低渗煤层预裂爆破裂纹扩展规律数值模拟
发布时间：2019-02-12 10:00
【摘要】：瓦斯抽放是防瓦斯灾害的有效方法之一，由于我国高瓦斯低渗透煤层透气性系数普遍偏低，，平均瓦斯抽放率为30%左右。煤层预裂爆破技术是利用爆生气体和爆炸冲击波的能量使炮孔周围的煤体产生裂隙和膨胀变形使原生裂隙进一步扩展，达到瓦斯抽采效率的目的。但预裂爆破后裂纹扩展规律及其影响范围现场难以测量，因此，本文采用理论与数值模拟相结合的方法进行低渗流煤层预裂爆破数值模拟研究。 论文首先给出了高瓦斯低渗透煤层物理力学特性和瓦斯在煤体内的扩散、解吸和渗流规律，其次结合预裂爆破自身特性，揭示了煤层在爆炸应力波动作用和爆生气体准静态作用下的损伤断裂机理。通过对爆生气体对裂纹扩展规律的影响分析。煤层预裂爆破裂纹扩展机理是应力波、爆生气体和煤层内的瓦斯压力共同作用的结果。最后利用AUTODYN程序中用户自定义材料模型功能，通过改变影响煤体裂纹扩展的参数，得到单孔和双孔在不同孔距及不同爆参工况条件下裂纹扩展规律和裂纹扩展范围及合理孔距。研究结果对高瓦斯低透气性煤层预裂增透提高瓦斯抽采率具有重要指导作用。
[Abstract]:Gas drainage is one of the effective methods to prevent gas disaster. Because of the low permeability coefficient of high gas and low permeability coal seam in our country, the average gas drainage rate is about 30%. The technology of coal seam pre-splitting blasting is to make use of the energy of explosion gas and blast wave to make the coal body around the hole produce cracks and expand the original fissure to further expand the original fissure, so as to achieve the purpose of gas extraction efficiency. However, it is difficult to measure the crack propagation law and its influence range after pre-splitting blasting. Therefore, the method of combining theory with numerical simulation is used to study the numerical simulation of pre-splitting blasting in low-seepage coal seam. Firstly, the physical and mechanical characteristics of high gas and low permeability coal seams and the diffusion, desorption and seepage laws of gas in coal body are given, and then combined with the characteristics of pre-splitting blasting itself. The damage and fracture mechanism of coal seam under explosion stress fluctuation and explosive gas quasi-static action is revealed. The effect of explosion gas on crack propagation is analyzed. The mechanism of crack propagation in coal seam pre-splitting blasting is the result of the interaction of stress wave, explosion gas and gas pressure in coal seam. Finally, using the user-defined material model function in AUTODYN program, by changing the parameters that affect the crack growth of coal body, the law of crack propagation and the range of crack propagation and the reasonable hole spacing of single hole and double hole under different hole spacing and different blasting parameters are obtained. The results can be used to improve the gas drainage rate in high gas and low permeability coal seam.
【学位授予单位】：辽宁工程技术大学
【学位级别】：硕士
【学位授予年份】：2013
【分类号】：TD712.6
本文编号：2420333
[Abstract]:Gas drainage is one of the effective methods to prevent gas disaster. Because of the low permeability coefficient of high gas and low permeability coal seam in our country, the average gas drainage rate is about 30%. The technology of coal seam pre-splitting blasting is to make use of the energy of explosion gas and blast wave to make the coal body around the hole produce cracks and expand the original fissure to further expand the original fissure, so as to achieve the purpose of gas extraction efficiency. However, it is difficult to measure the crack propagation law and its influence range after pre-splitting blasting. Therefore, the method of combining theory with numerical simulation is used to study the numerical simulation of pre-splitting blasting in low-seepage coal seam. Firstly, the physical and mechanical characteristics of high gas and low permeability coal seams and the diffusion, desorption and seepage laws of gas in coal body are given, and then combined with the characteristics of pre-splitting blasting itself. The damage and fracture mechanism of coal seam under explosion stress fluctuation and explosive gas quasi-static action is revealed. The effect of explosion gas on crack propagation is analyzed. The mechanism of crack propagation in coal seam pre-splitting blasting is the result of the interaction of stress wave, explosion gas and gas pressure in coal seam. Finally, using the user-defined material model function in AUTODYN program, by changing the parameters that affect the crack growth of coal body, the law of crack propagation and the range of crack propagation and the reasonable hole spacing of single hole and double hole under different hole spacing and different blasting parameters are obtained. The results can be used to improve the gas drainage rate in high gas and low permeability coal seam.
【学位授予单位】：辽宁工程技术大学
【学位级别】：硕士
【学位授予年份】：2013
【分类号】：TD712.6
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