Seepage Field And Stability Analysis Of Unsaturated Soil Slope Under The Nonorthogonal Infiltration Of Rainfall Condition

Slope engineering is almost involved in the field of civil engineering,and its stability is also a hot topic for many scholars to study.However,in recent years,the intensive study of rainfall infiltration and related rainfall experiments and numerical analysis have proved that the traditional rainfall orthogonal infiltration boundary has defects in unsaturated soil slope analysis under rainfall infiltration conditions.It is of great significance to study the infiltration law of rainwater on unsaturated soil slope under non-orthogonal rainfall infiltration conditions and truly and effectively predict the slope stability under rainfall conditions.Based on the saturated-unsaturated seepage theory and rainfall infiltration theory,and consider the non-orthogonal rainwater infiltration boundary synthetically,the change of seepage field in slope is analyzed under different rainfall conditions.According to the calculated results of transient seepage field and the theory of shear strength of unsaturated soil,the transient stability of slope is analyzed.In order to study the above problems,the following work has been done in this paper:(1)Based on the law of conservation of energy and Darcy's law,the saturated-unsaturated seepage differential equation is deduced by using the saturated-unsaturated soil seepage theory.And according to the non-orthogonal infiltration boundary under rainfall,the treatment method of rainfall infiltration is given.The finite element Galerkin solution of saturated-unsaturated seepage under rainfall condition is deduced by using element method.The seepage field of slope under non-orthogonal infiltration of rainwater is studied by programming TU-2Dseep,and the distribution of pore water pressure in seepage field is analyzed,so the law of rainwater infiltration is obtained.(2)Based on the theory of shear strength of unsaturated soil,the ultimate equilibrium slice method is improved.How pore water pressure affects the weight of soil is dealt with and an improved slice method is established to apply to the stability analysis of saturated-unsaturated soil slope.(3)By The finite element program TU-2Dseep,analyzing the transient seepage field in slope under different rainfall conditions,such as rainfall intensity,rainfall duration,rainfall type,soil condition and initial pore water pressure distribution,and obtaining the corresponding distribution map of transient pore water pressure.Based on the seepage field that is obtained from the transient analysis of slope,the stability of slope is calculated under the above rainfall conditions,so that the transient stability safety factors of slope are obtained under different rainfall conditions.This paper discusses the changing law of seepage field on slope under different rainfall conditions and the influence of seepage field change on slope stability by the program TU-2Dseep,so that to further understand the mechanism and law of unsaturated soil slope instability under rainfall.It is certain theoretical significance and practical value,which can be used for slope stability analysis,landslide disaster prediction and slope control in rainy areas.