office. Thanks to everyone for the help. Sincerely, Matthew Trainum | ||
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Subject: RE: Cost Estimate From: Rick Ruegsegger Date: 07/23/2004 | ||
| When it was uncertain which form of geophysical testing would be successful for a given site, ODOT has established a form of contract which included separate pay items for the initial application of each of the contracted forms of testing in a small,critical area. The contract then also included separate unit-priced additional testing for each form of geophysical testing. This form of contract allowed us to initially try a couple types of testing in a critical portion of the site, and then secondarily perform larger site investigations utilizing the form(s) of testing which was(were) proven effective initially. During our SUM-77-2.50 Emergency Mine Remediation project in 2001, ODOT had a geophysical consultant use ground penetrating radar (GPR) to look for mine voids and shafts. The water table at the site was fairly high, the soils included clays, and the mine voids we were looking for (beneath the groundwater and clay soils) were water-filled. We realized that these site characteristics would probably limit the success of GPR. However, we still ran GPR in an effort to look for near-surface voids (to proactively detect imminent subsidence conditions) and to search for the actual ocations of mapped abandoned vertical mine shafts (which would have been randomly filled to the surface with materials significantly different from the surrounding natural glacial soils). The GPS equipment utilized was a Noggin "Smart Cart ", which was about the size and configuration of a push-style lawn mower. (I will e-mail you some photos). Under a past research project for our office, the USGS successfully demonstrated the use of resistivity as a geophysical technique to locate air-filled mine voids on our JAC-32 Emergency Mine Remediation Project. Their 2002 report is entitled "Use of Electrical Resistivity to Detect Underground Mine Voids in Ohio (USGS Water- Resources Investigations Report 02-4041). Based on my past experience and the site you have described, I would probably be thinking about trying resistivity or seismic testing. If our office was going acquire one type of geophysical gear, we would probably go with resistivity gear because of the likelihood of high groundwater and/or clay soils at Ohio roadway locations, and also because the testing imagery is more or less immediately available. In my experience, seismic testing can produce good information, but several days are needed to process the raw data via a computer in order to provide imagery. I will call you regarding the geophysical consultants which have been involved with ODOT mine-related work. |
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