基于双剪统一强度理论的挡土墙土压力计算

Calculation of Earth Pressure of Retaining Wall from the Perspective of Double Shear Unified Strength Theory

在工程实践中采用未考虑中间主应力对强度影响的经典的朗肯土压力理论来对挡土墙进行支护设计时往往存在误差较大的问题。文章基于双剪统一强度理论,将平面应变条件下的强度准则引入挡土墙土压力计算中,推导了基于双剪统一强度理论的挡土墙主动以及被动土压力计算新解。分析结果表明:中间主应力系数b对挡土墙的主动以及被动土压力值均有较大的影响,随着b值的增大,挡土墙主动土压力减小,墙后填土拉张区开裂深度增大,挡土墙被动土压力增大。因此,在工程应用中若能合理地考虑中间主应力对挡土墙土压力的影响,则会产生一定的经济效益。

There is often a large error in the support design of the retaining wall when the classical Rankine earth pressure is used without considering the influence of the intermediate principal stress on the strength in engineering practice. From the perspective of the double shear unified strength theory, this paper introduces the strength criterion under plane strain conditions into the retaining wall. In the calculation of earth pressure, a new calculation solution of active and passive earth pressure of retaining wall based on the double shear unified strength theory is deduced. The analysis shows that the intermediate principal stress coefficient b has a great influence on the active and passive earth pressure values of the retaining wall. With the increase of the b value, the active earth pressure of the retaining wall decreases. And with the increase of the b value, the cracking depth of the backfill tension zone increased. This is because the strength criterion under the plane strain condition is used to analyze the earth pressure, the strength potential of the material can be fully utilized. Therefore, if the influence of the intermediate principal stress on the earth pressure of the retaining wall can be reasonably considered in the engineering application, certain economic benefits will be produced.