湖北三鑫金铜矿扇形中深孔爆破参数优化数值模拟研究

Numerical Simulation of Sanxin Gold and Copper Mine in Hubei Province Blasting Parameters

湖北三鑫金铜矿进入深部开采后,采用扇形中深孔爆破破岩方式回采顶底柱,由于布孔方式和岩石物理力学性质发生变化,导致扇形中深孔爆破存在大块率高、缩口严重等问题。运用ANSYS/LS-DYNA数值模拟软件对不同孔网参数的中深孔爆破过程进行数值模拟计算。基于现场岩石实际物理力学性质和实际炸药材料参数建立了1.4 m、1.6 m、1.8 m三种不同孔底距和1.6 m、1.8 m、2.1 m三种不同排间距数值计算模型,通过分析炮孔爆破过程中关键时刻模型有效应力云图,确定出扇形中深孔爆破方式的岩石低应力区集中在两炮孔中心线中上部位置,再通过将布置在模型关键位置监测单元的Von Mises有效应力峰值与岩石材料的最大动态抗拉强度对比,确定出当孔底距为2.1 m,排间距为1.4m时低应力区内监测单元的Von Mises有效应力峰值与岩石的最大动态抗拉强度最为接近,确定出三鑫金铜矿扇形中深孔爆破的最优孔网参数:最优孔底距2.1 m,最优排间距1.4 m。经现场应用试验验证在相同炸药单耗的情况下,更优的孔底距、排间距设计能够有效的降低扇形中深孔爆破的大块率高、缩口严重的问题。研究成果可为矿山后续回采工作提供指导,对于存在类似问题的地下金属矿山开采具有一定参考价值。

After entering deep mining of Sanxin Gold and copper mine in Hubei Province,a fan-shaped medium-deep hole blasting is adopted to excavate the top and bottom pillars.Due to the changes of hole layout and physical and mechanical rock properties,the fan-shaped medium-deep hole blasting has many problems,such as high bulk rate and serious shrinkage.To simulate the process of medium-deep hole blasting with different hole network parameters,the ANSYS/LS-DYNA numerical simulation software is used.Based on the actual physical and mechanical properties of on-site rock and the actual explosive material parameters,the numerical calculation models of three different hole bottom distances(1.4 m,1.6 m and 1.8 m)and three different row distances(1.6 m,1.8 m and 2.1 m)were established.By analyzing the effective stress cloud at the critical moment during the hole blasting process,the rock low-stress area of fan-shaped medium-deep hole blasting is concentrated on the upper and middle positions of the center lines of the two holes.By comparing the Von Mises effective stress peak on the monitoring unit at the key model position with the maximum dynamic tensile strength of rock material,it is determined that the effective stress peak is most close to the maximum dynamic tensile strength when the hole bottom distance is 2.1 m and the row spacing is 1.4 m.Therefore,these parameters are the optimal hole network parameters of fan-shaped medium-deep hole blasting of Sanxin Gold and copper mine.The field application test proves that a better hole bottom spacing and row spacing design can effectively reduce the problems of high bulk rate and serious hole shrinkage in fan-shaped medium-deep hole blasting under the same single explosive consumption.The research results can provide a guidance for subsequent mining work,and it has certain reference value for underground metal mine mining with similar problems.