Stability Analysis Of High Embankment Slope Under Different Rainfall Conditions

In southern China, the rainstorm is a common factor of inducing slope failure, which is often experienced by long duration, large intensity and wide distribution. It is an indisputable fact that the geological hazards such as landslide and debris flow are closely related to rainfall. Taking the slope stability under rainfall in consideration can predict engineering disaster and avoids unnecessary economic losses. The new method of rainfall infiltration boundary and the initial pore water pressure is applied in this paper. Based on Guangfozhao highway, This paper studied the slope stability of Guangfozhao highway K85+160 section under the different rainfall conditions, from three aspects, experimental research, software development and numerical simulation. The main research content is as follows:Firstly, through field sampling and laboratory experiments, the seepage characteristics and mechanical properties of silty clay has been researched. The relationship between matrix suction and water content, the function of seepage coefficient and the shear strength of the silty clay are obtained by the experiments.In addition, the independent development of rainfall infiltration boundary and the initial pore water pressure is applied in this paper, the numerical simulation results show that the applying of rainfall infiltration boundary and the initial pore water pressure can make it fit the experimental results better. Besides, a new method of unsaturated slope stability analysis based on FLAC 3D platform under the condition of rainfall is expounded in this paper.Finally, on the basis of the methods and parameters above, the slope stability of Guangfozhao highway K85+160 section under the different rainfall conditions is analyzed by FLAC 3D. Numerical simulation results show that when the duration of rainfall is in a certain period of time, the bigger rainfall intensity will bring a lower slope safety factor, and the safety factor of slope will be reduced faster; but when the rainfall time is over a certain period of time always, the smaller rainfall intensity will lead to a lower slope safety factor, whereas there is no significant correlation between the safety factor and the intensity of rainfall. The effect of rainfall on slope stability can be considerably reduced by enhancing the whole soft soil layers.