Numerical Simulation Of Evolution Of Shear Band In Partial Soil

The instability of earth structure do great damage to humans life and property safety.Assuming the slip surface of soil in advance,traditional stability analysis method suppose that all the points on the sliding surface reach the limit equilibrium state at the same time.This is not in accordance with the fact.The practice of engineering shows that the failure of earth structures is the process of initiating of shear band caused by a point of failure and propagating to penetrate through the whole soil structure.Research shows that the initiation of shear band in earth structure is warning signs of losing stability and the failure process of earth structure is the process of generating and evolution of shear band.In order to simulate the propagation process of shear band in soil,basing on extended finite element method and limit equilibrium theory,a new criterion for shear band propagation in soil is proposed which considering the redistribution of stress and the mechanism of shear band.This criterion is employed to simulate the failure process of shear band in soli slop,foundation,retaining wall and soil specimen in plane strain conditions.Numerical examples show:(1)The present criterion,which reflecting the mechanism of shear bands,can effectively simulate the failure processes of earth structures and this method can avoid the mesh dependence.This criterion does not require the introduction of a weak element to induce the initiating of shear band,which is used to capture the position of the initial shear band.(2)The process of propagating of shear band with extended finite element method for shear band propagating does not need remeshing.The results calculated with different meshing densities are the same,which shows that the extended finite element method is less sensitive to mesh.(3)The shear band of ideal soil specimen in plane strain conditions is generated from the center position,and extends to the boundary.Slip face in soli slope calculated by considering the process of shear band propagating is different from calculated by the traditional analysis method,and the former are in accordance with the actual accident situation.(4)There is an uploading process in small local area near shear band,and the process is accompanied by the release of energy.