京张高铁清河站地下交通枢纽分体建造工法研究

Split Construction Method for Underground Traffic Hub Structure Attached to Qinghe Station of Beijing-Zhangjiakou High-Speed Railway

为解决京张高铁清河火车站地下交通枢纽负1层的地下人行通道、公交通道和地下连廊通道需要和清河火车站同时投入运营,而常规的明挖顺作工序无法满足工期要求的问题,提出分体建造方案。即:先采用明挖顺作法完成负1层结构和永久钢管柱的施工,以满足负1层结构和清河站同步投入运营的需求,然后采用盖挖法施工负2层结构。主要研究与结论如下:1)讨论分体建造的施工工序以及钢管柱施工、明挖+盖挖连接节点的处理、负2层钢支撑安装与拆除、负2层施工对钢管柱稳定性影响的控制等分体建造方案关键技术,并针对关键技术提出了解决措施;2)采用有限元数值模拟方法并结合现场监测结果,分析施工过程中的结构关键受力构件钢管柱的变形,得出钢管柱的竖向变形和水平变形均远远小于设计允许的变形控制值;3)从总工期、工程造价和实施效果进行分析,本工程采用的分体建造工法不占优势,但由于负1层施工仅仅81 d就完工交付使用,确保了负1层的各种交通设施能够随清河站的开通同步投入运营,提出的分体建造工法为高铁车站地下交通枢纽按期投入运营提供了保障。

Since the underground pedestrian walkway,bus passageway,and underground corridor on the first floor of the underground transportation hub structure of the Qinghe railway station of Beijing-Zhangjiakou high-speed railway has been operational simultaneously with the Qinghe railway station,the conventional open-cut construction scheme cannot meet the requirements of the targeted construction period.As a result,the split construction scheme is proposed and applied.The split construction method includes constructing the underground first-floor structure and steel tube columns using the open-cut method and constructing the underground second floor using the cut-and-cover method.The main studies and conclusions are drawn as follows:(1)The split construction sequence,steel tube column construction,connection point between open-cut and cut-and-cover methods,steel support installation and demolishing in the underground second floor,and the influence of constructing the underground second floor on the stability of the steel tube columns are discussed,and corresponding methods are proposed.(2)The deformation of essential stress structures,steel tube columns,and the construction period is analyzed by finite element numerical simulation and site monitoring results.The analytical results show that the vertical and the horizontal deformation of the steel tube column is considerably lower than the steel tube column allowance.(3)The split construction in this project is not beneficial in terms of the construction schedule,cost,and effect,but the synchronous operation of each traffic facility and Qinghe station was guaranteed,indicating a possibility of constructing the underground transportation hub structures and highway station.