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为避免高地应力软弱破碎围岩隧道开挖过程中发生过大变形引起隧洞周围岩体产生塑形挤入,初支曲屈、开裂甚至垮塌,利用FLAC3D有限差分数值计算手段开展软弱破碎地质条件下隧道大变形特性研究。结果表明:F3、F4断层附近区域隧道相对变形指标分别为2.8%和3.6%,可能发生中等或严重大变形;拱顶和边墙打设4.0m径向锚杆,可控制约50%变形量;上台阶设置扩大拱脚能有效控制拱顶沉降和拱脚水平位移,但对拱脚以下断面收敛变形控制效果不明显。其结论可为软弱破碎地质条件下大变形隧道设计施工提供一定参考和借鉴。
In order to avoid the deformation of surrounding rock mass caused by the high deformation in the excavation process of surrounding rock mass, the rock masses around the tunnel are distorted and deformed, and the primary tripping, cracking and even collapsing are carried out. The weak crushing geological conditions are calculated by using FLAC3D finite difference numerical method Research on Large Deformation Characteristics of Tunnels. The results show that the relative deformation indexes of the tunnel near the fault F3 and F4 are 2.8% and 3.6%, respectively, and moderate or severe deformation may occur. The vault and sidewall are laid with 4.0m radial bolts, which can control about 50% deformation The enlargement of the arch on the step can effectively control the settlement of the vault and the horizontal displacement of the arch, but the effect of convergence control on the following section of the arch is not obvious. The conclusion can provide some reference and reference for the design and construction of large deformation tunnel under weak and fragile geological conditions.