Study on Construction Response Characteristics of Large Cross-Section Tunnel Crossing Huge Karst Cave Backfill

The existence of giant karst cave can cause collapse and water inrush hazards during the excavation tunnel, causing serious economic losses. In this paper, based on FEA software MIDAS, a numerical simulation model for backfilling large through cross-section tunnel was established. distribution characteristics change rules displacement field, stress horizontal support stress, plastic zone surrounding rock backfill were explored. first stage leads to sharp increase in tunnel’s deterioration zone, which should be strengthened monitored. arch, waist, wall footing areas prone concentration. two layers force show certain regularity, showing gradually smooth growth trend. Meanwhile, site monitoring results arch settlement convergence mega cavern analyzed. that calculation good agreement with values data. average errors final crown 8.6% 15.9%, respectively, verified correctness modeling method. This project provide reliable experience construction similar tunnels.