大倾角煤层安全高效开采的关键是对围岩的稳定性控制，揭示倾角效应下煤岩体的采动力学行为是大倾角煤层多尺度围岩协同控制的理论基础。采用岩石力学实验、数值模拟与理论分析综合互馈的研究手段，探究了采动影响下煤岩体层间应力传递、主应力偏转及非均衡变形破坏等力学特征的倾角效应。结果表明：

(1) 单轴加载条件下煤岩组合体交界面处的主应力大小和方向的分布特征随倾角增大呈现两种演变状态，煤岩组合体的第一主应力由“煤体受压+岩体受拉”状态转变为“煤体受拉+岩体受压”状态；第三主应力大小随倾角增大呈“煤减+岩增”的单调演变趋势；主应力方向随倾角增大由“煤顺+岩逆”转变为“煤逆+岩顺”的偏转状态，交界面上侧岩体与下侧煤体随倾角变化时的主应力偏转状态相互对称。

(2) 工作面中部区域轴压与围压随倾角增大保持不变，而上部区域载荷大小随倾角增大而减小，下部区域载荷由于埋深增大随倾角增大而增大；煤体与岩体的岩性差异导致煤岩体内部应力传递规律发生改变，常规三轴加载条件下的峰值强度变化规律随倾角增大呈先减后增的变化趋势，工作面倾向上、中、下部区域煤岩体强度变化趋势与其相同，但极小值位置在不同倾角范围内；当煤岩组合体三轴强度较小时发生界面处的滑移破坏，当强度相比较大时主要是煤体的塑性变形破坏引发煤岩体的失稳。同一加载条件下，在倾角为0°时岩体第三主应力大于煤体，随着倾角增大，第一和第三主应力呈“煤减+岩增”的变化趋势；在采动影响下，工作面上部煤岩体主应力随着倾角增大而减小，下部规律与之相反；在从静水压力到原岩应力再到应力峰值的加载状态下，第一和第三主应力大小都呈上升趋势；在原岩应力和应力峰值加载状态下，煤体的主应力呈现先降低后升高的趋势，而岩体的第一和第三主应力随倾角增大而增大。

(3) 单轴加载条件下，交界面处的煤岩组合体主应力状态随倾角增大的转变使得煤岩组合体由“交界面上侧岩体+非交界面部分煤体”的组合破坏模式转变为“交界面下侧煤体+非交界面部分煤体”的组合破坏模式，即对应于煤岩组合体裂纹扩展规律由组合体的剪切变形破坏转变为界面处的滑移破坏，煤岩组合体单轴抗压强度随倾角增大而降低。三轴加载条件下的煤岩体主应力状态的转变情况与单轴加载条件存在类似规律；随着层面倾角增大，煤体强度增大，而岩体强度随之降低；当侧压系数较小时主要在不同角度呈现“交界面下侧煤体+非交界面部分煤体”和“交界面上侧岩体+非交界面部分煤体”的组合破坏模式，当侧压系数较大时，由于不同层面倾角下交界面处煤体强度大于岩体强度，则煤岩组合体破坏主要呈现“交界面上侧岩体+非交界面部分煤体”的组合破坏模式。

倾角效应导致的煤岩体层间应力传递、主应力偏转以及非均衡变形破坏等力学行为对于倾斜采场围岩稳定性研究具有重要意义。

The key to safe and efficient mining of steeply dipping coal seams is controlling the stability of surrounding rock. Understanding the dynamic behavior of coal rock mass under the dip effect is crucial for collaborative control of multi-scale surrounding rock of large dip angle coal seams. Through rock mechanics experiments, numerical simulations, and theoretical analyses, the mechanical characteristics of inter-layer stress transfer, principal stress deflection, and non-equilibrium deformation and failure of coal and rock mass under the influence of mining are investigated. The results show that:

(1) Under uniaxial loading, the distribution characteristics of the magnitude and direction of the principal stress at the interface of the coal-rock complex show two evolution states with the increase of the dip Angle. The first principal stress of the coal-rock complex changes from the state of "coal compression + rock tension" to the state of "coal compression + rock compression". The third principal stress shows a monotonic trend of "coal decreasing + rock increasing" with the increase of dip Angle. The principal stress direction changes from "coal clockwise + rock counterclockwise" to "coal counterclockwise + rock clockwise" with the increase of the dip Angle. The deflection states of rock and coal mass principal stress at different dip angles are symmetrical to each other.

