Analysis Of Water Inrush Disaster In Karst Tunnel And Research On Prevention Technology

In the process of tunnel design and construction,it is inevitable that more and more complex geological environments need to be traversed.Affected by the complex geological structure in karst areas,engineering accidents such as water inrush and mud inrush often occur during tunnel construction.The occurrence of these accidents severely restricts the rapid development of tunnel construction in karst areas;therefore,it is necessary to determine the characteristics and development of karst caves.Conduct research on the law,find the disturbance factors that affect the stability of the tunnel surrounding rock under different working conditions,establish an effective,economical and reasonable comprehensive prevention and control plan for tunnel crossing karst areas,and fundamentally solve the water inrush,Problems such as mud gushing have important technical value for tunnel construction in karst areas.This paper analyzes the water inrush accidents that occurred during the construction of Yiwan Railway and Yuhuai Line,combined with theoretical analysis,numerical calculation and other means to analyze the pairs of karst caves with different water pressures,sizes,distances,surrounding rock grades,and locations.Based on the influence of the stability of the surrounding rock of the tunnel,a prediction model for the safe thickness of the anti-outburst layer under different working conditions was established.Then,the existing advanced geological prediction and treatment technology of karst tunnels are summarized.The main results of this paper are:(1)Through checking the water inrush data of karst tunnels,it is clarified that the water inrush process of karst tunnels is divided into three stages: the storage of water inrush energy,the formation of water inrush channels,and the eruption of water inrush energy.These processes are affected by the geology of karst areas.Factors,hydrological factors and the influence of tunnel excavation.(2)The mechanism of water inrush disaster in karst tunnels was studied,and the stability of the rock strata between the tunnel and caverns played a key role in the occurrence of water inrush,and the anti-outburst layer was simplified into a mechanical model of elastic beams and slabs.The water inrush from karst tunnels is divided into two modes: rock disk water inrush from water-rich karst cavity and water inrush from karst pipeline.(3)Based on different water inrush modes,the effects of rock disc-shaped water-rich karst cavity and karst pipeline on the tunnel surrounding rock seepage field,stress field and displacement field were studied by using COMSOL Multiphysics numerical simulation software.According to the numerical simulation results: The influence of water-bearing structures with different water pressures,sizes,levels and locations of surrounding rock on the stability of tunnel surrounding rock,and the critical distances for the construction of rock-pan-type karst tunnels and karst pipeline-type tunnels under different working conditions are discussed.It provides a certain reference value for tunnel construction in karst areas in the future.(4)Through consulting related literature,summarized the advanced geological prediction methods commonly used in the construction of karst tunnels,including the geological method,the advanced pit method,the ground penetrating radar method,the infrared detection method,etc.,which focused on the Swedish geology used in the practice.The operation steps and results of the radar are analyzed,and the basic principles and treatment measures for water inrush prevention in karst tunnels are summarized.