基坑开挖中既有下穿地铁隧道隆起变形分析

为了研究下卧隧道的隆起变形规律及其影响因素,结合南京火车站站前广场龙蟠路隧道西段上跨地铁1号线双线盾构隧道的基坑支护工程,开展了坑内满堂加固、人工抽条和桩板支护等盾构隧道抗隆起措施设计.采用三维有限差分程序FLAC3D对基坑支护及其开挖的全过程进行了数值模拟,并通过与现场实测数据的对比分析,研究了地铁隧道的变形规律及其...

Heave deformation of existing tunnels under new tunnel excavation

Based on the foundation supporting project of the running double track shield tunnels of Nanjing Metro Line 1, which was underlying Long pan tunnels in Nanjing Railway Station Square, a series of design methods to resist the heave of the two existing shield tunnels were developed, including the pit reinforcement, artificial strip excavation and pile sheet retaining. Furthermore, FLAC3D was employed to simulate the foundation support and the whole excavation process. The deformation regularity and influence factors of the shield tunnels were studied by comparing the numerical results with the filed data. It was concluded that the numerical method could simulate the real excavation process of the new tunnel. Under the condition of small deformation, the displacement of the shield tunnels was basically identical with that of the soil. Pile sheet retaining method associated with pit reinforcement can effectively control the heave deformation of the metro tunnels during soft soil excavation. This study made a good example for the future similar engineering.