复杂地层长距离叠落大盾构隧道设计分析

以珠海兴业快线工程为依托,从抗浮、变形影响等方面对叠落隧道的竖向净距进行分析。结果表明:当竖向净距控制为0.5D(D为下部隧道的直径)时,上部隧道开挖对下部隧道的影响较小。根据有限元分析,上部隧道开挖时,土体卸载,对下部隧道管片受力有利。但这是一个动态的应力重分布问题,具有不确定性。

Design and Analysis of Long-distance Overlapped Large Shield Tunnels in Complex Stratum

Relying on Zhuhai Xingye Expressway Project, the vertical net distance between overlapped tunnels are analyzed from the aspects of anti-floating and deformation effects. The result shows that the influence of the upside tunnel excavation on the lower tunnel is small when the vertical net distance is controlled at 0.5D(D is the diameter of lower tunnel). Based on the finite element analysis, when the upside tunnel is excavated, the unloading of soil is beneficial to the stress of lower tunnel segments. However, it is a dynamic stress redistribution issue with uncertainty.