强蠕变软土条件下地铁基坑的施工变形特性分析

以宁波市地铁1号线东环南路站基坑工程为研究对象，分析了基坑工程围护结构变形和外围地表沉降的变化规律.结果表明，基坑开挖对围护结构变形及外围土体沉降的影响具有明显的时间效应，施工过程中应严格控制深层土体的开挖时间，并需要及时架设支撑及浇注混凝土底板.同时，结合有限元数值计算和位移转化系数的方法推算了考虑软土强蠕变性的基坑变形长时位移，所得结果与其监测结果相吻合，从而验证了所采用的监测方法的可行性.

Analysis of Deformation Properties of Subway Station Foundation Pit in Soft Soil with High Creep Property

In order to investigate the effect of soft soil with strong creep resistance on the deformation during construction, based on the foundation pit engineering of the South East Outer Ring Road Station in Ningbo, the deformation of the building envelope and the external surface subsidence were analyzed. The results show that the effect of the foundation excavation on the deformation of the building envelope and the external surface subsidence has an obvious time effect. So the time of deeper soil excavation should be strictly controlled followed by timely erection of support and pouring of concrete floor. Meanwhile, the deformation and long term displacement of the pit were calculated by combining the finite element modeling (FEM) with the displacement aging coefficient and taking the strong creep resistance into account. The numerical results conform to the monitored results,
which verifies the feasibility of the method, and provides reference for similar excavation engineering.