下穿高层建筑特大跨度超大断面偏压隧道施工方法研究

结合重庆市轨道交通3号线下穿高层建筑特大跨度超大断面隧道工程,对其采用双侧壁导坑主楼侧先开挖、双侧壁导坑裙楼侧先开挖、单侧壁导坑主楼侧先开挖、单侧壁导坑裙楼侧先开挖等4种施工方法条件下全过程进行弹塑性数值仿真分析。结果表明:对于下穿高层建筑特大跨度超大断面隧道,在支护、支撑措施合理情况下,采用上台阶单侧壁导坑法能够满足变形和受力要求;隧道地表存在不对称荷载时采用双(单)侧壁导坑法施工,先开挖地表荷载较小侧导洞优于先开挖地表荷载较大一侧导洞。研究成果可供类似工程参考。

Methods for Excavation of Tunnel under Biased Loading with Super-large Span and Super-large Section Passing under High-rise Building

In order to find out the speeded-up process of excavating tunnels with super-large spans and super-large sections passing under high-rise buildings,the underground industry and Trade Station of Chongqing Rail Transit Line 3 was supposed to be excavated with four methods and elastic-plastic numerical simulations were made for all the complete processes of construction accordingly.The four excavation methods are respectively the double-sided drift excavation method with first excavation on the main-building side,the double-sided drift excavation method with first excavation on the apron-building side,the single-sided drift excavation method with first upstep excavation on the main-building side and the single-sided drift excavation method with first upstep excavation on the apron-building side.The main building is the Industry and Trade Building with 22 storeys.The simulated results show as follows: With respect to super-large span and super-large section tunnels passing under high-rise buildings,the single-sided drift upstep excavation method can satisfy the deforming and stressing requirements when rational strutting and supporting measures are taken;when unsymmetrical ground surface loading exists,the double-sided drift excavation method and the single-sided drift excavation method way be adopted,and first drift excavation on the side of small loading is superior to first drift excavation on the side of large loading.The research results provide reference to similar engineering projects.