上保护层开采卸压范围及保护效果研究
发布时间：2018-08-06 18:27
【摘要】：通过理论分析、数值模拟和结合现场试验的研究方法,对上保护层开采条件下下被保护煤层周围岩体的应力分布、煤层膨胀变形特征和裂隙发育、煤层透气性变化规律及煤层透气性系数的优化算法进行系统的研究,同时对煤层底板岩体受力进行分析,建立底板岩层沿煤层走向的力学模型,为了更好地定性和定量地分析底板支承力的分布特征,将模型做相应的简化,推算出底板应力分布的计算公式,总结出煤层底板岩层所受应力分布规律。 在保护层开采与瓦斯抽采中煤层透气性系数是关键因素,钻孔径向流量法是求取该系数的最常用的方式,结合有关的原理与图文辨析的方式,详细研究了煤层透气性,时间以及与流量三者的联系,在此基础上进行研究,针对科研工作和现场管理的实际情况,提出了求解透气性系数的两种新算法及其计算流程,并对时间准数F0与参数AB函数关系中的间断点问题进行讨论和分析,解决了此区间内求解透气性系数相应计算公式等问题。 通过现场实测得到下被保护煤层的卸压效果、膨胀变形特征与煤层透气性变化规律。7a煤层原始瓦斯压力为1.9MPa,原始瓦斯含量为8.03m3/t；8煤层回采后,7a煤层最大残余瓦斯压力为0.3MPa,其最大残余瓦斯含量为2.64m3/t。当保护层54208工作面推过钻孔40m左右的范围内,7a煤层的变形量是最大的,为18.2mm；与其对应的最大拉伸变形率为4.8%0,配合的底板岩巷网格式上向穿层抽采钻孔此时煤层钻孔抽采瓦斯纯量最大为2.9m3/min。经统计卸压区域的7a煤层瓦斯抽采率为75.6%。同时通过煤层透气性系数的优化算法计算得出卸压后7a煤透气性系数为4.1057m2/MPa·d,较原始透气性系数0.0284m2/MPa2·d,扩大了216倍。工作面走向方向对被保护层卸压角为60。；沿倾向方向下卸压角为75。,上卸边界为采空区,因此不需要测试。在8煤的保护范围内,7a煤已经消除突出危险性,为下一步的安全开采奠定了基础。现场试验结果与理论分析和数值模拟结果一致。
[Abstract]:Through theoretical analysis, numerical simulation and field test, the stress distribution, expansion deformation characteristics and fracture development of the protected coal seam surrounding rock mass under the mining condition of the upper protective layer are studied. The variation law of coal seam permeability and the optimization algorithm of coal seam permeability coefficient are studied systematically. At the same time, the mechanical model of floor rock layer along coal seam strike is established by analyzing the stress of coal seam floor rock mass. In order to qualitatively and quantitatively analyze the distribution characteristics of the supporting force of the floor, the model is simplified accordingly, the formula of the stress distribution of the floor is deduced, and the stress distribution law of the coal seam floor is summarized. The permeability coefficient of coal seam is the key factor in mining and gas drainage of protective layer, and the radial flow method is the most common way to obtain the coefficient. Combined with the related principle and the method of graph and text analysis, the permeability of coal seam is studied in detail. According to the actual situation of scientific research and field management, two new algorithms to solve the permeability coefficient and their calculation flow are put forward. The discontinuity point problem in the relation between the time datum F0 and the parameter AB function is discussed and analyzed, and the corresponding calculation formula for the permeability coefficient in this interval is solved. Through the field measurement, the pressure relief effect of the protected coal seam is obtained. The characteristics of expansion deformation and the change law of coal seam permeability. The original gas pressure of coal seam is 1.9 MPA and the original gas content is 8.03 m3 / t. The maximum residual gas pressure is 0.3 MPA and the maximum residual gas content is 2.64 m3 / t after mining in 8 coal seam. The deformation of coal seam of 7a is the largest (18.2mm) within the range of 40m or so pushed through the borehole in 54208 working face of protective layer. The corresponding maximum tensile deformation rate is 4.80, and the maximum amount of gas extracted by coal seam boreholes is 2.9 m3 / min. The gas extraction rate of 7a coal seam is 75.6 by statistical pressure relief area. At the same time, through the optimization algorithm of coal seam permeability coefficient, it is found that the coal permeability coefficient is 4.1057m2/MPa d 7 years after unloading, which is 216 times larger than the original gas permeability coefficient 0.0284m2/MPa2 d. The angle of relief of working face strike direction to protected layer is 60. The angle of unloading pressure along the direction of inclination is 75.The upper and unloading boundary is goaf, so it is not necessary to test. Within the protection range of No. 8 coal, 7a coal has eliminated the outburst danger and laid a foundation for safe mining in the next step. The field test results are consistent with the theoretical analysis and numerical simulation results.
【学位授予单位】：安徽理工大学
【学位级别】：硕士
【学位授予年份】：2013
【分类号】：TD713;TD322.5
本文编号：2168611
[Abstract]:Through theoretical analysis, numerical simulation and field test, the stress distribution, expansion deformation characteristics and fracture development of the protected coal seam surrounding rock mass under the mining condition of the upper protective layer are studied. The variation law of coal seam permeability and the optimization algorithm of coal seam permeability coefficient are studied systematically. At the same time, the mechanical model of floor rock layer along coal seam strike is established by analyzing the stress of coal seam floor rock mass. In order to qualitatively and quantitatively analyze the distribution characteristics of the supporting force of the floor, the model is simplified accordingly, the formula of the stress distribution of the floor is deduced, and the stress distribution law of the coal seam floor is summarized. The permeability coefficient of coal seam is the key factor in mining and gas drainage of protective layer, and the radial flow method is the most common way to obtain the coefficient. Combined with the related principle and the method of graph and text analysis, the permeability of coal seam is studied in detail. According to the actual situation of scientific research and field management, two new algorithms to solve the permeability coefficient and their calculation flow are put forward. The discontinuity point problem in the relation between the time datum F0 and the parameter AB function is discussed and analyzed, and the corresponding calculation formula for the permeability coefficient in this interval is solved. Through the field measurement, the pressure relief effect of the protected coal seam is obtained. The characteristics of expansion deformation and the change law of coal seam permeability. The original gas pressure of coal seam is 1.9 MPA and the original gas content is 8.03 m3 / t. The maximum residual gas pressure is 0.3 MPA and the maximum residual gas content is 2.64 m3 / t after mining in 8 coal seam. The deformation of coal seam of 7a is the largest (18.2mm) within the range of 40m or so pushed through the borehole in 54208 working face of protective layer. The corresponding maximum tensile deformation rate is 4.80, and the maximum amount of gas extracted by coal seam boreholes is 2.9 m3 / min. The gas extraction rate of 7a coal seam is 75.6 by statistical pressure relief area. At the same time, through the optimization algorithm of coal seam permeability coefficient, it is found that the coal permeability coefficient is 4.1057m2/MPa d 7 years after unloading, which is 216 times larger than the original gas permeability coefficient 0.0284m2/MPa2 d. The angle of relief of working face strike direction to protected layer is 60. The angle of unloading pressure along the direction of inclination is 75.The upper and unloading boundary is goaf, so it is not necessary to test. Within the protection range of No. 8 coal, 7a coal has eliminated the outburst danger and laid a foundation for safe mining in the next step. The field test results are consistent with the theoretical analysis and numerical simulation results.
【学位授予单位】：安徽理工大学
【学位级别】：硕士
【学位授予年份】：2013
【分类号】：TD713;TD322.5
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