Study On Calculation Method Of The Earth Pressure Under The Influence Of Deformation

The study on the size and distribution of lateral earth pressure on supporting structure is an important subject in soil mechanics research.The classical Coulomb and Rankine earth pressure theory is widely used in the current foundation design because of its clear concept and simple calculation.However,the limit equilibrium theory,represented by the classical earth pressure theory,is derived from the assumption that the rigid retaining wall reaches the ultimate displacement,a large number of studies have shown that the lateral earth pressure on supporting structure is closely related to the deformation of supporting structure,the lateral earth pressure on flexible supporting structure which widely used in foundation pit engineering is nonlinear.Therefore,the limit equilibrium theory has its limitations,this paper analyzed the stress and strain of the soil,and proposed a formula for calculating non-limit earth pressure of supporting structure under the"drum"displacement model.The main results of this paper are as follows:(1)From the analysis of Stress State of Soil under Shear Strength Theory and the summarization of various theories of earth pressure calculation,it is found that the limit equilibrium theory represented by classical earth pressure theory is limited in its application.(2)Combined with unloading and loading stress path triaxial test,the relationship between the value of the friction angle and the displacement of supporting structure is established by improving Mohr Stress Circle which based on Mohr-Coulomb Strength Theory;And then,the"drum"displacement mode of flexible supporting structure is discussed,the formula for calculating the non limit earth pressure with the value of the friction angle as the basic unknown quantity is established by the application of horizontal layer analysis;Clarifying the relationship between displacement,the value of the friction angle and non-limit earth pressure,taking the value of the friction angle as a role of“bridge”,and finally the relationship between the non-limit earth pressure and the displacement is established;Based on indoor earth pressure test,the rationality of the non-limit earth pressure formula is deduced.(3)Based on the non-limit earth pressure calculation formula deduced in this paper,the basic idea of the finite element method of the improved bar supporting structure is described;Taking the situation that the static earth pressure on both sides of the supporting structure as the initial conditions,and using Matlab software to compile the corresponding program for iterative operation can achieve the goal of predicting the deformation of the supporting structure;The results of this paper are compared with the results of the reference,it shows that the deformation of the two is in good agreement,therefore,the feasibility of the non-limit earth pressure calculation formula and the predict method of deformation are both verified.(4)The relevant parameters affecting the deformation of the supporting structure are studied.Contrasting the deformation of the supporting structure under different values of Cohesion c,internal friction angle?,model parameters S_a and S_p,the supporting stiffness EI,the deformation law of supporting structure is discussed respectively.