(2) The axial pressure and confining pressure in the central region of the working face remain unchanged with the increase of dip Angle, while the load in the upper region decreases with the increase of dip Angle, and the load in the lower region increases with the increase of dip Angle due to the increase of buried depth. The lithology difference between coal and rock mass results in the change of stress transfer law in coal and rock mass. Under conventional triaxial loading condition, the change law of peak strength decreases first and then increases with the increase of dip Angle. The change trend of coal and rock mass strength in the upper, middle and lower regions of working face inclination is the same, but the minimum value is in different dip Angle ranges. When the triaxial strength of coal and rock mass is small, the sliding failure at the interface occurs. When the strength ratio is large, it is mainly the plastic deformation failure of coal mass that causes the instability of coal and rock mass. Under the same loading condition, when the dip Angle is 0°, the third principal stress of rock mass is greater than that of coal body. With the increase of the dip Angle, the first and third principal stresses show a trend of "coal decrease + rock increase". Under the influence of mining, the principal stress of coal rock mass in the upper part of the working face decreases with the increase of dip Angle, while the law of the lower part is opposite. Under the loading state from hydrostatic pressure to primary rock stress and then to stress peak, the first and third principal stresses both show an upward trend. Under the loading state of primary rock stress and peak stress, the principal stress of coal firstly decreases and then increases, while the primary and third principal stresses of rock mass increase with the increase of dip Angle.

(3) Under uniaxial loading, the change of principal stress state of coal-rock mass at the interface with the increase of dip Angle makes the combined failure mode of coal-rock mass at the interface change from "rock mass above the interface + non-interface part of coal mass" to "coal mass below the interface + non-interface part of coal mass". That is, the crack propagation law of coal and rock mass changes from shear deformation failure to slip failure at the interface, and the uniaxial compressive strength of coal and rock mass decreases with the increase of dip Angle. The transformation of the principal stress state of coal rock mass under triaxial loading is like that under uniaxial loading. With the increase of the dip Angle, the strength of coal mass increases, while the strength of rock mass decreases. When the side pressure coefficient is small, the combined failure modes of "coal body below the interface + non-interface part of coal mass " and " rock body above the interface + non-interface part of coal mass " are mainly presented at different angles. When the side pressure coefficient is large, the strength of coal body at the interface is greater than that of rock body at different plane angles. Therefore, the failure mode of coal and rock mass mainly presents the combined failure mode of " rock mass above the interface + non-interface part of coal mass ".

The mechanical behaviors such as stress transfer between strata, principal stress deflection and non-equilibrium deformation and failure caused by dip Angle effect are of great significance for the stability study of surrounding rock in inclined stopes.

[1] 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.

[2] 鲜学福,谭学术.层状岩体破坏机理[M].重庆:重庆大学出版社,1989.

[3] 梅松华.层状岩体开挖变形机制及破坏机理研究[D].中国科学院研究生院(武汉岩土力学研究所),2008.

[4] 杨科,池小楼,刘帅.大倾角煤层综采工作面液压支架失稳机理与控制[J].煤炭学报 2018,43(07): 1821-1828.

[5] 王家臣,赵兵文,赵鹏飞,等.急倾斜极软厚煤层走向长壁综放开采技术研究[J].煤炭学报,2017,42(02):286-292.

[6] 伍永平,郎丁,解盘石.大倾角软煤综放工作面煤壁片帮机理及致灾机制[J].煤炭学报2016,41(08): 1878-1884.

[7] 石平五,刘晋安,周宏伟.大倾角煤层底板破坏滑移机理[J].矿山压力与顶板管理 1993,Z1: 115-119.

[8] 勾攀峰,辛亚军.大倾角煤层回采巷道顶板结构体稳定性分析[J].煤炭学报,2011,36(10): 1607-1611.

[9] 田双奇.大倾角煤层长壁伪俯斜采场顶板运移规律[D].西安科技大学,2020.

[10] Chi XL, Yang K, Fu Q, et a1. The Mechanism of Mining-Induced Stress Evolution and Ground Pressure Control at Irregular Working Faces in Inclined Seams[J]. Geotechnical and Geological Engineering, 2020, 38:91-107.

[11] Chi XL, Yang K, Wei Z, et a1. Breaking and mining-induced stress evolution of overlying strata in the working face of a steeply dipping coal seam[J]. International Journal of Coal Science& Technology, 2020.

[12] Singh TN, Gehi LD. State behavior during mining of steeply dipping thick seams a case study[C].Proceedings of the International Symposium on Thick Seam Mining,l993,311-315.

[13] 池小楼.大倾角软煤层分层综采再生顶板力学特性与围岩稳定控制[D].安徽理工大学 2021.

[14] Bondarenko Y V, Makeev A Y, Zhurek P, et al. Technology of coal extraction from steep seams in the Ostrava-Karvina basin[J]. Ugol'Ukrainy;(Ukrainian SSR),1993,3.

[15] Aksenov V V, Lukashev G E. Design of a universal equipment set for working steep seams[J]. Ugol';(Russian Federation),1993,4.

[16] Kulakov V N. Geomechanical conditions of mining steep coal beds[J]. Journal of Mining Science, 1995, 31(2).

