天津地铁5号线穿越东风立交桥区段方案研究

随着城市轨道交通建设速度加快，线路穿越城市密集建筑区地段越来越多。为了解决地铁穿越建构筑物密集的城市中心区域地铁选线难题，以天津市轨道交通5号线穿越东风立交桥区域为例，对区域内线站位布设方案、区间盾构隧道设计及桥梁桩基托换等工程技术方案进行研究。主要结论如下： 1）线路采用左右线上下重叠布置方式，较传统的常规方式占用地下空间少，增加线路选线的自由度，可有效避让线路两侧密集建筑物基础，减少拆迁，降低工程造价，解决了拥挤空间内的布线难题。2）上下重叠盾构隧道采用先下后上的施工顺序及在下洞设置钢支架、采用多孔注浆等设计、施工控制措施，可减少上下洞体的相互影响。3）匝道桥桩基托换采用桩基主动托换法施工，可有效控制桥墩沉降。

Study on Scheme of Tianjin Metro Line 5 to Cross Dongfeng Interchange

As more and more urban rail transit works are built, some Metro lines have to pass through dense building/structure areas. In this paper, the scheme of Tianjin Metro Line 5 to cross Dongfeng Interchange is analyzed, and the arrangement of the Metro stations, the design of the shield bored running tunnels and the underpinning of the existing bridge piles are studied in detail. Conclusions drawn are as follows: 1) The scheme of up down overlapping tunnel tubes adopted has such advantages as occupying less underground space, increasing the freedom of the Metro line, avoiding some existing pile foundations, reducing the demolition and resettlement and reducing the construction cost; 2) The lower tunnel tube should be built before the upper one, and countermeasures including steel support and grouting should be taken, which can reduce the mutual effect between the tunnel tubes; 3) Active underpinning should be adopted for the foundation piles of the ramp bridge, which can effective control the settlement o f the piers. 