Application And Development Of Finite Element Limit Equilibrium Method Program For Soil Structure Stability Analysis

As a serious geological disaster,landslides will cause a large number of casualties and huge property losses.Therefore,slope stability analysis is very important for the design of geotechnical structures and landslide disaster prevention.Some scholars believe that the problem of earth pressure and foundation bearing capacity can also be analyzed by the theory of slope stability analysis.At present,most of the slope stability analysis methods in engineering applications have some deficiencies.For example,the rigid body limit equilibrium method requires certain assumptions to be solved;the limit analysis method calculation process is more complicated;the finite element strength reduction method may exist in some cases Problems that violate the nature of the material.However,the finite element limit equilibrium method can avoid the above problems,and the theory of this method can achieve good results in the stability analysis of soil structures under any working conditions.Based on previous studies,this paper introduced the theory of the finite element limit equilibrium method in detail,and develops a calculation program.Using the program to analyze the three classic problems of soil science and compare them with the results obtained by traditional theory to prove the reliability of the program.The main work are as follows:(1)The relationship between the limit equilibrium state of a point in the soil and the limit equilibrium state of the soil along the sliding surface is discussed.On this basis,the safety factors of the soil along the whole and local sliding surfaces are defined,and use them as the evaluation criteria for the overall and local stability of the soil.(2)The particle swarm algorithm and Hooke-Jeeves search method are used to search for the critical sliding surface,which improved the local and global search capabilities.The search for the local damage area is achieved by generating some local small sliding surfaces.The program was developed in Python language.(3)In this paper,the program developed based on the finite element limit equilibrium method is compared with the results obtained in the slope stability analysis by traditional theoretical methods.The distribution of the shear stress and shear strength of the soil on the critical sliding surface calculated by the finite element limit equilibrium method is satisfied with the actual feature,its position and safety factor are consistent with results of the Ordinary method,simplified Bishop method,and finite element strength reduction method.The results obtained by the reduction method are not much different.In the analysis of the earth pressure problem,the local failure and the critical sliding surface obtained by the finite element limit equilibrium method conform to Rankine earth pressure theory.In the analysis of the bearing capacity of the foundation,the progressive failure of the foundation is obtained by gradually increasing the foundation load.The limit load obtained by the finite element limit equilibrium method is similar to the result calculated by the Prandtl theory.