Study On Slope Strain Localization Based On Local Strength Step Reduction

With the development of China's economy,infrastructure projects and other construction projects have also been vigorously developed.The strain localization of soil instability will occur in the construction of slope foundation pit facilities,which directly affects personal safety and property safety.At present,people mainly use the strength reduction method for the research of this problem.This method is simple and practical,and the stress and strain distribution at each point of the slope can be obtained.However,little research has been done on the progressive failure process and related influence parameters in the process of slope strain localization,and the slope engineering is complicated.It is not easy to achieve by simulation alone,and we still need a lot of research.Based on this,this paper studies the strain localization progressive failure process of the slope.The main research contents and conclusions are as follows:(1)Read and collate the literature related to slope engineering at home and abroad,systematically grasp the basic principle of slope strain localization and its research status at home and abroad.The application of finite element strength reduction method in ABAQUS finite element simulation software is briefly described.The advantages and disadvantages of various strength reduction methods and their existing problems are discussed.(2)Based on the idea of progressive failure,a method to reduce local soil strength stepwise for homogeneous slope is proposed.At first,the yield approach index(YAI)is regarded as the evaluation index of the damaged area,and the local breakage areas are assigned to different reduction coefficients according to the damage order.Then,the local slope body is calculated in ABAQUS and the slope progressive deformation is studied until the overall failure takes place.The calculation results show that the internal initial breakage area of the slope is involved in the form process of the potential sliding surface and contributes to the progressive deformation of the slope in the later stage;the leaping problem of the plastic strain value at the boundary of the reduction area on the potential sliding surface is effectively solved,and the progressive failure process of the slope is reasonably reproduced.(3)For the local strength step reduction method proposed in this paper,the related parameters of step reduction are studied.Firstly,the relationship between the YAI and the strength reduction factor k and the damaged area of the slope foot were studied;secondly,the influence of Kc and K? on the strength reduction factor k and location of the slip zone were studied;finally,the influence of mesh size and element type on the local strength step reduction method were studied.(4)Relying on one of the slope project of the Lebai Expressway in Guangxi Zhuang Autonomous Region,the slope was simulated based on the local strength step reduction method,and the whole gradual process of slope failure was obtained.Several slope reinforcement and protection measures commonly used in slope engineering were introduced.After comprehensive consideration,the treatment measures for slopes strengthened by anti-slide piles was selected,and four monitoring points were set on the airside surface of the slope to monitor the slope progressive deformation during the destruction process.By setting anti-slide piles on different feature points of the slope,it is best to set the anti-slide pile on the slope top.