【作者】 李忠华；

【导师】 潘一山；

【作者基本信息】 辽宁工程技术大学 ， 工程力学， 2007， 博士

【摘要】 目前对通常的冲击地压的发生机理已经有些基本认识,对其预测与防治已形成一些基本方法和技术。但迄今为止很少见到对高瓦斯煤层冲击地压的发生机理、预测、防治进行系统专门的研究。本文选择阜新矿区五龙等矿为试验矿井,采用理论分析、实验室试验和现场实验相结合的研究方法,对高瓦斯煤层冲击地压发生机理及预防技术进行研究。主要内容如下。1.现场调研与实验研究通过现场调研,对试验矿井地质情况、瓦斯赋存与抽放情况和冲击地压发生情况进行了统计分析。通过实验室试验测定了试验矿井煤样的视密度、抗压强度、弹性模量等物理力学参数,测定瓦斯渗透率、水渗透率、峰值强度与瓦斯含量的关系、弹性模量与瓦斯含量的关系、湿润接触角、浸水过程中力学性质随含水率的变化规律。2.高瓦斯煤层冲击地压发生理论研究揭示了高瓦斯煤层冲击地压发生机理、冲击地压发生后的瓦斯涌出机理、瓦斯煤层冲击地压与煤和瓦斯突出的区别与联系。建立了高瓦斯煤层冲击地压发生理论及其数学模型,对煤巷和采煤工作面冲击地压进行了解析分析。瓦斯压力存在一个临界值,当瓦斯压力大于临界值时,Klinbenberg效应消失,煤对瓦斯的吸附达到饱和,有效应力系数随瓦斯压力增大而减小,渗透系数随瓦斯压力增大而增大,表现为高瓦斯特性。含瓦斯煤体孔隙中的瓦斯对煤体通过孔隙压力以有效应力的方式施加于煤体,煤体的变形破坏过程受有效应力控制,在有效应力作用下,煤体中的裂纹发生发展,当局部的有效应力超过峰值强度时,此局部区域的煤体成为应变软化的非稳定介质,形成了由此局部区域的非稳定介质与外部区域的稳定介质组成的变形系统。采掘过程中,在瓦斯吸附、解吸、渗流与煤层变形耦合作用下,系统处于非稳定平衡状态,遇外部扰动时,系统将会失稳而形成冲击地压灾害。高瓦斯煤体发生冲击地压时,在冲击点形成了瓦斯卸压带,在瓦斯压力差和浓度差作用下,煤体内瓦斯的解吸、扩散和渗流同时进行,因此会有大量瓦斯涌出,并会持续一段时间。瓦斯煤层冲击地压与煤和瓦斯突出的孕育过程是完全相似的,但发生过程和能量来源有很大区别。瓦斯煤层冲击地压是煤层变形系统整体受压失稳而发生的,而煤和瓦斯突出是拉性有效应力超过煤抗拉强度发生的拉伸失稳破坏。高瓦斯煤层冲击地压的发生条件与瓦斯压力和煤的力学性质有关。煤巷冲击地压的临界载荷随瓦斯压力增大而增加。采煤工作面冲击地压的临界载荷随有效应力系数和瓦斯压力增大而增加。3.高瓦斯煤层冲击地压预测技术研究考虑瓦斯的作用与影响,确定了瓦斯煤层钻屑量指标,讨论相关参数对钻屑量指标的影响规律,并与不考虑瓦斯情况的钻屑量指标进行了对比分析。确定了钻屑法检测冲击地压危险的工艺参数,通过现场实施验证了其正确性和可行性。考虑瓦斯的作用与影响时,钻屑指标低于不考虑瓦斯影响时的理论值,随瓦斯压力增大而减小,随有效应力系数增大而减小4.高瓦斯煤层冲击地压防治技术研究分别应用单孔介质和双孔介质模型,建立瓦斯煤层注水过程水气驱替理论。通过求解平面径向流水气驱替基本方程,得到计算注水时间的解析式。对阜新矿区煤层注水防治瓦斯煤层冲击地压的可行性进行了研究,确定了瓦斯煤层注水防治冲击地压的工艺参数和过程,并通过现场实施进行了验证。提出了阜新矿区高瓦斯煤层冲击地压总体防治方案、具体解危措施和冲击地压后瓦斯涌出防治措施。煤被水湿润后物理力学性质发生改变,凡是注水充分的工作面,冲击地压发生的频度和强度均大大降低。瓦斯煤层注水过程是水驱替瓦斯的过程。煤体孔隙率、瓦斯压力和注水半径越大注水时间越长,渗透率和注水压力越大注水时间越短。注水工艺参数主要有注水半径、注水量、注水时间、注水孔封孔长度、注水压力等。更多还原

