重庆市某医院迁建项目对既有轨道交通结构安全影响分析

Analysis of the Impact of a Hospital Relocation Project in Chongqing on the Safety of Existing Rail Transit Structures

山城重庆市地质环境复杂,土地资源有限。随着轨道交通与城市建设的高速发展,轨道交通下穿/近接建筑物的情况越发普遍,这给城市地下空间开发带来了严峻的挑战。文章采用MIDAS/GTS软件建立有限元模型,分析建筑结构基坑支护施工过程中对既有轨道交通隧道结构的安全影响以及隧道结构内力变化特性。结果表明:区间隧道洞体开挖过程中,隧道围岩处于整体稳定状态,仰拱拱脚及侧墙少部分围岩存在受拉破坏风险;因拟建项目的施做而引的轨道9号线区间暗挖隧道变形均小于控制指标,拟建项目轨道结构变形风险可控;通过对地层结构法提取的轨道隧道结构初期支护、二次衬砌及共建段衬砌结构内力进行验算,验算结果满足规范要求。

The mountain city of Chongqing has complicated geological environment and limited land resources.With the rapid development of rail transit and urban construction,the situation of under/near buildings of rail transit is more and more common,which brings severe challenges to the development of urban underground space.In this paper,MIDAS/GTS software is used to establish the finite element model,and the safety impact of the construction process of the foundation pit support on the existing rail transit tunnel structure and the change characteristics of the internal force of the tunnel structure are analyzed.The results show that:the surrounding rock around the tunnel is in an overall stable state during the excavation of the tunnel body,and there is a risk of tensile failure for the arch foot and a small part of the side wall of the inverted arch;the displacement of the hidden excavation mechanism of the proposed project is less than the index,and the deformation risk of the track structure of the proposed project is controllable.The internal force extracted by the stratum structure method for the lining structure of the primary support,secondary lining and co-construction section of the track tunnel structure was verified,and the verification results met the requirements of the specification.