急倾斜煤层广泛赋存于我国西部地区，其安全开采对区域经济发展具有重要的能源保障作用。受重力倾角效应和多次采动复合效应作用，急倾斜近距离煤层采场围岩结构复杂，动力灾害频发。因此，以新疆龙泉煤矿急倾斜近距离煤层开采为工程背景，采用数值模拟、物理相似模拟实验、理论分析等研究方法，分析了急倾斜近距离煤层复合采场应力传递路径和复合采场裂隙发育及围岩运移特征，揭示了采场围岩“P-S-P”链式结构的形成演化机理，提出了链式结构失稳模式及判定条件，主要结论如下：

（1）受重力-倾角作用和多次采动复合效应作用，急倾斜单一采场围岩形成顶板倾斜中上部“非对称拱形”应力释放区、顶板倾斜下部应力集中区、底板倾斜上部应力集中区、底板倾斜下部应力释放区。急倾斜复合采场形成过程中，上工作面倾斜下部区域应力集中与释放现象减弱，复合采场形成后，间隔岩层应力分布区域由对立分布演变为间隔分布，采场外侧应力集中与释放区面积增大，应力峰值明显增大，区段煤柱周围应力集中与释放范围减小，应力峰值明显增大。

（2）在同一稳定岩层中，应力竖直传递；在软硬岩层交界面附近，应力分别沿层面传递和垂直于层面传递。复合采场应力传递路径可分为“R-P-F”、“R-P-F-P”、间隔岩层应力传递路径3大类，其中“R-P-F”、“R-P-F-P”应力传递路径控制采场整体范围的应力分布及演化，间隔岩层应力传递路径控制间隔岩层和煤柱的应力分布及演化。在复合采场形成过程中，间隔岩层应力传递路径复杂演化，最终应力传递路径为上煤层上工作面底板倾斜上部→下煤层上工作面顶板倾斜下部→上煤层下工作面底板倾斜上部→下煤层下工作面顶板倾斜下部，呈自上而下螺旋传递特征。

（3）急倾斜工作面开挖完毕后，顶板垮落特征呈“倾斜非对称”拱壳状，不同埋深、不同采高的垮落拱壳略有差别；垮落顶板对底板起到破坏和保护的“二象性”作用。顶板垮落后下滑充填采空区，在垂向形成采空“下部充填、中部铰接、上部空域”的特征，中部铰接对顶底板支撑最明显，形成相对稳定的的“V”形铰接结构。复合采场围岩结构包括：工作面两侧的“R-P-F”结构、同水平煤柱间的“P-S-P”结构、跨水平煤柱间的“P-S-P”结构，其中跨水平煤柱间的“P-S-P”结构为跨间隔岩层结构，是控制复合采场围岩稳定性的关键。

（4）分析了急倾斜近距离煤层复合采场链式结构形成演化过程，给出了基于区段煤柱关键柱、间隔岩层关键域的两种失稳模式，确立了两种失稳模式的判定条件，初步制定了基于区段煤柱关键柱的关键防控、断链减灾防治措施，为该类煤层的链式灾害防治指明防治关键点，为复合采场围岩稳定性控制提供理论指导。

The steeply inclined coal seam is widely located in the western region of China, and its safe mining plays an important role in energy security for regional economic development. Due to the gravity-dip effect and multiple mining compound effect, the stope-surrounding rock structure of near steeply inclined coal seam is complex and dynamic hazards are frequent. Therefore, taking the near steeply inclined coal seam mining in Xinjiang Longquan coal mine as the engineering background, numerical simulation, physically similar simulation experiments and theoretical analysis are used to analyze the stress transfer path of the composite stope of near steeply inclined coal seam and the characteristics of fracture development and surrounding rock transport in the composite stope, revealing the "P-S-P" chain structure of stope surrounding rock. The main conclusions are as follows:

（1）Under the comprehensive influence of gravity-dip angle and mining action, the roof and floor of the steeply inclined working face form the "asymmetric arch" stress-release area in the upper part of the inclined roof, the stress-concentrated area in the upper part of the inclined floor, the stress-release area in the lower part of the inclined floor, and the stress-concentrated area in the lower part of the inclined roof. During the formation of the steeply inclined composite stope, the stress concentration and release phenomenon in the inclined lower area of the upper working face is weakened; with the formation of the composite stope, the stress distribution area of the interval rock seam evolves from opposing distribution to interval distribution, the area of the stress concentration and release area on the outside of the stope increases, and the stress peak increases significantly, and the area of the stress concentration and release around the sectional coal column decreases, and the stress peak increases significantly.

（2）In the same stable rock formation, the stress is transferred vertically; near the rock formation level, the stress is transferred along the level; when spanning multiple rock formations, the stress is transferred perpendicular to the level. Compound stope stress transfer paths can be divided into three major categories: "R-P-F", "R-P-F-P" and "R-P-F-P". The "R-P-F" and "R-P-F-P" stress transfer paths control the stress distribution and evolution of the overall range of the stope, and the interval rock layer stress transfer paths control the stress distribution and evolution between the working faces. During the formation of composite stope, the stress transfer path of interval seam evolves many times, and the transfer path is the inclined upper part of the bottom plate of the upper working face of the upper coal seam → the lower coal pillar → the lower coal pillar. coal pillar in the upper coal seam → the inclined upper part of the bottom plate in the lower working face of the upper coal seam → the inclined lower part of the top plate in the lower working face of the lower coal seam, showing the top-down spiral transfer characteristics.

（3）When the steeply inclined working face is excavated for 10 cm and 20 cm, the roof starts to appear fissures and delamination respectively; After the excavation of the working face is completed, the roof collapse is characterized as "inclined asymmetric" arch shell, and the collapse arch shell varies slightly for different burial depths and mining heights; the collapsed roof plays a "duality" role on the floor, which is manifested as the impact damage of the collapse on the floor and the protection of "floor protection layer" formed by the collapse. After the roof collapse, it slides down and fills the goaf with gravity, and forms the characteristics of "lower filling, middle hinge structure, upper airspace" in the vertical direction, in which the middle hinge structure supports the roof and floor most obviously, and the "V-shaped" hinge structure has good structural stability, and the upper and lower sides have gangue distribution. The stable structure of composite stope surrounding rock includes: "R-P-F" structure on both sides of the working face, "P-S-P" structure between the same horizontal coal pillars, and "P-S-P" structure between cross horizontal coal pillars, among which "P-S-P" structure between cross horizontal coal pillars is the structure of cross sandwiched rock between two near stope, which is the key to control the stability of composite stope surrounding rock.

（4）The process of chain structure formation and evolution in the composite stope of near steeply inclined seam is analyzed, two instability modes based on the key pillar and the critical zone of interval rock layer are given, the judgment conditions of the two instability modes are established, the prevention measures based on the key pillar like prevention and control of key pillar and chain-cutting disaster mitigation are initially formulated, which indicate the key for the prevention and control of chain disasters in near steeply inclined seam and provide the theoretical guidance for the stability control of the surrounding rock in the composite stope.

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