城市轨道交通深基坑工程承压水风险与控制研究

Risk of the Artesian Water and Control Measurements for the Deep Excavation of Urban Rail Transit Engineering

随着我国城市轨道交通建设发展,北京、上海、广州等特大型城市轨道交通线路网逐渐形成,出现不同线路交错、轨道交通线路与其他城市设施空间交叉等情况,这使得地下车站深度不断增加,深基坑工程受深部承压水风险日益突出。收集了27个承压水风险工程案例,统计分析了围护结构隔断或未隔断承压含水层等不同情况下,承压水风险与围护结构类型、承压含水层面覆土厚度等的相关性;采用故障树法探讨了深基坑工程坑底突涌、围护结构漏水、流砂等风险事件及风险因素,根据风险工程案例对承压水风险主次因素进行排列;结合工程实例应用分析,提出了承压水风险预防应对措施,提出了设置备用降压井和基坑开挖前试抽水试验等风险应对措施,为类似工程提供参考。

With the development of urban rail transit communication engineering in China,the rail transit network of megacities was gradually formed,such as Beijing,Shanghai and Guangzhou,and the transfers of different lines or the spatial crosses of the rail lines and the other city facilities were developed,therefor the depth of subway stations was increasing and the accidents caused by the artesian water were increasing meanwhile.In this paper,based on the twenty-seven cases,the relationship of the risk of the artesian water and the type of the retaining structure and the thickness of the soil above the artesian water,and the fault tree analysis was employed to identify and array the factors of the risk of the artesian water.Then,a case was discussed to propose the precautions and the emergency measurements of the risk of the artesian water for the deep excavation engineering.Finally,the measurements of the emergency dewatering wells and the pumping test before the excavation were proposed.