摘要
造缝切顶是改变坚硬岩层破断运移规律,进而控制采场强矿压的有效手段。为了实现定向、弱扰动、大间距的造缝切顶,开发了一种坚硬顶板复合爆破定向造缝技术。在系统性的介绍该技术关键设备——高能射孔枪的结构组成的基础上,分析了复合爆破定向造缝切顶的工艺流程;基于AUTODYN数值计算软件,阐明了基于聚能射流和高压劈裂的复合爆破定向成缝机制;采用LS-DYNA软件构建了聚能射流及高压劈裂数值模型,优化了射孔弹尺寸及助推剂用量;开展了坚硬顶板复合爆破定向造缝地面实验,揭示了相邻孔间裂缝扩展延伸特征,验证了射孔弹尺寸和助推剂用量的合理性;在塔山煤矿8311工作面进行了坚硬顶板复合爆破造缝切顶工业实验,监测了8311工作面推进过程中2312临空巷道煤柱不同深度的垂直应力峰值,得出如下结论:(1)复合爆破技术定向造缝机制是聚能射流冲击岩石侵彻面上形成的压力远大于岩石的强度,造成岩石发生破碎,形成定向孔道;二次爆燃产生的高压气体进入射孔孔道内,在“气楔”作用下沿着孔道形成连续平整的裂隙面。(2)在射孔弹口径为40 mm、助推剂为4片时,复合爆破定向造缝技术可以实现1.5 m钻孔间距下中粒砂岩层劈裂。(3)现场实测表明,在采用复合爆破定向造缝技术后临空巷道煤柱的垂直应力峰值平均降低31%,有效的控制了巷道矿压。
Cutting a hard roof is an effective means to change strata movements and control strong ground pressure in coal mining faces.In order to achieve directional,weak-disturbance and large-spacing seam making,an innovative technology of directional roof slitting by composite blasting(DRSBCB)was developed.Firstly,the composition of a high energy perforating gun,a key equipment for this technology,was systematically introduced.Then the process of directionally roof cutting by the DRSBCB was analyzed.The directional crack formation mechanism of the DRSBCB was clarified by the AUTODYN,that was shaped charge jet and high-pressure fracturing.The LS-DYNA software was used to build numerical models of shaped charge jet and rock slitting by a high-pressure gas,and the size of perforating charge and the amount of booster were optimized by the models.A ground experiment of the DRSBCB was carried out.The experimental results revealed the characteristics of crack propagation between adjacent holes,and verified the rationality of perforation charge size and booster amount.An industrial experiment of the DRSBCB was carried out in the 8311 workface of the Tashan Coal Mine.Vertical stress peak values at different depths of coal pillars of the 2312 gob-side roadway were monitored during the advancing process of the 8311 workface.Then,the following conclusions are drawn:(1)The mechanism of the DRSBCB is that the pressure on the rock penetration surface by the shaped charge jet is far greater than the rock strength,so the rock is broken to form directional channels.The high-pressure gas,generated by the secondary deflagration,enters the channels and forms a continuous and flat fracture surface along those channels under the action of“air wedge”.(2)When the diameter of perforating cartridge is 40 mm and the booster is 4 pieces,the DRSBCB technology can achieve the splitting of medium sandstone strata at a 1.5 m borehole spacing.(3)The field measurement shows that the vertical stress peak of the pillars near the goaf roadway decreases by 31%on average after the DRSBCB is adopted,which effectively controls the roadway surrounding rocks.
作者
于斌
邰阳
李勇
匡铁军
张文阳
孟祥斌
YU Bin;TAI Yang;LI Yong;KUANG Tiejun;ZHANG Wenyang;MENG Xiangbin(State Key Laboratory of Coal Mine Disaster Dynamics and Control,Chongqing University,Chongqing 400044,China;Research and Developmen£Centre,Jinneng Group Co.,Ltd.,Datong 037000,CAina)
出处
《煤炭学报》
EI
CAS
CSCD
北大核心
2023年第1期126-138,共13页
Journal of China Coal Society
基金
国家自然科学基金资助项目(52204127)
重庆市科学家包干制资助项目(CSTC2022YCJH-BGZXM0005)
中国博士后基金面上资助项目(2021M700595)。
关键词
坚硬顶板
复合爆破
造缝切顶
强矿压
hard roof
composite blasting
roof cutting
strong ground pressure
