摘要
在煤矿瓦斯治理工程中,预裂爆破是改善低透气性煤层渗透率的有效措施之一,其效果取决于爆破裂纹的产生与扩展程度。为研究低透气性煤层预裂爆破裂纹产生与扩展的特征及规律,将爆破过程看作平面应变问题,基于HJC模型、HIGH_EXPLOSIVE_BURN材料模型和JWL状态方程,构建了深孔预裂爆破数值模型,并采用六面体单元进行网格划分;基于此,采用LS-DYNA软件对数值模型进行解算,分析了爆破孔周围破碎区和裂隙区的产生与发展过程,探讨了爆破孔周围煤体的裂隙与应力变化特征;最后,针对煤层预裂爆破参数选取,给出了合理化建议。研究表明:采用2号岩石乳化炸药,药卷直径94 mm,炮孔直径120 mm的爆破条件下,爆破产生的破碎区范围为1.43 m×1.25 m,裂隙区半径约为3.4 m,主裂隙长度为2.0~2.62 m;爆破孔与控制孔连线方向主要受压应力作用,切向受拉压应力作用,控制孔左右两侧切向受拉压作用显著;不同炮孔先后爆破产生的应力波与裂隙区应力场发生叠加,对裂隙的产生发展具有一定影响;煤层预裂爆破的合理布孔参数需综合考虑煤层对爆破应力波的衰减作用、空孔壁面对爆破应力波的反射作用以及双孔爆破应力波的叠加作用。
In the practice of gas control engineering in coal mine,pre-split blasting is one of the effective measures to improve the permeability of low-permeability coal seams,and its effect depends on the generation and expansion of blast cracks.In order to research the generation and expansion characteristics of pre-split blasting cracks in low permeability coal seams,the blasting process is regarded as a plane strain problem.Then the numerical model for pre-split blasting is constructed based on the HJC model,the HIGH_EXPLOSIVE_BURN material model,the JWL equation of state,and meshing with hexahedral elements.Furthermore,the LS-DYNA software is used to solve the numerical model so that to analyze the generation and development process of the crushed and fractured zone areas around the blasting hole.In addition,the characteristics of cracks and stress changes in the coal body around the blasting hole are also worth discussion.Finally,reasonable suggestions are given for the selection of pre-split blasting parameters in coal seams.The research shows that when No.2 rock emulsion explosive with a diameter of 94 mm is charged into a blast hole with a diameter of 120 mm,the crushed area around the blast hole is 1.43m 1.25 m,and the radius of the fractured zone is about 3.4 m with the length of the main crack within 2.0~2.62 m.The connection direction between the blasting hole and the control hole is mainly affected by the compressive stress,while the tangential direction is mainly affected by tensile and compressive stresses.And the left and right sides of the control hole are also significantly affected by tension and compression.The stress waves generated by successively initiated blasting holes are superimposed on the stress field in the fractured area,which has a certain influence on the generation and development of the cracks.The reasonable layout of the pre-split blasting holes in the coal seam should be comprehensively considered with the attenuation effect of the coal seam on blasting stress waves,the reflection eff
作者
张飞燕
陈玥玥
韩颖
孙金山
年鑫喆
ZHANG Fei-yan;CHEN Yue-yue;HAN Ying;SUN Jin-shan;NIAN Xin-zhe(College of Safety Science and Engineering,Henan Polytechnic University,Jiaozuo 454003,China;School of Energy Science and Engineering,Henan Polytechnic University,Jiaozuo 454003,China;State Key Laboratory Cultivation Base for Gas Geology and Gas Control,Jiaozuo 454003,China;Collaborative Innovation Center of Coal Work Safety and Clean High Efficiency Utilization,Jiaozuo 454003,China;State Key Laboratory of Precision Blasting,Jianghan University,Wuhan 430058,China;Hubei Key Laboratory of Blasting Engineering,Jianghan University,Wuhan 430058,China)
出处
《爆破》
CSCD
北大核心
2022年第3期106-111,共6页
Blasting
基金
国家自然科学基金资助项目(51974108、51404093)
河南省博士后科研项目(001701014)
河南省高校基本科研业务费专项资金资助项目(NSFRF210315)
河南省瓦斯地质与瓦斯治理重点实验室—省部共建国家重点实验室培育基地开放基金项目(WS2020B12、WS2012A09)
河南理工大学博士基金资助项目(B2008-15、B2012-093)。
关键词
低透气性煤层
预裂爆破
裂纹扩展
数值模拟
控制孔
low permeability coal seam
pre-split blasting
crack propagation
numerical simulation
controlled hole
