Research On Analysis Method Of Cohesive Earth Pressure Behind Retaining Wall

As a retaining structure,retaining walls are widely used in foundation pits,highways,railways and other projects.The size and distribution of the earth pressure on the retaining walls are clearly defined,which has important engineering significance for the design of safe and economical retaining walls.With the development of geotechnical engineering,the nature of the fill behind the retaining wall is becoming more and more complex,not only the non-cohesive sand,but also the occurrence of many cohesive fills.At present,the research on the objectively existing soil arching effect in soil is limited to non-cohesive soils,and there are few studies in cohesive soils.This is the purpose of this paper.For this reason,this article aims to explore the influence of soil arching effect on the analysis method of cohesive soil earth pressure under active and passive states.(1)First,establish a reasonable earth pressure calculation model for the retaining wall.Through the overall force balance analysis of the sliding the soil wedge behind the wall to obtain the inclination of the active and passive sliding crack surface of the viscous filling behind the rough wall;Then,by analyzing the law of soil stress state change and transmission behind the rough wall,determine the axis shape of the principal stress soil arch,and use the minimum and maximum principal stress soil tracks to describe the main soil elements at any position in the active and passive states.The deflection direction of the stress;at the same time,based on the principle of coordinate translation and mechanical balance,the deflection law of the principal stress direction on the wall-soil contact surface and the slip surface is obtained.(2)Based on the force analysis of the soil arch unit,the advanced theory of dividing the soil layer along the minimum and maximum principal stress trajectory to form a curved thin layer unit is introduced,and the method for determining the geometric parameters of the curved soil arch is improved;then,combined with the wall The principle of the deflection of the principal stress direction at the soil contact surface and the slip surface is given,and the principal stress deflection at any position on the interface of the curved thin layer element is given.At the same time,considering the influence of the soil under the influence of the gravity field,it is assumed that the principal stress follows the soil arch.The direction is linearly distributed;the force model of the curved thin-layer element is established,and the analysis method of the lateral earth pressure under the active and passive limit states of the translational displacement is obtained by analyzing the static balance force.This method reflects the influence of the roughness of the wall back and the properties of the soil(friction angle and cohesion in the soil)on the earth pressure acting on the retaining wall;at the same time,it effectively avoids ignoring the existence of shear stress based on the horizontal layer analysis method.The lack of uniform distribution of vertical stress simplifies the horizontal layer analysis method based on the lateral earth pressure coefficient and vertical stress to solve the lateral earth pressure solution process.(3)By comparing the results of the earth pressure derived by the theoretical method of this paper with the actual measured value and the existing advanced theories,it verifies the rationality and superiority of the theoretical method of this paper.At the same time,in order to qualitatively grasp the influence of various factors such as wall-soil friction angle,soil internal friction angle,and cohesion on the magnitude,distribution,and resultant force,and the height of the resultant force,the control variable method is used to A large number of parameters are analyzed for each influencing factor.