砂土地层中考虑基坑施工效应的柔性挡墙主动土压力研究

以基坑施工过程中柔性挡墙墙后主动土压力为研究对象，假定柔性围护结构最大变形位于开挖面处，墙后滑面为通过墙趾的平面，推导出考虑基坑开挖及支护的墙后滑面倾角一般表达式。采用水平层析法，研究墙体内凸型变形时的主动土压力分布、主动土压力合力及其作用点。研究表明，理论结果与实测结果规律一致，大小相近；随着基坑开挖深度的增加，滑面倾角减小，基坑开挖对周边环境的影响范围增大，土压力合力增大，对合力作用点位置的影响较小；当基坑开挖深度减小时土体内摩擦角和墙土间摩擦角增大时主动土压力非线性分布更加明显，主动土压力合力减小，合力作用点距墙趾的距离增大。

Research on active earth pressure of flexible retaining wall considering construction effect of foundation pit in sandy soil

The active earth pressure acting on the flexible retaining wall during excavation of foundation pit is analyzed. The retaining wall is assumed to deflect as bulge shape that the maximum displacement is located at the excavation surface. The slip surface is assumed as a plane through the wall toe. A general slip surface angle is deduced by considering excavation depth and support of foundation pit. The active earth pressure distribution, lateral soil force and its application are obtained based on the horizontal thin layer analysis method. The results show that the theoretical results are consistent with the measured results. As the excavation depth increased, the angle of the slip surface decreased; the influence scope and the active earth pressure are enlarged; the influence on the position of resultant force is small. When the excavation depth decreases, the soil friction angle and soil wall friction angle increase, the nonlinear distribution of active earth pressure becomes more obvious; the resultant force decreases; and the distance between the application point of resultant force and the wall toe increases.