富水断层破碎带大断面隧道设计与快速施工

为解决石峡隧道穿越F7断层及其次生断层影响带、实现快速施工满足通车工期要求的目的，通过数值计算、现场监测等手段，对超前支护、初期支护、锁脚锚杆措施进行了优化，优化措施在工程应用中取得了良好的效果。实践证明： 自进式管棚集钻进、注浆、支护于一体，增强了围岩的稳定性并大幅提高了超前支护施作效率；管棚保护下的两台阶快速开挖方法可实现初期支护的早封闭、少扰动，大幅提高了施工进度；不同角度、长度锁脚锚杆对拱顶沉降、周边收敛的影响规律，应结合围岩与衬砌变形规律选取合理的设计参数；管棚保护下的两台阶快速开挖方法及R51锁脚锚杆有效控制了围岩稳定和初期支护变形。

Design and Fast Construction Technology for Large Cross Section Tunnel in Water Rich Fracture Zone

To successfully cross F7 fault and related secondary fracture zones and realize fast construction of Shixia tunnel, the advance support, primary support, and foot locking anchor bolt are optimized through numerical calculation and field monitoring methods. The recommended measures have achieved good results in engineering application. The practical results reveal the following: (1) The self propelled pipe shed integrates drilling, grouting, and support, which enhances the stability of surrounding rock and greatly improves the construction efficiency of advance support. (2) The two bench rapid excavation method under the protection of pipe shed can realize early closure and less disturbance of primary support, and greatly improve the construction progress. (3) The influence law of various angles and lengths of foot locking anchor bolt on crown settlement and peripheral convergence vary, hence, reasonable design parameters should be selected according to the deformation law of surrounding rock and lining. (4) The two bench rapid excavation method under the protection of pipe shed and R51 foot locking anchor bolt can effectively control the stability of surrounding rock and the deformation of primary support.