Study on the Soil Water Characteristic Curve and Shear Strength Characteristics of Granite Soil with Different Weathered Degree

Abstract

In this paper, the soils of the weathered granite with double layer soil slope in the hot and humid areas are studied. The water holding characteristics of compacted samples are studied by the pressure plate technique and vapor equilibrium method with saturated salt solution, and the effect of saturation on the shear strength is studied. The experimental results show that the residual soil has better water holding capacity than the completely weathered soil, which has greater air-entry value and residual suction value, and the gradient of the transition zone is smaller. There is an optimal saturation in this two weathered soils to reach the peak of the shear strength. The influence of shear strength index is different: the effect of saturation on the internal friction angle is little, but the effect on the cohesion is significant. The different weathered degree affects the soil properties such as the mineral composition and grain size gradation of two weathered soils. The residual soil has higher clay content and residual iron oxide, which affects two weathered soils in the soil water characteristic cure (SWCC) and shear strength of the characteristics. The mechanism of these differences can be clearly elucidated by analyzing the matrix suction and the cementation between soil particles, which provides a theoretical basis for the engineering management of weathered granite slopes.