针对隧道穿越断层破碎带易发生围岩失稳的问题，基于突变理论提出考虑开挖扰动效应的敞开式TBM隧道围岩失稳分析模型。首先，通过建立简化的力学模型，引入采用Weibull分布函数描述的岩体本构模型，构建基于掘进参数的TBM开挖扰动参数拟合公式，并综合考虑地下水弱化效应对岩体本构模型进行修正； 其次，结合构建的简化力学模型与修正岩体本构模型，建立基于尖点突变理论的断层破碎带TBM隧道围岩失稳分析模型，进一步推导围岩失稳判据的量化评价参数； 最后，以某TBM隧道工程为依托，检验失稳判据的可靠性及准确性。分析结果表明： 围岩的稳定性受其抗剪能力影响显著，同时受开挖扰动和地下水的影响较为明显； 随着扰动参数和地下水压力的增大，围岩失稳风险增大。注浆加固手段可有效提高围岩的稳定性，理论上可提高围岩剪切模量至加固前的1.2~1.8倍，围岩失稳临界扰动参数从0.06增加到0.38~0.95，失稳临界水压力提高了21.9%~101.2%。现场采用化学注浆措施后，浆液能有效地充填岩体裂隙并显著增强围岩的抗剪能力，提高断层破碎带隧道围岩稳定性。
When tunnels pass through fault fracture zones, the surrounding rock is prone to instability. To address this issue, the study proposes an instability analysis model for open-type TBM tunnels that considers the excavation-disturbance effect based on catastrophe theory. First, a simplified mechanical model is established, and the rock-mass constitutive behavior is described using a Weibull distribution function. A fitting formula for TBM excavation-disturbance parameters is developed using tunneling parameters, and the constitutive model is modified to incorporate groundwater-induced weakening. Second, by integrating the simplified mechanical model with the modified constitutive model, a cusp-catastrophe-based analysis model for surrounding-rock instability in TBM tunnels crossing fault fracture zones is constructed, and quantitative evaluation parameters for the instability criterion are derived. Finally, the reliability and accuracy of the instability criterion are verified through a TBM tunnel case study. The results indicate that the shear resistance of the surrounding rock predominantly governs its stability, while excavation disturbance and groundwater also exert notable influences. As the disturbance parameter and groundwater pressure increase, the risk of surrounding-rock instability rises. Grouting reinforcement effectively improves surrounding-rock stability by increasing the shear modulus 1.2－1.8 times the prereinforcement value. The critical disturbance parameter increases from 0.06 to 0.38－0.95, and the critical water pressure increases by 21.9%－101.2%. Field application of chemical grouting shows that the grout effectively fills rock-mass fractures, substantially enhances shear resistance, and improves the stability of the surrounding rock in fault fracture zones.
