Encircling Face Electromagnetic Method Of Coal Floor Inrush Monitoring Technology Research

Traditional geophysical prospecting methods such as direct current method, transientelectromagnetic method, radio wave penetration method, seismic CT method etc. are staticobservation results at a certain time.In the process of mining face,as the floor stressrelease,bottom water bearing structure or fissure in the floor under the action of confined waterdevelop into water channels gradually and break the water-resisting layer and lead to inrushaccident.Water bearing structure or fissure is changing along with the mining face,so we need amethod to realize long-term real-time monitoring for the upgrow of water bearing structure orfissure,aiming at the above problem encircling face electromagnetic method of coal floor waterinrush technology is put forward.Referring to ground fixed source loop transient electromagnetic theory,according to theactual construction environment of coal mining work face,the encircling face electromagneticmethod is put forward.Research work was from theoretical research,numerical simulation andphysical simulation experiment,using the result of numerical simulation,the paper analyzed theencircling face method in the whole space layered medium,the abnormal body of different depthand different position,multiple abnormal bodies response between different measuring lines andpoints. Physical experiment simulated uniform whole space,different position and depth abnormal body.Through numerical simulation and physical experiment results analysis, arbitrarymeasuring points in transmit loop has obvious response of different abnormal water-bearingbody and it can be used to predict working face floor water inrush information providing atheoretical basis for the design of encircling electromagnetic observation system.According tothe results of numerical simulation and physical simulation experiment, this paper puts forwardthe encircling face electromagnetic floor inrush real-time monitoring system. Combined with thedistance between water-bearing fissures and coal floor,using the electromagnetic response signalto describe inrush coefficient method and the water inrush coefficient of water inrush is dividedinto three water inrush prediction threshold:remind threshold;waring threshold;alarm threshold.Through the above study,proved the validation of encircling electromagnetic method,laid asolid theoretical foundation for the instrument development and practical application.