基于尖点突变理论的隧道围岩失稳判据与变形控制方法研究OACHSSCD

To identify the critical state of tunnel surrounding rock instability under complex geological conditions and establish deformation control criteria,this study takes the Macaozi Tunnel as the engineering background.Based on catastrophe theory,and combined with the strength reduction method and finite element numerical simulation,this study investigates surrounding rock stability from the perspective of energy evolution.Using the plastic dissipation energy of the surrounding rock as the characteristic parameter,this study establishes a catastrophe model,calculates the catastrophe characteristic value,and determines the safety factors and displacement control values under the CRD excavation method at different burial depths.The results show that the catastrophe characteristic value can effectively characterize the evolution of the surrounding rock from stability to instability,and the system undergoes catastrophic failure when it changes from positive to negative.Under the CRD method,the safety factors at burial depths of 50 m and 30 m are 3.45 and 3.35,respectively,and the results obtained from the energy criterion are generally consistent with those from the displacement criterion.The study shows that this method can accurately identify the critical state of surrounding rock instability and provide a quantitative basis for tunnel construction deformation warning and support parameter optimization.