Study On The Stability Of Slope Variability In Soil Parameters Under Rainfall

China is a vast country which widely exists essential topographic feature that landslide occurred. It is also one of the country where there the landslide occurred most frequently in Asia, even in the world. Rainfall is the main cause of landslide,and it is very important to understand the failure mechanism and factors of landslide in order to accurately predict and control it. The current studies are almost focused on the deterministic research method. However, the natural variability of soil parameters is too strong to ignore, especially the variability of saturated hydraulic conductivity.To explore the influence of variability of saturated hydraulic conductivity, the main work and results obtained are as follows:1.The variability of saturated hydraulic conductivity is regarded as the only factor of the horizontally variation of the soil, and the Green-Ampt infiltration model is extended to consider the spatial variability of saturated hydraulic conductivity. In this paper, the analytical model of the seepage field of the slope under two conditions is developed. On the basis of the limit equilibrium method, the limit state function of the slope is obtained. Finally, the above calculation procedure is programmed by MATLAB.2.The influence of the variation of saturated hydraulic conductivity on the safety factor of rainfall slope is discussed in this paper by a assumed infinite slope stability model. The following conclusions are drawn from the analysis:?at the same time, the slope section in area above the wetting front to the surface of slope at a certain depth,the variability of saturated hydraulic conductivity and water content were negatively correlated, but the area under the wetting front to the bottom of the slope is just the opposite. The smaller the CoV (the coefficient of variability) of saturated hydraulic conductivity is, the more stable of the variation of water content is; conversely, the more unstable of the variation of water content is means the greater of the CoV of the saturated hydraulic conductivity is. ? In the early stage of rainfall, in the area that rainfall infiltration completely above the wetting front, the CoV of saturated hydraulic conductivity is smaller, the safety coefficient decreased more quickly; in the junction region around the wetting front, the area that rainfall infiltration and the non infiltration zone, the CoV of saturated hydraulic conductivity is smaller, the growth rate of the safety coefficient is faster. When the duration of rainfall lasts long enough,the influence of the variability of the saturated hydraulic conductivity decreases gradually.