大跨度暗挖车站施工引起地表沉降之研究

Large Span Underground Metro Station Construction Induced Ground Subsidence

以青岛地铁3号线某车站现场长时间监控量测数据的统计分析为基础,研究在以花岗岩为主的硬岩地质条件下,地铁大跨度暗挖车站穿越围岩差异较大地层时,采用双侧壁导坑法开挖引起地表沉降的一般规律。分析结果表明:地表沉降最大值的范围为57.68mm^74.63mm,地表沉降槽宽度参数的范围为0.544mm^0.73mm,施工引起的地层损失率范围为5.9%~7.23%。所得结论可为暗挖车站使用该工法施工引起的最大地表沉降和环境影响(周围构筑物和管线等)预测提供依据。运用变位分配原理对分步开挖中对地表沉降贡献比例的分析,可达到通过分步沉降控制实现总体沉降的控制的目标。

A regression analysis was performed on the field monitored data for the ground subsidence induced by the construc- tion of a metro station in No. 3 Line in Qingdao City. The bedrock conditions of the Qingdao City consist of predominantly hard rock, such as, granite. The Double Lateral Walls Heading Excavation Method is usually used in the excavation of the large span metro station. The construction monitoring results indicate that the maximum ground subsidence range is from 57. 68 to 74.63 mm. The width of the cracks induced by the ground subsidence is between 0. 544 and 0.73 mm. The construction induced ground loss ratio is between 5.9 and 7.23%. These results can be used in the evaluation of the impact of the construction induced ground subsidence and its environmental effect （on the adjacent buildings and the underground utilities）. The total ground subsidence control can be achieved throughout the controlling of the incremental subsidence in each construction step by using the weighted displacement distribution principle in the underground excavation project.