Feng Shuailong, Chen Xiangjun, Dong Xiaozhen, Wang Lin, Li Gaojian
State Key Laboratory Cultivation Base for Gas Geology and Gas Control, Henan Polytechnic University, Jiaozuo 454003, China.
State Collaborative Innovation Center of Coal Work Safety and Clean-Efficiency Utilization, Henan Polytechnic University, Jiaozuo 454003, China.
ACS Omega. 2023 May 2;8(19):16800-16808. doi: 10.1021/acsomega.3c00284. eCollection 2023 May 16.
To study the influence of small faults on the gas content of Coal Seam 3# in the Changping mine field, the influence scope and degree of small faults on Coal Seam 3# and gas content in the Changping mine field are analyzed based on the field measured data such as the gas content on both sides of the fault, the initial speed of gas emission, and the solidity coefficient of the coal seam, combined with the FLAC3D stress simulation results, and the influence area of small faults is zoned from the perspective of gas control. The analysis results show that the measured gas content in the hanging wall of SF250 fault with a drop of 1.3 m and SF353 fault with a drop of 1.9 m is 7.14 and 9.47 m/t, respectively, and the gas content in the footwall is 5.29 and 7.41 m/t, respectively. The gas content in the hanging wall is obviously higher than that in the footwall; the gas content in the coal seam near the small fault surface is slightly lower. With the increase of the distance from the fault surface, the gas content in the coal seam decreases first and then increases; the firmness coefficients of hanging wall coal of small fault are 0.40 and 0.45, respectively, and those of footwall coal are 0.73 and 0.75, respectively. The firmness coefficient of hanging wall coal seam is obviously smaller than that of footwall coal seam. The closer it is to the fault surface, the smaller the firmness coefficient of coal is, and the greater the initial gas release speed is; the permeability coefficient of the coal seam far from the fault surface in the hangingwall of the small fault shows a decreasing trend after an increasing trend. The maximum stress of the coal seam is 21.85 MPa at 14 m from the hangingwall of the fault to the fault, and the minimum stress of the coal seam is 2.79 MPa at 1 m from the footwall of the fault to the fault. The stress of the hangingwall of the fault is greater than that of the footwall of the fault, and the stress concentration area is 14 m from the hangingwall of the fault to the fault.
为研究小断层对长平井田3#煤层瓦斯含量的影响，基于断层两侧瓦斯含量、瓦斯初始涌出速度、煤层坚固性系数等现场实测数据，结合FLAC3D应力模拟结果，分析了长平井田小断层对3#煤层及瓦斯含量的影响范围和程度，并从瓦斯治理角度对小断层影响区域进行了分区。分析结果表明，落差1.3 m的SF250断层和落差1.9 m的SF353断层上盘实测瓦斯含量分别为7.14 m³/t和9.47 m³/t，下盘瓦斯含量分别为5.29 m³/t和7.41 m³/t。上盘瓦斯含量明显高于下盘；靠近小断层面处煤层瓦斯含量略低。随着距断层面距离的增加，煤层瓦斯含量先减小后增大；小断层上盘煤层坚固性系数分别为0.40和0.45，下盘煤层坚固性系数分别为0.73和0.75。上盘煤层坚固性系数明显小于下盘煤层。越靠近断层面，煤层坚固性系数越小，瓦斯初始释放速度越大；小断层上盘远离断层面处煤层渗透系数呈先增大后减小趋势。断层上盘距断层14 m处煤层最大应力为21.85 MPa，断层下盘距断层1 m处煤层最小应力为2.79 MPa。断层上盘应力大于下盘应力，应力集中区域为距断层上盘14 m范围。
