地震作用下挡土墙抗倾覆稳定安全系数研究

基于拟动力法，考虑墙背面和填土面倾斜的工况，推导出挡土墙在地震作用下的抗倾覆稳定安全系数的计算表达式。数值算例结果表明，稳定安全系数随着填土内摩擦角、墙土外摩擦角和墙背面倾角的增大而增大，随地震放大系数、水平加速度影响系数和填土面倾角的增大而减小。其中，只有在地震作用较大时，放大系数的影响才逐渐显现，同时，摩擦角的影响却相对减弱；墙背面倾角和填土面倾角不同时，稳定系数随地震作用的变化趋势基本一致。通过对比2种计算方法的结果可知，拟动力法由于考虑了地震周期和地震波效应的影响，计算得到的稳定安全系数比拟静力法大。

STUDY OF OVERTURNING STABILITY SAFETY FACTOR OF RETAINING WALL UNDER SEISMIC ACTION

Based on pseudo-dynamic method，a formula of stability safety factor of retaining wall against overturning under seismic action is derived，considering the inclination conditions of retaining wall back and backfill soil. Numerical results indicate that the stability safety factor increases with the increase of soil friction angle，wall friction angle and wall inclination angle；but it decreases with the increase of seismic amplification factor，horizontal seismic acceleration coefficient and backfill inclination angle. Thereinto，only under violent earthquake action，the seismic amplification effect can emerge gradually；at the same time，the influences of friction angles on the stability relatively weaken instead. The various trends of stability safety factors with seismic actions are in basic agreement under different wall inclination angles and backfill inclination angles. Comparing the calculating results by two methods，the overturning stability safety factor by pseudo-dynamic method considering the effects of earthquake period and seismic waves into account，is larger than that by pseudo-static method.