Slope Stability Analysis Of Carbonaceous Shale With Soft Interlayer Under Rainfall Conditions

In the process of infrastructure construction in mountainous areas,the problem of slope landslides is often encountered,and the destruction of structures and even casualties and major economic losses are caused.Therefore,it is necessary to study the instability mechanism of the slope.Theoretical analysis and numerical simulation are used to study the slope stability of carbonaceous shale with soft intercalation under rainfall conditions,which has certain theoretical and engineering significance.The main contents of this study are as follows:(1)The basic mechanical parameters of carbonaceous shale were obtained through geotechnical experiments,and the experimental data were processed by mathematical methods to obtain the effective mechanical parameters of carbonaceous shale.(2)Using the method of orthogonal test,the influence of four different parameters of soft and soft sandwich on the stability of carbonaceous shale was studied,three levels were set for each parameter,namely the quadrature test of nine test groups of 4 factors and 3 levels,and the numerical simulation analysis was carried out under each set of parameters with Geo-studio software to obtain the safety factor and displacement value at the respective parameter level,and then the sensitivity of each factor was analyzed by the extreme difference analysis method.(3)The finite element software Geo-studio is used to simulate the slope stability,and 8 feature points and two feature sections are set up,and the permeability change law of feature points and feature sections under four different rainfall conditions is studied.It is concluded that the greater the intensity of rainfall,the longer the rainfall time,the greater the impact of the slope seepage field,and in the position of the weak interlayer near the surface of the slope,due to the relatively large amount of water,the depth of the impact of rainfall is relatively large,and the soil in the vicinity is the first to reach saturation.(4)The role of rainfall will make the safety factor of the slope have a more obvious decrease,especially the rock mass with the presence of soft interlayers,with the infiltration of rainfall,the shear strength of the slope will decrease,and it is likely to make the slope slide along the soft interlayer.Through the comparative analysis of the slope stability safety factor and displacement change before and after the use of prestressed anchor cable+slope hanging net sprayed concrete reinforcement,it is concluded that this reinforcement measure can effectively improve the stability of the slope.