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基于水压致裂法的断层防水煤柱合理留设研究
Study on Reasonable Retainment of Fault Waterproof Pillar Based on Hydro-fracturing Method
【作者】 王进尚;
【导师】 胡耀青;
【作者基本信息】 太原理工大学 , 采矿工程, 2012, 硕士
【摘要】 煤炭是我国的主要能源之一。但是,随着矿井深度的不断延伸,煤炭资源的开采受水害威胁日趋严重,已经成为影响煤矿安全生产的五大灾害之一。煤矿绝大多数突水发生都与断层有着直接或间接的关系,留设断层防水煤柱是防止构造突水的重要措施。因此,研究断层防水煤柱的合理留设将是一件很有意义的课题。本文通过水压致裂原位测试方法实测了太原东山煤矿煤层的抗拉强度,为断层留设防水煤柱提供了科学依据。主要从以下几个方面做了一些研究:(1)比较全面地介绍了断层突水机理,“活化”是回采影响断层突水中断层成为突水通道的必要条件,而不是充分条件,断层面中的裂隙张开并连通是断层突水通道的充分条件。(2)总结了水压致裂的理论原理,分析了煤层水力压裂特征,通过实验室试验和工业性试验,‘水压致裂原位测试方法测煤的抗拉强度是可行的。(3)研究了太原东山煤矿所处的构造部位,得出断层是该矿井的突水主要通道。采取针对性措施主要有注浆改造、探放水和留设防水煤柱,其中应用较多的是留设防水煤柱方法。(4)利用水压致裂原位测试方法分别实测了太原东山煤矿71505工作面、51519工作面和750南皮带运输大巷并获得煤层抗拉的强度参数。(5)应用所测煤层抗拉强度0.63MPa,并综合考虑矿山压力、构造应力和水压力对断层防水煤柱影,确定太原东山煤矿防水煤柱尺寸,该参数使得防水煤柱宽度大为缩小,明显增加了煤矿的可开采储量,具有很大的应用前景。(6)利用ANSYS程序结构建立了二维数值模拟模型,分别对随着断层上下盘进行工作面的开挖,巷道开采过程引起断层附近应力、应变的活动规律进行模拟,进一步验证了上盘比下盘开挖更容易使断层发生活化其准确性,为今后确定断层防水煤柱有着重要的价值。实践证明,水压致裂方法原位测试获得煤层的强度参数符合实际,设备简单,测值直观,具有代表性,适用性强,测试周期短等优点,该方法在矿井水害方面有广阔的发展前景和应用范围,对断层防水煤柱科学留设具有很大的意义。
【Abstract】 The coal is one of our country’s main energie, however, as the depth of mine is increasing continuall, the water disaster are threatening Coal Resources more seriousl, and the water disaster has became a serious problem which influence coal mine safety production. The most coal mining water inrush have relationship with fault, leaving fault waterproof pillar is the important measure of preventing water-burst. So, the study of leaving fault waterproof pillar is significative. In this paper, the tensile strength of coal seam of Dong Shan coal mine was measured with the method of hydro-fracturing, it provides scientific basis for the leaving fault waterproof pillar. The main endeavor and contributions of the dissertation are as follows:(1)、This paper describes mechanism of water-inrush through fault,"activation" is the necessary conditions for fault when it became water inrush channel, but no sufficient condition. Fault crack opening and connected is the sufficient condition for fault when it became water inrush channel.(2)、This paper summarizes mechanism of the method of hydro-fracturing and analysis characteristics of the hydraulic fracturing of coal seam, through the laboratory test and, it is reasonable that the tensile strength of coal seam was measured with the method of hydro-fracturing.(3)、This paper study tectonic position of Dong Shan coal mine, it is obtained that fault is the main channel of water inrush. Some measures was implemented,such as, Grouting transform technique、surveying water technique and leaving waterproof pilla, and the technique of leaving waterproof pillar has been more applied.(4)、The tensile strength of coal seam which in the71505face、the51519face and750conveyance road of Dong Shan coal mine was measured with the method of hydro-fracturing.(5)、In this paper, based on comprehensive consideration of the influence of tensile strength of coal seam、ground pressure、tectonic stress and water pressure on waterproof pillar, the dimensions of waterproof pillar was determined. The parameter reduced the width of waterproof pillar, recoverable reserves of coal was increased significantly. It has wide application prospect.(6)、Two-dimensional numerical model was established by means of ANSYS, in the process of excavating of hanging wall and footwall of the fault, the stress--strain laws in the fault nearby was simulated, it was further verified that excavating of hanging wall was more to activate the fault than footwall. it has important values for determining the dimensions of waterproof pillar of fault. Practice proves that strength parameter of coal layer obtained by methods of normal position of hydro-fracturing conforms to reality, the equipment is simple, measurement data is direct and is typical, so it has strong usability, the measurement period is short, this method has broad development perspective and application scope in aspect of water disaster in coal mine, it has important meanings to scientifically set water-proof pillar of fault.
【Key words】 hydro-fracturing; strength of coal layer; water-proof pillar; numerical simulation;