关键词: 先隧后站, 洞桩法, 暗挖车站, 交互影响, 数值模拟, 模型试验, 力学行为

Abstract: 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.

Key words: tunnel construction before station construction, pile-beam-arch method, mined metro station, interaction, numerical simulation, model tests, mechanics behavior