Research On The Calculation Method Of Non-ultimate Earth Pressure For Rigid Retaining Walls Based On Soil Arch Effect

The retaining wall is a common retaining structure in engineering,and the calculation of the earth pressure of the retaining wall is the key to the design of the retaining wall.In actual engineering,the earth pressure of the retaining wall will change with the change of the displacement mode of the retaining wall,and the magnitude of the earth pressure is also closely related to the displacement of the retaining wall.In actual engineering,most retaining walls fail to reach the limit state,so it is necessary to study the earth pressure in the non-limit state of the retaining wall.For this reason,based on the previous research results,aiming at the rigid retaining wall with inclined wall back,considering the displacement mode,wall displacement,soil arch effect and horizontal soil shear stress,the non-limit limit under different displacement modes is deduced Theoretical solutions of active and passive earth pressure intensity,resultant force magnitude,and resultant force action point height.The rationality of the formula in this paper is preliminarily verified by comparative analysis with the existing model test results.Finally,using finite element software,a numerical simulation model is established to analyze the plastic strain of the fill behind the wall,to study the failure law of the fill behind the wall under different displacement modes,and to compare and analyze the numerical simulation solution with the theoretical solution in this paper to verify the formula of this paper rationality.The main research contents and conclusions include:(1)Using the soil strength parameters and lateral soil pressure coefficients in the non-limit state,for the retaining wall with an inclined wall back,considering the displacement mode,wall displacement exertion,soil arching effect and shear stress between horizontal soil layers,the introduction The method of numerical iteration adopts the method of horizontal layering to deduce the theoretical solutions of non-limit active and passive earth pressure strength,resultant force magnitude and height of resultant force point under different displacement modes.(2)The intensity distribution of active and passive earth pressure is different under different displacement modes.For the active state in T mode,it is shown as a convex parabolic distribution with a lower center of gravity;for the passive state in T mode,it is shown as a concave parabolic distribution with a lower center of gravity;for the active state in RB mode,it is shown as a triangular distribution;For the passive state in RB mode,the expression form is a convex parabolic distribution with the center of gravity upward(as the displacement ratio increases,the center of gravity moves down);for the active state in RT mode,it is a convex parabolic distribution with the center of gravity downward;for The passive state in RT mode is manifested as a concave parabolic distribution with a lower center of gravity.(3)Under different displacement modes,the distribution of earth pressure intensity is different under the three cases of considering the soil arching effect and shear stress at the same time,without considering the shear stress,and without considering the soil arching effect and shear stress.It can be consistent with the model test value,so it is necessary to consider the soil arching effect and shear stress at the same time.(4)Through the analysis of the corresponding numerical simulation model established by the finite element software,it can be seen that the displacements required for different displacement modes to reach the limit state are different.For a rigid retaining wall with wall height H=3m and clay backfill,in active state,T mode requires 0.13%H,RB mode requires0.4%H,and RT mode requires 0.37%H;for passive state,T mode requires 1%H,3%H in RB mode,and 2.67%H in RT mode;the displacement amount reaching the limit state is generally shown as RB mode>RT mode>T mode.For different displacement modes,the plastic strain development of the backfill of the wall is different.For the active state under the T mode,the shape of the slip surface is a straight line;for the passive state under the T mode,the shape of the slip surface is a straight line;for the RB mode In the active state of,the shape of the sliding surface is a straight line;for the passive state in RB mode,the shape of the sliding surface is a curve;for the active state in RT mode,the shape of the sliding surface is a curve;for the passive state in RT mode,the shape of the sliding surface is The surface shape is a plurality of curves interpenetrating each other.(5)Comparing and analyzing the numerical simulation solution with the theoretical solution in this paper,except for the non-limit active earth pressure strength in RT mode,the distribution trend of the theoretical solution and the numerical simulation solution in this paper are consistent,and can be well matched numerically.