Landslide Evolution Rule of Cut Slopes in Expansive Soils

Abstract

Expansive soils in cut slopes are prone to sliding for a period of time after excavation. They are commonly found during construction in expansive soil subgrade. Their sliding is not directly affected by the height and ratio of the slope. To understand the evolution of their deformation and the consequences of failure to implement effective engineering treatment, the finite difference procedure FLAC is used to analyze the regularity of the excavation process of expansive soil slopes and obtain the displacement, stress, and strain. The safety factor for slope cutting calculated by using the strength reduction method decreases as the slope depth increases, but is still stable after the complication of excavation. In addition, the thermodynamics module of the finite difference procedure FLAC is used to simulate the humidity field of the atmospheric effects for the expansive soil slope and to obtain the variability of the displacements, stresses, and strains of the cut slope after wetting and drying cycles. The numerical simulation results are basically in accordance with field observation results during and after the construction of cut slopes in the Sitang interchange ramp of the Bailong expressway in Guangxi Zhuang Autonomous Region, China. The four stages of evolution of expansive soil cutting slopes are summarized. It is proposed that flexible supporting structure technology should be used.