大倾角煤层是指煤层倾角为35°～55°的煤层，是国内外采矿界公认的难采煤层。大倾角煤层安全高效开采的关键是对“支架-围岩”系统的稳定性控制，而顶板及其上覆岩层作为该系统的构成元素与施载体，是系统稳定性控制的基础。据此，本文采用物理相似模拟实验、数值计算和理论分析相结合的研究方法，对大倾角煤层长壁开采中覆岩应力传递演化特征与变形破坏演化规律及其倾角效应展开系统研究。结果表明：

（1）沿工作面走向，采空区上方覆岩破坏运移呈现对称性，即直接顶冒落充填采空区，直接顶上方岩层在到达极限悬露距离时发生破断并形成铰接结构，该结构对覆岩的破坏运动产生约束，覆岩垮落形态近似对称分布。沿工作面倾向，覆岩中上部区域位移量较大并先于下部区域发生破坏，破坏块体对采空区进行充填，呈现采空区下部充填密实，中部区域充满，上部区域部分充填的非均匀特性，并在工作面支架后方形成“倒三角”的临空面。随着工作面推进距离增大，覆岩下部区域位移受采空区矸石充填影响位移空间较小，而上部区域位移空间充分，覆岩破坏范围向岩层中上部区域延伸，垮落形态呈现非对称拱形。

（2）工作面推进过程中，覆岩进行自我调节活动，应力重新分布。沿工作面走向，覆岩垂向应力呈对称拱形分布，并在工作面推进距离大于3L后，垂向应力峰值趋于稳定。沿工作面倾向，采空区上方覆岩垂向应力分布呈非对称拱形特征，基于覆岩垂向应力计算的主应力偏转等值线亦呈现非对称分布特征，等值线数值随覆岩层位增高而减小，随着工作面推进距离增加，覆岩主应力偏转等值线分布形态由“m”向“n”型转化，结合优势扩展裂隙角的分析，分析采空区中上部区域覆岩主应力偏转程度较大位置易发生破坏，促使覆岩破坏向岩层中上部延伸。

（3）随煤层倾角增大，沿工作面倾向，覆岩垂向应力拱形应力释放区范围减小，拱体扁平程度有所增大，拱顶位置向岩层中上部迁移，覆岩垂向应力分布非对称性增强。基于覆岩垂向应力计算的主应力空间展布形态及主应力偏转等值线分布特征非对称性显著，表现为覆岩应力传递拱的扁平化程度增加，拱顶向上迁移；覆岩下部区域主应力偏转等值线影响范围减小，而上部区域主应力等值线分布范围有所增加，主应力偏转等值线分布形态逐渐向覆岩中上部区域延伸等。沿工作面走向，工作面前方下部区域竖向切应力随煤层倾角增大而增大，基于摩尔库伦准则计算稳定系数k值，得出工作面前方区域破坏临界线随着岩层倾角的增大向煤层深部偏转。

（4）随煤层倾角增大，采空区矸石接顶长度a呈现非线性增加，基于采空区矸石非均匀约束特征，建立顶板梁结构力学模型和覆岩非对称拱结构力学模型。顶板挠度曲线随着煤层倾角增加而减小，挠度峰值位置向顶板中上区域迁移，在距上、下端头约20 m处出现转角峰值；覆岩非对称拱峰值位置随煤层倾角增大而向岩层中上部迁移，同时非对称拱的拱高有所减小。

"Steeply dipping seams" are coal seams with a dip angle of 35° to 55°, which are difficult to mine safely and efficiently in the mining industry worldwide. To control the stability of the "support-rock" system and ensure safe and efficient mining of these seams, it is essential to focus on the roof and its overlying rock formations as the load-bearing body of the system. Therefore, this study combines physical similarity simulation experiments, numerical calculations, and theoretical analysis to investigate the evolution characteristics of stress transfer, deformation, and failure of overlying strata in longwall mining of steeply dipping seams, and their dip angle effects. The findings indicate that effective control of the stability of the "support-rock" system is possible with proper management of the roof and overlying rock formations. The results show that:

