Research And Program Realization Of Sliding Stability Analysis Based On Sarma Method For Transient Saturated Slope

Rainfall infiltration often leads to the occurrence of transient saturated zone within the slope,causing the transient water pressure distribution within the slope,the soil mass and the matrix suction variation,thus affecting the slope stability.The Sarma method is widely used in the stability analysis of slopes because of its few basic assumptions,strict formula derivation and so on.However,the traditional Sarma method does not consider the influence of transient water pressure and the stability of transient saturated slopes can not be well analyzed.In this paper,based on the traditional Sarma method,the improved Sarma method to calculate the influence of transient water pressure and substrate suction is deduced.Then the corresponding slope safety factor calculation program SA is prepared and verified by two examples for correctness of the program is obtained.Finally,the sensitivity of a certain embankment slope is analyzed for the factors affecting the stability of transient saturated slopes.The main research work and conclusions are as follows:(1)Sarma method slope stability saturated transient analysis methods based on improvement.Traditional safety factor introduced Sarma method formulas discussed transient saturated zone and the evolution of transient water pressure distribution;incorporated water pressure transient scale factor,consider the impact of transient matrix suction and water pressure.The formula of Sarma stability safety factor is deduced when the sliding surface is located inside and outside the transient saturated zone.(2)Transient saturated slope stability analysis program implementation and verification.According to the improved Sarma method to solve the safety factor,the calculation program SA was compiled by using FORTRAN language.Then Introduced water pressure,matric suction,soil weight value,stability safety factor calculating program module implementation;combined with homogeneous slope and heterogeneous slope,the correctness of calculation program SA is verified.(3)Analysis of factors affecting the stability of transient saturated slope.Based on a project,analyze of the factors influencing the stability of transient saturated slopes was carried out using the calculation program SA.The results show that:? With the increase of soil mass,the slope safety factor shows a decreasing trend;The slope stability is more sensitive to the shear strength indexes CB/? B ofthe safety factor of slope increases with the increase of the shear strength parameter of the the bottom sliding surface,the increase of bottom sliding surface.?With the increase of transient water pressure,the safety factor of slope shows a decreasing trend;the combination of lateral transient water pressure and water pressure at the bottom of block has a more significant effect on slope safety coefficient;the larger the coefficient of transient water pressure ratio,the greater the adverse impact on slope stability will also be.?As the matrix suction and suction friction angle increase,slope safety factor also increases;when the thickness is greater than the maximum transient saturated zone depth sliding surface slope,the difference coefficients of different security matrix corresponding to suction and suction friction angle are zero;with the increase of the thickness of the transient saturated zone,the influence of the matrix suction and the suction friction angle on the slope safety factor decreases gradually.