Research On Characteristics Of Seepage And Stability In Crack Bank Slope Under Rainfall

Rainfall is one of the main cause of slope failures,according to the statistics slope instability is often appeared in crack bank slope under rainfall,it shows that the slope instability have close relationship with rainfall infiltration and crack,to analysis evolution rules on seepage field and stability in crack bank slope has important theoretical and realistic significance for preventing and controlling slope failures.Based on the saturated permeability coefficient and soil water characteristic curve by the determination test of soil permeability parameter,this paper establishes numerical model of natural crack bank slope,expounding the theory of saturated-unsaturated seepage and rainfall infiltration,the seepage field in crack bank slope is calculated under rainfall,and analysis the evolution rules of transient saturated zone and infiltration affected zone,slope stability is also studied by using limit equilibrium method.The rainfall pattern,crack position,crack angle and crack depth influencing on seepage field and slope stability characteristics is studied mainly,the main research content is as follows.(1)The introduction of calculation method of saturated-unsaturated seepage.Based on the Darcy’s law and energy conservation law,the derivation process and definite condition of saturated-unsaturated seepage control equation is deduced,at the same time,this paper expounds the basic theory of soil water characteristic curve and slope rainfall infiltration.(2)The test research on soil permeability parameters.Saturated permeability coefficient and soil water characteristic curve have very important influence on the characteristic of slope seepage stability under rainfall,this paper get value of saturated permeability coefficient by variable water head permeability test,and use the centrifuge method to obtain soil water characteristic curve.The soil infiltration parameters are confirmed accurately by these tests.(3)The theoretical illustration of saturated-unsaturated seepage and analysis of slope seepage evolution under rainfall.This paper calculates the crack bank slope transient seepage field in different rainfall pattern,crack position,crack angle and crack depth by using SEEP/W module of GeoStudio software,and studies the influence on bank slope transient saturated zone in different rainfall pattern,crack position,crack angle and infiltration area in different crack depth,these conclusions have important significance on analysis of crack bank slope stability under rainfall.(4)The theoretical illustration of analysis method of slope stability and the calculation analysis of bank slope stability.Based on the seepage field obtained by seepage analysis,studies the crack bank slope stability under rainfall,including analysis of influence on seepage field and slope stability characteristics in different rainfall pattern,crack position,crack angle and crack depth,these conclusions have reference significance on similar crack slope stability prediction.