Influence mechanism and calculation of the minimum safe thickness of waterproof rock mass in karst tunnels  

作　　者：AN Pengtao LI Maoxiang ZHANG Wenjun LIU Xiong 

机构地区：[1]Guangxi University,Nanning 530000,China [2]State Key Laboratory of Featured Metal Materials and Life-cycle Safety for Composite Structures,Guangxi University,Nanning 530000,China

出　　处：《Journal of Mountain Science》2025年第2期695-709,共15页山地科学学报(英文)

基　　金：jointly funded by the guangxi Science and Technology Base and Talent Project(AD23026104);the Key Research and Development Program Project in Guangxi(AB23026121)。

摘　　要：Due to the influence of karst cave development and route selection,the location relationship between concealed karst cave and tunnel is more random.In order to explore the influence rule of karst cave location on the minimum safe thickness of water-proof rock mass,a simplified calculation model of water-proof rock mass thickness when the karst cave is located at any location around the tunnel is established,and the influence of multiple factors on the overall stability of water-proof rock mass is considered.Based on the cusp catastrophe theory,the analytical expressions for the safety thickness of waterproof rock mass are derived.Based on the finite difference principle,the analytical expressions of the safety thickness of water-proof rock mass are verified.In order to improve the application range of the analytical formula derived in this paper,the analytical formula is optimized based on the instability principle differences between the simplified calculation model and the elastic compressive bar.The research results show that the necessary condition solution is more applicable and much safer than the sufficient condition solution.Tectonic stress,rock beam length and karst cave water pressure are significantly positively correlated with the safe thickness of the waterproof rock mass.The calculated results of the semioptimized formula and the unoptimized formula are constant values,independent of the karst cave location.While the calculated results of the fully optimized formula are variable values,correlated with the karst cave location,the thickness of the waterproof rock mass gradually decreases as the karst cave location moves from the top of the tunnel to the bottom of the tunnel.The unoptimized formula does not consider the influence of the lateral force of the rock beam,and is not suitable for the working condition with large lateral force,the calculation results of the semi-optimized formula and the fully optimized formula are not very different and are biased to safety,so it can be given priority.

关 键 词：Tunnel engineering Water inrush disaster Safe thickness Waterproof rock mass Concealed karst cave 

分 类 号：U458[建筑科学—桥梁与隧道工程]