针对城市核心区地铁建设普遍存在的盾构穿越未完工暗挖车站引发的施工交互影响难题，以广州地铁13号线纪念堂站为工程依托，该站地处典型的上软下硬复合地层，采用洞桩法施工，且受制于狭小场地被迫实施先隧后站。为定量揭示盾构过站时机对围岩-结构体系力学行为的作用机制，建立扣拱形成并回填后过站与扣拱形成前过站的对比工况，综合采用模型试验与数值模拟手段，对比分析先隧后站不同盾构过站时机的围岩变形以及各结构的应力演化特征。结果表明： 1）洞桩法暗挖车站施工地表沉降曲线呈单峰状，上方扣拱形成后盾构过站对围岩扰动较小，地表沉降值减少5.9％； 地层荷载得到了较大的释放，盾构管片应力集中程度较小，应力最大值减小24％。2）正洞上方扣拱应力最大，盾构过站对扣拱的应力影响较小。3)在此类工程中，采用暗挖车站上方扣拱形成并回填后过站是较优的施工方案。
Tunnels in urban core areas often cross mined metro stations under construction, inducing interaction between them. Herein, a case study is conducted on Memorial Hall station on Guangzhou metro line 13, which is located in typical upper-soft and lower-hard composite strata. The pile-beam-arch (PBA) method is employed, and the tunnel is excavated before the station due to limited site space. To quantitatively reveal the mechanism of influence of shield tunneling timing on the mechanical behavior of the surrounding rock-structure system, two representative construction scenarios—shield passing through the station after buckled arch formation of the station′s core bearing structure and shield passing through the station before buckled arch formation—are established and compared. By comprehensively employing model tests and numerical simulations, the characteristics of surrounding rock deformation and stress evolution in key structures under different shield passage timings are examined. The findings demonstrate the following: (1) The surface settlement curve of the station constructed by the PBA method exhibits a single-peak shape, and shield passage through the station after buckled arch formation causes less disturbance to the surrounding rock, with surface settlement reduced by 5.9%. The ground load is released to a greater extent, and the degree of stress concentration in the shield segment is smaller, with a maximum stress reduction of 24%. (2) The stress of the buckled arch above the main tunnel is the largest, and shield passage through the station has little influence on the stress of the buckled arch. (3) The results demonstrate that shield passage through the station after buckled arch formation is a priority in similar projects.
