煤与瓦斯压出动力演化过程及机理实验研究

发布时间：2018-04-19 21:54

本文选题：煤与瓦斯压出 + 煤岩动力现象　；参考：《中国矿业大学》2014年博士论文

【摘要】：随着煤矿开采深度的增加，地应力和瓦斯压力越来越大，应力、瓦斯压力和煤体耦合作用越来越复杂，煤岩动力灾害发生越发频繁，造成的危害越来越严重，以往较少出现的煤与瓦斯压出动力灾害日趋增多，而针对其发生机理鲜见研究。本文建立煤岩动力现象模拟试验系统，试验研究不同煤岩动力现象的显现特征，分析压出过程中应力和瓦斯压力的变化规律及影响因素；研究含瓦斯煤体层裂结构的形成过程，建立煤与瓦斯压出层次破坏演化模型；分析现场煤与瓦斯压出灾害的关键因素，对现场工作面危险性进行划分，提出防治措施。全文主要取得了以下研究成果：建立了煤岩动力现象模拟试验系统，试验研究了不同煤岩动力现象的显现特征，并探讨了煤岩动力现象显现特征不同的原因。研究发现：煤与瓦斯压出抛出煤体距离较小，造成的动力效应不明显；煤与瓦斯突出煤体破碎程度最大，抛出距离大并且具有明显的方向性；含瓦斯煤冲击破坏煤体破裂成块状，煤体破裂面光滑。煤体弹性能和瓦斯潜能的释放比例以及煤体性质的不同是动力现象显现特征不同的主要原因。研究了煤与瓦斯压出的发展变化规律及影响因素。研究发现：煤体压出是一个较缓慢的力学过程，应力呈现出先升高后降低的趋势，瓦斯压力释放速度较慢，并且释放速度与其和压出口之间的距离密切相关，煤体发生层裂破坏。随着瓦斯压力和应力的升高，残留孔洞从无到有并逐渐增大，煤体破坏越发剧烈；随煤体强度的升高，残留孔洞逐渐缩小并且趋于消失；顶底板强度越大，煤体变形破裂越严重。通过数值模拟研究了工作面回采过程中，应力、瓦斯压力和煤体塑性变形区的变化规律，分析了埋藏深度、煤层参数和初始瓦斯压力对压出危险性的影响。研究表明随埋藏深度、瓦斯压力的升高以及煤层厚度和强度的降低，煤体发生压出的危险性逐渐升高。基于弹塑性断裂力学计算得到了含瓦斯煤裂纹的临界扩展角度及方位角，推导得出了考虑游离瓦斯和吸附瓦斯的煤体强度准则，分析了裂纹扩展长度与三向应力的关系；以工作面前方极限平衡区为对象，研究了煤体层裂结构形成过程以及不同外界扰动形式对煤体稳定性的影响，，计算得到了含瓦斯层裂结构失稳破裂的临界载荷及压出发动的能量条件，分析了压出发动煤体破裂失稳形式。研究得到了压出发展过程煤体发生逐层破坏的形式及应力、瓦斯压力演化规律，分析了煤体破裂面形成原因，揭示了固气逐层变化的破坏失稳机理。研究分析了煤与瓦斯压出灾害发生的关键影响因素，基于此对工作面进行了危险区域划分，制定了有针对性的分区域动力灾害防治措施，保证了工作面的安全生产。研究成果对进一步认识深部回采过程中应力、瓦斯和煤体耦合作用规律，为防治煤与瓦斯压出事故提供了理论基础和科学依据。
[Abstract]:With the increase of coal mining depth, the stress and gas pressure are becoming more and more, the stress, gas pressure and coal body coupling are more and more complex, the coal and rock dynamic disasters are more and more frequent, causing more and more serious harm. The simulation test system of coal and rock dynamic phenomenon is set up, the characteristics of different coal and rock dynamic phenomena are studied, the change law of stress and gas pressure in the process of pressure and the influence factors are analyzed, the formation process of the crack structure of coal bearing coal body is studied, the secondary damage evolution model of coal and gas pressure outlet is established, and the coal and gas in the field are analyzed. According to the key factors of the disaster, the danger of the working face is divided, and the prevention measures are put forward.
The simulation test system of coal and rock dynamic phenomena is set up. The characteristics of different coal and rock dynamic phenomena are studied and the reasons of different characteristics of coal and rock dynamic phenomena are discussed. The research shows that coal and gas pressure out of coal body is less distance and the dynamic effect is not obvious; coal and gas outburst coal body breakup degree is the biggest, throw out. The main reason for the different characteristics of the dynamic phenomenon is that the coal body fracture surface is smooth, the ratio of the release ratio of the coal body elastic energy and the gas potential and the nature of the coal body are different.
The development and change rules of coal and gas pressure are studied and the influence factors are studied. It is found that the coal body pressure is a slow mechanical process, the stress appears to rise first and then decrease, the release rate of gas pressure is slow, and the release velocity is closely related to the distance between the pressure outlet and the coal body. As the pressure and stress increase, the residual holes are gradually increased and the coal body is more severe. With the increase of coal strength, the residual holes gradually shrink and tend to disappear, the greater the strength of the top and bottom, the more serious the deformation and fracture of the coal body is.
Through numerical simulation, the variation of stress, gas pressure and plastic deformation zone of coal body during the working face recovery process is studied. The influence of buried depth, coal seam parameters and initial gas pressure on the risk of pressure out is analyzed. The study shows that the coal body is pressed out with the depth of buried, the increase of gas pressure and the decrease of the thickness and strength of coal seam. The danger is increasing.
Based on the elastoplastic fracture mechanics calculation, the critical expansion angle and azimuth angle of the coal bearing coal crack are obtained. The strength criterion of coal body considering the free gas and the adsorbed gas is derived. The relationship between the crack growth length and the three direction stress is analyzed, and the formation of the structure of the coal seam is studied by the limit equilibrium area ahead of the working face. The influence of the process and the different external disturbance forms on the stability of the coal body is calculated, and the critical load and the energy conditions for the burst initiation are calculated. The failure mode of the coal body rupture is analyzed. The form and stress of the coal body damage by layer and the evolution of gas pressure are obtained. The cause of formation of coal fracture surface is analyzed, and the mechanism of destruction and instability of solid gas by layer by layer is revealed.
The key factors affecting the occurrence of coal and gas pressure occurrence are analyzed and analyzed. Based on this, the dangerous area is divided into the working face, and the prevention measures for the dynamic disaster in the area are formulated, which ensures the safe production of the working face.
The research results provide a theoretical basis and scientific basis for further understanding the stress in the process of deep mining, the law of the coupling action of gas and coal, and providing a theoretical basis and scientific basis for the prevention and control of coal and gas pressure accidents.

【学位授予单位】：中国矿业大学
【学位级别】：博士
【学位授予年份】：2014
【分类号】：TD712

【参考文献】