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水利工程中的大坝、输水隧洞、泄水建筑、铁路与公路隧道等均会遇到断层;本文以大伙房水库输水工程27+500 m～27+560 m断面破碎断层为工程背景,建立三维有限元数值模型,进行了断层破碎带施工的围岩力学效应分析。研究表明:断层破坏了原岩体介质的连续性,使水平及垂直应力分布失去对称性,出现明显的“偏压”现象。在断层破碎带处拱脚及其边墙处产生高剪应力区,使得初期支护的内力增加约120～130%,导致拱脚及边墙的位移大幅增加;因此建议在断层破碎带施工时,应采取超前支护措施(包括固结灌浆、超前锚杆、超前小导管),并且二次衬砌应紧跟初期支护施工,充分利用时空效应的影响,以最大限度地控制洞室施工阶段的变形,保证施工的稳定与安全。
In the water conservancy project, the dam, the water conveyance tunnel, the drainage construction, the railway and the highway tunnel all encounter the fault. Based on the engineering background of the 27 + 500 m ~ 27 + 560 m section broken fault of the Dahuofang reservoir water conveyance project, The three-dimensional finite element numerical model is established and the mechanics effect analysis of surrounding rock is carried out. The results show that the fault ruptures the continuity of the original rock mass and loses the symmetry of the horizontal and vertical stress distribution, resulting in obvious “bias ” phenomenon. The high shear stress zone at the arch foot and its side wall at the fault fracture zone causes the internal force of the initial support to increase by about 120-130%, resulting in a significant increase of the displacement of the arch foot and the side wall. Therefore, it is suggested that during the construction of the fault fracture zone , Advanced support measures (including consolidation grouting, advance anchor and small lead pipe) should be taken and the secondary lining should be closely followed by the initial support construction to make full use of the effect of space-time effect so as to control the construction stage of the cavern to the maximum extent The deformation, to ensure the stability and safety of construction.