【作者】 李志华；

【导师】 窦林名；

【作者基本信息】 中国矿业大学 ， 采矿工程， 2009， 博士

【摘要】 断层冲击矿压是由于采矿活动引起断层突然相对错动而猛烈释放能量的现象。目前对断层冲击矿压的研究,工程实录较多,理论或试验研究很少。针对目前研究存在的问题,采用相似模拟试验、FLAC5.02D数值模拟、理论分析和工程实践等方法进行研究,研究了采动影响下断层冲击矿压危险性变化规律,建立了断层滑移诱发煤岩冲击的力学模型,揭示了断层冲击矿压力学机制,分析了采动影响下断层活化矿震活动规律,进行了断层冲击矿压现场防治实践,并对顶板卸压爆破技术参数进行了优化设计。通过断层冲击矿压相似模拟试验和FLAC5.02D数值模拟软件,研究了采动影响下断层冲击矿压危险性。研究表明,工作面由断层下盘向断层推进:在采动影响下断层正应力下降,剪应力上升,断层发生“活化”,顶板稳定性变差,工作面支承压力增加;工作面过断层后,矿压显现不明显。工作面由断层上盘向断层推进:断层面正应力上升,顶板易于形成平衡结构;工作面推过断层后,断层正应力迅速下降,断层滑移量增加,顶板稳定性差,工作面支承压力增加。不同微震信号具有不同的频谱特征。采用FLAC5.02D数值模拟软件研究了断层、顶板物理力学属性对工作面支承压力的影响。研究表明:工作面在断层下盘向断层推进时,顶板强度对工作面支承压力影响最显著;工作面在断层上盘向断层推进时,断层倾角对工作面支承压力影响最显著。当工作面在断层下盘向断层推进时冲击矿压危险性远高于工作面从上盘向断层推进时的危险性。基于“砌体梁”理论,研究了断层倾向对顶板平衡结构和工作面支承压力的影响。建立了断层滑移诱发煤岩冲击的粘滑-粘弹脆性体突变模型,断层滑移诱发煤岩冲击分为两种力学机制,一是在断层活动条件下“断层滑移失稳动态诱发冲击矿压机理”;二是在断层相对稳定条件下“断层滑移稳态诱发冲击矿压机理”。断层滑移失稳动态诱发冲击矿压强度更猛烈,断层滑移速度与工作面推进速度、工作面距断层距离、断层力学性质、断层正压力和开采深度有关。采用微震监测系统对工作面过断层时的矿震活动规律进行了重点分区监测,研究表明:当工作面接近断层时,在采动影响下,断层发生“活化”,矿震活动频繁,矿震震动能量和震动次数均有所增加。当工作面处于断层线时,矿震活动处于峰值位置。工作面离开断层后,矿震活动迅速降低。以济三煤矿6303工作面为现场实践点,进行断层冲击矿压防治研究。采用矿井地质构造预测数理统计法对矿井断层展布进行了预测评价。对危险区域采用钻孔卸压、煤体卸压爆破和顶板卸压爆破等措施同时治理煤层和顶板,从而降低冲击危险性。该论文有图98幅,表21个,参考文献158篇。更多还原

【Abstract】 The fault rockburst is a serious natural disaster in coal mine operation. At present, many fault rockburst have been recorded in practice. However, the studies of theory and experiment were deficient. Aiming at the insufficiencies, the research methods of similar material simulation experiment in laboratory, FLAC5.02D numerical simulation, theory analysis and engineering research have been carried out in this dissertation. The rules of risk of fault rockburst were researched during coal mining operation. A mechanics model is established of fault slip induced rockburst, and the criterion was discovered. The evolvement rules of micro-seismic(MS) signals were analyzed when working face advancing to the fault. The practices of prevention and cure about fault rockburst have been carried out in-situ, and optimized the parametes of relieving shot in roof.The effect of coal mining operation on fault rockburst is studied by using similar material simulation and FLAC5.02D numerical simulation. The results indicate that when the working face advances from the footwall to the fault itself, the slip displacement increases due to the decrease of normal stress and the increase of shear stress, the fault begins to activate, roof rock-mass is broken and with poor stability, the abutment pressure ahead of working face obviously increases. The underground pressure is low when the working face has passed the fault. However, when the working face advances from the hanging wall to the fault itself, it is difficult for the fault to activate due to the increase of normal stress, the roof rock-mass is ease to become balance structure. The slip displacement increases due to the decrease of normal stress and the increase of shear stress after the fault have passed the fault, the stability of roof becomes weak and the abutment pressure increases. The different MS such as coal mining operation, roof collapse, fault activation, are different frequency spectra.The FLAC5.02D software is used to study the effect of fault and roof on abutment pressure. The results indicate that the effect of roof strength on abutment pressure is obvious when the working face advances from the footwall to the fault itself, and the effect of fault dip angle on abutment pressure is obvious when the working face advances from the footwall to the fault itself. The risk of a fault rockburst is higher when the working face advances from the footwall to the fault itself than when the face advances from the hanging wall to the fault.The voussior beam theory was used to explain the effects of faults with different dip direction on roof balance structure and underground pressure. A mechanics model of Strike-Slip and Viscous-Elastic-Brittle is established in order to study the mechanism of fault slip induced rockburst. According to damage mechanism, the fault slip induced rockburst can be analyzed by the following two mechanics criterion. The first mechanism is fault slip dynamically induce rockburst when the fault with a high slip velocity, such as fault slip destabilization. The second mechanism is fault slip statically induce rockburst when the fault with a low slip velocity. In the first kind, more energy is violently released comparability. The velocity of fault slip is related to the velocity of working face advancing, the distance from working face to the fault, strength property of fault, normal stress of fault plane and the mining depth.A zoning monitoring method is applied to study the evolvement rules of MS signals when the working face advancing to the fault based on the Seismological Observation System. The results indicate that the fault begins to activate when the working face approach to the fault, MS signals is activity with the increase of total energy, maximum energy and frequency. The MS signals reach peak value when working face in fault zone. The MS signals quickly decrease when the working face far away from the fault.The researches of prevention and cure about fault rockburst have been carried out in the No.6303 working face of the Jining No.3 Coal Mine. The forecasting technique of mine geological structure was applied to forecast the fault. The strength of coal and rock mass can be weakened in risk range by using some active measures of rockburst such as unload with borehole, relieving shot in coal seam, relieving shot in roof. So, the danger of fault rockburst can be avoided or reduced.更多还原