盾构区间下穿并截除人行天桥部分桥桩的对策

以沈阳地铁2号线工业展览馆站—文体路站区间(以下简称工—文区间)下穿文化路立交桥人行天桥并截除部分桥桩为例,为确保盾构掘进过程中该天桥桥体的安全,通过对桥桩截桩后管片后期承载力、结构变形等特点建立三维数值模型,并进行计算分析后,进一步优化设计方案,同时采取了以下措施:施工前先对人行天桥两端桥墩处采用临时钢托架进行支撑加固;掘进过程中合理优化盾构掘进参数,同时采取同步注浆与二次补强注浆措施,不但避开了立交桥主桥桥桩,同时还避免了采用桩基托换这一高风险、高代价方案。竣工并通车运营后,经过近1年的跟踪监测,桥梁结构稳定,最终变形收敛至稳定值,充分验证了该措施的可行性。

Countermeasures for Shield Cutting and Passing Underneath Piles of Existing Pedestrian Bridge

A shield bored running tunnel of Line 2 of Shenyang Metro passes underneath the piles of an existing pedestrian bridge, and some of the piles have to be cut. In the paper, 3D numerical simulation is established and analysis is made on the load bearing capacity and structural deformation of the segment structure after the piles are cut; and accordingly the design is optimized and countermeasures, such as temporary support for the piles of the existing pedestrian bridge installed before the shield reaches, optimizing the shield boring parameters during boring, and simultaneous grouting and secondary reinforcing grouting, are taken. The monitoring shows that the pedestrian bridge keeps stable and the countermeasures taken are effective.