Slope Stability Analysis Based On Induced Strength Reduction

The strength reduction method is a typical method for slope stability analysis,the global strength reduction method has a large range of reduction,and the reduction efficiency is not too high.The implementation way of induced reduction is put forward and verified by engineering examples.By using FLAC3D software,the application effects of Druck-Prager and Mohr-Coulomb on global and local strength reduction were studied.The results show that compared with the overall strength reduction,the local strength reduction has the characteristics of reducing the number of calculation iterations and relatively conservative calculation results.There are some differences in the safety coefficient values from the strength reduction of the two strength criteria.Adopt method of the simplified layered saturation,Based on the intensity reduction method,the numerical simulation of slope stability under rainfall conditions was carried out.With the infiltration of rainfall,the safety factor of slope gradually decreases,the overall slope gradually reaches saturation,and the time from the start to the occurrence of slope instability is shortened.Three instability criteria commonly used in strength reduction method are analyzed and compared.The results show that the suitable method is as follows: firstly,the approximate range of the safety factor of slope is obtained by using the non-convergence criterion,and then the safety factor of slope is obtained by combining the dichotomy method and the through criterion of plastic zone.Through laboratory model tests and field tests of rain-induced slope instability,The relationship between slide block displacement and slope Angle is studied and the linear relationship between slide block displacement and slope Angle is obtained.Using the cutting slope of Shenzhen outer ring expressway as the background,the limit equilibrium method,global strength reduction method and local induced strength reduction method were used to study the safety factor Shenzhen outer ring express under saturated and natural working conditions,the results show that the safety factor values obtained by the three calculation methods were basically the same.However,Local induced strength reduction has the advantages of less calculation times.Considering that the slope sliding surface with weak interlayer and broken zone is relatively regular,it is suitable to adopt local induced strength reduction method.