【Abstract】 There is some basic knowledge to the mechanism of common rockburst, the conventional method and technique of rockburst forecast and prevention formed already, however, the special exposition is few about the mechanism, forecast and prevention of rockburst occurring in high gassy seam so far. Wulong and some other coal mines in Fuxin Coal Area were selected as experiment mine in this paper. The mechanism, forecast and prevention technique of the rockburst occurring in high gassy seam were studied with the method combining theoretical analysis with spot practice and test in laboratory. The main contents are as follows.1. Spot investigation and test in laboratory.Some specific data of test mines were collected and analyzed through spot investigation, such as geological structure, rockburst, inherent gas and its pumping.The physical and mechanical properties of coal sample were determined through tests in laboratory. Their properties are apparent density, compression strength, elastic modulus, gas permeability, water permeability, contact angle, relation of compression strength and gas content, relation of elastic modulus and gas content, variation of mechanical properties with water ratio in the different soaking water time and so on.2. Theoretical research of rockburst occurring in high gassy coal seam.The mechanism of rockburst occurring in high gassy coal seam and gas gushing after rockburst were revealed. The distinction and connection were discovered between rockburst occurring in gassy seam and burst of coal and gas. The theory and its mathematical model of rockburst occurring in high gassy seam were established. This theory was applied to analyze the rockburst of tunnel and coal face.There is a critical value of gas pressure. When gas pressure is greater than this critical value, the Klinbenberg effect disappears, the gas adsorbing quantity reaches saturation, the effective stress coefficient decreases and the permeability increases if gas pressure increases. This is the behavior of high gassy seam.The action of gas to coal mass is called porous pressure, and the coal mass undertake effective stress. The process of its deformation and rapture is controlled by the effective stress. In this process the cracks appear and expend. When effective stress is greater than compression strength in some areas the coal mass become to strain softening media that is instable. Total system consists with instable media in some areas and stable media in outer areas. In process of the excavation this system understands the coupling action of gas adsorption, desorption, transfusion and coal deformation, its balance state is instable. In situation of external disturbance its balance will be lose and rockburst will occur.When the rockburst occurs a band is formed around the rockburst point. The pressure and density of gas decrease in this band. The gas desorption, diffusion and transfusion happened at the same time, a great quantity of gas will pour out and continue after rockburst.By comparative analysis between rockburst occurring in gassy seam and burst of coal and gas it show that the breeding process is similar completely but occurring process and source of energy is different. When the coal seam deformation system undertake compression stress and lose stability the rockburst will occur. When tensile effective stress is greater than tensile strength of coal the system appear tensile instability and the burst of coal and gas will occur.The occurring conditions relate to gas pressure and mechanical properties of coal. The critical load of tunnel rockburst increases if gas pressure increases. The critical load of coal face increases if gas pressure and effective stress coefficient increase.3. Research of forecast technique of rockburst occurring in high gassy seam.Drilling bits index of gas seam was determined and the inference law of someparameters were discussed. Comparative analysis was made to no gas situation. Some technological parameters of drilling bits method were determined. The correctness and feasibility were verified through actual operation. Drilling bits index of gassy seam is lower, it decreases if gas pressure and effective stress coefficient increase.4. Research of prevention technique of rockburst occurring in high gassy seam.Theories of driving and replacement of water and gas were established throughporous medium model and double-porous medium model respectively. The expression of water injection time was obtained by solving fundamental equation of plane radical flow. The feasibility of water injection into coal seam to prevent rockburst in Fuxin Mining Area was analyzed. The technological parameters and process were improved. It was verified through actual operation. The prevention scheme of rockburst occurring in high gassy seam, dispelling rockburst danger measure and gas gushing prevention method were put forward.The physical and mechanical properties of coal will be transformed after soaking water. The face of full water injection the frequency and intensity of rockburst will decrease greatly. The water injection into coal seam is a process of driving and replacement of water and gas among coal seam. The water injection time increases if porous ratio, gas pressure and water injection radius increase, the time decreases if permeability and water injection pressure increase. The technological parameters consist of radius, quantity, time and pressure of water injection, closing length and so on.更多还原