Composite Properties from Instrumented Load Tests on Mini-Piers Reinforced With Geotextiles

摘要

Four pairs of large-scale instrumented geosynthetic reinforced soil (GRS) square columns were load tested to study the effects of varying reinforcement strength to spacing ratio, to discern the lateral pressures during construction and during load testing, and to derive shear strength parameters of the GRS composite. Each pair was identical in every respect, except one was loaded with a dry-stacked concrete masonry unit (CMU) facing in place and the other without. Lateral pressures during construction were found to be small for the facing type used in this study. Also, based on the derived GRS composite shear strength parameters, it was found that (1) the GRS composite Mohr-Coulomb envelopes are not parallel to those for the unreinforced soil; (2) the reinforcement increased the composite cohesion compared to the unreinforced soil (cohesion increases with decreasing spacing and increasing reinforcement strength); (3) the composite friction angle is less than that of the unreinforced soil (friction angle increases with decreasing reinforcement strength and increasing spacing); (4) as the composite friction angle increases, the active lateral earth pressure coefficient decreases; and (5) the benefits of reinforcing a soil become increasingly significant as the reinforcement spacing decreases.