Slope Cracks in the Safety Assessment of the Rainfall Period

Abstract

Unsaturated cracked slopes are easily to be affected by rainfall in the soil. Actually, some of the rainfall becomes the surface runoff and the rest permeates the crack under the ground in water cycle system. The infiltration makes the groundwater level rise. It also increases the pore water pressure and slide stress of the soil and decreases the anti-shear strength of soil. That makes the slope fracture or deform. However, most of the slope stability analyses set the physical properties of the soil as constant values but neglect the influence of the crack and infiltration. Those analyses underestimate the influence of the crack and the change of water content to the anti-shear strength of the soil. Therefore, it was unable to predict the possible damage time point by these evaluation results. The knowledge and methodology of the rainfall combine infiltration and slope stability analysis in this research. Simulations of the moisture content of the soil and the groundwater level are performed by FEMWATER numerical model. The simulating conditions are based on the different cracked positions and rainfall durations. The data of moisture content changes of the soil will be transformed into the parameters of safety factors fitted by STEDWIN numerical model. The influence of the slope stability with different cracked positions was gained from the simulations.