The Evolution Laws And The In-situ Research Of Close-distance Seam Group Ming-induced Permeability Characteristics

For most of the coal mines in China with a low permeability and poor ventilation, the actualproduction process has difficulty in extraction and pre-drainage CBM through ground drilling.In the process of coal mining, mining sphere of influence, pressure release full and miningfractured are conducive to CBM desorption. Through theoretical analysis, calculate-deduction,laboratory modeling and numerical simulation method, and on the basis of previous studies aboutthe law on single coal seam mining fissures, studying the fissures’ temporal evolution law on theclose distance coal seams which are under the influence of coal-mining. Multidimensionalpiecewise equation are been constructed to describe the the time and space concepts of the crackfield. Through many ways of monitoring, the real resource and passage of gas after the protectivelayers of close distance coal seams is been mined. And on the basis of this, the law on the gas’storage and transportation in the whole coal-rock structure has been studied. In this paper, throughthe ways of analysis of field data and tracer gas, we tested the changes of permeability and therelease of gas during the coal seam group mining process while pressure-relief coal seam beingmined in different pressure-relief protective area. We have explored a new tool to monitor themining fractured space-time evolution, which is able to predict the test and revise the laws of gasstorage and transportation. It has provided both theoretical and practical basis in choosing a morereasonable gas prevention and control technology and coordinated extraction of coal and gas.