（1） Along the trend of coal seam, the overburden destruction above the mining area shows symmetry, i.e. the direct top fall fills the mining area, the rock layer above the direct top breaks and forms an articulated structure when it reaches the limit overhang distance, this structure restrains the destruction movement of the overburden, and the overlying collapse pattern is approximately symmetrically distributed. Along the tendency of coal seam, the upper part of the overburden is more displaced and breaks before the lower part, the breakage block fills the hollow area, showing the non-uniform characteristics of the lower part of the hollow area is filled, the middle part is filled and the upper part is partially filled, and the "inverted triangle" of the hollow surface is formed behind the working face support. As the working face advances, the displacement of the lower part of the overburden is affected by the gangue filling of the quarry area, but the displacement of the upper part is sufficient, and the overburden damage extends to the middle and upper part of the rock layer, and the collapse pattern presents an asymmetric arch.

（2） During the advance of the workings, the overburden is self-regulating and the stresses are redistributed. The overburden vertical stresses are symmetrically arched   along the trend of coal seam and stability at a peak value greater than 3L. Along the tendency of coal seam, as coal seams tend to be uneven, the stress distribution in the overlying rock also becomes asymmetrical, forming an arch-like shape. The main stress deflection contour, which is calculated based on the overburden vertical stress, also becomes asymmetrical and decreases in value as the depth of the overburden increases. These effects become more pronounced as the working face advances further, the contour distribution pattern of the overlying principal stress deflection changes from "m" to "n" type ", Combined with the analysis of the dominant extended fracture angle, the analysis of the overburden main stress deflection in the middle and upper part of the mining area is prone to damage, which leads to the extension of overburden damage to the middle and upper part of the rock layer.

（3） As the coal seam' s inclination angle increases, the overlying rock's vertical stress arch stress release area decreases, causing the arch to flatten and move towards the middle and upper part of the rock seam. The asymmetry of overlying rock vertical stress distribution increases, resulting in the distribution pattern of principal stress deflection contours becoming significantly asymmetric. The principal stress deflection and influence range in the middle and upper regions of the overlying rock gradually increase, while the deflection and influence range of the principal stress in the lower overlying rock decrease. This trend is consistent with the law that the distribution of the overlying rock plastic zone decreases with increasing inclination angle. The stability coefficient k is calculated using the Mohr-Coulomb model, and it is determined that the critical line of failure in the area before work shifts to the deep part of the coal seam with increasing inclination angle.

（4）With the increase of coal seam inclination, the gangue joint length a in the mining area shows a non-linear increase, based on the gangue's non-uniform constraints in the mining area , the structural mechanics model of the roof beam and the structural mechanics model of the overburden asymmetric arch are established. The deflection curve of the roof slab decreases as the coal seam inclination increases. Additionally, the peak position of the deflection moves to the middle and upper regions of the roof slab. Furthermore, the peak corner appears approximately 20 meters away from both the upper and lower ends of the slab; the peak position of the overlying asymmetric arch moves to the middle and upper part of the rock seam with the increase of the coal seam inclination, and the height of the asymmetric arch decreases at the same time.

伍永平, 贠东风, 解盘石, 等. 大倾角煤层长壁综采理论与技术[Ｍ]. 北京:科学出版社, 2017.

伍永平, 贠东风, 解盘石, 等. 大倾角煤层长壁综采:进展、实践、科学问题[J]. 煤炭学报, 2020, 45(01): 24-34.

罗生虎, 王 同, 田程阳, 等. 大倾角煤层长壁开采顶板应力传递路径倾角效应[J]. 煤炭学报, 2022, 47(02): 623-633.

伍永平, 刘孔智, 贠东风, 等. 大倾角煤层安全高效开采技术研究进展[J]. 煤炭学报, 2014, 39(8): 1611-1618.

伍永平. 大倾角煤层开采“R-S-F”系统动力学控制基础研究[M]. 西安:陕西科学出版社, 2006.

Yang Ke, Wei Zhen, Chi Xiaolou, et al. Fracture criterion of basic roof deformation in fully mechanized mining with large dip angle [J]. Energy Exploration & Exploitation, 2021, 39(3).

Bondarenko Yu V, Makeev A Yu, Zhurek P klega. Technology of coal extraction from steep seams in the Ostrava-Karvina basin [J]. Ukraine: N. p, 1993, (3): 45-48.

Aksenov,V. V, Lukashev, G. E. Design of universal equipment set for working steep seams [J]. Ugol, 1993, (4): 5-9(Russia).

