【摘要】 为探究倾斜巨厚煤层综放开采条件下覆岩裂隙场的分布特征和卸压瓦斯储运规律，同时研究瓦斯抽采方法的优选机制，以新疆某高瓦斯矿井为研究对象，开展了大型二维物理相似模拟试验.分析了采场覆岩的运动形态，得到了覆岩应力演化特征，计算了覆岩位移、角度和概率熵变特征，阐明了卸压瓦斯运储区“类冷却塔”形成机理，推演了瓦斯运储区发育形态，构建了瓦斯运储区数学理论控制模型，并以此提出卸压瓦斯分域抽采技术.研究结果表明：倾斜巨厚煤层综放开采条件下，卸压瓦斯运储区呈现“类冷却塔”分布特征，运储区煤壁侧前方的最大应力变化值为37 MPa,应力集中系数为7.60.覆岩碎胀系数呈“两翼高-中部低”的非对称分布特征，碎胀系数由1.19升高到1.61.此外采用PCAS图像分析软件得到空隙和裂隙的分布规律、空间关系，开切眼侧的裂隙结构发育程度明显比工作面侧的更为完全，并定义了分形维数1.28和裂隙长度15 mm为卸压瓦斯运储区的判定参数指标.考虑瓦斯在采空区的运移、扩散及储集形态，建立倾斜巨厚煤层卸压瓦斯运储区数学理论控制模型，并给出了卸压瓦斯运储区的各边界计算公式.指导设计高位定向长钻孔的布置参数，取得了良好的抽采效果.研究结果在新疆硫磺沟矿区得到初步应用，为倾斜巨厚煤层综放开采瓦斯高效抽采提供了理论参考，保障了类似条件下矿井安全高效的回采.更多还原

【Abstract】 To explore the distribution characteristics of the fracture field and the law of pressure-relief gas storage and migration in the goaf under the condition of fully mechanized top coal caving mining in an inclined extremely thick coal seam, and to study the optimization mechanism of gas extraction methods, a large-scale two-dimensional physical similarity simulation experiment was carried out in a gassy coal mine. The movement form of overlying strata in the stope was analyzed, the stress evolution characteristics of the overlying strata were obtained, the displacement, angle, and probability entropy change characteristics of the overlying strata were calculated. The formation mechanism of “similar cooling tower” in pressure relief gas transportation and storage area was clarified, the development form of gas transportation and storage area was deduced, the mathematical theory control model of gas transportation and storage area was constructed, and the pressure relief gas drainage technology was proposed. The results show that under the condition of fully mechanized caving mining in an inclined thick coal seam, the pressure-relief gas transportation and storage area exhibits a “cooling tower” distribution pattern. The maximum stress change value in front of the coal wall side of the transportation and storage area is 37 MPa, and the stress concentration coefficient is 7.60. The bulking coefficient of the overburden rock shows an asymmetric distribution characteristic of “high on both wings and low in the middle”, and the bulking coefficient increases from 1.19 to 1.61. In addition, PCAS image analysis software was used to obtain the distribution law and spatial relationship of voids and cracks. The development degree of the crack structure on the open-off cut side is significantly more complete than that on the working face side. A fractal dimension of 1.28 and a crack length of 15 mm are defined as the judgment parameter indexes of the pressure-relief gas transportation and storage area. Considering the migration, diffusion, and reservoir form of gas in the goaf, a mathematical theoretical control model of the pressure-relief gas storage area in the inclined thick coal seam was established, and a boundary calculation formula for the pressure-relief gas storage area was derived. This model guides the design of the layout parameters of high-level directional long boreholes and has achieved favorable extraction results. The research results have been preliminarily applied in the Liuhuanggou coal mine, which provides a theoretical reference for the efficient extraction of gas in fully mechanized caving mining in inclined extremely thick coal seam and ensures the safe and efficient mining of mines under similar conditions.更多还原