中文摘要：

土工离心模型试验在岩土工程领域的研究方面发挥着重要的作用。结合上海轨道交通某线路越江隧道修复工程,开展了38m超深基坑开挖的离心模型试验。试验所采用的几何相似比例为1∶120,根据抗弯刚度和抗压刚度相似原则,分别对地下连续墙和支撑结构进行模拟。通过对试验结果的分析,得出在使用地下连续墙围护结构条件下,在压缩性高、孔隙比大、强度低等特点的冲淤沉积地层中超深基坑开挖时围护结构的变形、周围地层的变形、支撑内力以及挡墙前后土压力等的变化规律,用于综合评判基坑的稳定性。研究结果旨在为实际工程应用提供参考,也为将来类似超深基坑的设计和施工提供借鉴和指导作用。

英文摘要：

For the rehabilitation of the cross-river tunnel of Shanghai Urban Rail Transit,a centrifuge model test is carried out to simulate the excavation of a foundation pit of 38 m deep. The geometric scale is 1：120. According to the principles of equal bending rigidity and compressive rigidity,respectively,the concrete diaphragm wall is simulated with aluminum alloy plate,and brace structures with aluminum alloy pipes. In such type of highly compressible alluvial silt deposit strata,with high porosity and low strength,using diaphragm wall as the retaining structure,the behavior characteristics of the system are analyzed,such as the retaining wall deformation,ground surface settlement,brace axial force,earth pressure inside and outside of the retaining wall,for comprehensive assessment of the stability of the pit excavation.