武汉地区淤泥质软土地铁车站深基坑开挖风险控制

本文以武汉地铁七号线长丰站为例，通过事故树理论分析得出超深基坑开挖过程中存在接缝漏水、纵坡失稳、基坑变形、涌水涌砂、周围地表沉降、基坑基底隆起等风险。针对性的对长丰站5月份超深基坑开挖过程中的地连墙墙体测斜、土体沉降、立柱沉降等监测数据进行分析，分析结果表明地连墙倾斜过大、立柱沉降、地连墙渗漏等是基坑变形过大的征兆，也是超深基坑开挖过程中常见风险，因此需要通过采取及时架设钢支撑、放坡开挖、加强监测、及时降水等措施进行控制。通过及时的安全预警及采取针对性措施使得长丰站基坑开挖风险得到了有效地控制，长丰站主体结构得以顺利完工。通过对长丰站基坑开挖风险的成功预警与控制，以期为武汉地区淤泥质软土超深基坑开挖风险控制提供建议。

Risk Control of Ultra-deep Metro Station Pit Excavation in Wuhan Soft Soil Area

Taking Changfeng station of Wuhan Metro Line Ⅶ as an example, this article shows that the process of ultra-deep excavation have many risks by theoretical analysis of Fault Tree, such as leaking joints, longitudinal instability, pit deformation, gushing water and sand, surface subsidence around the base hang basement uplift and so on. The article analyses the monitoring data during the excavation of Changfeng station in May including the inclinometer of underground continuous wall, soil subsidence, post settlement and so on. The analysis results show that large underground continuous wall inclinometer, upright settlement, underground continuous wall seepage etc. are the signs of large pit deformation, as well as common risks of ultra-deep excavation process. So we should erect steel braces timely, grading excavation, strengthen monitoring and provide rainfall timely to control them. By timely warning and taking appropriate security measures, the excavation pit risk of Changfeng station was controlled effectively, and the main structure of Changfeng station was completed successful. The success of early warning and control of Changfeng station excavation risks can provide recommendations for the Wuhan soft soil excavation.