LIN Z B, WANG S, LIN P Z,et al.Impact analysis of karst caves on surrounding rock deformation-failure and water inrush in large-section tunnels[J].Journal of Henan Polytechnic University(Natural Science) ,2026,45(4):49-57.

doi:10.16186/j.cnki.1673-9787.2024100009

Received:2024/10/11

Revised:2024/12/19

Published:2026/06/17

Impact analysis of karst caves on surrounding rock deformation-failure and water inrush in large-section tunnels

Lin Zhibin1, Wang Song1, Lin Peizhong2, Zhang Boyang1, Yang Dafang1

1.School of Civil Engineering， Henan Polytechnic University， Jiaozuo  454003， Henan， China;2.Henan Natural Resources Monitoring and Land Consolidation Institute， Zhengzhou  450016， Henan， China

Abstract: Objectives To analyze the influence of karst caves on the construction of large-section tunnels， and to investigate the deformation， failure， and water inrush characteristics of tunnel surrounding rock under various occurrence states of karst caves. Methods Based on the Shuangbei Tunnel project， considering the stress-damage-seepage coupling effect of the surrounding rock， numerical simulations were conducted using FLAC3D software. The simulations analyzed the displacement， failure zone， water-conducting fracture channels， and water inflow characteristics of the large-section tunnel surrounding rock under five factors and four levels： the angle between the karst cave and the tunnel center， the clear distance between the karst cave and the tunnel， the diameter of the karst cave， the water pressure in the karst cave， and the initial permeability coefficient of the rock mass surrounding the karst cave. The range analysis method was systematically used to evaluate the impact of karst caves on the deformation， failure， and water inrush degree of the tunnel surrounding rock.  Results The results show that： under conditions without a karst cave， the maximum displacement of the tunnel surrounding rock is 104.1 mm， the failure zone exhibits a "butterfly-shaped" distribution， with failure width and height of 7.0 m and 25.9 m， respectively. When a dry （water-free） karst cavity exists near the tunnel， the plastic zone of the surrounding rock expands and extends toward the karst cave， and the maximum displacement increases by approximately 30%~42%. When a water-rich， high-pressure karst cave exists near the tunnel， one or several water-conducting fracture channels form in the rock mass between the tunnel and the karst cave， and the maximum displacement of the surrounding rock exceeds 1，000 mm. The range values for the influence of the five karst cave occurrence parameters on the maximum displacement of the tunnel surrounding rock are 215.8， 443.4， 453.1， 869.3， and 227.5 mm， respectively. The range values for the influence on the failure area of the tunnel surrounding rock are 351.8， 102.1， 372.5， 243.3， and 166.4 m⟡， respectively. The range values for the influence on the total water inflow of the tunnel surrounding rock are 1，797.3， 2，829.4， 1，747.6， 2，336.5， and 2，816.0 m³/h， respectively. Conclusions When karst caves near the tunnel contain no groundwater， their impact on the stability of the large-section tunnel surrounding rock is relatively small. When groundwater is present， there exists a critical water pressure value that triggers the formation of water-conducting fracture channels between the tunnel and the karst cave， leading to overall sliding instability and water inrush. Among the five karst cave occurrence parameters， the water pressure in the karst cave determines the final displacement magnitude of the tunnel surrounding rock. The diameter of the karst cave and the angle between the karst cave and the tunnel center are key parameters affecting the extent and degree of failure of the tunnel surrounding rock. The clear distance between the karst cave and the tunnel， the initial permeability coefficient of the rock mass surrounding the karst cave， and the water pressure in the karst cave are the most important parameters controlling local and overall water inflow into the tunnel.

Key words:karst cave;large section tunnel;surrounding rock deformation-failure;water inrush;influence degree;range analysis