The disaster law and control measures of high-stress tunnels in fault areas: a case study

In recent years, the frequent occurrence of dynamic disasters in tunnels with high stress in fault areas has greatly threatened engineering safety. The typical case - a tunnel influenced by fault slip on is taken as a research object. A series of physical simulation experiments and numerical simulations are conducted to analyze the stress evolution laws in the tunnel roof, shoulder, and coal pillar, along with the stress distribution characteristics across the working face at different excavation stages. The disaster mechanisms, the influence law of fault parameters and control measures for such tunnels are clarified. The main experiment results are as follows. The tunnel located in the hanging wall of the fault experiences a more pronounced increase in stress. Additionally, the closer the tunnel is to the fault plane in the hanging wall, the higher the stresses in the roof, shoulders, and coal pillar sides. For example, the stress at measurement point J_β-3 in the β measurement section is 63.4% higher than that at point J_α-3 in the α measurement section. Moreover, the surrounding rock at different locations of the tunnel is more severely affected by the fault deeper inside, while the shallow parts experience less influence. Meanwhile, the pressure relief effect by the artificial pre-splitting for high-stress tunnels is proven by the established quantitative evaluation indicators for stress increase and decrease. Among them, the application of the new technology results in a maximum reduction of 145.4% in stress change rate. Through this study, a preliminary measure for controlling the surrounding rock of high-stress tunnels in fault areas is proposed, which can provide a reference for the control of similar tunnels.