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6 / 2023-05-05 22:28:23
Study on the evolutionary fractal characteristics of high seepage zone of unloading gas with different recovery rates in thick coal seam mining and target extraction technology
comprehensive mining face; recovery rate; unloading gas high seepage area; extraction technology; fractal dimension
6. Coal mine gas control and utilization
全文录用
Yibo Zhang / Xi'an University of Science and Technology
Pengxiang Zhao / Xi'an University of Science and Technology
Shugang Li / Xi'an University of Science and Technology
Yongyong Jia / Xinjiang Uygur Autonomous Region Coal Science Research Institute
Haifei Lin / Xi'an University of Science and Technology
Qiudong Shao / Xinjiang Changji Heze Tengda Mining Co. LTD
In order to study the influence of recovery rate of overburden unloading gas high permeability zone in mining workings, the study of fracture evolution law of overburden unloading gas high permeability zone under different recovery rates (70%<80 %<90 %<100 %) was carried out by using the combination of physical similar simulation test and theoretical analysis, and the evolution law of fracture fracture of overburden unloading gas high permeability zone in high permeability zone was obtained. The evolution law of fractal dimension with the change of recovery rate was obtained. The results show that after the coal seam is mined, according to the change of seam fracture volume, when the recovery rate is 70 %, the fractures are fully developed in the range of O~O1 (advancing distance of 0~30 m) on the cutter side and W~W1 (advancing distance of 65~90 m) on the working face side; when the recovery rate is 80 %, 90 % and 100 %, the fractures are mainly in the range of O~O2 (advancing distance of 0~35 m) on the cutter side and W~W1 (advancing distance of 65~90 m) on the working face side. In the range of O~O2 (advancing distance of 0~35 m) on the cuthole side and W~W2 (advancing distance of 60~90 m) on the working face side, the overburden fracture density is changed in three stages of A (5~30 m from the cuthole), B (30~57.5 m from the cuthole) and C (57.5~90 m from the cuthole); the maximum fracture density of gas transportation channels on the cuthole side is 8.8, 9.4, 10.3 and 12.6 respectively, 10.3 and 12.6 fractures/m, and 8.1, 8.8, 9.7 and 11.2 fractures/m on the working face side; the fracture rate on the overburden surface shows a trend of decreasing and then increasing from the fall zone to the fracture zone. Through the fractal dimension analysis of overburden fractal network, the distribution characteristics of gas flow active zone, unloading gas high permeability zone and unloading gas storage zone were determined, and the geometric boundary of unloading gas high permeability zone and the gradient of fractal dimension of unloading gas high permeability zone under different recovery rates were quantitatively characterized by the amount of detachment, fracture density, surface fracture rate and fractal dimension of fractal network. The end-state widths were 9.21 m, 9.59 m, 10.42 m and 10.97 m, and the heights were 46.67 m, 51.08 m, 54.19 m and 56.66 m as the recovery rate increased, and the unloading gas hyperpermeability zone was determined to be located within 20-50 m from the coal bed roof. Finally, based on the theory of mining fracture ellipse throwing zone, the overburden unloading gas high permeability zone shaped dimension control model was established and applied considering the influence factors of recovery rate, and the process of unloading gas high permeability zone prevention and control system was drawn to further realize the purpose of efficient gas extraction. Through simulation experiments and theoretical analysis, the maximum gas concentration of the experimental working face, upper corner and return air tunnel were all controlled within 0.6 %, which effectively controlled the gas abnormality problem.

 
重要日期

  • 会议日期

    08月18日

    2023

    至

    08月20日

    2023

  • 07月07日 2023

    初稿截稿日期

  • 08月20日 2023

    注册截止日期

主办单位
International Committee of Mine Safety Science and Engineering
承办单位
Heilongjiang University of Science and Technology
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