【作者】 刘超；

【导师】 唐春安；

【作者基本信息】 大连理工大学 ， 岩土工程， 2011， 博士

【摘要】 煤与瓦斯突出是复杂的矿山动力灾害现象之一,目前是煤矿工程中的世界性难题。严重的瓦斯突出灾害不仅造成巨大的经济损失,而且还可能造成重大的人员伤亡。近年来煤矿动力灾害事故更是频频发生,特别是煤矿日渐转入深部开采后,煤岩高地应力、高瓦斯压力及高渗透性的现象愈加明显,以瓦斯突出等为主的煤矿动力灾害已成为我国工业安全领域的主要灾害,给煤矿的高效安全开采带来更多的技术难题。本文以淮南新庄孜矿六水平典型的强突出工作面为研究对象,通过理论分析、数值模拟、数理统计理论、非线性分形理论以及现场工业性试验等手段,提出了煤与瓦斯突出致灾机理及危险性预警的新思路、新方法,着重探讨了诱发煤岩突出灾害的本质机理和微破裂前兆规律。另外,借助于微震监测技术,重点阐述了采掘工作面煤与瓦斯突出危险性评价指标与预警模型,系统研究了采场覆岩采动裂隙的演化特征与瓦斯富集区的确定方法,取得了一些有意义的研究成果。基于含瓦斯煤岩破裂过程气固耦合作用模型,采用RFPA2D-GasFlow程序一方面分析并完善了应力场-损伤场-瓦斯渗流场的多场耦合时空演化规律；另一方面模拟再现了瓦斯突出过程背景应力场演化特征及其微破裂前兆活动信息的规律。运用RFPA2D软件模拟了载荷下煤岩样的初始裂纹出现及扩展过程,揭示了煤岩破坏过程的微震效应及其演化规律,进一步验证了煤岩破裂过程中存在的微震现象。研究表明,微震效应在研究煤岩体微裂纹、微缺陷的演化规律和力学机制以及局部变形特征有着独特的优势,借助于该特征可以实现对煤岩破坏过程的实时动态监测,从而为瓦斯突出动力灾害的预测预报提供了技术基础。为了满足煤矿井下对微震监测系统的要求,研制开发、改进并重新设计了系统的部分软硬件设备与安装装置及其安装方法；采取人工爆破试验标定波速模型的方法,研究了监测区域波速的优化选取及其对震源定位精度的影响,并提出了传感器的布置原则；基于长短项平均值法(STA/LTA)信号检测滤除原理,建立了一套多参量识别与滤除噪音的综合分析方法,并对滤出后的信号在三维可视化图中进行了标定。考虑到评价指标的时间效应,建立了突出危险性长短时评价指标；基于正态分布函数理论,建立了描述突出危险性的2σ预警模型,并采取人工放炮诱发煤与瓦斯突出的方法,验证了上述预警模型的可行性。研究了断层滑移失稳力学机制及准则,推导了断层结构力学模型,阐述了断层带活动规律与突出之间的关系。结合实例分析,深入研究了2σ预警模型评价掘进及其含断层巷道突出危险性的过程,并采取多种方法对预警结果进行了校检,证明了2σ预警模型的可靠性。结合覆岩破坏的基本理论,建立了采动覆岩的力学模型,揭示了覆岩内分别形成了拉应力及剪应力区,且拉应力区主要分布在冒落带破断线之内；剪应力区主要分布在竖向裂隙带内。采用数值模拟的方法对覆岩采动裂隙的初始萌发、扩展直至宏观裂纹贯通的过程及其声发射、能量的动态演化规律进行了详细的分析。并运用分形几何理论,定量地描述了覆岩破坏是一个降维有序、耗散结构的发展过程。在留巷钻孔法抽采卸压瓦斯机理的基础上,提出了覆岩裂隙区内存在着一个不规则闭合的“圆柱形横卧体”竖向裂隙场的观点,并依据该裂隙场的分布规律对顶板倾向低位钻孔进行了优化。更多还原

