Stability Analysis Of Saturated-Unsaturated Soil Slope Subjected To Rainfall

Landslide is closely related to rainfall, and for unsaturated soil slope the rain infiltration is the most important one that results in landslide. It is of great significance for the precaution of landslide to make a deep study of the landslide law under rainfall and establish a quantitative model for analysis. In order to analyze the influence of rainfall on the unstaturated soil slopes' stability, on the basis of the rainfall infiltration theory, the saturated-unsaturated seepage theory, the unsaturated shear strength theory, the slope stability analysis method, it is analyzed completely that the influence of rainfall intensity, rainfall duration and saturated coefficient of permeability to seepage field and stability of the unstaturated soil slope, and gains some beneficial conclusions.On the base of basic seepage physics equation, regarding pressure hydraulic head as a basic unknown quantity to deduce saturated-unsaturated seepage differential equation, the FEM format of differential equation is deduced based on Galerkin method. According to the seepage calculational program with MATLAB software under the condition of rainfall, the disposal of pore water pressure is calculated and the influence of seepage field with the variation of rainfall intensity, rainfall duration, coefficient of staturated permeability is studied.The pore water pressure is imported to the unsaturated shear strength theory and is regarded as the important factor for the slope stability analysis. According to the slope stability analysis program with MATLAB software, variational rule of slope stability coefficient of security and the influence of variation of several parameters are obtained. The presented methods and models could be widely used for the numerical analyses on the stability of unsaturated soil slopes.