基于朗肯土压力分析原理和拟静力方法,对地震条件下挡土墙后无限倾斜黏性填土进行受力分析,选取菱形的微小单元体为研究对象,采用应力莫尔圆图解法对微小单元体进行应力状态分析,在此基础上推导出倾斜填土条件下黏性土地震主动土压力计算公式,分析外摩擦角、水平地震系数、竖向地震系数、内摩擦角、黏聚力对地震主动土压力系数的影响规律。算例结果表明:经典朗肯土压力公式和倾斜填土面黏性土朗肯主动土压力公式只是本文公式的特殊情况;该公式不仅适用于地震条件还适用于静力条件,和现有几种计算地震主动土压力方法进行了对比分析;本文公式和现有几种方法计算结果相差较小,其最大差值不超过8%;在地震作用下外摩擦角取值大小对地震主动土压力系数影响不大。
The diamond shaped element is selected to represent the mechanical characteristics of inclined backfill. A formulation of earth pressure of cohesive soil backfill slope considering seismic action was proposed based on the Rankine earth pressure theory and the Mohr-Coulomb yield criterion. The effects of external friction angle, horizontal and vertical seismic coefficients, values of cohesion and internal friction angles of soil were studied. The results show that the formula of classic Rankine active earth pressure and Rankine active earth pressure of cohesive soil backfill slope are the special cases of the proposed method. A special case was analyzed to verify the proposed formula, and the result is approximately equal to that obtained by the earlier researchers. The maximum errors in different calculation methods do not exceed 8%. The external friction angle has little effect on the seismic active earth pressure coefficient.