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。
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 selfpropelled 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 twobench 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 twobench 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.