邻近地铁隧道的软土深基坑变形实测分析

上海外滩596地块超深基坑紧邻地铁9号线区间隧道及一系列管线和建筑物。为控制基坑施工对周边环境(尤其地铁隧道)的影响,本项目设计采取分坑顺作、两墙合一地下连续墙、钢支撑轴力补偿体系、被动区加固、抽条分块开挖等系列措施。实测结果表明,远离地铁侧的地下连续墙最大变形为45.6 mm,邻近地铁侧地下连续墙最大变形为17.2 mm,邻近地铁隧道的最大隆起量为12.9 mm。所采用的设计方案满足了地铁的变形控制要求。

Deformation of a deep excavation adjacent to metro tunnels in soft soils

The deep excavation of Shanghai Bund 596 Plot is adjacent to the metro tunnels of Line 9, pipelines and buildings. In order to control the impact of excavation construction on the metro tunnels, many measures are adopted in the design of the project. The deep excavation is divided into four small pits, and the block excavation method was adopted. Dual-purpose diaphragm walls are used as retaining walls. The steel struts with automatic axial force compensation system are adopted in the small pits just adjacent to the metro tunnels. The soils in the passive zone are reinforced by triaxial cement-soil mixing piles. The monitored results show that the maximum lateral displacement of the diaphragm walls far away from the tunnels and that just adjacent to the tunnels are 45.6 and 17.2 mm, respectively. The maximum upheaving of the tunnels is about 12.9 mm. The design scheme satisfies the requirements of deformation control of the adjacent tunnels.