赵鹏翔,张文进,李树刚,等. 高瓦斯厚煤层综采工作面推进速度影响下的瓦斯运–储区交叉融合机理[J]. 煤炭学报,2023,48(9):3405−3419. doi: 10.13225/j.cnki.jccs.2022.1257
引用本文: 赵鹏翔,张文进,李树刚,等. 高瓦斯厚煤层综采工作面推进速度影响下的瓦斯运–储区交叉融合机理[J]. 煤炭学报,2023,48(9):3405−3419. doi: 10.13225/j.cnki.jccs.2022.1257
ZHAO Pengxiang,ZHANG Wenjin,LI Shugang,et al. Mechanism of cross-fusion in gas transportation-storage area in fully mechanized mining face of high gas thick coal seam under different advancing speeds[J]. Journal of China Coal Society,2023,48(9):3405−3419. doi: 10.13225/j.cnki.jccs.2022.1257
Citation: ZHAO Pengxiang,ZHANG Wenjin,LI Shugang,et al. Mechanism of cross-fusion in gas transportation-storage area in fully mechanized mining face of high gas thick coal seam under different advancing speeds[J]. Journal of China Coal Society,2023,48(9):3405−3419. doi: 10.13225/j.cnki.jccs.2022.1257

高瓦斯厚煤层综采工作面推进速度影响下的瓦斯运–储区交叉融合机理

Mechanism of cross-fusion in gas transportation-storage area in fully mechanized mining face of high gas thick coal seam under different advancing speeds

  • 摘要: 裂隙结构具有复杂性和不规则性,对上覆岩层卸压瓦斯的运移和储集具有决定性影响。为了确定高瓦斯厚煤层综采工作面推进过程中瓦斯运移区和储集区交叉融合的动态变化对瓦斯赋存的影响以及在不同推进速度下上覆岩层中的瓦斯运储规律,采用二维物理相似模拟实验分析覆岩裂隙分布特征和瓦斯运–储区的几何变化规律,探究不同推进速度下运–储区随周期来压交叉融合的变化特征,并以工作面推进速度为关键参数,建立瓦斯运–储区的推速效应量化表征模型,揭示推进速度影响下瓦斯运–储区的对称周期性构建机制。结果表明,瓦斯的运–储区内外边界和运–储交界分别位于裂隙开合度和贯通度的突变区域,随着推进速度的增大,运–储区边界从采空区中部向两侧缩减;随着工作面推进,瓦斯储集区逐渐过渡成为运移区,两区域范围相互交叉融合,整个过程中运–储区在循环“构建—破坏—构建”,最终形成完整的对称椭圆抛物带状的覆岩裂隙场;裂隙熵的变化随工作面的推进先增大后减小,裂隙率的变化随工作面的推进分别经历了2次增大和减小,表明瓦斯运移区和储集区随工作面推进呈“初次形成—交叉融合—区域分离扩大”的动态变化;此外,在采动裂隙椭抛带理论的基础上,构建瓦斯运–储区推速效应量化表征模型,建立瓦斯运–储区边界及状态判定流程,揭示推进速度影响下的瓦斯运–储区交叉融合演化机理和对称形态的周期性构建机制,为研究采空区卸压瓦斯分布和实现瓦斯富集区定向精准抽采提供指导。

     

    Abstract: The fracture structure is complex and irregular, which has a decisive influence on the migration and storage of pressure-relief gas in overlying strata. During the advancing process of the fully mechanized mining face in the high-gas thick-coal seam, in order to determine the impact of dynamic change of intersection and fusion of the gas transport and storage area on the gas occurrence, and the gas transport and storage law in the overlying strata under different advancing speeds, the two-dimensional physical similarity simulation was conducted to analyze the fracture distribution characteristics of the overlying strata and the geometric change law of the gas transport-storage area, and explore the change characteristics of the gas transport-storage area with the periodic weighting under different advancing speeds. Additionally, taking the advancing speed of the working face as a key parameter, the quantitative characterization model of the propulsion speed effect of the gas transport-storage area was established, and the symmetrical periodic construction mechanism of the gas transport-storage area under the influence of the advancing speed was revealed. The results show that the inner and outer boundaries and the boundary between the gas transport area and storage area are located in the mutation areas of the fracture openness and through degree respectively. With the increase of the advancing speed, the boundary of the transport-storage area is reduced from the middle of the goaf to both sides. As the working face advances, the gas storage area gradually transits into a migration area, and the two areas cross and fuse with each other. During the whole process, the transport-storage area is in the cycle of “construction-destruction-construction”, and finally form a complete symmetrical elliptical parabolic banded overburden fracture field. The change of fracture entropy increases first and then decreases with the advance of the working face, and the change of fracture rate increases and decreases twice with the advance of the working face respectively, indicating that the gas migration area and the storage area show the dynamic change of “initial formation-cross fusion-regional separation and expansion” with the advance of the working face. In addition, based on the theory of mining-induced fracture elliptic paraboloid zone, the quantitative characterization model of propulsion speed effect of gas transport-storage zone was constructed, and the boundary and state determination process of gas transport-storage zone was established. The cross-fusion evolution mechanism and symmetric periodic construction mechanism of gas transport-storage area under the influence of advancing speed were revealed, which provide a guidance for studying the distribution of pressure-relief gas in goaf and realizing the directional and accurate extraction of gas enrichment zone.

     

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