航道开挖对下方已建地铁工程的影响性分析

Impact of waterway excavation on existing tunnel structure under it

为预测并控制航道大面积开挖对下方已建地铁结构变形的影响,以京杭运河浙江段Ⅲ级航道整治杭州段(新开挖航道)跨地铁1号线节点工程为例,分别研究正常开挖和采用一定措施时地铁盾构隆起位移的理论值。结合工程的地质条件和地铁安全运营要求,提出分块挖土条、坑内满堂加固和抗拔门架结构等多种抗隆起措施,并利用三维有限元分析软件对河道开挖全过程进行施工阶段数值模拟。结果表明,该措施对控制地铁位移是有效的,能够满足地铁安全运行的要求。

In order to forecast and control the deformation of existing underground tunnels induced by canal excavation,based on a metro-crossing canal excavation example of Zhejiang section of the Beijing-Hangzhou Canal in Hangzhou,we study the theoretical deformation values of the tunnel structure under both common excavation scheme and the scheme with certain heave resistance measures.A series of construction measures are attempted,including block excavation,foundation reinforcement and uplift frame structure to resist the shift of underlying metro line 1,based on all the geological conditions and design requirements that have been known.Moreover,a 3D finite element model is established to simulate the whole excavation process,and the results prove that the measures designed for controlling the deformation of subway shields are effective and can fulfill the requirements of safety operation of metro tunnel.