An analytical solution for stresses and deformations of tunnels in a non-uniform stress field based on strain-softening model and Mogi-Coulomb criterion
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Abstract In this study, a mechanical model for tunnels excavated in a non-uniform stress field is developed. A new strain-softening model simultaneously considers the weakening of cohesion and internal friction angle is proposed. Then, an analytical solution for the post-peak region radii, stresses, and displacements is deduced. Taking a tunnel in Taoyuan coal mine as an engineering example, the post-peak region radii, surface displacement, and stresses distribution are determined. The effects of the horizontal-to-vertical stress ratio, intermediate principal stress, residual cohesion, and residual internal friction angle on tunnel deformations are discussed. The results show that the post-peak region radii and stresses distribution around the tunnel varies with direction due to the non-uniform stress field. The post-peak region radii and surface displacement are larger with consideration of intermediate principal stress. Tunnels surrounded by rock masses with a higher residual cohesion and internal friction angle experience lower post-peak region radii and surface displacement.
摘要 本研究构建了非均匀应力场中掘进隧道的力学模型。提出了一种同时考虑黏聚力与内摩擦角弱化效应的新型应变软化模型。随后推导了峰后区域半径、应力与位移的解析解。以桃园煤矿某隧道为工程实例,确定了其峰后区域半径、表面位移及应力分布规律。探讨了水平-垂直应力比、中间主应力、残余黏聚力与残余内摩擦角对隧道变形的影响。研究结果表明,受非均匀应力场影响,隧道周围峰后区域半径与应力分布随方向发生变化。考虑中间主应力时,峰后区域半径与表面位移更大。围岩残余黏聚力与内摩擦角越高的隧道,其峰后区域半径与表面位移越小。




