露天矿台阶爆破过程爆堆空间形态数值分析研究

Numerical Analysis of Muckpile Spatial Profile during Bench Blasting in Open-pit Mine

露天矿台阶爆破时,爆堆表面形态与内部质点的运动轨迹是露天矿精准采矿的重要影响因素,尤其对于矿化不均匀的矿体。针对爆堆空间形态三维分布规律是露天矿爆破效果评价难点的问题,以太钢袁家村铁矿项目为背景,开展台阶爆破爆堆形态计算分析研究,提出了一种基于离散元的计算方法。该方法利用三维激光扫描技术获取台阶岩体节理产状,进而建立台阶节理分布模型,结合单孔爆破药量与起爆模式开展台阶爆破过程爆堆空间形态数值分析研究,通过对各爆破点附近的单元进行监测,从而确定各质点运动轨迹;通过数值软件模拟台阶爆破后爆堆的三维形态;最后利用爆堆实际的形态与坡面角比对验证数值计算结果的准确性。结果显示:经过数值分析计算的爆堆高度、爆堆前冲距离、爆堆破面角与无人机现场实际测量数据较为吻合;模拟的爆堆内部1、2号点前冲距离较大分别为26.1 m、14.71 m,5、6号点的前冲距离较小分别为9.18 m、9.83 m且运动较为平缓。通过对爆堆空间形态数值分析,可以为露天矿的精准采矿提供理论基础。

During bench blasting in open-pit mines,the surface profile of the muckpile and the movement trajectory of the internal particles are important influencing factors for precision mining in open-pit mines,especially for ore bodies with uneven mineralization.Aiming at the problem that the three-dimensional distribution of the muckpile spatial profile is a difficult problem in the evaluation of the blasting effect of open-pit mines,this paper proposed a calculation method based on discrete element and carried out the calculation and analysis of the bench blasting muckpile profile by relying on the Yuanjiacun Iron Mine of Taiyuan Iron and Steel Co.,Ltd.This method first used three-dimensional laser scanning to scan the joints in the area to be studied to obtain joint occurrences,and tested the mechanical parameters of the rock mass;then,the joint distribution model is established according to the statistical results,and the single-hole blasting charge and initiation mode are combined to carry out blasting calculation simulations.During the calculation process,monitor the cells near each blasting point,determine the motion trajectory of each particle,and determine the three-dimensional profile of the muckpile;finally,the accuracy of the numerical results is verified by comparing the actual shape of the muckpile with the slope angle.The results show that the height,impact distance and rupture angle of muckpile calculated by numerical analysis are in good agreement with the actual data measured by UAV.The simulated forward thrust distances of No.1 and No.2 in the muckpile are 26.1 m and 14.71 m,respectively,while the forward thrust distances of No.5 and No.6 are 9.18 m and 9.83 m,respectively,and the movement is relatively gentle.Through the numerical analysis of the space form of muckpile,it can provide a theoretical basis for the precision mining of open-pit mine.