任意柔性挡墙变位诱发地表沉降的解析理论预测

Analytical theory of ground settlement induced by movement of flexible retaining wall

将任意挡墙水平变位模式分解为抛物线柔性模式和梯形刚性模式,并通过求解平面应变方程,得到挡墙在抛物线柔性变位模式下的理论解,给出地表土体的沉降曲线,分析土体沉降规律,同时将理论解应用于工程案例分析,通过与4个基坑开挖实例沉降归一化曲线的对比,分析解的适用性。结果显示,当挡墙发生抛物线变位模式时,地表沉降整体规律为向下凹槽型,最大沉降发生在距离墙背一定距离处,与实际情况相符。理论解形式表明,最终的表达式与弹性参量无关;归一化的沉降曲线显示,理论预测的最大沉降位置与实测值接近,且土体沉降模式与实测结果一致,说明理论解是合理的。

This paper divides the wall deformation into two parts, the parabolic flexible part and the trapezoidal rigid part. By solving the two-dimensional partial differential equations of plane strain, the basic solution of parabolic boundary problem is obtained. The settlement curves are given to show the characteristic of ground settlement. The theoretical solution is used to analyze the problem in practical engineering. The applicability of this theoretical solution is analyzed by qualitative comparing with the normalized settlement curves of four foundation pit excavation cases. The parabolic deformation of wall will cause concave-type settlement profile, in which maximum surface settlement occurs at a distance away from the wall back. The theoretical prediction indicates that the ground settlement is independent of the soil elastic properties; and the location of largest surface settlement is close to the measured data, as well as the pattern of soil settlement, which indicates that the theoretical solution is reasonable.