软弱地层敞开式TBM大规模塌方成因及处理措施研究

综合应用TSP地震波检测、CFC超前探水和现场岩石的点荷载试验等多种手段,对新疆某引水隧洞敞开式TBM穿越软弱地层发生的大塌方原因进行综合分析,认为绢云母片岩和黑云母石英片岩在刀盘切削作用和震动影响下沿节理面和裂隙面岩层松动、错落,导致围岩大面积失稳坍塌。针对敞开式TB M穿越软弱围岩大塌方的成因,提出松散岩体初步加固,强化初期支护体系,建立喷射混凝土作业平台,建立刀盘覆盖层,塌方空腔回填的完整综合处理措施。敞开式TBM穿越软弱围岩大塌方段的空腔内部施作拱顶"保护壳"的处置技术,充分利用腔体内部空间,提高了拱顶保护壳的施工效率,成功指导了塌方段的处理和后续段的安全施工,可为类似工程提供参考。

Research on Causes and Treatment Measures of Large-scale Collapse of Open Type TBM in Weak Stratum

In combination with TSP seismic wave detection,CFC advanced water exploration and point load test of on-site rock,the author comprehensively analyzed the causes of large scale collapse of the open type TBM passing through a weak stratum in a water diversion tunnel in Xinjiang,and considered that the sericite schist and the biotite quartz schist loosened and staggered along the joint surface and the fracture surface under the influence of the cutting action and vibration of the cutterhead,resulting in large-scale instability and collapse of the surrounding rock.Aiming at the cause of collapse while the open type TBM crossing the weak surrounding rock,the complete comprehensive treatment measures were proposed,including the preliminary reinforcement of loose rock mass,strengthening the initial support system,establishing the shotcrete working platform and cutterhead cover layer,and backfilling the cavity.The open type TBM passes through the inside cavity of the large collapsed section of the soft surrounding rock is used as the disposal technology of the dome"protective shell",which makes full use of the internal space of the cavity,improves the construction efficiency of the dome protective shell,and successfully guides the treatment of the collapse section and the safe construction of the subsequent sections.It could provide reference for similar projects.