Theoretical And Numerical Test Verification Of Earth Pressure On Retaining Wall Under Finite Displacement Condition

With the development of infrastructure,retaining wall,as a common retaining structure,is used in excavation of foundation pit,support of excavated fill area and slope treatment.On the basis of previous studies,this paper establishes the earth pressure calculation method which can consider the displacement of retaining wall.（1）This paper assumes that the problem of earth pressure behind the retaining wall is a plane strain problem,that is,the y-direction strain is 0.The linear elastic theory is used to express the y-direction stress as the x and z-direction stress,and then it is substituted into the generalized Hooke’s law to obtain the consideration under finite displacement The earth pressure calculation formula of the y-direction stress;and the earth pressure and soil strain behind the wall under the limit state condition are obtained according to the Mohr-Coulomb strength theory.（2）Due to the displacement of the retaining wall,the x and y stresses of the soil will change.From the active limit state to the passive limit state,the main principal stress of the soil will be reversed once and the small principal stress will be reversed 1-2 times.When the stress state of the soil behind the retaining wall,the strain behind the wall is divided into the active limit earth pressure strain point,the static earth pressure strain point,the large principal stress reversal point,the small principal stress reversal point and the passive ultimate earth pressure strain point 5Strain points,the earth pressure behind the retaining wall can be divided into 4 zones through these 5 strain points.（3）The modulus of soil in practical engineering is affected by confining pressure,so the tangent modulusof duncan-tensional model is used to modify the above formula.Under the assumption that the influence range of retaining wall is the wall height and the deformation is evenly distributed in this range,the relation between the displacement of retaining wall and the soil strain behind the wall is obtained.When the soil behind the wall is in the active soil pressure state,the condition of wall soil separation under each motion mode is proposed according to the soil pressure behind the wall is 0.（4）In the numerical simulation of discrete element,it is very difficult to obtain the mesoscopic parameters corresponding to the macroscopic mechanical properties of materials.In this paper,the influence of the mesoscopic parameters on the macroscopic properties in the anti-rolling linear bonding model is studied by using the control variable method.It is found that the main influencing factor of the elastic modulusof the material is the contact modulus^*,the secondary factors are the stiffness ratio6)^*and the maximum attractive force₀;The main influence factor of Poisson’s ratioμis the stiffness ratio6)^*,and the secondary influence factors are friction coefficient^*and maximum attraction₀;The main influencing factors of cohesion（8 are friction coefficient^*,maximum attractive force₀,and the secondary factors are stiffness ratio6）^*;The shape of the stress-strain curve is mainly affected by the friction coefficient^*;on this basis,a large number of numerical biaxial compression tests have been performed to obtain the meso-parameters corresponding to the results of the indoor test.（5）The active earth pressure state of the finite displacement soil is the process of the z-stressunchanged and the x-stresscontinuously decreasing during the triaxial test.Whenandare small and large principal stresses respectively,the molar stress circle and resistance The shear strength envelope reaches the active limit state when it is tangent;the passive earth pressure states areand,which are large and small principal stresses,respectively,and the molar stress circle they form reaches the passive limit state when they tangent to the shear strength envelope.In this paper,the discrete element numerical simulation biaxial compression test is used to simulate the earth pressure of the soil behind the retaining wall under the condition of limited displacement by changing the magnitude of the surrounding pressure.The calculation method proposed in this paper is initially verified.The established earth pressure calculation formula under the condition of limited displacement agrees well,which verifies the validity and rationality of the earth pressure calculation formula established under the condition of limited displacement,which can provide a reference for future earth pressure calculation.