Study On Gas Migration Law And Prevention Of Coal Bearing Tunnel

In recent years,China has vigorously developed infrastructure construction.Tunnel engineering is an indispensable part of infrastructure.Tunnels inevitably encounter some tunnels with complex geological conditions when crossing mountain ranges.Sometimes,they must cross coal-bearing gas tunnels.This paper takes the Fenshuiling tunnel as the research background,adopts a series of theories of tunnel surrounding rock elastoplastic mechanics theory,surrounding rock loose circle theory,gas seepage theory,gas migration theory and gas governance theory.By simulating the researched content and taking on-site tests to obtain the first-hand information of the research site,a comprehensive monitoring and monitoring system for gas and ventilation used in the construction and use of tunnel engineering is proposed.The specific research content and results are as follows:(1)Through the theoretical analysis method,the mechanics and gas variation law of coal-bearing tunnels are analyzed,which are the stress and variation law of surrounding rock of coal-bearing tunnel,the stress and variation law of radial surrounding rock of coal-bearing tunnel,The mechanical analysis of the surrounding rock of coal-bearing tunnel floor and its change law and the mechanical analysis of coal-bearing tunnel gas migration.The results show that under the action of gas construction stress,the desorbed gas in the coal rock ran out through the crack,and then as the crack gradually increased,the adsorbed gas ran out through the crack,causing the gas to migrate along the crack under its pressure.The relationship between the fissure change,the radius of the plastic ring of coal and rock mass,and the force required to generate the bottom drum of coal-bearing tunnel.(2)Using FLAC3D finite-difference software to study the coal-bearing tunnel migration and treatment,the seepage characteristics and migration law of the surrounding rock gas,the coal-bearing tunnel construction mechanics numerical simulation study,and the coal-bearing tunnel gas-bearing analysis Seepage field distribution characteristics,gas seepage effect on stress field distribution,gas seepage effect on coal rock surrounding rock deformation,etc.(3)Research on tunnel gas control methods from four aspects: prediction of coal-bearing tunnel gas,coal-bearing tunnel gas prevention measures,coal-bearing tunnel gas prevention measures effect verification,coal-bearing tunnel gas prevention measures effect verification.The treatment method is to adopt the continuous gas drainage method of the cross-set drainage drill field along the direction of the tunnel to ensure a safe distance of 60 m in front of the tunnel face and 15 m around the tunnel.(4)The gas and ventilation monitoring and monitoring system for coal-bearing tunnels are studied.For the first time,it is proposed to combine gas monitoring unit,wind speed and direction unit,sound and light alarm unit,and switch monitoring unit into one system.A gas pressure automatic locking device is designed to solve a series of problems such as inaccuracies and large errors caused by the artificialization of the current tunnel gas data and ventilation monitoring,and realize the automation of tunnel gas and ventilation monitoring and monitoring.