An Analysis Method Of Earth Pressure Against Retaining Wall Based On Principal Stress Trajectory

The earth pressure of retaining wall is an important basis for the design of retaining wall,also is one of the important topics in the study of soil mechanics.Rankine and Coulomb earth pressure theory has always been the mainstream analysis and calculation method of retaining wall earth pressure,but the Rankine's earth pressure theory can't consider the effect of friction between the wall and soil on the soil pressure.The Coulomb earth pressure theory can consider the influence of the friction between the wall and soil on the earth pressure,but in the analysis process of soil pressure it consider sliding wedge behind wall as a rigid body,ignoring the loose body properties of the backfill behind the wall and influence of the principal stress direction deflection caused by the friction between the wall and soil.At present,a large number of scholars analysis the influence of the friction between the wall and soil on the earth pressure of retaining wall by considering the principal stress direction deflection caused by the friction between the wall and soil.A friction effect between retaining wall and soil is an important factor which must be considered in analysis of earth pressure against retaining wall.Therefore,aiming at the deficiencies of the existing earth pressure theories of retaining wall,firstly,through introducing the concept of principal stress trajectory,this paper deeply and respectively discusses the pattern of principal stress trajectory in soil behind retaining wall under active and passive state and put forward a corresponding method to determine the geometric parameters of principal stress trajectory based on the mechanical mechanism which the friction between retaining wall and soil will inevitably lead to the deflection of principle stress direction in soil behind retaining wall.Afterwards,on this basis,an analysis method of active earth pressure against retaining wall,which back is rough and soil surface is horizontal and subjected to vertical load for uniform distribution,has been put forward by layering along a maximum principal stress trajectory,simultaneously,another analysis method of passive earth pressure has also been proposed by delaminating along a minimum principal stress trajectory,thereby,a new earth pressure theory has been developed which can reasonably reflect the influence of friction between retaining wall and soil on earth pressure.Finally,the rationality and feasibility of the earth pressure theory proposed in this paper have been demonstrated through comparison analysis among the results obtained by the proposed and existing theories of earth pressure,furthermore,several laws about influence of friction between retaining wall and soil on earth pressure have also been revealed,and the comparison analysis still have shown that it is more secure to design retaining wall by the proposed theory than existing theories of earth pressure.