【Abstract】 Coal and gas outburst is one of the complex dynamic disasters and also the difficult subject worldwide in this area. Generally, serious outburst disasters not only cause huge economic losses, but also engender possibly great casualties. Over recent years, the disasters of coal and gas outburst occur more frequently, especially after the coal mines are being gradually transferred to deep mines, the phenomenon of high geo-stress, gas pressure and permeability become increasingly apparent, has become a major disaster mainly from outburst of industrial safety field in China, bringing more technical difficulties on the early-warning and control of coal and gas outburst. In this paper, taking some typical strong outburst face of sixth level in Xinzhuangzi coal mine, in Huainan as the research object, A new idea and new method for hazard mechanism and early-warning of coal and gas outburst is proposed, furthermore, the essence mechanism and micro-fracture precursor law for induced outburst are mainly discussed with the use of the theoretical analysis, numerical simulation, mathematical statistics theory, non-linear fractional theory and industrial field tests, In addition, the evaluation indexes and early-warning model of coal and gas outburst hazard in extracting coal face are emphatically elaborated, and the evolution features and gas-rich region determining method of overlying rock mining crack are systematically studied by means of microseismic monitoring technology, consequently some significant research results have been obtained.Based on the gas-solid coupling model of coal-rock with gas failure process, on one hand, the multi-field coupling evolution law for stress field, fracture field and seepage field is analyzed and improved; on the other hand, the evolution features for background stress field and its activity information for micro-fracture precursor of outburst process are simulated reconstruction by using of RFPA2D-GasFlow.The process of initial cracks occurring and extending for coal-rock sample under vertical loading is simulated in terms of RFPA2D, the microseismic effect and its evolution law of coal-rock failure process is revealed deeply, and the microseismic phenomenon is further verified. The results show that the microseismic effect has its special advantage to study evolution law of micro-cracks, mechanical mechanism and local deformation features for coal-rock mass, and based on this feature, the failure process of coal-rock is real-time and dynamic monitored, finally, which provides technical basis for prediction and forecast of gas outburst disasters. In order to meet the needs of microseismic monitoring system for coal mine underground, part of system software-hardware equipments, installation devices and its installation method are developed, improved or redesigned. Taking the artificial burst test to calibrate velocity model method, the optimization of velocity selection for monitoring area and its effects on the source location accuracy are studied, and the layout principle for sensors also put forward. A set of comprehensive analysis method for multi-parameters identifying and filtering out noise is established based on the long and short average method (STA/LTA) detecting principle for complicated signals.Taking time effect evaluation into account, the evaluation index of outburst hazard length is established; on account of the normal distribution theory, a 2 a warning model is established to describe outburst hazard, the feasibility of which is verified by manual blasting inducing coal and gas outburst. The mechanical mechanism and criterion of slip instability is investigated, and then the mechanical model of fault structure is derived, based on the above, the relationship between fault zone activity law and outburst is derived. Combined with case analysis, the outburst hazard evaluate process of the tunneling and roadways with faults with the 2 a warning model is further studied, and then whose warning results are checked in various ways, which proved the reliability of 2 a model.With the basic overburden rock failure theory, a mining overburden mechanical model, which believes that tensile and shear stress areas are respectively formed within overburden zone, is established, the tensile stress mainly distributes within break line of caving zone, and the shear one within the vertical fracture zone. A detailed analysis by numerical simulation is carried out for the initial fracture germination, propagation until macroscopic extension, the acoustic emission property and the energy dynamic evolution of overburden. With the fractal geometry theory, a quantitative description of overburden failure process is reduced ordered and dissipative. Based on the mechanism of mining pressure relieved gas with roadway retained drilling, we believed that there is an irregular and close vertical fracture field which is a "cylindrical lying mass" within the fracture zone. According to the distribution law of the field, low order drilling on the roof is optimized.更多还原