地震作用下挡土墙抗滑动稳定性的拟动力分析

Pseudo-dynamic analysis of retaining wall sliding stability under seismic action

鉴于重力式挡土墙作为一种常用的支护结构,其滑动稳定性分析是抗震设计的重要内容,然而其理论研究却并不完善,基于前人的理论成果,采用拟动力法,对地震作用下挡土墙的抗滑动稳定安全系数进行推导计算。通过算例对比,分析讨论地震放大系数,地震加速度影响系数,填土内摩擦角,墙土外摩擦角,墙背面倾角,填土面倾角对抗滑动稳定性的影响。研究结果表明:挡土墙的抗滑动稳定性随着填土内摩擦角、墙土间外摩擦角和墙背面倾角的增大而不同程度地增大,随着地震放大系数、地震加速度影响系数和填土面倾角的增大而减小。此结论与采用Mononobe-Okade方法所得结论一致,但是,拟动力法考虑土体和挡土墙的动力学性质影响,与真实情况更符合,有利于从力学机理上深入分析。

The sliding stability analysis of gravity retaining wall, as a kind of widely used supporting structure, plays an important role in seismic design, but the theoretical research isn＇t mature yet. Based on predecessors＇ research achievements, the stability safe factor of retaining wall against sliding under seismic action was derived and calculated with pseudo-dynamic method. Through case comparison,the influences of parameters such as seismic amplification factor, seismic acceleration coefficients, soil friction angle and wall friction angle, wall inclination angle, backfill inclination angle on sliding stability were evaluated and discussed. The results indicate that the sliding stability of retaining wall increases in varying degrees with the increase of soil friction angle and wall friction angle, wall inclination angle, and decreases with the increase of seismic amplification factor, seismic acceleration coefficients and backfill inclination angle. The conclusion corresponds to those obtained by Mononobe-Okade method, but pseudo-dynamic method considers the dynamic properties of backfill and retaining wall, which is more in line with the real situation and conducive to deep mechanical mechanism analysis.