Composite Behavior of Geosynthetic Reinforced Soil Mass

CHAPTER 7. SUMMARY AND CONCLUSIONS

This study investigated the composite behavior of a GRS mass. It focused on the strength of a GRS mass, CIS in a GRS mass, the lateral deformation of a GRS wall with modular block facing, and the development of a rational design procedure for determining the required reinforcement strength of a GRS wall by considering both lateral stresses in the fill and lateral wall deformation of the wall system.

The following tasks were carried out:

• Reviewed previous studies on composite behavior of a GRS mass and CIS in an unreinforced soil mass and a GRS mass.
  
  
• Designed a GSGC test for investigating the composite behavior of a GRS mass and conducted five GSGC tests with well-controlled conditions and extensive instrumentation to monitor behavior under different reinforcement spacing, reinforcement strength, and confining pressure.
  
  
• Developed an analytical model for the relationship between reinforcement strength and reinforcement spacing and derived an equation for calculating composite strength properties.
  
  
• Developed a hand computation analytical model for simulation of CIS in a GRS mass.
  
  
• Performed FE analyses to simulate the GSGC tests, generate additional data (with different confining pressures) for verifying the analytical models in this study, and investigate the behavior of GRS composites.
  
  
• Verified the analytical models using measured data from the GSGC tests, relevant test data available in the literature, and FE analyses.
  
  
• Developed an analytical model for predicting lateral movement of GRS walls with modular block facing.

The findings and conclusions of this study are as follows:

• The results of the GSGC tests were consistent and appear very reliable. The tests provide direct observation of the behavior of a GRS mass as related to reinforcement strength and spacing. The tests also provide a better understanding of the composite behavior of a GRS mass and can be used for validation of analytical models in this study and other models of GRS structures in the future.
  
  
• An equation describing the relative effects of reinforcement spacing and reinforcement strength was developed and verified. Based on the equation, the required reinforcement strength in a GRS wall can be determined, as can the composite strength properties and ultimate pressure carrying capacity of a GRS mass.
  
  
• An analytical model for calculating lateral deformation of a GRS wall with modular block facing was developed and verified. The required tensile strength of reinforcement in design can be determined for a prescribed value of the maximum allowable lateral movement of a wall.
  
  
• An analytical model for simulating compaction operation of a GRS mass was developed. The model allows CIS in the fill to be determined.
  
  
• The presence of geosynthetic reinforcement has a tendency to suppress dilation of the surrounding soil and reduce the angle of dilation of the soil mass. The dilation behavior offers a new explanation of the reinforcing mechanism, and the angle of dilation provides a quantitative measure of the degree of reinforcing effect of a GRS mass.