摘要
针对低透气性松软煤层瓦斯难以抽采的现实问题,进行了松软煤层水介质不耦合装药预裂爆破增透的研究。理论上,分析了水不耦合装药爆破在孔壁上形成的初始冲击波压力,并结合断裂力学计算得出煤体中形成的粉碎区和裂隙区范围。同时,利用ANSYS/LS-DYNA三维数值模拟软件,建立了水和空气不耦合装药的松软煤体爆破模型,进行了数值模拟对比分析。研究结果表明:水不耦合爆破后,松软煤体中形成的裂纹数量以及裂隙区范围明显较优,采集到的应力曲线,水不耦合装药爆破后形成的压、拉应力峰值分别是空气不耦合装药爆破的3.71倍和2.58倍;水不耦合装药爆破改善了爆破效果,应用于低透气性松软煤层的预裂爆破增透中,能够有效提高煤层的透气性,抑制瓦斯动力灾害事故。
Aiming at the practical problem that it is difficult to extract the gas from the soft coal seam with low permeability,the permeability improvement by the presplitting blasting under the uncoupled charge with water medium in the soft coal seam was studied. In theory,the initial shock wave pressure formed on the hole wall by the blasting with water uncoupled charge was analyzed,and the ranges of comminuted zone and fracture zone formed in the coal body were obtained by combining with the fracture mechanics calculation. At the same time,the blasting models of soft coal body under the uncoupled charge with water and air were established by using the three-dimensional numerical simulation software ANSYS/LS-DYNA,and the comparative analysis of numerical simulation was carried out. The results showed that after the blasting with water uncoupled charge,the number of cracks and the range of fracture zone formed in soft coal body were obviously better,and by the collected stress curves,the peak values of compressive stress and tensile stress after the blasting with water uncoupled charge were 3. 71 times and 2. 58 times as much as those of the blasting with air uncoupled charge,respectively. The blasting effect was improved by the blasting with water uncoupled charge,which can effectively improve the permeability of coal seam and restrain the gas dynamic disaster accidents when it is used in the presplitting blasting and permeability improvement of soft coal seam with low permeability.
引文
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