露天矿山孔间延时起爆条件下的岩石破碎效果研究  

Study on Rock Fragmentation under Condition of Delayed Initiation between Holes in an Open-pit Mine

作　　者：于传泽 郭连军 邓丁 王雪松 柴青平 YU Chuan-ze;GUO Lian-jun;DENG Ding;WANG Xue-song;CHAI Qing-ping(School of Architecture and Civil Engineering,Shenyang University of Technology,Shenyang 110870,China)

机构地区：[1]沈阳工业大学建筑与土木工程学院,沈阳110870

出　　处：《爆破》2024年第2期1-7,共7页Blasting

基　　金：国家自然科学基金资助项目(No.51974187)。

摘　　要：为获取某露天矿山最优起爆延时时间,提高爆破效率,结合ANSYS/LS-DYNA软件建立了三维台阶爆破模型,布置前排炮孔2个、后排炮孔1个,三角形布孔,起爆方式采用反向起爆,在布孔区设置5个应力监测点。对排间延时42 ms及孔间延时11、13、15、17、19、21、23 ms的不同延时时间下岩石破碎效果进行模拟试验,并监测其有效应力。为便于细致观察爆炸应力波在岩石中传播规律,另做前排两炮孔延时起爆剖面模型。结果显示:当排间延时42 ms,孔间延时17 ms时,各监测点的平均最大有效应力达到峰值,整体岩石破碎更为有利。延时爆破优势在于后爆炮孔可以在先爆炮孔基础上进一步对岩石产生破坏作用,前排炮孔先期起爆作用使得后排炮孔成为临新自由面的前排炮孔。经现场试验论证,利用块度识别软件split-desktop分析爆堆照片中岩石块度分布,得出在排间延时42 ms及孔间延时17 ms条件下,岩石块度尺寸在20 cm以下占比77.24%,在50 cm以上占比极少,为0.31%,整体破碎效果较好,能够满足矿山生产运营需求,为露天矿山开采提供一定数据支撑。To optimize the initiation delay time of an open-pit mine and enhance blasting efficiency,a three-dimensional bench blasting model is developed using ANSYS/LS-DYNA software.The model consists of 2 blast holes in the front row and 1 blast hole in the back row arranged in a triangular pattern.The bottom initiation was employed,and 5 stress monitoring points were placed within the hole placement area.Simulated tests were conducted to evaluate rock fragmentation under different delay times between rows(42 ms)and between holes(11,13,15,17,19,21,and 23 ms),while monitoring their effective stress levels.Additionally,a delayed detonation profile model for the two front row boreholes was established to observe the propagation characteristics of explosion stress waves.The results indicate that when the delay time between rows is set at 42 ms and between holes at 17 ms,it leads to peak values of maximum effective stress at each monitoring point which facilitates overall rock fragmentation.The advantage of time-delay blasting lies in its ability to enhance rock damage by utilizing the pre-blast hole as a foundation,while the front-row hole acts on the post-blast hole through pre-detonation effects,creating a new free surface.Through field testing and demonstration,we analyzed the distribution of rock fragmentation in blasting pile photos using split-desktop software.The findings indicate that with an inter-row delay time of 42 ms and an inter-hole delay time of 17 ms,approximately 77.24%of rocks are below 20 cm in size,while only a negligible proportion(0.31%)exceeds 50 cm.Overall,the crushing effect is satisfactory and meets both production and operational requirements for open-pit mining operations.

关 键 词：延时时间 爆破效率 有效应力 块度分布 岩石破碎 

分 类 号：TD235[矿业工程—矿井建设]