Research on the movement law of overlying rock strata and gas drainage experiment in fully mechanized caving face in Wangjialing Coal Mine
In order to achieve safe and efficient mining of the fully mechanized caving face in a mine with low gas content and high gas emission,with Wangjialing Coal Mine as the background,combined with physical similarity simulation experiments,UDEC numerical simulation,and micro-seismic monitoring,the movement law of the overlying strata on the fully mechanized caving face in Wangjialing Coal Mine was systematically analyzed.On the basis,on-site gas drainage experiments were conducted in the pressure relief zone.The research results indicated that as the working face advanced,the distance between the direct roof collapse height and the coal seam floor,the distance between the separation layer crack and the roof both increased,and the height of the cavity decreased;there were more cracks in the gas migration channels on both sides of the goaf than in the compacted area.Before the initial weighting,the vertical stress in the goaf decreased with the advancement of the working face;after the initial weighting,the vertical stress in the goaf increased with the advancement of the working face.A total of 2 572 micro-seismic events occurred on the roof of the intake and return air roadways,the coal seam,and the roof and floor of the goaf,and the stress concentration was significant within a range of 50 m in front of the working face,which needed more attention to advanced support and prevention.The average step distance of periodic weighting in the 12301 working face was 20-26 m,the height of the mining fracture zone was 90-110 m,and the periodic weighting occurred 4-6 times.In the on-site gas drainage test at pressure relief zone,the gas drainage amount of the reasonable level working face was 1.5 times that of the other level working faces,and the gas concentration in the upper corner of the working face and the return air flow was less than 0.8％,the gas control effect was significant.
low gas mineoverlying rock stratacracksnumerical simulationmicro-seismic monitoringgas drainageWangjialing Coal Mine
万方数据
维普
