Numerical Modeling of Rainfall-induced Slope Failure

Abstract

Slope failure caused by heavy rainfall is an important geotechnical concern in many countries. Geotechnical engineering properties such as soil-water characteristics, strength and stress-strain behaviors of soil as well as climate conditions have become important parameters for reliable numerical simulation of slope stability. In this study, a numerical simulation was performed by considering both the hydraulic (e.g., permeability and soil water characteristic curve (SWCC)) and a strength parameter (i.e., cohesion) to evaluate the stability of unsaturated slopes during rainfall with the finite difference method (FLAC2D). A slope located in Namyangju, Korea was chosen as a testbed. Thus, the geometry, hydraulic and geotechnical properties of the site were used as the input parameters in the numerical modeling. The results suggest that different slope failure modes are generated by different rainfall intensities. The effects of soil permeability, SWCC, and cohesion on the slope stability were also investigated with parametric studies. The permeability and SWCC properties have important roles in the ground infiltration behavior of unsaturated soils, which results in a generation of excess pore water pressure. Moreover, the results showed that cohesion has a significant effect on the safety factor of unsaturated slopes.