Shear Strength Behavior of an Unsaturated Clayey Soil

Abstract

Recently, the study of shear strength of unsaturated soil is gaining more interest in research and practice. In this study, the triaxial shear test and filter paper method were undertaken to study the shear strength behavior of unsaturated soil. The clayey soil from central India was tested to understand the unsaturated shear strength behavior. The shear strength behavior was analyzed by plotting relationship between shear strength (τ) versus matric suction (ua − uw). The failure envelope resulting from relationship between the shear strength and matric suction shows nonlinear behavior and provides the shear strength parameter with respect to suction (∅b ). In this experimental program, the shear strength behavior of unsaturated soil is studied using the soil–water characteristic curve (SWCC), and the nonlinearity between shear strength and the matric suction is observed. The nonlinearity is mainly due to desaturation of soil which starts from air entry value and continued till residual suction value and is affirmed and supported by the experimental results obtained in this study.