Study On Slope Stability Based On Finite Element Strength Double Reduction Method

The disasters caused by slope instability belong to one of the three major disasters in the world,and the stability analysis and safety evaluation of slopes are of great significance for safeguarding people’s lives and property.However,the traditional strength reduction method usually adjusts the shear strength parameters according to a certain proportion,and the shear strength coefficient remains unchanged.However,many studies have shown that in the actual process of slope instability,the stage and proportion of soil cohesion and internal friction angle to play the role of shear resistance are different.The process of the two in the slope from stable state to unstable state is not a simple proportional degradation process,that is,the assumption process of the traditional strength reduction method is not consistent with the actual situation.Based on this,in order to make the strength reduction method more practical,this paper introduces the strength double reduction method of unequal proportion reduction on the basis of the traditional strength reduction method,that is,in the process of reducing the shear strength parameters of slopes,the reduced correlation coefficient is changed to reflect the different deterioration mechanisms of different slopes in the process of instability,and the main influencing factors are discussed in depth.This article uses ABAQUS software to study the theory and method of the strength double reduction coefficient method,and analyzes the stability of Tongjiaping slope and excavation based on this theory.The main content is as follows:(1)A detailed introduction is given to the analysis methods for slope stability,with a focus on the current research status of the finite element strength double reduction method for slope stability analysis.The reduction of model parameters and the determination process of the relationship between the double reduction coefficients are described in detail,and a method for determining the comprehensive safety factor of slopes using the double reduction coefficients is explored.This study compared the four criteria for slope instability and found that the difference in the results of determining the safety factor for homogeneous slopes was not significant,but not every criterion could be applied to all slope models.In this study,it is considered that in the finite element stability analysis of heterogeneous slopes,in addition to using the instability criteria of finite Metacomputing,it is also necessary to comprehensively evaluate the safety coefficient by combining the penetration criteria of plastic zone,the displacement catastrophe criteria of characteristic points,and the energy catastrophe criteria.(2)This study carries out fitting analysis on the value of shear strength parameters in the critical state of slope,explores a relationship curve of shear strength parameters in the critical state of slope,that is,the exponential function correlation curve of e,and verifies the curve.It is found that the error of shear strength parameters determined by this curve is very small,which can well reflect the relationship of critical shear strength parameters,Based on this curve,a strength double reduction safety factor analysis was conducted on the example slope model,and it was calculated that this reduction model can better reflect the safety factor of the slope,which has high practicality.(3)Based on the proposed finite element strength double reduction model,through in-depth exploration,explore the elastic modulus E and Poisson’s ratio ν、 Soil weight γ、Shear strength parameter index c and φ Sensitivity of the impact on the comprehensive safety factor of the slope.Based on the double strength reduction method and the method of determining the weighted comprehensive safety factor with unfixed values,this study conducted a sensitivity study on the following factors related to the reduction.The study found that the soil moisture content and shear strength parameters have a large impact on the comprehensive safety factor of the slope.This method can effectively evaluate the stability of a variety of soil slopes,and compare with the results of the comprehensive safety factor of the slope determined by other methods.(4)This study is based on the strength double reduction theory and uses ABAQUS software to analyze the stability of Tongjiaping heterogeneous slope.The finite element strength double reduction method and single factor reduction method are used to analyze the safety of heterogeneous slope,and the safety factor of complex heterogeneous slope is calculated.At the same time,groundwater conditions are introduced to explore their impact on the comprehensive safety factor of heterogeneous slope,Research has found that the double reduction method of slope strength can be better combined with practical engineering.The Tongjiaping slope is in a stable state under normal working conditions,but the rapid increase in soil moisture content during the water storage period leads to a rapid decrease in the comprehensive safety coefficient of the slope.(5)Exploring the impact of slope excavation on slope safety,simulating actual excavation projects,and studying the appropriate excavation plan for Tongjiaping slope based on the strength double reduction theory.The study found that secondary excavation should be used for Tongjiaping slope to reduce the possibility of Tongjiaping landslide during the water storage period.