Kulakov,V. N. Geomechanical conditions of mining steep coal beds [J]. Journal of Mining Science, 1995, (7): 136-143(Russian Federation).

Mrig, G. C; Sinha, A. N. Proposing a new method for thick, steep and gassy XV seam of Sudamdih. International symposium on thick seam mining: problem and issues (ISTS'92), 445~456, 1992(India).

Mathur, R. B; Jain, D. K; Prasad, B. Extraction of thick and steep coal seams a global overview. 4th Asian mining. Exploration, exploitation, environment. 475-488, Nov.24-28, 1993(India).

李天才, 刘天应. 大倾角煤层分段走向密集采煤法[J]. 矿山压力与顶板管理, 1990, (2): 43-46.

黄建功, 李维光, 等. 大倾角大采高俯伪斜采面矿压显现实测研究[C]. 岩石力学与支护学术会议, 1996.

绿水洞煤矿大倾角煤层综采技术研究[R]. 四川: 华蓥山矿务局, 西安: 西安矿业学院, 1996.

解盘石, 伍永平. 大倾角煤层长壁大采高开采煤壁片帮机理及防控技术[J]. 煤炭工程, 2015, 47(1): 74-77.

解盘石, 伍永平, 王红伟, 等. 大倾角煤层大采高综采围岩运移与支架相互作用规律[J]. 采矿与安全工程学报, 2015, 32(1): 14-19.

李建民. 开滦矿区大倾角煤层开采技术[M]. 北京: 煤炭工业出版社, 2009.

李建民. 开滦复杂煤层综合机械化开采技术[M]. 北京: 煤炭工业出版社, 2007.

东峡煤矿大倾角特厚易燃煤层群综采“小放高”放顶煤技术研究[R]. 兰州: 华亭煤业集团公司东峡煤矿, 西安: 西安科技大学, 2004.

东峡煤矿大倾角特厚易燃煤层群综采放顶煤技术研究[R]. 兰州: 华亭煤业集团公司东峡煤矿, 西安科技大学, 2006.

刘旺海. 大倾角煤层长壁采场煤矸互层顶板破断机理研究[D]. 西安:西安科技大学, 2020.

Singh, T. N; Gehi, L.D et al. State behavior during mining of steeply dipping thick seams-A case study, Proceedings of the International Symposium on Thick Seam Mining, 311-315, 1993, Dhanbad, India.

Huang Changfu, Li Qun, Tian Shuguang. Research on prediction of residual deformation in goaf of steeply inclined extra-thick coal seam [J]. Plos One. 2020, 15: 1-14.

Yin Yanchun, Zou Jianchao, Zhang Yubao, et al. Experimental study of the movement of backfilling gangues for goaf in steeply inclined coal seams [J]. Arabian Journal of Geosciences. 2018, 11(12).

郭 峰, 郎 丁, 黄克军, 等. 大倾角软煤综放采场支架-围岩系统失稳研究[J]. 煤炭科学技术, 2018, 46(04): 123-128.

李 鹏, 纪 磊, 王 敏. 大埋深大倾角工作面综采设备快速更换通道支护技术[J]. 煤炭科学技术, 2020, 48(S2): 29-33.

沈 平, 姜永东, 杨启军, 等. 大倾角煤层沿空留巷弓形柔性掩护支架控制技术[J]. 煤炭科学技术, 2021, 49(03): 37-42.

王国法, 徐亚军, 李丁一. 大倾角综采工作面液压支架刚柔组合倾覆力矩平衡的支护原理及其应用[J]. 岩石力学与工程学报, 2018, 37(S2): 4125-4132.

解盘石, 张颖异, 张艳丽, 等. 大倾角大采高煤矸互层顶板失稳规律及对支架的影响[J]. 煤炭学报, 2021, 46(02): 344-356.

刘 啸. 大倾角综采工作面过断层支架失稳机理及控制技术[J]. 煤炭科学技术, 2021, 49(10): 16-22.

罗生虎, 伍永平, 刘孔智, 等. 大倾角大采高综采工作面煤壁非对称受载失稳特征[J]. 煤炭学报, 2018, 43(07): 1829-1836.

王红伟. 大倾角煤层长壁开采围岩应力演化及结构稳定性研究[D]. 西安: 西安科技大学, 2014.

