高压水射流冲孔煤体裂隙发育规律研究

发布时间：2018-12-12 08:22

【摘要】：随着社会快速发展,煤炭能源需求量快速增大,各地区煤炭开采深度逐步加大。煤层深度增加,瓦斯含量升高。低透煤层高瓦斯问题成为煤矿安全生产面临的主要问题。高压水射流冲孔增透技术是煤矿开采过程中解决高瓦斯问题的重要技术措施。因此,基于高压水射流冲孔技术,研究冲孔后煤体裂隙发育规律对解决煤层高瓦斯问题具有重要意义。针对高压水射流冲孔时冲孔位置、冲孔角度、冲孔孔径等参数进行了研究,根据矿井实际情况确定了符合现场生产要求的参数值。运用ABAQUS数值模拟软件,建立掘进工作面高压水射流冲孔后裂隙发育模型,通过实验和分析计算确定模型基本参数和边界条件。建立裂隙发育的应变-能量模型,对裂隙发育规律进行研究。研究结果表明:冲孔后孔壁周围不同位置、不同方向裂隙发育情况不同,裂隙发育先沿直线发育随后发生偏转,发育方向逐渐偏向合应力方向。裂隙沿合应力方向发育时一直沿直线发育。根究裂隙单方向发育情况确定整个平面发育范围。通过确定偏转点位置,得到了裂隙发生偏转后平面内裂隙密度的变化。根据不同密度情况将裂隙发育范围进行了密度等级划分;运用ABAQUS数值模拟软件,对裂隙发育立体轨迹进行了研究。结果表明:轴向应变是改变轴向裂隙发育的主要因素,根据能量守恒定律分析,确定改变轴向应变可改变裂隙沿轴向和垂直轴向发育的规律。生产中可根据需要减小轴向应变量,实现控制裂隙形态的目的;运用扫描电镜技术,对冲孔后距孔洞不同方向、不同距离的测点进行分析。结果表明:现场工作面裂隙发育情况与模拟情况具有一致性,两者互相验证,可指导生产实践。
[Abstract]:With the rapid development of society, the demand for coal energy increases rapidly, and the coal mining depth increases gradually. The coal seam depth increases and the gas content increases. The problem of low permeability coal seam and high gas becomes the main problem of coal mine safety production. High pressure water jet perforation and antireflection technology is an important technical measure to solve the problem of high gas in coal mining process. Therefore, based on high pressure water jet punching technology, it is of great significance to study the law of coal body fissure development after punching in order to solve the problem of high gas in coal seam. The punching position, punching angle, punching aperture and other parameters during high pressure water jet punching are studied. According to the actual situation of the mine, the parameters that meet the requirements of field production are determined. Using ABAQUS numerical simulation software, the fracture development model after high pressure water jet punching in tunneling face is established. The basic parameters and boundary conditions of the model are determined by experiment and analysis. The strain-energy model of fracture development was established and the regularity of fracture development was studied. The results show that the crack development is different in different directions around the hole wall after punching, and the fracture development first develops along a straight line and then deflects, and the development direction gradually deviates towards the direction of stress convergence. The fracture develops along the straight line when it develops along the direction of the combined stress. The single direction development of the root crack determines the whole plane development range. By determining the position of deflection point, the change of fracture density in plane after fracture deflection is obtained. According to the different density, the fracture development range is divided into density grades, and the three-dimensional trajectory of fracture development is studied by using ABAQUS numerical simulation software. The results show that axial strain is the main factor to change the development of axial fractures. According to the law of conservation of energy, it is determined that the law of fracture development along axial and vertical direction can be changed by changing axial strain. In production, the axial strain can be reduced according to the need, and the fracture shape can be controlled. The measuring points in different directions and distances from the hole after punching are analyzed by using the scanning electron microscope technology. The results show that the development of the crack in the working face is consistent with the simulation, and the mutual verification between them can guide the production practice.
【学位授予单位】：华北理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TD712

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