Integrated early warning and reinforcement support system for soft rock tunnels: A novel approach utilizing catastrophe theory and energy transfer laws

Abstract

The initial support strength of deep-buried soft rock tunnels during excavation is often inadequate, and the timing of reinforcement support is inappropriate. This inadequacy leads to significant deformations in the tunnel, causing the energy released by the surrounding rock to exceed the energy that the support system can absorb, ultimately resulting in tunnel collapse. Tunnel deformation monitoring and anchorage support, when combined with energy transfer laws, are thus imperative for studying collapse prediction, the timing of reinforcement support, and parameters of the reinforcement support system of the surrounding rock. In this paper, a novel approach for early warning and support control in tunnel construction facing large deformations is introduced, and a predictive model for surrounding rock instability utilizing catastrophe theory and energy transfer laws is developed. By analyzing the correlations of rock deformation and energy dissipation, the timing of anchor reinforcement support was determined using function fitting techniques. Further, an energy transfer model under reinforced anchoring support was established, and the energy absorption parameters of the support body were determined. Also, the support parameter design scheme was proposed. The results indicate that the early warning and reinforcement support scheme proposed in this paper reduces the release of potential energy by 35.71 %; decreases the number of steps needed to reduce kinetic energy to zero by 66.67 %; reduces the total dissipated energy in joint shear by 33.68 %; increases the total stored strain energy in the material by 5.70 %; and reduces the total dissipated work in plastic deformation by 26.15 %. Additionally, this plan effectively controls the originally predicted large deformation area of the meter level to within 350 mm.