School of Energy and Mining Engineering, China University of Mining and Technology(Beijing)
New Energy Development andDisaster Prevention Research Center, China University of Mining and Technology(Beijing)
School of Mechanics and CivilEngineering, China University of Mining and Technology
School of Mining and Geomatics Engineering, Hebei University ofEngineering
Handan Niuerzhuang Mining Co., Ltd.

为了研究高应力区煤体在放顶煤开采方式下的应力场−渗流场的耦合演化规律,以横观各向同性下的火柴棍模型为基础,构建了由煤基质和裂隙组成的弹性系统,建立了三向应力条件下煤体渗透率演化规律模型,并结合采场应力场空间分布规律,构建煤层增透率空间分布模型。在改变围压、轴压和气体压力的条件下,将渗透率模型和室内试验结果对比,并将增透率空间分布模型与顺层抽采钻场的瓦斯抽采相关数据对比分析,结果表明:煤体渗透率随载荷与气体压力的增加而减小,并呈指数型;渗透率模型可以较好地定量描述煤体渗透率在加卸载条件下的变化,与多组试验数据的相关系数和拟合优度均大于0.9;增透率空间分布随距离增大呈指数下降,可分成4个阶段:原岩稳定阶段、增压降低阶段、卸压增加阶段、破坏稳定阶段;根据增透率模型和现场数据对比,煤层在卸压增加阶段和破坏稳定阶段处于增透状态,煤层增透范围Lr=55.62m;煤层增透率模型可以较好地描述煤层增透率的空间分布规律,其与现场数据的相关系数和拟合优度均大于0.96。

In order to study the coupling evolution law of stress-seepage field in high stress zone under the top-coal caving method, a permeability model under three-dimensional stress was established for coal. The modelconsists of two parts: the transverse isotropic model based on the matchstick model, and an elastic systemcomposed of coal matrix and fractures. The permeability model is combined with the spatial distribution law of stope stress field to construct the spatial distribution model of the mining-induced coal permeability change ratio(MPCR). Laboratory test results under different conditions of confining, axial and gas pressure are compared withpermeability models. The results show that: the permeability decreases exponentially ss the load and gas pressureincrease. The permeability model can quantitatively describe the change of coal permeability under loading andunloading conditions, and the correlation coefficient and fit goodness obtained by comparing the results withmultiple sets of experimental data are greater than 0.9. The MPCR spatial distribution decreases exponentiallywith the increase of distance from the working face, and can be divided into four stages: The stress stabilizationphase of virgin rock, the MPCR decreases with increasing stress, the MPCR increases with decreasing stress, theconstant MPCR with the damage of the coal. According to the comparison between permeability model and fielddata, the permeability of coal seams increases in stages of the MPCR increases with decreasing stress and theconstant MPCR with the damage of the coal, covering the range of coal seam of 55.62 m (L=55.62 m). Themodel can better describe the spatial distribution of MPCR, and the correlation coefficient and goodness-of-fitcoefficient with the field data are greater than 0.96.

中国矿业大学(北京)基本科研业务费−博士研究生拔尖创新人才培育基金资助项目(BBJ2023004);国家自然科学基金资助项目(51474220)

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ZHAO Hongbao, JING Shijie, LI Zuoquan, et al. The coupled stress-seepage behavior of bottom coal in deep top-coal cavingmethod[J]. Journal of Mining and Strata Control Engineering, 2024, 6(5): 053023.