上软下硬地层地铁车站上注下支拱盖法施工技术研究

Study on the Construction Technology of the Arch-cover Method of Upper-injection and Lower-support for Subway Station in Upper-soft and Lower-hard Ground

以某地铁1号线学苑广场站为工程背景,针对上软下硬地层情况,改进原有的CRD和PBA工法,提出了上注下支的扣拱施工方案。运用有限差分软件分析不同开挖顺序对施工稳定性影响,确定先开挖下导洞再开挖上导洞的施工顺序,对施工方案进行验证;接着对施工期间地铁车站地表沉降情况进行研究,模拟了地铁车站的施工过程,分析各施工工序对地表变形的影响,得到地表变形规律。并与现场监测结果进行对比分析,验证数值模拟的准确性,研究结果为地铁车站安全施工提供了依据。

The Xueyuan Square Station of a metro line 1 is taken for the project background,the original CRD and PBA methods are improved against the upper-soft and lower-hard ground,thus the arch-cover method of upper-injection and lower-support is proposed. Using finite difference software to analyze the influence of different excavation sequence on the stability of construction,the construction sequence of excavating the upper pilot after the completion of lower pilot excavation is determined,and the construction scheme is verified. Then,the surface settlement of subway station during construction is studied,the construction process of subway station is simulated,and the influence of the construction process on the surface deformation is analyzed,therefore the surface deformation law is obtained. The results are compared with the field monitoring results,verifying the accuracy of numerical simulation. The results provide a basis for the safety construction of subway station.