Study on Mechanism of Expansive Soil Slope Failure and Numerical Simulation

Swell-shrinking, crack development, and over-consolidation are the characteristics of expansive soil, and it is an over-consolidation soil undergoing dry-wet cycles. Therefore, there are some faults to analyze expansive soil slope stability adopting the traditional strength criterion and calculation methods. In this paper, the Bilinear Strain-Hardening/Softening Ubiquitous-Joint (BSHSUJ) model in FLAC^3D is adopted to analyze the slope stability combined with strength reduction method. Results showed that the BSHSUJ model can be used to analyze the expansive soil slope stability considering cracks and soil softening. The area of major plastic shear strain expanded gradually from the slope base and top to the middle and was linked totally. The developing process of concentrated area of plastic shear strain is the forming process of shear zone actually. The characteristic of expansive soil landslide as progressive development can be simulated well. The numerical analysis simulates the progressive failure of expansive soil slope clearly and the application for slope stability by FLAC^3D is feasible.