深埋隧洞TBM施工围岩参数劣化特性及演化机理研究

Study on Deterioration Mechanism of Surrounding Rock Parameters in TBM Construction of Deep-Buried Tunnel

摘要: 鉴于隧洞开挖会导致损伤区岩体参数发生一定程度劣化的工程实际，依托某大型深埋软岩引水工程，通过构建相应的数值试验模型，分析了TBM (Tunnel Boring Machine)连续开挖工况下隧道围岩参数的动态调整过程，探索了深埋软岩隧道围岩参数的动态劣化规律。结果表明采用TBM连续开挖时，隧道损伤区围岩参数劣化是一个连续的过程。具体表现为开挖过程中围岩的摩擦角由初始值φ₀逐渐增大为φ_e，黏聚力由初始值c₀逐渐减小为c_e；随着支护结构的完成，围岩的摩擦角较开挖过程中表现出降低的趋势，由φ_e最终衰减为φ_d，而黏聚力则较开挖过程中开始增大，最终由c_e演变为c_d。

Abstract: In the engineering fact that tunnel excavation will cause a certain degree of deterioration of rock mass parameters in the damaged zone of surrounding rock, based on a large-scale municipal transportation project, a corresponding numerical test model is established., a numerical model of the diversion tunnel under the condition of TBM (Tunnel Boring Machine) continuous excavation is established. By analyzing the dynamic adjustment process of tunnel surrounding rock parameters during TBM continuous excavation, the dynamic deterioration law of surrounding rock parameters in deep-buried soft rock tunnels is studied. It is considered that when TBM is used for continuous excavation of deep-buried soft rock tunnels, the deterioration of surrounding rock parameters in the damaged zone is a continuous process, which is specifically manifested in that during the excavation process, the friction angle of the surrounding rock gradually increases from the initial value φ₀ to φ_e, and the cohesion gradually decreases from the initial value c₀ to c_e; with the completion of the support structure, the friction angle of the surrounding rock shows a decreasing trend compared with that in the excavation process, finally attenuating from φ_e to φ_d, while the cohesion starts to increase compared with that in the excavation process, eventually evolving from c_e to c_d.