地震作用下挡土墙主动土压力及转动位移分析

分析地震引起的挡土墙位移及墙后土压力，对于评估挡土墙可靠性具有重要意义。基于拟动力法，考虑时效、地震波传播的相位差、超载、墙背摩擦角、填土黏聚力以及填土开裂等影响，建立地震作用下挡土墙主动土压力计算模型，获得挡土墙绕墙趾转动模式下主动土压力大小、分布形式及作用点高度。同时，考虑挡土墙本身受地震荷载作用的影响，求出挡土墙绕墙趾的转动位移。通过与Mononobe-Okabe法对比可知，文中获得的主动土压力值与Mononobe-Okabe法接近，但Mononobe-Okabe法低估了主动土压力作用点高度，表明采用Mononobe-Okabe法设计存在风险。通过算例分析了地震系数、墙背摩擦系数、超载大小、时间、填土黏聚力和内摩擦角对挡土墙转动位移的影响。

Analysis of active earth pressure and rotational displacement at retaining wall under seismic loads

It is significant for the reliability assessment of retaining wall to analyze the displacement and earth pressure induced by earthquake. Based on the pseudo dynamic method, a new model is proposed to compute the active earth pressure. The proposed model considers time effects, phase difference of wave spread, overload friction on the back of retaining wall, cohesion and internal frictional angle of backfill soil. Then, the active earth pressure, distribution pattern and height of action point are obtained. Meanwhile, taking the seismic response of retaining wall, the rotational displacement about the toe of retaining wall is determined. Comparison between the Mononobe-Okabe method and present model is carried out. The results show that the active earth pressure obtained by present model is similar to the Mononobe-Okabe method. But the height of action point obtained by Mononobe-Okabe method is lower than present model; this revealed that seismic engineering design by using Mononobe-Okabe method may be led to risk. Finally, the dependence of the rotational displacement of retaining wall on the seismic coefficients, friction on the back of retaining wall, surcharge, time effect, cohesion and internal friction angle of backfill soil are discussed by case studies.