[17] 伍永平.大倾角煤层开采“R-S-F”系统动力学控制基础研究[D].西安科技大学,2003.

[18] 伍永平,解盘石.大倾角煤层开采覆岩空间倾斜砌体结构.煤炭学报,2010,35(8):1252-1256.

[19] 伍永平,解盘石,任世广.大倾角煤层开采围岩空间非对称结构特征分析[J].煤炭学报2012,25(2): 182-184.

[20] 解盘石.大倾角煤层长壁采场覆岩结构及其稳定性研究[M]:陕西科学技术出版社 2016:43-50.

[21] 王红伟.大倾角煤层开采覆岩结构特征分析[D].西安科技大学,2010.

[22] 解盘石,伍永平.大倾角煤层长壁开采覆岩空间活动规律研究[J].煤炭科学技术 2012,40(9):1-5.

[23] 郭金帅.大倾角综采面覆岩活动规律研究[D].中国矿业大学,2015.

[24] 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):14-18.

[25] 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].西安科技大学,2014.

[26] 伍永平,王红伟.大倾角长壁开采围岩宏观应力拱壳分析[J].2012,7(4):560-564.

[27] 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.

[28] 罗生虎,伍永平,解盘石,等.大倾角大采高综采工作面支架受载与失稳特征分析[J].煤炭学报,2018,43(12),3320-3328.

[29] 罗生虎,伍永平,解盘石,等.大倾角煤层走向长壁开采支架稳定性力学分析[J].煤炭学报,2019,44(09),2664-2672.

[30] 王金安,张基伟,高小明,等.大倾角厚煤层长壁综放开采基本顶破断模式及演化过程(Ⅰ)-初次破断[J].煤炭学报,2015,40(06):1353-1360.

[31] 王金安,张基伟,高小明,等.大倾角厚煤层长壁综放开采基本顶破断模式及演化过程(Ⅱ)-周期破断[J].煤炭学报,2015,40(08):1737-1745.

[32] 乔福祥,尹鹤峰,陶厚礼,等.大倾角“三软”煤层工作面矿压显现规律及岩层控制的研究[J].矿山压力与顶板管理,1993(3.4):105-109.

[33] 朱现磊,杨仁树,蔡志炯,等.大倾角松软煤层综放开采矿压显现规律研究[J]. 煤炭科学技术,2014,42(5):25-28.

[34] 尹光志,李小双,郭文兵.大倾角煤层工作面采场围岩矿压分布规律光弹性模量拟模型试验及现场实测研究[J]. 岩石力学与工程学报,2010,29(S1):3336-3343.

[35] 赵元放,张向阳,涂敏.大倾角煤层开采顶板垮落特征及矿压显现规律[J]. 采矿与安全工程学报,2007,(2):231-234.

[36] 伍永平,尹建辉,解盘石,等.大倾角煤层长壁开采矸石滑移充填效应分析[J].西安科技大学学报,2015,35(5):529-533.

[37] 相啸宇,张伟,王忠武,等.急倾斜采空区矸石充填顶板控制变形分析[J].煤矿开采,2017,36(1):48-50.

[38] 王港盛,田慧强,徐铎.倾斜煤层充填机理梁式模型力学分析[J].煤炭技术,2011,16 (3):47-50.

[39] 杨科,孔祥勇,陆伟,等.近距离采空区下大倾角厚煤层开采矿压显现规律研究[J].岩石力学与工程学报,2015,34(S2):4278-4285.

[40] 杨科,陆伟,潘桂如,等.复杂条件大倾角大采高旋转综采矿压显现规律及其控制[J].采矿与安全工程学报,2015,32(2):199-205.

[41] 杨科,孔祥勇,陆伟,等.近距离采空区下大倾角厚煤层开采矿压显现规律研究[J]. 岩石力学与工程学报,2015,34(S2):4278-4285.

[42] 王家臣,张锦旺.综放开采顶煤放出规律的BBR研究[J].煤炭学报,2015,40(03):487-493.

[43] Zhang JW, Wang JC, Wei W, et al. Experimental and numerical investigation on coal drawing from thick steep seam with longwall top coal caving mining. Arabian Journal of Geosciences,2018.11(5).

[44] 孟宪锐,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(11):14-17.

[45] 吕秀江,耿妹华,郝彬彬.复杂条件下大倾角对放顶煤冒放规律的影响研究[J].河北工程大学学报,2007(4):93-96.

[46] 杨怀敏,崔景昆,刘惠德.大倾角采煤工作面矿山压力显现规律的研究[J].河北建筑科技学院学报,2003(1):69-71.

[47] 谢俊文,高小明.急倾斜厚煤层走向长壁开采技术[J].煤炭学报,2005(5):546-549.

