Study on time-varying mechanism of energy dissipation structure in depressed-pressure gas transport and storage area of inclined thick coal seam mining

ZHAO Pengxiang; CHANG Zechen; LI Shugang; ZHUO Risheng; JIA Yongyong; LEI Wen; SHAO Qiudong; PEI Wenbo

doi:10.13247/j.cnki.jcumt.20240150

Abstract：In order to determine the generation and evolution law of depressurized the gas trans-port and storage areas under the influence of energy dissipation structure of overlying rock dur-ing mining of inclined thick coal seam.Based on the main mining face of B5 # coal seam in Tengda Mining,Heze,Changji,Xinjiang,the time-varying law of overlying rock fissure was investigated by theoretical research and physical similarity simulation experiment.The region-al scope of the pressure relief gas transport and storage areas was defined.The energy dissipa-tion structure in overlying rock in the depressurized gas transport and storage areas was de-fined.The types,formation criteria and evolution rules of energy dissipation structures were determined.And the time-varying mechanism of energy dissipation structures in the depres-surized gas transport and storage areas of inclined thick coal seam mining was revealed.The results shown that the abrupt change point of fracture density 5.5/m and the abrupt change point of penetration degree 0.57 were important parameters in the mining process.These two parameters could be used to divide the fracture field into gas reservoir area,gas migration area and compaction area.According to the energy accumulation form,the energy dissipation struc-ture of overlying rock could be divided into point energy dissipation structure and line energy dissipation structure.The energy dissipation structure had a"half moon"shape.The error be-tween the calculated value of energy dissipation structure instability failure criterion and the measured value of field microseismic monitoring was less than 9.58％.The final drilling hole was arranged in the gas transport and storage areas.The average single-hole gas extraction pu-rity and gas extraction volume fraction increased by 156％and 196％compared with that be-fore regulation.The average gas volume fraction in the upper corner,working face and return air roadway was reduced to 0.31％,0.12％and 0.22％.The gas extraction effect was good.The research results further provided some theoretical guidance for high efficiency extraction of depressurized gas in inclined thick coal seam.