Rock masses that have a well-defined structure may also present a remarked in situ stress anisotropy; thus, the misalignment of a tunnel with the geostatic principal stresses and/or with the principal axes of material anisotropy is very likely. Analytical solutions for tunnels in transversely anisotropic rock available in the literature assume alignment of the tunnel with the geostatic principal stresses and with one of the principal directions of the material anisotropy (i.e. 2D plane strain condition). Such assumption is quite restrictive. In this paper, a new analytical formulation for circular deep tunnels in fully anisotropic rock is presented. It provides the full stress and displacement fields around a tunnel misaligned with the geostatic principal stresses or with the directions of material anisotropy. The analytical solution has been verified by comparing its predictions with results from 3D FEM modelling, for a number of scenarios with increasing complexity. A parametric analysis has been conducted to investigate the interplay that exists between the orientation of the axis of the tunnel and the directions of the principal geostatic stresses and/or the directions of material anisotropy.

中文翻译：

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各向异性地基和各向异性地应力下深圆形隧道的解析解

具有明确结构的岩体也可能表现出明显的地应力各向异性；因此，隧道与地静力主应力和/或材料各向异性主轴的错位是很可能的。文献中可用的横向各向异性岩石隧道的分析解决方案假设隧道与地静主应力和材料各向异性的主要方向之一（即二维平面应变条件）对齐。这种假设是相当严格的。在本文中，提出了全各向异性岩石中圆形深隧道的新解析公式。它提供了隧道周围与地静主应力或材料各向异性方向不一致的完整应力和位移场。分析解决方案已通过将其预测与 3D FEM 建模的结果进行比较来验证，适用于许多复杂性不断增加的场景。进行了参数分析以研究隧道轴线方向与主要地静应力方向和/或材料各向异性方向之间存在的相互作用。