Constant water content direct shear testing of compacted residual soils

Mechanical behavior of residual soils are studied by performing constant water content direct shear tests on reconstituted specimens using total stress analysis. The testing program involves initial degree of saturation (Sr) and applied normal stress as the control parameters. For three different soil samples, a total of 55 direct shear tests are conducted at Sr = 60%, 80%, and saturated conditions, in the normal stress range of 15-60 kPa. The results showed that shear strength increases with decreasing Sr and the relationship between shear strength and Sr is nonlinear. More dilative response is observed with decreasing Sr and decreasing applied normal stress. Maximum dilatancy and Sr relationship is nonlinear. At large displacements, samples prepared at different Sr levels showed similar ultimate shear resistances under similar applied normal stresses. It is concluded that Sr and applied normal stress dramatically influence the mechanical behavior of compacted residual soils studied.

Automated summary

The mechanical behavior of residual soils was studied through constant water content direct shear tests, revealing that shear strength increases with decreasing saturation and the relationship between shear strength and saturation is nonlinear. Additionally, a more dilative response was observed with decreasing saturation and applied normal stress.