淤泥质土及粉细砂地层盾构施工地表沉降监测分析

Monitoring and Analysis of Surface Settlement during Shield Tunneling in Mucky Soil and Fine Sand Layer

淤泥质土和粉细砂为地铁隧道施工的主要不良地质土层。分析盾构掘进在该土层造成的地表沉降规律,这有利于采取合适的施工技术对策。以佛山地铁2号线花仙区间为实例,对淤泥质土及粉细砂地层盾构施工地表沉降监测数据进行了分析。结果表明:在淤泥质土层中,地表沉降主要发生在管片脱出盾尾和后期的固结沉降阶段;在粉细砂层中,地表沉降主要发生在盾构掘进和管片脱出盾尾阶段,且盾构施工对粉细砂层的影响大于对淤泥质土层的影响。

Fine sand and mucky soil layer are the major adverse geological layers for metro tunnel construction. In this paper, the rules of surface settlement in fine sand and mucky soil layers caused by shield advancement are analyzed to find appropriate technical measures for the construction. Taking the Flower Fairy Section on Foshan metro Line 2 as example, the monitoring data of surface settlement during shield tunneling in mucky soil and fine sand layer are analyzed. The result shows that the surface settlement mainly occurs at the shield tail and the later consolidation settlement stage in the mucky soil layer shielding. While in the fine sand layer, the surface settlement often occurs in shield tunneling and segment withdrawal stage, the influence of shield construction on the fine sand layer is larger than that on the muddy soil layer.