Computational Study On Non-limit Earth Pressure Of Rigid Retaining Wall Under Translational Mode

The results obtained by the classical earth pressure theory are all the earth pressure value in the limit state.In actual engineering,the earth pressure will gradually change with the development of the retaining wall displacement,and the earth pressure is related to the wall displacement.A large number of tests and engineering practice have found that,in general,the displacement of the retaining wall is small and fails to reach the active or passive limit state.Therefore,the earth pressure of most retaining walls in normal operation is between the static earth pressure and the ultimate earth pressure.In the design of retaining wall,if the classical earth pressure theory is still adopted,it may cause unnecessary waste and unsafe engineering accidents.In order to improve the accuracy of retaining wall engineering design,it is very important to study the calculation of earth pressure under the condition of non-ultimate displacement.On the basis of previous researches,the theory of non-limit earth pressure of rigid retaining structure under translational mode is studied in depth by using theoretical analysis method.Based on the shear strength characteristics of unsaturated soil,the soil pressure of active and passive non-limit unsaturated soil is deduced through the horizontal layer analysis method,and the influence law of the physical characteristic parameters of filling soil on the soil pressure is analyzed.Considering the influence of the translational displacement mode of retaining wall and earthquake action,using the horizontal layer analysis method and based on the pseudo-dynamic method calculation model,the calculation formulas of active and passive non-limit seismic earth pressure are derived.The difference between the dip Angle of the most dangerous slip surface in this paper and the existing theoretical solution is compared and analyzed,and the influence law of displacement on seismic earth pressure is discussed and analyzed.The main research contents and conclusions include:(1)Based on the generalized shear strength formula of unsaturated soil,and considering the influence of filling weight change,wall displacement,soil arching effect and shear stress between soil layers,the calculation formulas of active and passive non-limit unsaturated soil pressure under the consideration of wall translational displacement are derived through the force analysis of horizontal layer.(2)The active non-limiting earth pressure decreases with the increase of matric suction.The passive non-limit earth pressure increases with the increase of matric suction.When the wall height is about 0?0.6H,the distribution of active non-limit earth pressure without considering the effect of interlayer shear stress is larger than that without considering the effect of interlayer shear stress,and the distribution of active non-limit earth pressure is opposite for the lower part with the wall height of 0.6H.The distribution of passive non-limit earth pressure without considering the influence of intersoil shear stress is smaller than that with considering the influence of intersoil shear stress in the range of 0?0.6H of wall height,while the lower part of the wall height of 0.6H is larger than that with considering the influence of intersoil shear stress.The distribution of active and passive non-limiting earth pressure of non-cohesive soil is larger than that of cohesive soil,while the distribution of passive non-limiting earth pressure of non-cohesive soil is smaller than that of cohesive soil.(3)Based on the basic assumption of the pseudo-dynamic method,considering the time and phase changes,a more accurate calculation method for calculating the dip Angle of the most dangerous sliding surface was obtained by using the horizontal layer analysis method,and the formulas for calculating the active and passive non-limiting earth pressure distribution under earthquake action were deduced.(4)With the increase of the internal friction Angle,the dip Angle of the most dangerous slip surface of active non-limit seismic earth pressure increases,and the variation range is large.The dip Angle of the most dangerous slip surface of passive non-limit seismic earth pressure decreases with the increase of the internal friction Angle.The shape of seismic earth pressure distribution curve does not change with the change of displacement ratio of retaining wall.With the increase of wall height,the active non-limit seismic earth pressure on retaining wall increases gradually,and then decreases gradually after reaching the peak value.The distribution of earth pressure is nonlinear.With the increase of the wall height,the passive non-limit seismic earth pressure on the retaining wall decreases gradually,and the earth pressure also presents the characteristics of nonlinear distribution.