Stability Analysis And Evaluation Of Highway Slope In Mountainous Area Under Rainfall Inifltration

Landslide is a universal phenomenon of highway soil slope in rainy season，undernormal circumstances，the slope is stable，but with the rainfall time and water infiltration，landslide may have occurred during the rainy season．Investigation shows that，the vast majorityof slope instability occurs in the rainfall or after rainfall，this shows that the influence of rainfallinfiltration on slope stability has important significance．Whether the slope instability，orlandslide， may cause a great loss to the economic development and people’s life andproperty．Therefore，the study of slope stability has been one of the focuses concerned by expertsand scholars．This paper is aimed at the existing problems of slope stability in the current research．First，the typical climate environment and the geological conditions of Fujian province was combinedto make a study of the highway soil slope of mountain area．The instability mechanism andrelevance of influence factors of unsaturated residual soil slope under rainfall infiltration wasstudied by experiment and theoretical analysis；Then，confirm the main factors affecting slopestability and its correlation by sensitivity analysis；finally，establish evaluation model of soilslope stability by applying numerical simulation method．Provide a theoretical reference forimproving the soil slope stability analysis and doing further research on the same orsimilar．Provide a theoretical reference for timely and effective landslide prevention andreinforcement design of highway residual soil slope in Fujian area．The main research contentsand results are as follows：The instability mechanism of homogeneous unsaturated residual soil slope under rainfallinfiltration was deeply analyzed；The control equation of unsaturated soils in two-dimensionalseepage was derived，and given the boundary conditions；The main influence factors of slopestability have been systematic analyzed from two aspects of internal and external；According to the triaxial test of unsaturated residual soil in Fujian area，in the case ofdifferent water content and confining pressure，the shear strength variation was determined：withthe increase of water content conditions，the shear strength of soil decreases，the shear strength parameters of cohesion was decreases，while the change of internal friction angle didn’tsignificantly．Under certain conditions of water content，with the increase of confining pressure，the shear strength gradually increase，axial strain increasing before the test failure，stress-straincurves were hardened；When the confining pressure under certain conditions，with the watercontent increasing，the peak intensity decrease；Utilizing the distance analysis method to optimize the grey correlation analysis，the greycorrelation degree analysis was improved to make sensitivity evaluation of the residual soil slopeinstability influence factors under rainfall infiltration．By comparing and sorting the weight ofthe influence factors，getting the correlation order of factors:c’＞φ’＞L＞R＞H＞β＞γ＞k_s；The weight of the effective cohesion and effective internal friction angle were18.41%and16.28%．Using ABAQUS finite element software to establish slope seepage analysis model，anglicizing the rainfall intensity and rainfall duration affected on residual soil slope displacementand pore water pressure changes through emulation；using the FEM strength reduction method tocalculated the residual soil slope safety factor under the condition of rainfall；According to theinfluence factors of slope stability，on the basis of the basic model，calculating the safety factorof the slope under different conditions，anglicizing the influence rule of different influencefactors on the slope safety factor，and evaluating the stability；When the rainfall intensity is morethan100mm/d，rainfall duration is more than72h，the slope is unstable；when the slope angle ismore than60，or slope height is more than30m，slope instability may occur．...