[48] 黄国春,陈建杰.坚硬顶板、软煤、软底大倾角煤层综采实践[J].煤炭科学技术 2005(8):33-35

[49] 李峰,尚二考.急倾斜煤层走向长壁工作面矿压观测研究[J].河北煤炭,2007(2):15-17.

[50] Lekhnitskii S G, Fern P, Brandstatter J J, et al. Theory of elasticity of an anisotropic elastic body[J]. Physics Today, 1964, 17(1): 84.

[51] Pinto, I. J. Stress and strain in an anisotropic-orthotropic body[J]. Proc. First Cong of the Int. Soc. For Rock Mech,Lisbon,1966:625-635.

[52] Wardle, L. J, Gerrard, C. M. The "equivalent" anisotropic properties of layered rock and soilmasses [J]. Int. J. Rock Mech.Min.Sci.1972,4:155-175.

[53] Salaman, M. D. G. Elastic Moduli of A stratified Rock Mass[J]. Int. J. Rock Mech. Min. Sci, 1968, 5: 519-527.

[54] Gerrard, C. M. Equivalent Elastic Moduli of a Rock Mass Consisting of orthorhombic layers[J]. Int. J. Rock Mech. Min. Sci. 1982,19.

[55] 曾纪全,来结合,全海.溪洛渡水电站软弱岩带固结灌浆试验效果检测[J].岩石力学与工程学报,2001,20(supp):1851-1857.

[56] 张泽天,刘建锋,王璐,等.组合方式对煤岩组合体力学特性和破坏特征影响的试验研究[J].煤炭学报,2012,37(10):1677-1681.

[57] 郭东明,左建平,张毅,等.不同倾角组合煤岩体的强度与破坏机制研究[J].岩土力学,2011,32(5):1333-1339.

[58] 杨科,刘文杰,窦礼同,等.煤岩组合体界面效应与渐进失稳特征试验[J].煤炭学报 2020,45 (5):1691-1700.

[59] CHEN Y, ZUO J, LIU D, et al. Deformation failure characteristics of coal-rock combined body under uniaxial compression: experimental and numerical investigations[J]. Bulletin of Engineering Geology and the Environment, 2019, 78(5):3449-3464.

[60] 窦林名,田京城,陆菜平,等.组合煤岩冲击破坏电磁辐射规律研究[J].岩石力学与工程学报,2005,24(19):3541-3544.

[61] 左建平,陈岩,张俊文,等.不同围压作用下煤-岩组合体破坏行为及强度特征[J].煤炭学报,2016,41(11):2706-2713.

[62] 解北京,严正.基于层叠模型组合煤岩体动态力学本构模型[J].煤炭学报,2019,44(2):463-472.

[63] 李成杰,徐颖,张宇婷,等.冲击荷载下裂隙类煤岩组合体能量演化与分形特征研究[J].岩石力学与工程学报,2019,38(11):2231-2241.

[64] 宋录生,赵善坤,刘军,等.“顶板–煤层”结构体冲击倾向性演化规律及力学特性试验研究[J].煤炭学报,2014,39(增1):23–30.

[65] 杨磊,高富强,王晓卿,等.煤岩组合体的能量演化规律与破坏机制[J].煤炭学报,2019,44 (12):3894-3902.

[66] 王学滨.煤岩两体模型变形破坏数值模拟[J].岩土力学,2006,27(7):1066-1070.

[67] 郭伟耀,周恒,徐宁辉,等.煤岩组合体力学特性模拟研究[J].煤矿安全,2016,47(2):33-35,39.

[68] 曹吉胜,戴前伟,周岩,等.考虑界面倾角及分形特性的组合煤岩体强度及破坏机制分析[J].中南大学学报(自然科学版),2018,49(1):175-182.

[69] 付斌,周宗红,王友新,等.不同煤岩组合体力学特性的数值模拟研究[J].南京理工大学学报,2016,40(4):485-492.

[70] 伍永平,解盘石,贠东风,等.大倾角层状采动煤岩体重力-倾角效应与岩层控制[J].煤炭学报,2023,48(01):100-113.

[71] 左保成,陈从新,刘才华.相似材料试验研究[J].岩土力学, 2004, 25 (11) :1805-1808.

[72] 黄彦华,杨圣奇,刘相如.类岩石材料力学特性的试验及数值模拟研究[J]. 实验力学,2014,29(2):239-249.

[73] 殷鹏飞.层状复合岩石试样力学特性单轴压缩试验与颗粒流模拟研究[D].徐州:中国矿业大学,2016.

[74] 徐芝纶.弹性力学[M].北京:高等教育出版社,2016.

[75] 谢和平,周宏伟,刘建锋,等.不同开采条件下采动力学行为研究[J].煤炭学报,2011,36 (07):1067-1074.

[76] 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.