Reinforced Clay Subject to Undrained Triaxial Loading

Research into reinforced clay using triaxial testing of reinforced and unreinforced samples of saturated remolded clay shows that continuous impermeable reinforcement can cause a reduction in strength under rapid loading. This reduction in strength is caused by the generation of high pore-water pressures, near the center of the sample, which migrate radially outwards causing a net reduction in the effective minor principal stress. The same effect is observed with permeable reinforcement at wide spacings. At closer spacings the permeable reinforcement acts as a drain allowing for partial dissipation of high pore-water pressures. This results in an increase in strength even for rapid rates of loading. Impermeable reinforcement can be associated with an increase in strength when the clay is not fully saturated. Test data indicate a linear relationship between reinforced sample strength and the degree of saturation independent of cell pressure. Test results are presented and analyzed for the effects of permeable and impermeable reinforcement spacing in saturated clay. Similarly, test results are presented for partially saturated clay with impermeable reinforcement.