矿山采动煤岩体强度劣化致诱动力灾害及其防治依然是制约安全开采的难题之一。急倾斜煤层赋存环境复杂，开采过程中诱发的动力灾害现象频发，严重制约现场安全开采与矿区可持续发展。本论文以乌鲁木齐矿区为研究背景，基于现场工程地质调查、理论分析与岩石力学实验、科学计算及现场综合监测等多种方法，开展急倾斜煤岩体强度劣化与动力灾害防治基础研究，为安全开采提供了理论与科学基础。主要研究成果如下： 1、系统完成了急倾斜煤岩体现场工程地质调查与结构特征分析。调查区域内构造裂隙较少，无大的地质构造，煤岩体多处于破坏后再稳定结构。构建急倾斜煤岩体宏观裂隙分布特征统计模型，调查区域内急倾斜煤岩体可划为破碎区、塑性区及弹性区；借助数字化X射线摄影系统(Digital Radiography, DR)扫描技术，建立了急倾斜煤岩体细微观结构特征随机演化模型，明确了导致采空区顶板出现大面积悬顶及整体性垮落的内在诱因，为后续力学实验与数值计算提供现场数据及理论基础。 2、揭示了急倾斜煤岩体强度劣化形成过程与“时-空”演化机制。连续加载下煤岩体强度劣化呈现渐进性破坏特征；依据声发射(Acoustics Emission, AE)参量特征将实验过程分为初始受载阶段、弹性阶段、微破裂阶段及峰后破裂阶段，并建立破坏能与AE能量间的函数关系；试样表面温度辐射区域可作为判定后续破裂位置依据之一。评价预制结构面对煤岩体力学性态的影响程度，预制结构面对急倾斜煤岩体强度劣化起到决定作用，平行结构面对试样力学响应特性影响最为显著；预制结构面导致煤岩体能量耗散特征表现为AE能量数级增大、热红外温度辐射区域主要集中于预制结构面附近且以高温异常区域为主。 3、揭示了加-卸载过程中煤岩体强度劣化致灾机理与应力-温度-声发射(Stress-T-AE)的关联特征。急倾斜煤岩体的宏观破裂形式分别为共轭型与X型破裂，煤岩体表面热红外温差经历先升后降。岩体AE特征以高能量大事件为主，煤体则产生大量低能量小事件。急倾斜煤岩体的强度劣化为一个细微观裂纹分形演化过程；含平行结构面与45°结构面煤岩体中新生裂隙起裂位置均位于预制结构面的端部，组合型结构面煤岩体中新生裂隙起裂位置一般位于结构面端部及结构面之间的区域。初次加-卸载时，预制结构面角度越大，AE特征参量数量级愈高，第2次加-卸载时，预制结构面角度越大，相应的AE特征参量的数量级愈低。含预制结构面试样表面温度最大值经历先降后升，而最小值则持续性增加。 4、构建了考虑次生裂隙网的煤岩体“应力-裂隙-渗流(Stress-Crack-Seepage)”强度劣化耦合效应评价模型。急倾斜煤岩体的渗透率及孔隙率均随着注水压力及外部载荷的改变而变化显著；模型的主裂隙通道内水体流速最大且随着注水压力的增大而不断地增加；较大的流速一般发生在具有较大压力梯度的细小裂隙处，模型出水位置同样具有较高流速；模型内次生裂隙通道对水体压力分布起到决定性作用；分析模型出口稳定性，模型出口流速分量最大值均位于模型两侧且随着外部荷载的增加而增大，流速最大区域迁移特征的量化描述可作为判定急倾斜煤岩体次生裂隙场演化机制的重要方法。 5、定量化评价了急倾斜煤岩体动力灾害防治效果。以急倾斜煤层采空区顶板弱化处理为背景，优化顶板弱化方案参数，制定了提升煤岩体强度劣化程度与防治动力灾害的采空区顶板耦合弱化方案，采用电磁辐射与微震监测完成煤岩体应力演化机制与破裂效果的评估。实践结果反映出采空区顶板耦合弱化方案成功削弱了急倾斜煤岩体应力集中效应，改变了煤岩体能量存储与释放的方式，动力灾害问题得到了较好的控制和解决。 论文研究结果在促进煤岩体动力灾害致灾机理及防治基础研究方面具有较好的科学及实用价值，为各类煤层赋存条件下形成煤岩体动力失稳致灾防治措施提供了指引。

Coal-rock mass dynamic hazard prevention and control induced by Coal-rock mass strength deterioration (CMSD) is still one of fundamental and scientific problems to constrain safe mining. In steeply inclined coal seams, there exists complex environment and mining settings which restrict substainable development of the coal mine area. With Urmchi coal restrict as the research background, the hybrid methodology, including engineering geological investigation, theoretical analysis, rock mechanics, scientific calculation and in-situ monitoring, has been formed for the relative researches on Coal-rock mass strength deterioration and its dynamic hazard prevention and control in mining steeply inclined coal seams. All research results would offer theoretical and scientific basis for safe mining. Thesis completed following achievements: (1) In-situ engineering geological investigation and structural characterisitcs analysis have been finished systematically in investigation zone. There are seldom remarkable geological structure and cracks and coal-rock masses are stable after failuring. The thesis has built up statistical model on distribution mechanism of the macro-crack. Coal-rock masses was divided into broken zone, plastic zone and elastic zone in the mining steeply inclined coal seams. Besides, random evolution model on structural characteristics of mesco-micro-scale crack has also established. According to the model, the inner cause that large-scale void roofs were supending and caving suddenly are clear, which will provide in-stiu data and theoretical basic for subsequent rock mechanics and numerical simulation sperately. (2) Formation and spatial-temporal evolution mechanism of CMSD has been revealed by continous loading experiment. Also, we confirmed initial structural plane effect on CMSD remarkably. With the continous loading, CMSD mode of specimens can be regarded as progressive failure being accompanied by bigger dispersion in basic mechanical parameters. By AE traits of all specimens, the experimentwould be concluded as four stages under the loading, that is, initial stage, elastic stage, plastic stage and post-peak loosening stage. Besides, quantitative relationship between failure energy of the specimens and AE energy has been