中文摘要：

采用摩尔-库仑弹塑性模型的有限元分析方法和岩体开挖卸荷理论,并考虑地应力对隧洞的作用机制,建立丹巴水电站双洞四机引水隧洞软岩段三维开挖大型三维模型并进行岩体力学计算,分别以不同的掌子面推进深度进行开挖,从洞口开挖至一定深度。统计不同掌子面推进深度下各步开挖不同关键点处的位移变化情况,进行比选,建议工程实际应当选用的最佳掌子面推进深度;在该推进深度下,统计不同洞段不同位置的各向位移预留量,为超前支护的必要性提供依据和超前支护的施工提供数据支持,以保证工程施工的顺利进行,为后续类似工程设计提供参考。

英文摘要：

A large three-dimensional model of double hole four dimensional Danba hydropower station diversion tunnel excavation is established, and rock mechanics are calculated by using the Mohr-Coulomb model finite element analysis method and unloading rock mass theory and method, and the effect of stress on tunnel is considered to excavate in different depths of tunnel face, from the hole to a certain depth. The displacement changes of tunnel faces at different key points at each excavation are counted. In comparison, the depth of the best tunnel face propulsion should be selected. Under the propulsion depth, the amount of reserved displacements at different segments and locations of holes is counted to provide data support of necessity of advanced support so as to ensure the construction process successfully. It provides references for other similar engineering design.