软土盾构隧道近接施工应力迁移规律研究

在多线叠交隧道空间布置形式下,盾构近距离穿越既有隧道施工对既有隧道的影响主要通过扰动周边的土体,使其应力发生改变,进而影响既有隧道的应力状态。针对外力作用下衬砌和土体两种不同介质进行耦合作用时应力的快速迁移现象,构建了考虑土体流变特性的盾构近接施工应力迁移模型,推导出新建隧道以任一穿越角度施工时,既有隧道和扰动土体在时间域内的应力迁移解析式,并讨论了取值参数的敏感性程度。分析结果可为今后类似多线叠交隧道工程的设计和施工提供理论指导。

Study on Stress Migration Patterns of Approaching Construction for Shield Tunnel in Soft Soil

Under the spatial distribution for multi-line overlapped tunnels, the effect of shield construction disturbance on the existing tunnels when they are traversed by the new tunnel is studied. The stress of both existing tunnels and soil will be changed quickly. In view of the phenomenon for stress migration patterns caused by the coupling between lining and soil, the construction stress migration model considering the rheological properties of soil when shield nearly meets is established. Analytic expression for stress migration patterns between tunnel and soil in time domain are calculated during the construction of shield crossing within any angle. What’s more, the degree of the sensitivity of the parameter values is analyzed. The research results can provide some theoretical basis and prophase guidance for similar projects in the future.