In order to solve the problem of pressure relief gas control under high-strength fully mechanized top-coal caving in low-gas-thick-coal seams, this paper studies the evolution of overburden structures and the distribution characteristics of fissure fields during the initial and stable period of working face by physical simulation and numerical analysis. The mathematical model of coupling between mining fracture field and pressure relief gas field is established. The results reveal the distribution characteristics of pressure relief gas field that considers mining-induced fissure field. According to the distribution of mining gas accumulation area, the high directional long boreholes have been put forward to control the pressure relief gas in goafs, and the effect has been tested. The results show that the initial pressure and three periodic pressures occurred from the cutting hole to 135 m in the initial mining period of the working face. The height of collapse zone developed to 22 m, and fracture height developed to 75 m. The development height of caving zone is stable at 25∼27 m, and the development height of fissure zone is stable at 75∼95 m. The process and distribution of pressure relief gas flow in goaf are obtained by solving the numerical model of pressure relief gas flow in mining fissure field. The gas accumulation area is located within 25∼55 m from return laneway and 25∼50 m from the roof of coal seam. After the implementation of high directional long drilling gas drainage technology in the initial mining period and the stable mining period, good results have been obtained in the gas control, where the average concentration of gas extraction is 5.8%, the average gas flow rate is 0.71 m³/min, and the gas concentration in upper corner and return air is less than 0.8%. The results can provide a reference for pressure relief gas control under similar conditions.

中文翻译：

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低瓦斯厚煤层高强度综采开采上覆地层卸压气高位抽放孔的合理布置

为解决低瓦斯厚煤层高强度综放放顶煤卸压瓦斯控制问题，研究了初期和后期裂隙场的覆盖结构演化特征和裂隙场分布特征。通过物理模拟和数值分析得出工作面的稳定期。建立了采压裂隙气田与卸压气田耦合的数学模型。结果揭示了考虑采矿引起的裂隙场的卸压气田的分布特征。根据矿井瓦斯聚集区的分布特点，提出了高定向长井眼控制采空区卸压瓦斯的方法，并进行了效果测试。结果表明，在工作面初始开采期间，从切削孔至135 m出现了初始压力和三个周期性压力。塌陷区高度发展到22 m，裂缝高度发展到75 m。崩落带发育高度稳定在25〜27 m，裂隙带发育高度稳定在75〜95 m。通过求解开采裂隙场中卸压气流的数值模型，得到了采空区卸压气流的过程和分布。瓦斯聚集区位于距回巷25〜55m范围内，距煤层顶板25〜50m范围内。在初期开采期和稳定开采期实施高定向长排瓦斯抽采技术后，在瓦斯治理方面取得了良好的效果，³ / min，并且上角和回风中的气体浓度小于0.8％。研究结果可为相似条件下的泄压气体控制提供参考。