我国陕北主要赋存浅埋近距离煤层，目前多数矿井进入下煤层开采阶段。实践表明，近距离煤层开采煤柱应力集中严重，地表不均匀沉降显著，地裂缝发育加剧，安全与减损开采成为亟待解决的科学难题。采空区遗留区段煤柱是导致以上问题的根源，研究煤柱群结构效应与应力场、位移场及裂隙场（三场）演化规律，实现煤柱减压与地表减损的耦合控制，对煤炭科学开采具有重要意义。论文采用统计分析、物理模拟、数值计算与理论分析相结合的方法，掌握了顶部单一煤层和煤层群开采的三场分布与演化规律，提出了煤柱群结构分类，揭示了煤柱群结构效应，建立了减缓煤柱应力集中和减轻地表损害的三场耦合控制模型，提出了实现煤柱减压与地表减损的合理煤柱布置方式。论文主要研究工作及创新性结果如下：

（1）掌握了顶部单一煤层开采的应力场、覆岩移动场、裂隙场分布规律。通过建立煤柱底板应力计算模型，分析了煤柱集中应力传递规律；建立了采空区倾向结构分区，得到了覆岩下沉曲线的方程表达式，揭示了单一煤层开采的裂隙发育规律。提出了单一煤层开采的三场分区：煤柱应力集中区-裂隙微弱区-垂直位移最小区；拉应力集中区-裂隙发育区-倾斜变形最大区；重新压实增压区-裂隙闭合区-垂直位移最大区，为研究浅埋近距离煤层三场演化规律提供了基础。

（2）揭示了近距离煤层开采不同煤柱群结构的覆岩三场演化规律，提出了煤柱减压和地表减损的控制途径与原则。提出了下煤柱的布置应避开上煤柱传递的集中应力和上采空区中部增压区；确定了不同煤柱错距的地表沉降落差分段，得出了在沉降落差稳定段实现减缓地表不均匀沉降的控制原则；将覆岩裂隙与地裂缝分为永久裂隙（缝）和可控裂隙（缝），揭示了煤柱错距对可控裂隙（缝）的控制机理。煤柱减压和地表减损的原则是实现三场的耦合控制，途径是确定合理的煤柱布置方式。

（3）提出了煤柱群结构的分类，揭示了煤柱群结构效应，确定了“非压实区的分离煤柱群结构”可实现集中应力、地表不均匀沉降、覆岩裂隙和地裂缝耦合控制和安全减损开采。基于煤柱群结构分类，定量分析了覆岩垂直应力，确定了下煤柱垂直集中应力计算方法，提出了不均匀沉降度指标，得到了工作面采空区岩层与土层的下沉量表达式，给出了煤柱区覆岩与地表下沉量计算方法，采用分形理论定量描述了覆岩裂隙发育规律，实现了覆岩三场定量分析。

（4）建立了基于煤柱集中应力控制的减压模型，给出了避开上煤柱传递集中应力的最小减压煤柱错距，以及避开上采空区中部增压区的最大减压煤柱错距；基于位移场和裂隙场控制的“非压实区的分离煤柱群结构”，建立了浅埋近距离煤层开采的减损模型，得到了合理减损煤柱错距的确定方法。根据减压煤柱错距与减损煤柱错距的耦合交集，提出了煤柱减压与地表减损耦合控制方法，分析了其主要影响因素。

Northern Shaanxi mainly reserves shallow buried closely spaced multi-seams, in recent years, most mines enter the lower seam mining. Engineering practice shows that under the closely spaced multi-seams conditions, the concentrated stress of coal pillars is serious, the uneven subsidence and the fractures of surface are obvious, how to realize safe and damage-reducing mining has become a scientific problem to be solved. Coal pillars in the goaf are the source of the problems above, therefore, revealing the pillars structural effect and its three-field (stress field, displacement field and fracture field) evolution characteristics, realizing coupling control of pillar pressure-reducing and surface damage-reducing, has great significance to the scientific mining of the coalfield. Combining with the statistic analysis, physical simulation, numerical calculation and theoretical analysis, the distribution and evolution characteristics of single and repetitive mining are obtained, besides, the classification of pillars structure is put forward, the pillars structural effect is revealed, the three-field coupling control models based on decreasing the concentrated stress and surface damage are established, and the reasonable coal pillars arrangement method based on pillar pressure-reducing and surface damage-reducing is given. The main research work and innovative results are as follows:

(1) The distribution characteristics of stress field, displacement field and fracture field of upper single seam mining are obtained, through establishing the stress calculation model of coal pillar floor, the stress transfer characteristics of upper pillar are analyzed. The overburden subsidence equations based on tendency structure zones are obtained, and the fractures development of single seam mining is revealed. Overall, the three-field coupling zones of single seam mining are given, concentrated stress of pillar - unobvious fractures - the minimum movement zone, concentrated tensile stress - obvious fractures – maximum incline deformation zone, and recompact high pressure - close fractures – maximum movement zone. it provides basis for the three-field evolution of repetitive mining.

(2) The three-field evolution characteristics with different pillars structural are revealed, the control method and principle of pillar pressure-reducing and surface damage-reducing are proposed. The arrangement of lower pillar should avoid the transfer concentrated stress by upper pillar, and also the high pressure zone pf upper middle goaf. The surface subsidence fall stages based on coal pillar malposition distance is determined, and it shows that the subsidence fall stable stage is good for the control of uneven subsidence. The overburden and surface fractures are devided into perpetual fractures and controlled fractures, and the control mechanism of coal pillar malposition distance to controlled fractures is revealed. The principle of pillar pressure-reducing and surface damage-reducing is three-field coupling control, and its method is the reasonable pillars arrangement.

(3) The classification of pillars structural are proposed, and the pillars structural effect is revealed. When the upper and lower pillars form “separate multi-pillars structure in uncompacted zone”, the concentrated stress, surface uneven subsidence and the concentrated fractures can be controlled effectively, and it is beneficial to safe and damage-reducing mining. Based on the classification of pillars structural, the overburden vertical stress is analyzed quantificationally, and the calculation method of lower pillar vertical stress is determined. The index of uneven subsidence degree is put forward, and the overburden subsidence equations are obtained, meanwhile, the surface subsidence of pillars zone is given. The fractal theory is applied to analyze the fractures development, overall, it realizes the quantitative analysis of three-field.

(4) The pressure-reducing model based on concentrated stress control is established, and the minimum pressure-reducing pillar malposition distance to avoid concentrated stress by upper pillar is determined, and the maximum pressure-reducing pillar malposition distance to avoid the high pressure zone of middle is also given. Based on the control of displacement field and fracture field, and “separate multi-pillars structure in uncompacted zone”, the damage-reducing model of shallow buried closely spaced multi-seams is established, and the damage-reducing pillar malposition distance is obtained, according to the coupling intersection of pressure-reducing and damage-reducing pillar malposition distance, the coupling control method of pillar pressure-reducing and surface damage-reducing is proposed, and the main influence factors are analyzed.