高瓦斯煤层群应力—裂隙—渗流耦合作用机理及其对卸压抽采的影响

发布时间：2018-03-17 15:00

  本文选题：高瓦斯煤层群　切入点：卸压开采　出处：《中国矿业大学》2017年博士论文　论文类型：学位论文

【摘要】：卸压开采结合瓦斯抽采是实现高瓦斯煤层群煤与瓦斯共采的有效方法。而应力-裂隙-渗流耦合作用机理是高瓦斯煤层群卸压开采的基础问题,直接影响着卸压开采的成败和效果。为此,论文采用理论分析、实验室实验、数值模拟以及现场实测相结合的研究方法建立了煤层群重复采动应力-裂隙-渗流耦合模型,分析了其耦合作用机理,提出了卸压开采效果评价方法,掌握了采动围岩稳定与渗透率演化的时空关系。研究成果为高瓦斯煤层群煤与瓦斯共采提供了理论基础。取得了如下主要创新成果:(1)研制了各向异性采动煤岩体渗透测试实验系统,揭示了不同损伤裂隙煤岩体应力-渗流作用机理。实现了煤体轴向和径向应力渗透率的测试。提出了覆岩“三带”损伤裂隙煤岩体试样分类及制备方法,测试了不同损伤煤岩体渗透率随工作面开采及瓦斯抽采的时空演化规律,建立了重复采动作用下煤岩体应力-渗透率模型,采用绝对和相对应力敏感性系数评价了煤岩样的应力敏感性及其演化特征。(2)提出了裂隙煤岩体流固耦合参数的数值模拟表征方法,揭示了应力-裂隙-渗流的耦合作用机理。构建了不同裂隙结构煤体渗透率的离散元数值模型,提出了节理裂隙数值模拟参数的标定方法,研究了煤体渗透特性的各向同性和各向异性特征,揭示了煤体裂隙对渗透率应力敏感性的内在影响机理;掌握了裂隙形态及参数与裂隙煤样渗透率的内在联系。分析了采动裂隙煤样三轴流固耦合应力-裂隙-渗流演化特征,阐明了偏应力条件下采动裂隙煤样轴向渗透率对围压及轴压敏感性差异的主要原因。(3)建立了重复采动覆岩应力-裂隙-渗流耦合模型,提出了卸压开采及瓦斯抽采参数的设计方法。运用实验室三轴流固耦合实验及现场煤层瓦斯抽采实测验证了模型的可靠性。实现了煤层群卸压开采覆岩三带渗透率演化规律及分布特征的定量分析,掌握了卸压开采及瓦斯抽采过程中瓦斯的渗流路径及瓦斯压力的分布特征;确定了韩城矿区及淮南矿区上、下保护层开采的最小采厚及合理采厚,阐明了层间距与保护层采高的相关关系;设计了卸压瓦斯抽采钻孔布置方案。(4)建立了煤层群卸压开采效果评价模型,揭示了卸压开采覆岩运动的时空演化关系。建立了瓦斯分源模型,提出了卸压开采效果评价方法;定量分析了采空区垮落带各区域的压实时间、压实程度及渗透率分布特征,掌握了卸压开采围岩渗透率的时空演化规律;阐明了采空区垮落带压实应力、压实时间及渗透率三者之间的内在关系。
[Abstract]:Pressure relief gas drainage combined mining is an effective method for the realization of coal and gas outburst coal seams in high gas mining. And the stress fracture seepage coupling mechanism is the basic problem of coal seam gas pressure relief mining, directly affects the success or failure of unloading and effect of mining. Therefore, this paper uses theoretical analysis, laboratory experimental research, numerical simulation and field measurement was established with the coal seam group repeated mining stress fracture seepage coupling model, analyzes the coupling mechanism, the pressure relief mining effect evaluation method, grasp the temporal and spatial relationship between surrounding rock stability and permeability evolution of mining. Research results for high gassy coal seams coal and gas extraction provides a theoretical basis. The main innovative achievements are as follows: (1) developed anisotropic mining coal rock permeability testing system, reveals the different damage of fractured coal and rock stress seepage for With the implementation of coal. The mechanism of axial and radial stress permeability test. The overburden three zones of rock fracture damage of coal sample preparation and classification methods, different damage of coal rock mass permeability with mining and gas drainage of the time-space evolution of the established test, repeated mining of coal and rock under the action of stress permeability model, the absolute and relative stress sensitivity coefficient to evaluate the coal rock stress sensitivity and its evolution. (2) proposed to characterize the numerical method of coal mass flow solid coupling simulation, coupling mechanism of stress fracture seepage was revealed. Constructed the discrete element numerical model fracture structure of coal permeability, proposed joint numerical simulation parameter calibration method, studied the permeability of coal body in isotropic and anisotropic characteristics, reveals the fissures of coal permeability should be sensitive to the force The internal influence mechanism; grasp the inner link of fracture morphology and fracture parameters and the permeability of coal sample. The analysis of mining fissure coal three axial flow solid coupling seepage force characteristics evolution fracture, the deviatoric fissure coal permeability on axial confining pressure and axial pressure sensitivity was the main reason of the difference. Under the condition of force production (3) established a repeat of overlying rock fissure seepage stress coupling model, put forward the design method of mining pressure unloading and gas drainage parameters. Using the laboratory three axial flow solid coupling experiment and field methane drainage proved the reliability of the model. The unloading of coal seams the quantitative distribution of overburden pressure with three permeability evolution mining analysis, grasp the distribution characteristics of the seepage path and gas pressure relief and gas drainage in the process of mining gas; the Hancheng mine and Huainan mine, under the protection layer Minimum mining thickness and reasonable mining thickness mining, illustrates the layer spacing and the protective layer mining high correlation; design of pressure relief gas drainage borehole layout scheme. (4) developed coal seams depressurized mining effect evaluation model, reveals the evolution of pressure relief mining overburden movement. The relationship between the establishment of a gas the source model, put forward the depressurized mining effect evaluation method; quantitative analysis of the goaf caving zone compaction time of each area, the degree of compaction and permeability distribution characteristics, grasp the depressurized mining temporal rock permeability evolution law; clarifies the caving zone in goaf compaction stress, relationship between compaction the time and the permeability of the three.

【学位授予单位】：中国矿业大学
【学位级别】：博士
【学位授予年份】：2017
【分类号】：TD712.6
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本文编号：1625243