浅埋煤层群开采煤柱群结构效应及其应力场与裂缝场耦合控制

The reserves of shallow buried coal seams are rich in the West China. The surface cracks induced by shallow coal seam group seriously affect the ecological environment, and the pressure concentration of the underground coal pillars affect the safe mining. Mining practice lacks of effective control theory. The ground cracks and pressure coupling control is the scientific basis for shallow seam group safety and environmental mining, and the research has important theoretical significance. This research take the shallow seam group mining in Jurassic coalfield as the research object, using the combining method of field measurement, physical simulation, numerical calculation and theoretical analysis, according to the technical route of "shallow seam group mining stress distribution and cracks development—group pillar structure model effect—coupling weakness of stress and crack field in repeated mining", study the overburden stress distribution and surface crack development in shallow coal seam group mining, discover the gob pillar group structural form and its effect on deformation as well as stress field and fracture field, establish the group pillar structure model of shallow coal seam group mining，reveal the mechanism of cracks development and stress concentration, propose the group pillar structure effect and stress field vs. fracture field coupling control theory for environmental friendly shallow coal seam group mining. Most of the coal mines in the west of China have entered the stage of coal seam group mining, so the research has a broad prospect of engineering application.

我国西部浅埋煤层储量丰富，浅埋煤层群开采形成的地裂缝严重影响生态环境，地下煤柱集中应力影响安全开采，开采实践缺乏有效控制理论。浅埋煤层群开采的地裂缝和地压耦合控制是浅埋煤层群安全环保开采的科学基础，研究具有重要的理论意义。课题以陕北侏罗纪煤田浅埋煤层群开采为对象，采用现场实测、物理模拟、数值计算和理论分析相结合的方法，以“浅埋煤层开采的应力传递与裂隙发育规律—煤柱群结构效应—重复采动应力场和裂缝场耦合弱化”为技术路线，研究浅埋煤层群开采的覆岩与地表裂缝发育规律和煤柱群影响下的应力分布规律，以及煤柱群结构形态及其对岩层应力场和裂缝场的效应，建立浅埋煤层群采空区煤柱群结构模型，揭示裂缝发育和应力集中的机理，提出浅埋煤层开采煤柱群结构效应及其应力场与裂缝场耦合控制理论，为环境友好的浅埋煤层群开采提供科学支撑。我国西部大部分矿井已进入煤层群开采阶段，研究具有广泛的工程应用前景。

我国西部主要赋存浅埋煤层群，目前多数矿井进入下煤层开采阶段。实践表明，浅埋煤层群开采煤柱应力集中严重，地裂缝发育加剧，地表不均匀沉降显著，安全与减损开采成为亟待解决的科学难题。课题以陕北生态脆弱区浅埋煤层群开采为对象，以“煤层群开采应力传递、裂隙发育演化与地表下沉规律—煤柱群结构特征及其对应力传递、地表下沉和裂隙发育的影响—减压模型与减损模型的建立—重复采动应力场、位移场与裂缝场耦合控制”为技术路线，采用实测分析、物理模拟、数值计算与理论分析相结合的方法，分析了顶部单一煤层及重复采动的应力场、位移场和裂缝场演化规律，揭示了下煤柱集中应力、地表下沉、覆岩裂隙和地表裂缝发育与不同煤柱群结构的关系；提出了煤柱群结构的分类，揭示了煤柱群结构效应，确定了“减压区分离煤柱群结构”可实现集中应力、地表不均匀沉降、覆岩裂隙和地表裂缝耦合控制，是最佳煤柱群结构；建立了基于煤柱集中应力控制的减压模型和基于覆岩位移与裂缝控制的减损模型，提出了煤柱减压与地表减损耦合控制方法。浅埋煤层群分布广泛，产能巨大，研究具有重要的理论意义与广泛的应用前景。