【摘要】 隧道的开挖引起围岩应力状态的变化,改变了隧道围岩的力学性能。在三维非线性有限元计算的基础上,研究分析了隧道开挖全过程中隧道围岩应力、位移变化规律以及开挖结束后隧道周边的应力、位移状态。研究结果表明:隧道的开挖是一个先加载后卸载的过程,隧道开挖卸荷效应在隧道拱底表现最为明显,拱顶次之;在隧道轴线方向上开挖对周边围岩的影响范围约为掌子面前后各1倍的隧道跨度,在隧道横断面方向上约为2倍的隧道跨度,对隧道截面中心岩体的影响范围在隧道轴线方向上约为掌子面到达该断面前1倍的隧道跨度。此外,文中还将计算结果与工程实际进行了定性的比较和分析。更多还原

【Abstract】 The excavation of the tunnel induces the changes of the stress state of the surrounding rock,such changes alter the mechanical property of the surrounding rock.On the basis of a detailed 3-D finite-element analysis,the near-field stress path and displacement changing law during the progressive advancement of a tunnel face and the state of stress,displacement around the tunnel after the excavation finished are studied and analyzed.According to the study results,some conclusions can be drawn out.The surrounding rock of the tunnel undergoes a stress path from loading to unloading during the excavation.The unloading effect of the excavation has more evident expression on the bottom than on the arch crown of the tunnel,and insignificant expression on the side wall of the tunnel.The region affected by excavation on the surrounding rock is from 1B before the tunnel face to 1B behind the tunnel face at the tunnel axis and 2B around the tunnel perpendicular to the tunnel axis.B represents the tunnel span.The results of the analysis and engineering practice are compared and studied qualitatively in this paper.更多还原