WANG Hongwei, WU Yongping, LIU Ming, et al. Roof-breaking mechanism and stress-evolution characteristics in partial backfill mining of steeply inclined seams [J]. Geomatics, Natural Hazards and Risk. 2020, 11, pp. 2006-2035.

来兴平, 杨毅然, 单鹏飞, 等. 急斜煤层顶板应力叠加效应致灾特征综合分析[J]. 煤炭学报, 2018, 43(01): 70-78.

Lai Xingping, Sun Hui, Shan Pengfei, et al. Structure instability forecasting and analysis of giant rock pillars in steeply dipping thick coal seams [J]. International Journal of Minerals, Metallurgy and Materials, 2015, 22: 1233-1244.

罗生虎, 伍永平, 刘孔智, 等. 大倾角煤层长壁开采空间应力拱壳形态研究[J]. 煤炭学报, 2016, 41(12): 2993-2998.

罗生虎, 王 同, 伍永平, 等. 大倾角煤层长壁开采围岩应力传递路径时空演化特征[J]. 煤炭学报, 2022, 47(07): 2534-2545.

CHI Xiaolou, YANG Ke, FU Qiang, et al. The mechanism of mining-induced stress evolution and ground pressure control at irregular working face in inclined seams [J]. Geotechnical and Geological Engineering, 2020, 38: 91-107.

池小楼, 杨 科, 付 强, 等. 大倾角煤层分层综采再生顶板应力分布规律研究[J]. 采矿与安全工程学报, 2022, 39(05): 891-900.

Huang Xinglong, Chen Ying, Li Yang, et al. Analysis and Engineering Practice of Factors Affecting Top-Coal Recovery in a Large Dip Coal Seam [J]. Advances in Civil Engineering, 2022, 2022.

伍永平, 皇甫靖宇, 解盘石, 等. 基于大范围岩层控制技术的大倾角煤层区段煤柱失稳机理[J]. 煤炭学报, 2018, 43(11): 3062-3071.

解盘石, 伍永平, 罗生虎, 等. 大倾角大采高采场倾向梯阶结构演化及稳定性分析[J]. 采矿与安全工程学报, 2018, 35(05): 953-959.

解盘石, 段建杰, 皇甫靖宇, 等. 大倾角多区段开采顶板运移及其采空区充填规律实验研究[J]. 西安科技大学学报, 2020, 40(02): 212-220.

王红伟, 伍永平, 解盘石, 等. 大倾角煤层开采“关键域”岩体结构稳定性分析[J]. 采矿与安全工程学报, 2017, 34(02): 287-294.

王红伟, 伍永平, 曹沛沛, 等. 大倾角煤层开采大型三维可加载相似模拟试验[J]. 煤炭学报, 2015, 40(07): 1505-1511.

王红伟, 伍永平, 解盘石, 等. 大倾角采场矸石充填量化特征及覆岩运动机制[J]. 中国矿业大学学报, 2016, 45(05): 886-892.

黄建功. 大倾角煤层采场顶板运动结构分析[J]. 中国矿业大学学报, 2002(05): 74-77.

Lv Wenyu, Wu Yongping, Liu Ming, et al. Migration law of the roof of a composited backfilling longwall face in a steeply dipping coal seam [J]. Minerals, 2019, 9, (3).

Chen Ying, Wang Zhiwen, Hui Qianjia, et al. Overlying rock movement and mining pressure in a fully mechanized caving face with a large dip angle [J]. Frontiers in Earth Science, 2022.

Liu Jian, Chen Shanle, Wang Huajun, et al. The migration law of overlay rock and coal in deeply inclined coal seam with fully mechanized top coal caving [J]. Journal of Environment Biology, 2015, 36(4): 821-827.

张 浩, 伍永平, 解盘石. 大倾角大采高采场塑性区分布及主控因素效能[J]. 煤炭科学技术, 2023, (4): 1-10.

刘庆林, 孟祥瑞, 赵光明等. 大倾角综采工作面矿压显现规律研究[J]. 煤矿安全, 2008, (1): 22-24.

解盘石, 黄宝发, 伍永平, 等. 大倾角大采高采场覆岩应力路径时空效应[J]. 煤炭学报, 2023, (04): 1-14.

