Research On Multi-channel Sealing Device And Sealing Technology For Gas Drainage Borehole In Underground Coal Mines

Driven by the huge demand for energy for high-quality development,China's coal mining is moving towards coal seams with deeper burial and more complex conditions,which brings more serious gas hazard problems and causes a sharp increase in the pressure of safety production.The extraction of gas by construction boreholes is an important means to prevent and control gas hazards,and the sealing effect will have a direct impact on the efficiency of gas extraction,so improving the sealing efficiency is one of the research focuses in the field of underground gas extraction.With the continuous promotion of automation and mechanization in the underground,further requirements are put forward for underground hole sealing.Designing a sealing device to solve the problems of limited sealing length,low sealing efficiency and low automation in underground hole sealing construction,which can realize automatic sealing,will provide equipment basis and technical support for the automation and less human development of underground sealing application.Based on the project of “Underground Gas Prevention and Control Drilling and Sealing Robot" of the National Key Research and Development Program of the 13 th Five-Year Plan,this paper developed multi-channel hole sealing device based on the technology of pressure sealing process.Through theoretical calculations,numerical simulations,indoor tests and field tests,parameters such as seating and sealing pressure,slurry injection pressure and slurry diffusion law are analyzed,multi-channel pressure sealing process is studied,and an integral multi-channel sealing device is designed,which can realize automatic switching of slurry injection,gas return,slurry return and gas extraction.The field test proves that the sealing device can realize mechanized operation and has the ability to realize automation;under the guidance of the designed process,the device can meet the needs of hole sealing for boreholes within 100 mm in diameter,and the maximum sealing length can reach 20 m.