In response to the severe damage problem of deep and large section tunnels in the Dahaize coal mine, this article summarizes the characteristics of on-site tunnel damage through on-site investigation and reveals the mechanism of tunnel damage induction. On this basis, a targeted support optimization scheme with high bearing capacity flexible anchor rods as the core was proposed. In order to verify the rationality of the optimization plan, a Trigon model was established using UDEC, and the deformation amount, plastic zone range, and distribution characteristics of rock fractures in the roadway were compared between the original plan and the optimized plan under two different conditions. The simulation results show that after adopting the optimization scheme, the bearing capacity of the surrounding rock is significantly improved, the deformation and plastic zone range of the tunnel are significantly reduced, and the number of internal cracks in the surrounding rock is significantly reduced. After conducting industrial tests on site, the surrounding rock of the roadway tended to stabilize at 50 days, with a maximum subsidence of 197 mm in the roof. The overall shaping effect of the roadway on site was good.