竖向稳定渗流条件下的地震主动土压力分析

基于库仑土压力理论的基本假定和拟动力法的分析思路，以无黏性填土的刚性挡土墙为研究对象，考虑填土中存在竖向稳定渗流的两种工况，推导了地震主动土压力和修正土压力系数的计算表达式。通过程序求解问题并进行参数讨论，分析结果表明，主动土压力随水平地震加速度的增大而明显增大，竖向地震加速度对土压力影响较小，可以忽略不计。墙土摩擦角较小时，土压力随填土摩擦角的增大而单调减小，但当墙土摩擦角增大后，土压力随填土摩擦角的增大出现先减小后增大的情况。渗流方向向下时，土压力随水力梯度的增大而减小；渗流方向向上时，变化规律则相反。与已有的理论方法对比，计算结果基本吻合，验证了该理论方法的正确性。

Analysis of seismic active earth pressure under vertical steady seepage

The calculation expressions of seismic active earth pressure and modified earth pressure coefficient are derived based on the basic hypothesis of Coulomb’s earth pressure theory and a pseudo dynamic method. The formulas focus on a rigid retaining wall with cohesionless backfill and consider two kinds of conditions with vertical steady seepage. After the problem is solved by computer programs and parametric discussion is taken, the results indicate that the active earth pressure increases significantly with the increase of horizontal seismic acceleration; the effect of vertical seismic acceleration on earth pressure is relatively small, which can be ignored. The earth pressure decreases monotonously with the increase of soil friction angle when soil-wall friction angle is small; however, increasing soil friction angle makes the earth pressure initially decrease and then increase as soil-wall friction angle becomes larger. The seepage effect is also investigated, it is shown that the active earth pressure decreases with the increase of hydraulic gradient for downward seepage case, but increases for upward seepage case instead. Through comparison, the calculation results agree well with the existing methods so as to verify the validity of the proposed method.