No abstract

Reinforced sand shows larger dilatancy associated with a larger volume of shear zone in direct shear tests, compared to unreinforced sand. It is likely that multiple shear bands develop forming a thicken shear zone, resulting in larger dilatancy. Air-dried sand specimens reinforced with phosphor bronze strips installed perpendicularly to the shear direction were tested by using a medium scale direct shear test apparatus. The test results were analyzed with a new mechanical model using estimated thicknesses of shear zone as one on the major input parameters.

In order to investigate the deformation and strength characteristics of reinforced sand, a series of direct shear tests were performed. Phosphor bronze strips or sheets were used as reinforcement. Constant volume tests, as well as constant pressure tests, were conducted with different forms of reinforcement stiffness , surface area and surface friction. Test results show that the reinforcing efficiency is higher for reinforcement with larger surface area and rough surface texture. The dilatancy and shear displacement at the residual state also depends on the reinforcement property and geometry. The shear zone become wider in tests on reinforced sand than in tests on sand alone. As high dilatancy of reinforced sand, the peak shear stress and peak vertical stress increase a great deal than those of unreinforced sand.