针对离心模型试验中停机开挖、排液法、微型机器人开挖3种传统方法缺点进行分析,设计研制一种新型开挖模拟装置,对土体实际卸荷过程有更准确的模拟,并应用于一组砂土地基基坑开挖离心模型试验验证了可行性。与传统方法相比,能实现非停机开挖,较准确模拟土体侧压力,原理简单、造价低。试验中布置多种类型传感器形成立体测量,试验数据与数值分析结果形成对比分析。结果表明:悬臂式支挡结构的砂土地基基坑开挖地表沉降曲线呈悬臂型;引起挡墙最大弯矩位置随开挖逐渐下移,下移速率递减;开挖土体卸荷,引起主动区土压力减小,浅层开挖对深层土压力影响很小,深层开挖时,浅层土压力的变化不明显。最后对试验中存在的问题和有待改进之处作了讨论,对后续和同类试验提供指导和参考。 According to the analysis of the shortcomings of the three traditional methods of downhole excavation, drainage method and micro-robot excavation in the centrifugal model test, a new type of excavation simulation device is designed and developed to simulate the actual unloading process more accurately. Centrifugal model tests on a group of sand foundation pit excavation verify the feasibility. Compared with the traditional method, it can realize the non-stop excavation and simulate the soil side pressure accurately. The principle is simple and the manufacturing cost is low. Various types of sensors were arranged in the experiment to form a three-dimensional measurement. The experimental data and numerical analysis results were compared and analyzed. The results show that the ground settlement curve of the foundation pit with cantilever retaining structure is cantilevered, the maximum bending moment position of the retaining wall decreases gradually with the excavation and the descending rate decreases. The unloading of the excavated soil causes The earth pressure of the active area is reduced. The shallow excavation has little effect on the deep earth pressure. When the deep excavation, the change of the shallow earth pressure is not obvious. Finally, the problems existing in the experiment and the areas to be improved are discussed, which provide guidance and references for the follow-up and similar experiments.