Gas Drainage Technology Optimization And Drainage Model Study Of Close-distance Coal Seams Group

There are a series of problems of governing gas which is caused by complex overburden fracture evolution law on close-distance seam group mining. The paper analyzes verburden destruction law and gas emission law during condition of the first mining protective layer and superimposed mining protective layer on close-distance seam group,elects favourable gas drainage technologies, puts forward gas drainage pattern, and takes experiments in Yue Liangtian mine 1318116 working face and Jin Jia mine 111811 working face. The main contents and results of the research are as follows.The paper is to analyze destruction law and pressure-relief area distribution law of overburden and underburden during condition of first minging and superposition mining protective layer of close distance coal seam group, and discuss gas emission passage and approach, analyze influence of mining coal seam on permeability of coal or rock.The paper is to put forward conception of gas drainage technology usability evaluation,and establish index system consists of effectiveness, economy, security, applicability for the mine commonly gas extraction technology, use AHP to determine index weight, and uses fuzzy mathematics theory to establish evaluation model. Based on mine commonly gas extraction technologies, 12 kinds of gas drainage methods with better effect are selected by using evaluation model, and analyzes adaptability of all kinds of gas drainage technologies.Based on analyzing characteristics of gas migration and reservoir, there is to establish cracks and gas-rich region model during condition of first mining and superposition mining protective layer of close distance coal seam group, and present three-directions and whole process gas drainage pattern during coal mining process.There is to propose method of governing gas for 1318116 working face, namely, bedding drilling holes, the roof downwards drilling holes, the upwards drilling in the return airway, high-field drilling holes in the return airway, buring tubes in the return airway. The results show that isn’t gas exceeding,gas drainage rate is 69.0%~82.8%. There is to propose method of governing gas for 111811 working face,namely, bedding drilling holes, the floor upwards dirlling holes, high-field drilling holes in the return airway, drilling at special gas road, buring tubes in the return airway. The results show that isn’t gas exceeding, gas drainage rate is 70.33%~89.22%.Gas control effect is well.