原位保护技术在地铁基坑上跨大直径截污干管时的应用

Application of In-situ Protection Technology in Subway Foundation Pit Spanning Large Diameter Intercepting Sewers

针对城市核心区地下空间基坑时,管线无法迁改而只能采取原位保护所存在的基坑渗漏变形,甚至污水倒灌的风险,开展了技术攻关。以昆明轨道交通2号线二期六甲站1号风亭工程为例,探讨地铁大跨度深基坑上跨大直径截污干管时,MJS工法桩处理围护结构缺口、钢管抱箍、包封防止管节错位、隔离桩加分段分级跳仓开挖控制管道上浮或侧移等管道原位保护措施的适用性,以期为类似基坑工程提供有效参考。

In view of the risk of foundation pit leakage and deformation, even sewage backflow, when the underground space foundation pit in the urban core area cannot be relocated and the pipeline can only be protected in situ, a technical breakthrough is carried out. Taking the No. 1 Wind Pavilion Project of Liujia Station, Phase Ⅱ of Kunming Rail Transit Line 2 as an example, it is discussed that the applicability of MJS piles to deal with the gaps in the retaining support structure,steel pipe hoops, wrapping to prevent the dislocation of pipe joints, isolation piles plus staged alternative bay excavation to control the floating or lateral displacement of pipes when the large-span deep foundation pit of the subway spans large diameter intercepting sewers. It is expected to provide effective reference for similar foundation pit projects.