随着我国煤矿开采深度增加，开采强度增大，地质构造对煤层瓦斯赋存影响作用逐渐增强，煤层小断层作为采掘工作面广泛发育的小型构造之一，其构造影响区域煤体赋存特性的改变导致煤层瓦斯异常赋存，使得回采过程中瓦斯涌出量异常变化，煤与瓦斯动力灾害频发，严重影响煤矿安全高效生产。因此，研究煤层小断层影响下的煤体瓦斯赋存特性对科学合理防治瓦斯灾害具有一定指导意义。

       基于澄合矿区煤层小断层广泛发育的地质背景，通过现场采集不同规模的煤层小断层影响下的断层煤岩和原始煤岩样品，进行煤样基础参数测定，结果表明断层煤样水分和挥发分变化不大，灰分减小，固定碳增加；断层煤样坚固性系数在0.12~0.21之间，小于原始煤样；进一步对煤体粒径分布测定，发现中等粒径和小粒径煤颗粒质量占比增加，表明小断层影响下的煤体物理特性发生改变。

       采用电镜扫描、压汞实验、氮气吸附实验对煤体孔隙结构进行研究，发现断层煤样内部裂隙和孔隙较原始煤样更为发育；断层煤样微孔、中孔的孔容增大，过渡孔孔容变化不明显，大孔孔容减小；断层煤样的微孔、过渡孔和中孔累计比表面积较原始煤样增加，大孔累计比表面积减小。利用瓦斯吸附解吸仪和煤岩芯渗透率测定装置对煤体瓦斯吸附解吸及渗透特性进行分析，得出断层煤样瓦斯吸附量大于原始煤样，各阶段的瓦斯解吸量也大于原始煤样，断层煤样初始渗透率低于原始煤样，随气体压力增加，两者渗透差值逐渐减小；随煤层小断层规模增大，煤体瓦斯吸附、解吸能力显著增强，煤体渗透率则逐渐减小。

       通过构建含小断层煤层数值模型，模拟分析煤层小断层影响下的局部煤层应力特征，结果表明断层上盘煤层应力随与断层距离的增加，先快速减小，随后缓慢提升，之后趋于稳定，断层下盘煤层应力随与断层距离的减小，先是缓慢小幅增大，接近断层面时快速减小，断层面与煤层的交互处存在应力集中区域，且随着断距增加，应力峰值逐渐增大。通过现场瓦斯含量测定得到煤层小断层与瓦斯异常分布的关系，断层区域瓦斯含量处于2.1197m³/t~5.6331m³/t之间，主要在小断层上盘形成瓦斯富集区域，随断层规模增大，其对瓦斯异常超量赋存的影响作用增强。研究结果为矿井瓦斯灾害预测、煤层气开采和矿井瓦斯防治可提供一定理论依据。

        With the increase of coal mining depth and mining intensity in China, the influence of geological structure on coal seam gas distribution is gradually enhanced, and the small fault of coal seam is one of the small structures widely developed in the mining working face, and the change of coal distribution characteristics in the tectonic influence area leads to the abnormal distribution of coal seam gas, which makes the abnormal change of gas outflow during the recovery process and the frequent occurrence of coal and gas power disasters, which seriously affects the safe and efficient coal mine production. Therefore, it is of certain significance to study the coal gas distribution characteristics under the influence of small coal seam faults for scientific and reasonable prevention and control of gas disasters.

        Based on the geological background that small coal seam faults are widely developed in Chenghe mining area, we collected samples of faulted coal rock and original coal rock under the influence of small coal seam faults of different scales and carried out the determination of basic parameters of coal samples, the results showed that the moisture and volatile matter of faulted coal samples did not change much, ash decreased and fixed carbon increased; the solidity coefficient of faulted coal samples ranged from 0.12 to 0.21, which was smaller than that of original coal samples; further determination of coal body Further determination of the particle size distribution of the coal body showed that the mass proportion of medium and small size coal particles increased, indicating that the physical properties of the coal body changed under the influence of the small fault.

        The pore structure of the coal body was studied by electron microscope scanning, mercury pressure test and nitrogen adsorption test, and it was found that the internal fracture and pore size of the faulted coal sample were more developed than those of the original coal sample; the pore volume of microporous and medium pores of the faulted coal sample increased, the pore volume of transition pores did not change significantly, and the pore volume of large pores decreased; the accumulated specific surface area of microporous, transition pores and medium pores of the faulted coal sample increased compared with that of the original coal sample, and the accumulated specific surface area of large pores decreased. Using gas adsorption and desorption instrument and coal core permeability measurement device to analyze the gas adsorption and desorption and permeability characteristics of coal body, it is concluded that the gas adsorption amount of fault coal sample is larger than that of the original coal sample, and the gas desorption amount of each stage is also larger than that of the original coal sample, the initial permeability of fault coal sample is lower than that of the original coal sample, and the difference between the two permeability values gradually decreases with the increase of gas pressure; with the increase of the scale of small fault of coal seam, the gas adsorption and desorption capacity of coal body，the coal permeability decreases gradually as the size of the small fault increases.

        By constructing a numerical model of coal seam containing small fault, we simulate and analyze the local stress characteristics of coal seam under the influence of small fault in coal seam, and the results show that the stress of coal seam on the upper plate of fault decreases rapidly with the increase of distance from the fault, then increases slowly and then stabilizes, and the stress of coal seam on the lower plate of fault increases slowly and slightly with the decrease of distance from the fault, and decreases rapidly when it is close to the fault surface, and there is a stress concentration area at the interaction of fault surface and coal seam. The stress concentration area exists at the interaction between the fault surface and the coal seam, and the peak stress gradually increases with the increase of the fault distance. The relationship between the small fault of the coal seam and the distribution of gas anomaly was obtained through the field gas content measurement, the gas content in the fault area was between 2.1197m³/t~5.6331m³/t, and the gas enrichment area was formed mainly in the upper plate of the small fault, and the influence of the fault on the gas anomaly overload distribution was enhanced as the scale of the fault increased. The research results can provide some theoretical basis for mine gas disaster prediction, coalbed methane mining and mine gas control.

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