The Derivation Of The Loess Soil Pressure Caiculation Formula Under The Condition Of Surface Inclination Behind The Wall And Its Evaluation

The tensile strength of structural loess is significant,it will inevitably affect the precise calculation of earth pressure,and the backfill surface has a certain angle in actual working condition,the existence of the angle and its size can seriously affect the study and calculation of the earth pressure of the barricade.Therefore,it is necessary to consider the tensile strength of the structural loess and the condition of backfill surface inclination,use the reasonable theoretical calculation method to carry on the effective evaluation when calculating the earth pressure of the barricade.In this paper,in order to establish the calculation formula of earth pressure of the loess under the condition of backfill surface inclination,it is based on the advantages and wide applicabilities of joint strength theory to calculate earth pressure,while considering the influence caused by the backfill surface angle on the earth pressure calculation,then the active and passive ultimate stress balance analysis is carried out,finally the calculation formulas of active earth pressure and passive earth pressure of structural loess under the condition of backfill surface inclination based on the joint strength theory are deduced,then examples are introduced,the calculation formulas of earth pressure and Rankine’s earth pressure calculation formula under the condition of backfill surface inclination are compared and analyzed deeply.The main conclusions are as follows:(1)Under the condition of backfill surface inclination,the cracking depth of tension zone of backfill calculated by the joint strength theory is smaller than the cracking depth of tension zone of backfill based on Rankine’s active earth pressure calculation formula;With the increase of the cohesion and tensile strength of the soil,the cracking depth difference is larger.(2)Under the condition of backfill surface inclination,the loess active earth pressure based on the joint strength theory is larger than the Rankine’s active earth pressure,the loess passive earth pressure based on the joint strength theory is less than the Rankine’s passive earth pressure;With the increase of the backfill depth,the difference between the loess active(passive)earth pressure based on the joint strength theory and the Rankine’s active(passive)earth pressure under the condition of backfill surface inclination is smaller.(3)Under the condition of backfill surface inclination,with the increase of the cohesion and tensile strength of the soil,the difference between the active(passive)earth pressure of loess based on the joint strength theory and the Rankine’s active(passive)earth pressure is larger.(4)The active earth pressure of loess is the smallest when the backfill surface is flat(If the backfill surface angle is ignored,the active earth pressure would be relatively small,which makes the engineering calculation unsafe),and with the increase of the angle,the active earth pressure of loess is larger.And the cracking depth of tension zone of backfill is not related to the size of backfill surface angle.