孟祥军, 赵鹏翔, 王绪友, 等. 大倾角高瓦斯煤层采动覆岩“三带”微震监测及瓦斯抽采效果[J]. 煤炭科学技术, 2022, 50(01): 177-185.

解盘石, 吴少港, 罗生虎, 等. 大倾角大采高开采支架动载失稳机理及控制[J]. 煤炭科学技术, 2023, (04): 1-13.

赵洪亮, 袁 永, 张 琳. 大倾角松软煤层综放面矿压规律及控制[J]. 采矿与安全工程学报, 2007, 24(3): 345-348.

孟祥瑞, 问荣锋, 刘节影, 等. 千米深井大倾角煤层综放采场矿压显现实测研究[J]. 煤炭科学技术, 2007, 35(11): 14-17.

贠东风, 李浩男, 伍永平, 等. 大倾角煤层综采产效要素系统分析与促产提效精准策略研究[J]. 煤炭科学技术, 2023, (04): 1-11.

卢喜山. 大倾角硬厚煤层综放工作面支护技术及应用研究[D]. 北京: 中国矿业大学, 2011.

郭永红, 黄宝发, 解盘石, 等. 基于倾角效应的大采高采场顶板变形破坏规律研究[J]. 煤炭工程, 2022, 54(12): 109-114.

王 磊, 曹恒将, 蒋子龙, 等. 采空区矸石压实过程对煤柱支承压力的影响[J]. 煤矿安全, 2020, 51(03): 62-68.

宋振骐, 郝建, 汤建泉, 等. 断层突水预测控制理论研究[J]. 煤炭学报, 2013, 38(09): 1511-1515.

Sun Lingzhi, Xie Yunyue, Xiao Hongtian. Numerical Analysis of Stress Fields and Crack Growths in the Floor Strata of Coal Seam for Longwall Mining [J]. Mathematical Problems in Engineering, 2018.

张艳丽, 伍永平, 罗生虎, 等. 覆岩宏观支撑结构演化过程与特征[J]﹒中国矿业大学学报, 2020, 49(2): 280-288.

徐芝纶. 弹性力学[Ｍ]. 北京: 高等教育出版社, 2006.

罗生虎, 任 浩, 王 同, 等. 大倾角煤层长壁开采顶板结构时空演化特征[J]. 西安科技大学学报, 2023, 43(01): 37-46.

王家臣, 王兆会, 杨 杰, 等. 千米深井超长工作面采动应力旋转特征及应用[J]. 煤炭学报, 2020, 45(3): 876-888.

Hao Xianjie, Zhang Qian, Sun Zhuowen, et al. Effects of the major principal stress direction respect to the long axis of a tunnel on the tunnel stability: Physical model tests and numerical simulation [J]. Tunnelling and Underground Space Technology incorporating Trenchless Technology Research, 2021, 114.

Gong Bin, Liang Zhengzhao, Liu Xiangxin. Nonlinear deformation and failure characteristics of horseshoe-shaped tunnel under varying principal stress direction [J]. Arabian Journal of Geosciences, 2022, 15(6).

杜晓丽. 采矿岩石压力拱演化规律及其应用的研究[D]. 北京:中国矿业大学, 2011.

N. H. W. Fundamentals of Rock Mechanics [J]. Geological Magazine, 1977, 114(3).

庞义辉, 王国法, 李冰冰. 深部采场覆岩应力路径效应与失稳过程分析[J]. 岩石力学与工程学报, 2020, 39(4): 682-694.

赵洪宝, 刘一洪, 李金雨, 等. 采动卸荷与岩层倾角对底板损伤的协同影响效应[J]. 中国矿业大学学报, 2022, 51(06): 1056-1068.

马建全, 吴钶桥, 彭 昊, 等. 煤岩采动应力-裂隙带发育规律研究——以榆树湾煤矿为例[J]. 西安科技大学学报, 2022, 42(01): 107-115.

赵雁海, 俞 缙, 周晨华, 等. 考虑主应力轴偏转影响的远场拱壳围岩压力拱效应表征[J]. 岩土工程学报, 2021, 43(10): 1842-1850+1958.

罗生虎, 田程阳, 伍永平, 等. 大倾角煤层长壁开采顶板受载与变形破坏倾角效应[J]. 中国矿业大学学报, 2021, 50(06): 1041-1050.