Stability Analysis And Research Of Loess Slope In Northern Shaanxi Based On Numerical Simulation Method

There are a lot of heavy rains in northern Shaanxi and landslides are more frequent.Rainfall is one of the main reasons for the frequent landslides in the Loess Plateau.Therefore,it is of great theoretical value and practical significance to study the influence of water on the stability of loess slope in northern Shaanxi.At present,the limit equilibrium method and numerical analysis method are the main methods for slope stability analysis,while the traditional finite element strength reduction method is used for numerical analysis of slope stability,and the same reduction coefficient is used to reduce the shear strength parameters of rock and soil at the same degree synchronously.However,according to a large number of scholars relevant experiment results show that as the soil water content increasing,the shear strength parameters of the speed and degree of attenuation is not the same,so,the traditional strength subtraction to analyze the stability of the slope,slope and shear strength parameters of rock and soil mass attenuation relationship is not consistent with the actual,the internal friction Angle and cohesion should be reduced by introducing different reduction coefficients,that is,double coefficient strength reduction method should be developed.Reduction path is one of the important parts of double coefficient strength reduction theory.Because the history of stress path formed by soil in different areas is not quite the same,the reduction path of slope in different areas should be different when using double coefficient strength reduction method for numerical analysis.Based on the ABAQUS software platform,this paper conducts in-depth analysis on the supporting reduction mechanism of loess shear strength parameters in northern Shaanxi,and then puts forward the applicable double-coefficient strength reduction method for loess slope stability analysis in northern Shaanxi.The main research results are as follows:（1）By fitting the experimental data of shear strength of loess in northern Shaanxi with the increase of water content,the corresponding reduction relation between internal friction Angle and cohesion is obtained,and the definition of comprehensive safety factor is put forward.（2）The stability coefficients obtained by the three slope failure criteria in the double-coefficient strength reduction method are analyzed.The results show that the stability coefficients obtained by calculating the non-convergence criterion are too large,and the results obtained by the characteristic point displacement mutation criterion and the plastic strain zone transfixion criterion should be considered comprehensively.（3）Based on the grey correlation degree method and double coefficient strength reduction method,the sensitivity of rock mass bulk density γ and constitutive parameters E,μ,φ,c are analyzed,and the sensitivity of the influencing factors are φ,c,γ,E,μ respectively.（4）The double-coefficient strength reduction method is used to analyze the stability of the heterogeneous loess slope in northern Shaanxi,and the results are compared with the results of M-P method and traditional strength reduction method.It is found that both m-P method and traditional strength reduction method can evaluate the stability of the heterogeneous loess slope in northern Shaanxi.（5）Through the analysis of a landslide in Bata district,Yan ’an city,the study shows that the stability coefficients obtained by the double-coefficient strength reduction method are smaller than those obtained by the M-P method,but they are all within the engineering error range,which further verifies the rationality of the double-coefficient strength reduction method.