基于SPH-FEM耦合算法的台阶精准爆破延期时间研究及应用

Study on Bench Precision Blasting Delay Time Based on SPH-FEM Coupling Algorithm and Its Field Application

电子雷管在大型露天矿爆破中广泛使用,利用其精准起爆特性通过设置合理延期时间可有效改善爆破质量,对矿山生产降本增效具有重要意义。基于光滑粒子流体动力学—有限单元(SPH-FEM)耦合算法,利用LS-Dyna软件建立了多个巴润矿常规台阶尺寸的三维数值模型。针对电子雷管起爆条件下不同孔间和排间延时分别建立双孔、三孔SPH-FEM三维模型,从矿岩体SPH粒子应力和移动2个维度研究了被爆矿岩体的受力破碎、抛掷位移特征,并重点分析了不同排间延时下后排炮孔爆破漏斗的偏移角度。据此确定了最佳孔间、排间延期时间范围,并通过现场验证对比试验,选出了适合该爆区的最优延时。研究结果表明:在巴润矿现行孔排距条件下利用电子雷管精准起爆,孔间延时在20~30 ms内可达到较好的破碎效果;排间延时大于35 ms时,先爆炮孔为后续炮孔提供新的自由面和抛掷空间,且大于40 ms时应力趋于稳定;在现场验证试验中,试验区内边长1 m以下的破碎矿岩体占比达91%,较非试验爆区中同尺寸岩块占比提高了14%,破碎效果得到有效改善。

Electronic detonators are widely used in large open-pit mine blasting,using its precise detonation characteristics through the setting of a reasonable extension time can effectively improve the quality of blasting,and is of great significance to reduce costs and increase efficiency of mine production.This study employed a Smoothed Particle Hydrodynamics-Finite Element Method(SPH-FEM)coupled algorithm to establish multiple three-dimensional numerical models of conventional bench sizes in the Barun Mine using LS-Dyna software.Establishment of two-hole and three-hole SPH-FEM three-dimensional models for different inter-hole and inter-row delays under electronic detonator detonation conditions.From the perspectives of particle stress and movement in the rock mass SPH particles,the study investigates the force-induced fragmentation and throw displacement characteristics of the rock masses subjected to blasting.The study also focuses on analyzing the deflection angles of the blasting crater for rear-row blast holes under different inter-row delay conditions.Based on the analytical results,the optimal ranges for inter-hole and inter-row delay times are determined.Furthermore,the optimal delay for the specific blasting zone is selected through on-site comparative experiments for validation.The study findings indicate that under the current hole spacing settings in the Barun Mine,precise initiation with electronic detonators achieves favorable fragmentation effects when the interhole delay falls within the range of 20~30 milliseconds.When the inter-row delay exceeds 35 milliseconds,initiating the first blast hole provides new free surfaces and throwing space for subsequent blast holes,and stress stability is achieved when the delay exceeds 40 milliseconds.In the on-site validation experiment,the percentage of crushed orebodies with a side length of less than 1 m was 91%in the test area.Compared to non-test blast zones,the proportion of similarly sized rock blocks increased by 14%,indicating a significant improvement in fragmentation efficiency.