双线盾构隧道施工过程相互影响的数值研究

Numerical Modeling Study on Interaction between Twin Shields Tunneling

首先针对双线盾构隧道施工特点,建立了考虑切口水压、土体的扰动、盾尾释放位移、盾尾注浆体的硬化效应,能够进行动态模拟的三维弹塑性有限元模型。然后采用该模型进行双线盾构隧道施工过程的数值模拟分析,计算结果与现场监控量测数据做了对比分析,验证了作者所建立的双线盾构隧道施工过程数值模型的适用性,并总结得出近间距隧道的施工中,后建隧道对先建隧道的影响规律,以及后建隧道自身相对与单条隧道时的变化规律。通过对平行隧道盾构法施工不同参数的对比研究表明,隧道间距是控制两隧道相互影响的最主要因素,地层损失率次之,然后是土体弹性模量。而隧道埋深、切口水压、盾尾注浆压力对两隧道相互影响的作用较小。通过对重叠隧道盾构法施工不同参数的对比研究,分别得出了两种开挖类型的重叠隧道相互影响的规律。从减小隧道间相互影响出发,证明了下伏隧道先行开挖优于上覆隧道先行开挖的情况。

For modeling the twin shields tunneling, this thesis suggests a 3D elastic-plasticity FEM involving slurry pressure, soil disturbance, ground loss, grouting behind shield tail, dynamic tunneling, etc. The 3D elastic-plasticity FEM is approved through comparing the fields monitoring results with the numerical analysis results. This thesis studies parameters related to interaction between twin-parallel shields tunneling. These parameters include tunnels space, ground loss, soil stiffness, tunnel depth, slurry pressure and grouting pressure. It proves that tunnels space is the most important influencing factor, ground loss is the second and soil stiffness is the third one. As for tunnel depth, slurry pressure arid grouting pressure, they are less important factors. In this thesis, the twin-stacked tunnels are divided into two kinds： tunneling with underlying tunnel excavated first and that with overlying tunnel first. And the 3D elastic-plasticity FEM is used to study parameters of interaction between twin-stacked shields tunneling, including tunnels space, ground loss and soil stiffness. It suggests the interaction rules of the two kinds of twin-stacked tunnels. The results suggest that tunneling with underlying tunnel first excavated is better than that with overlying tunnel excavated first for reducing the interaction.