摘要
在对煤层深孔聚能爆破致裂分区研究的基础上,针对聚能爆破煤层裂隙扩展特征及范围进行了数值模拟研究.结果表明,炮孔周围可划分为爆破压碎区、爆破裂隙区和弹性变形区,根据裂隙类型及裂隙数目的差异,爆破裂隙区又可划分为裂隙密集区和主裂隙扩展区.受聚能装药结构的影响,压碎区的范围呈聚能罩开口方向小于其他方向的类椭圆状;裂隙密集区和主裂隙扩展区的范围均呈聚能罩开口方向大于其他方向的类椭圆状.煤层深孔聚能爆破致裂增透工程试验发现,随着远离炮孔,各个观察孔内瓦斯体积分数增幅受聚能爆破的影响呈"强-中-弱"阶梯状变化,与所构建的聚能爆破致裂分区模型比较一致,即聚能爆破载荷下煤层裂隙具有明显的分区特征,压碎区、裂隙密集区和主裂隙扩展区组成了煤层深孔聚能爆破的有效致裂范围.
Deep-hole directional cumulative-blasting cracking technology has unique advantages for improving coal seam permeability.This paper was concerned with the range of the effective fracture zone under cumulative blasting using a linear-shaped charge in a coal seam.Based on the analysis of the mechanism of the directional cumulative-blasting in coal seams,the response characteristics of the coal under the coupled effects of the blasting-induced shock wave,stress wave,detonation gas and the energy-cumulative effect,and the partition characteristics of the crack in the cumulative-blasting-affected area were studied by theoretical analysis;moreover,a numerical analysis model of cumulative blasting was established,and the propagation distribution characteristics and range of coal seam fracture under cumulative blasting were investigated through numerical simulation.The results of the theoretical analysis and simulation show that the cumulative-blasting-affected area can be divided into crushed,crack,and elastic-deformation zones;further,the crack zone can be divided into crack-intensive and main crack-propagation zones according to the type and number of cracks.Additionally,a partition model for the influence of deep-hole cumulative blasting with linear-shaped charge in coal seams was constructed.Meanwhile,under the influence of the shaped-charge structure,the crushed zone has an oval-like shape with a small radius in the direction of the shaped-charge jet,while the crack-intensive and main crack-propagation zones have oval-like shapes with a larger radius in the direction of the shaped-charge jet.In addition,field experiments of deep-hole cumulative blasting with linear-shaped charge in coal seams were carried out and the experimental results show that the influence of the cumulative blasting on the increase of the coal-seam-gas volume fraction in each observation hole weakened in a step-wise manner(strong-medium-weak)with increasing distance from the blasting borehole;this is consistent with the partition model of the
作者
郭德勇
赵杰超
吕鹏飞
朱同功
GUO De-yong;ZHAO Jie-chao;Lv Peng-fei;ZHU Tong-gong(School of Emergency Management and Safety Engineering,China University of Mining and Technology(Beijing),Beijing 100083,China;No.10 Mine,Pingdingshan Tianan Coal Mining Co.,Ltd.,Pingdingshan 467000,China)
出处
《工程科学学报》
EI
CSCD
北大核心
2019年第5期582-590,共9页
Chinese Journal of Engineering
基金
国家自然科学基金重点资助项目(41430640)
国家自然科学基金联合基金重点资助项目(U1704242)
关键词
煤层增透
聚能爆破
裂隙扩展
致裂范围
瓦斯抽采
seam permeability improved
cumulative blasting
crack propagation
cracking zone
coal-seam-gas drainage
