Research On The Influence Of Rain Infiltration To The Stability Of Expansive Soil Cutting Slope

Expansive soil is a special kind of clay that coming into being in the physical geological process, and has prominent dilatability when sopping up. With the constructing of some big engineering projects such as the South-north Water Transfer, Yangtze Gorges Project, Qinghai-Tiber Railway in these years, the problems and hazards of expansive soil are becoming more and more notable in a large number of slope engineering. At present, the saturated soil theory is used usually in many designs,which lead many hidden troubles to the stability of slopes. Rain Infiltration is an important factor to induce the landslide of the expansive soil slope. So it is theoretically and actually important to study the influences of the rainfall to the stability of expansive soil slope.Based on an expansive soil slope engineering in YiChang, the basal engineering characteristic of expansive soil are presented in the thesis. The relationship between shear strength, expansion and moisture content of YiChang expansive soil are studied through tests, which indicate that the shear strength and expansion of the expansive soil are strongly affected by its moisture content, the effects of moisture content variety caused by rainfall to the stability of the expansive soil cutting slope are also analyzed. The methods in common use of analyzing the slope stability are presented. The elasto-plastic FEM model of expansive soil slop is established based on the experiment results. The influence of the expansive force is introduced. The loading model including swelling force for the expansive soil road cutting slope is founded. The stability of the expansive soil cutting slope in condition of different soaking depth are analyzed using ANSYS software. The results show that with the increase of the slope soaking depths, the plastic zone of the slope develops gradually, and the destruction occurs on the surface mostly. And then, the critical gradients under different height of the slope are presented. Lastly, the destroying types, prevention and cure measures of the expansive soil cutting slope are summed up based on the discussing of the expanding and collapsing mechanism of the expansive soil slope.This paper provides references to search after the relationship between shear strength, expansion and water content of YiChang expansive soil and analyze the stability of the expansive soil slope under the influences of rainfall.