“四极三高”地质隧道施工关键技术与创新

Key Technologies and Innovations for the Construction of'Four Extreme and Three High'Geological Tunnel

目前对集穿越活动断裂带、高地应力、高地质灾害风险、软弱破碎岩性、地下水丰富等于一体的“四极三高”地质隧道施工技术研究较少。结合穿越岷江活动断裂带的成兰铁路“四极三高”红桥关隧道工程,针对其施工时极易发生变形侵限、钢拱架扭曲断裂、初支结构严重破坏,研发了长短锚杆与纵环向等刚度拱架组合体系、微三台阶上部预留大核心土的隧道开挖方法,加快了隧道施工进度以及初支结构封闭成环,有效控制了隧道大变形的发生;针对活动断裂带隧道错动大、震后结构损伤大的特点,研发了隧道穿越活动断裂带不等长多节段圆形衬砌结构体系,有效地增强了隧道结构的抗错动能力;研发了活动断裂带宽变形缝隧道结构防排水体系,解决了活动断裂带隧道渗漏水难题。这些创新技术的应用,实现了隧道安全快速掘进,可供类似工程参考。

At present,there is lttle research on the construction technology of'four extreme and three high'geological tunnels,which integrate the crossing of active fault zones,high geostress,high geological disaster risks,soft and fragmented lithology,and abundant groundwater.Combining the Hongqiaoguan Tunnel project of the Chengdu-Lanzhou Railway,which crosses the active fault zone of the Minjiang River,the tunnel is a four extreme and three high'tunnel,which is prone to deformation,steel arch distortion,fracture,and serious damage to the initial support structure during construction.We have developed a combination system of long and short anchor rods together with longitudinal and circumferential equal stiffness arches,as well as a tunnel excavation method with a large core soil reserved at the upper part of the micro three-bench.This has accelerated the tunnel construction progress and the closure of the primary support structure into a ring,effectively contrlling the occurrence of large deformation in the tunnel.In view of the characteristics of large dislocation and large structural damage after earthquakes in active fault zones,a circular lining structure system with unequal length and multiple segments has been developed for tunnels crossing active fault zones,effectively enhancing the anti-dislocation capacity of tunnel structures.A waterproof and drainage system for tunnel structures with wide deformation joints in active fault zones has been developed,solving the problem of water leakage in tunnels in active fault zones.The application of these innovative technologies has achieved safe and rapid tunnel excavation,which can be used as a reference for similar projects.