西安地裂缝对地铁隧道的危害及防治措施研究

西安地裂缝是一种独特的城市地质灾害,其活动对地铁建设造成严重威胁,西安地铁建设的关键是如何解决地铁隧道穿越地裂缝带的问题。以西安地铁穿越地裂缝带为研究对象,在地裂缝基本特征分析和未来活动趋势预测的基础上,分析了地裂缝活动对地铁隧道的危害模式,从结构、防水、地基基础与变形监测等方面提出了如下防治措施:结构上应采用扩大断面、预留净空、分段设缝加柔性接头和局部衬砌加强等措施;防水方面宜采用可卸式管片拼装双层结构法和波纹板强化橡胶复合材料制成的防裂止水带处理;地基基础处理方面采用地基注浆加固法和弹性囊变形恢复法处理;建立隧道衬砌和轨道的变形监测预警方案;地铁线路走向应尽量与地裂缝正交或大角度相交,避免小角度相交;严格禁止在地铁沿线一定范围内开采地下水。研究成果可为西安地铁隧道穿越地裂缝带的施工、结构和防水设计以及隧道病害监测与防治提供重要参考。

Metro tunnel hazards induced by active ground fissures in Xi’an and relevant control measures

The ground fissures in Xi’an are one of the particular urban geological hazards and have a serious threat on Xi’an metro construction,so it is the key for Xi’an metro construction to solve the problem of active ground fissures.On the background of Xi’an metro transversing the active ground fissure zones,the metro tunnel hazards induced by active ground fissures are analyzed based on the characteristics of ground fissures and their moving trend.The control measures are put forward from the following aspects: structural measures such as the enlarged cross-section,local reinforced lining,segmented tunnel lining and flexible joints;waterproof measures including the detachable segment method and a new flexible anti-cracking sealing strip made of fortified corrugated plate rubber complex material;foundation injected reinforcement and method of foundation deformation recovery of elastic sack;establishment of warning programs of the deformation of tunnel lining and metro track;design of the strike of metro line perpendicular with ground fissure zones or intersecting with large angle;and prohibition of groundwater withdrawal within a certain scope along the metro.The conclusions can be presented as the reference for the structural and waterproof design of metro tunnel going through the active ground fissure zones.