基坑挡墙变位诱发地表沉陷的模型试验研究

针对刚性挡墙不同变位模式，对基坑开挖过程中地表沉陷规律进行模型试验研究。开展的模型试验分别模拟了挡墙在平移（T模式）、绕墙趾转动（RB模式）和绕墙顶转动（RT模式）3种基本刚性变位模式下诱发的墙后地表沉陷，得到了土体沉陷曲线的分布规律。结果表明，挡墙平移时，墙后地表沉降呈勺型分布，最大沉降紧靠墙背处；挡墙绕墙趾转动时，墙后地表沉降近似呈三角形分布，最大沉降紧靠墙背处；挡墙绕墙顶转动时，墙后地表沉降近似呈抛物线分布，最大沉降位于距墙背一定距离的位置处。挡墙变位距离相同时，对于绕墙趾和绕墙顶转动模式，墙后土体沉陷的面积基本相等，两者沉陷面积之和近似等于平移模式的土体沉陷面积，另外，挡墙变位面积与墙后土体沉陷面积也近乎一致。将试验观察的沉陷曲线与既有的解析解作了对比分析，验证了二者的一致性。

Model tests on excavation-induced ground settlement due to movement of retaining wall

This paper performs a series of model tests to explore the law of ground settlement induced by moving rigid wall with various movement modes, i. e. translating mode (T mode), rotating around toe mode (RB mode) or rotating around top mode (RT mode). The different ground settlement curves have been achieved with respect to three basic movement modes. It has been found that T mode movement tends to cause a spoon-type settlement profile with the maximum surface settlement at the wall back, and RB mode produces a triangle profile with the maximum surface settlement at the wall back, and RT mode movement results in a parabolic type settlement profile with the maximum surface settlement at a certain distance away from the wall back. For RB and RT modes, their ground settlement curves almost share the same area if their maximum movements of retaining wall are equal to each other. It is also found that for RB and RT modes, the sum of ground settlement of two modes is approximately equal to that for T mode. In addition, the wall movement-induced displacement area is almost equal to that of ground settlement. The experimental observed surface settlement agrees with the existing analytical solutions.