高地应力下扇形孔爆破损伤特性分析及优化设计

Analysis of damage characteristics and optimization of fan-holes blasting design under high in-situ stresses

深部岩体具有高地应力的特征,给传统爆破开采方式带来了技术难度大、效率低、成本高等问题。为克服这些困难,采用LS-DYNA软件对扇形中深孔爆破过程进行数值模拟,研究地应力大小对岩体爆破损伤特性的影响。结合矿山实际开采条件,设计爆破试验方案。结果表明:在地应力作用下,岩石质点振动速度峰值和单元有效应力降低,爆破过程中的最大能量降低。使用响应面法,得到最小抵抗线和孔底距对力学响应的影响,并对其进行优化分析。孔底距为2.48 m,最小抵抗线为1.6 m时,获得了最佳的爆破成本和效果。本研究可为深部开采遇到的扇形孔爆破难题提供解决方案。

In deep mining,the rock mass is characterized by high in-situ stress,which makes the traditional drilling and blasting methods difficult,inefficient,and costly.To overcome this difficulty,LS-DYNA software was used to simulate the process of fan-hole blasting under in-situ stress.The blasting design was carried out for a 932.5 m depth of rock mass in combination with the actual mining conditions.The results show that the damage extent has an obvious correlation with in-situ stress level.The peak particle velocity,effective stress,and kinetic energy for rock mass were reduced under in-situ stress and the ore fragmentation was more heterogeneous.The effect of hole-bottom spacing and minimum burden on the mechanical response obtained from the simulation was analyzed by the response surface method,and the best blasting cost and effect were obtained with a hole bottom spacing of 2.48 m and a minimum burden of 1.6 m using the desirability function.This study can provide solutions to the fan-holes blasting difficulties that are encountered with deep mining.