Calculation Method Of Earth Pressure Against Gravity Retaining Wall-Back Subject To Superimposed Load

Gravity retaining wall is economical,easy to construct and widely used in highway engineering,railway engineering,water project,harbor engineering and mine engineering.With the development of society,to make full use of land resources,the position relationships between existing retaining wall and the various human engineering activities,structures and traffic systems are becoming more and more dense and therefore the adjacent superimposed load will affect the stability of retaining wall directly.However,the design,construction and operation of gravity retaining wall either seldom takes the effect of superimposed load into account or just considers the various distribution forms of superimposed load as infinite uniform distributed load.To make the design of gravity retaining wall more economical and safer,the study with regard to the influence of superimposed load on earth pressure against wall-back is carried out.Based on the Rankine's earth pressure theory and the Coulomb's earth pressure theory,by establishing the theoretical mechanical model and numerical analysis model of earth pressure against gravity retaining wall-back subject to superimposed load,the influences of superimposed load on the related parameters of earth pressure are analyzed.The main works and conclusions are listed as follow:(1)Based on the Coulomb's earth pressure theory,the equivalent-moment analysis method of earth pressure with the effect of general distributed strip superimposed load(that is the cross section of strip superimposed load can be arbitrary shape and there can be any number of strip superimposed load)is provided.This approach is applicable to the general earth pressure model of sloping backfill surface and inclined wall-back.Besides,the corresponding formulas of critical wedge failure angle,earth pressure and action position of earth pressure thrust under active and passive critical states are derived.In addition,the comparisons of calculation results among Coulomb's earth pressure theory,the standard recommendation method,other earth pressure models and this paper' s work are made.The results show that strip superimposed load has a significant effect on earth pressure and action position of earth pressure thrust,and different load parameters(namely the width of load,the intensity of load and the distance between load and wall)have different influence degree.(2)Based on the Rankine's earth pressure theory and elastic theory,a earth pressure model including the effect of shear stress produced by strip superimposed load is established to analyze the distribution of earth pressure against retaining wall-back under the state of limit equilibrium.Besides the corresponding formulas of active earth pressure,passive earth pressure and earth pressure at-rest are derived.Moreover,the comparison of calculation results among this paper' s work,Rankine's earth pressure theory and the standard recommendation method are also made.The results show that the strip superimposed load has a obvious local effect on the distribution of earth pressure.(3)Taking the design scheme of gravity retaining wall in actual potential slope control project as an analysis case,considering the effect of adjacent plant on the stability of retaining wall,the numerical earth pressure model subject to superimposed load is established,and the comparisons with theoretical analysis result mentioned above are also made.