Influence and Optimization of Inter-Row Delay Time on Blast Fragmentation in Tuff Bench Blasting
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摘要:岩石爆破块度直接影响后续装载效率与破碎成本，合理控制延时爆破参数是优化破碎效果的关键。本文基于应力波叠加理论，结合数值模拟与现场试验，系统研究了排间延时时间对致密坚硬凝灰岩爆破块度的影响规律。采用ANSYS/LS-DYNA建立台阶深孔爆破模型，在固定孔间延时19 ms的条件下，对比分析排间延时分别为35，40，45，50，55，60 ms时不利破碎区的最大有效应力响应。结果表明，当排间延时为40 ms时，不利破碎区平均最大有效应力峰值达35.69 MPa，应力场强化效应最显著。在此基础上，开展6组现场爆破试验（台阶高15 m，孔排距4.5 m×3.5 m），利用无人机航拍与Split-Desktop软件对爆堆块度进行定量分析。试验数据显示，孔间延时19 ms、排间延时40 ms组合下，爆破后最大块度尺寸最小（95.35 cm），大块率最低（4.86%），破碎效果最优。研究成果可为类似岩性条件下的矿山延时爆破参数优化提供理论依据与工程参考。
Abstract:Blast fragmentation directly affects subsequent loading efficiency and crushing costs, thus, appropriate control of delay blasting parameters is crucial for optimizing fragmentation performance. Based on the stress wave superposition theory, this study systematically investigates the influence of inter-row delay time on blast fragmentation in dense, hard tuff through integrated numerical simulation and field trials. A bench-scale deep-hole blasting model was established using ANSYS/ LS-DYNA, with the inter-hole delay fixed at 19 ms, to comparatively analyze the maximum effective stress response in poorly fragmented zones under inter-row delays ranging from 35, 40, 45, 50, 55, 60 ms. The results show that an inter-row delay of 40 ms yields the highest average maximum effective stress (35.69 MPa) in the poorly fragmented zone, indicating the most pronounced stress field enhancement. Subsequently, six field blasting tests were conducted, featuring a 15 m bench height and a hole pattern of 4.5 m×3.5 m. Unmanned aerial vehicle photogrammetry combined with Split-Desktop software was employed to quantitatively assess fragment size distribution. Field data demonstrate that the combination of 19 ms inter-hole delay and 40 ms inter-row delay achieves the optimal fragmentation outcome, with the smallest maximum fragment size (95.35 cm) and the lowest oversize ratio (4.86%). The findings provide both theoretical support and practical guidance for optimizing delay blasting parameters in mines with similar rock mass conditions.
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