established clearly. High and low temperature abnormal area would fortell specific fracturing location. On one hand, Structural planes took a decisive action for CMSD. Specially, the influence from parallel structural plane was most obvious. On the other hand, energy-dissipation trait of the specimens have changed notably due to the structural plane impact. Mechanical repsonse time was cut down, AE energy level incre ased sharply. In addition, the abnormal area of infrared radiation temperature mainly concerntrated on areas neighbouring the structural planes with high temperature abnormal areas. (3) Correlative traits between hazard-causing mechanism with CMSD and Stress-T-AE during loading-unloading experiment has been explored preliminary. Macroscopic fracturing mode of coal-rock mass structure specimens were seperately conjuated shape and X shape. Temperature difference of the specimens always rised at first and slumped suddenly. In specimen trait aspect of AE event, little AE large events were emerged in the rock mass specimens. Inversely, vast AE small events with low energy were derived from the coal mass specimens. In general, CMSD is a mesco-micro scale evloution on crack fractal parameters which obtained constant while the specimens scale altered in the mechanics experiment. Neocracks propagated at terminal of the parallel and 45 degrees structure planes. Besides, neocracks initiated at both terminal part of the planes and among the planes in the other kinds of structural planes. In first loading-unloading status, the greater were structure angles, the higer were the relevant AE energy values. However, the experimental result was opposite with lower AE energy values in second loading-unloading testing. Simultaneously, maximum and minimum values of specimen surface temerpature had various changing rules: the maximum ones decreased initially and then increased, however, the corresponding minimum ones increased from beginning to end. (4) With numerical simulation experiment, "stress-crack-seepage" strength deterioration coupling effect model for coal-rock masses has been established. At first, the final result of stress prediction was showed. Secondly, flow velocity would achieve the crest in the host crack of simulation model, and gradually add when external water-injection pressure evelated step by step. Moreover, the bigger value of flow velocity also occurred at some tiny cracks with larger pressure grandient. Also, the value near outlet zone would acquire a bigger value. Model crack decided water pressure distribution definitively. Overall, migration mechanism of the max flow velocity can be used as one of important criteria for internal crack propagation characteristics. Either sides of the outlets had the maximum values of flow velocity, which would increase with increment of external loading. (5) Being weakening handling of the void roof as practical application in mining steeply inclined coal seams, prevention and control schemes for its dynamic hazards have been developed in the end. Original weakening scheme was unsuccessful due to the roof stress concentration happening and lower degree of roof fragmentation. In a wake of roof coupling weakening, the scheme dropped the possibility that stress concerntration emerged in the void roof with the impressive degree of roof fragmentation. Meanwhile, the coupling weakening scheme altered storage-release mode of roof energy, which reduced the dynamic hazards being induced by the void roof thoroughly. Finally, prominent economic benefits were gained after the coupling weakening scheme implementation. Ultimately, all research achievements offer a methodology and theory for dynamic hazard prevention and control of the void roof in the mining steeply inclined seams so as to ensure safe, effecient and clean exploitation.