Stability Analysis Method Of Slope Considering The Effect Of Rainfall And Its Application

The stability of the road slope is determined by its internal and external factors. The internal factors of the slope are inherent, and the external factors mainly include rainfall events, earthquake, and human excavation. The slope failure occurred frequently because of rainfall events in recent years. A slope example of Xing-Lin Road in Yunnan was used to study how the rainfall infiltrates into a soil slope varying with the rainfall intensity, rain fall duration, soil properties and how the infiltration influences the stability of a slope by using the finite element and difference methods based on the saturated-unsaturated soil seepage theory. At last, refers to the span of the rock mechanics parameter of the slope of Xing-Lin Road, taking into account the effect of rainfall, a model used to calculate the optimum stable excavation angle of a slope which represents the slope is created using the orthogonal design,the span of the optimum stable excavation angle of the slope of Xing-Lin Road is found to guide the practice.In this thesis, the primary contents are as follows:1) Based on the fundamental seepage equation, introduced the basic differential equation of saturated-unsaturated seepage, in which the pressure head is the fundamental unknown quantity. A calculated model for analysis of saturated-unsaturated seepage field with the boundary condition of rain infiltration also has been set forth. Based on the model, a finite element computer program for analysis of 2D saturated-unsaturated seepage field with the boundary condition of rain infiltration has been summed up.2) The stability of different types of slopes under the condition of rain has been summarized. Considering the shear strength of unsaturated soil, the method of analysis of limit equilibrium can be used in the analysis of the stability of saturated-unsaturated soil slopes.3) Based on the actual rainfall condition in the slope of Xing-Lin Road, Considering the differ instance of rainfall intensity of 100 mm/d, 200 mm/d, 300 mm/d and rain fall duration of 24 hour, 48 hour, 96 hour, the stability of the slope of Xing-Lin Road are calculated by using the slope calculation software .The conclusion is that the stability of the slope gradually decreases with the increasing of either rainfall intensity or rain fall duration and the decreasing extent of the slope enhances with the increasing of rainfall intensity.4) The reinforced slope of Xing-Lin Road is advisable with the influencing of controlled rainfall type by estimating the stability of the slope which reinforced in the situation of rainfall.5) A model used to calculate the optimum stable excavation angle of a slope is established using the orthogonal design through the analysis of the examples of Xing-Lin Road, refers to the span of the mechanics parameter of the slope, taking into account the effect of rainfall, the span of the optimum stable excavation angle of the slope is worked out. By contrasted the results of the span of the optimum stable excavation angle of the slope considering the effect of rainfall with the results without rainfall, some useful conclusions are found to guide the practice.