基于LS−DYNA的高功率脉冲深孔破岩数值分析

Numerical Analysis of High−Power Pulse Deep Hole Rock Breaking Effects Based on LS−DYNA

  • 摘要: 高功率脉冲放电破岩技术作为一种新型破岩方法,有望为矿岩破碎提供有效解决方案。通过建立基于JWL状态方程的高功率脉冲破岩数值模型,探究了该技术的破岩机理与破坏规律。模拟12 m深孔工况下高功率脉冲放电间接破岩过程,分析了不同输入能量、电极间隔对单孔爆破效果的影响,以及不同钻孔间距、排距对多孔爆破应力波叠加效果的影响,并与相同工况下的传统炸药爆破进行对比。模拟结果表明:单孔爆破中,破碎区半径随输入能量增加呈对数型增长;在固定电极间隔条件下,破坏效果存在明确上限,当电极间隔为2、3、4 m时,对应破坏效果上限分别相当于同工况炸药爆破效果的90%、135%和180%。多孔爆破中,随钻孔间距与排距增大,破坏效果呈先增强后减弱趋势,当钻孔间距为3 m、排距为2.7 m时,应力波充分叠加并形成贯通裂隙,能量利用率最高。在孔深12 m、钻孔直径150 mm工况下,高功率脉冲破岩的最优参数为电极间隔3 m、单电极输入能量8 MJ、钻孔间距3 m、钻孔排距2.7 m。该数值模拟结果为实际工程应用提供了参数选择依据和理论指导。

     

    Abstract: High−power pulse discharge rock breaking technology, as a novel rock fragmentation method, holds promise for providing an effective solution for ore breakage. In this study, a numerical model based on the JWL equation of state was established to investigate the rock−breaking mechanism and failure patterns. The indirect rock−breaking process using high−power pulse discharge was simulated for a 12 m deep−hole condition. The effects of input energy and electrode spacing on single−hole blasting performance, as well as the influence of borehole spacing and burden on stress wave superposition in multi−hole blasting, were analyzed and compared with conventional explosive blasting under the same conditions. The simulation results show that in single−hole blasting, the crushed zone radius increases logarithmically with input energy. Under a fixed electrode spacing, the damage effect exhibits a clear upper limit: at electrode spacings of 2, 3, and 4 m, the corresponding upper limits of the damage effect are equivalent to 90%, 135%, and 180% of that of explosive blasting under identical conditions, respectively. In multi−hole blasting, as borehole spacing and burden increase, the damage effect first intensifies and then weakens. When the borehole spacing is 3 m and the burden is 2.7 m, the stress waves superimpose sufficiently to form interconnected fractures, achieving the highest energy utilization efficiency. Under the conditions of a 12 m hole depth and a 150 mm borehole diameter, the optimal parameters for high−power pulse rock breaking are an electrode spacing of 3 m, a single−electrode input energy of 8 MJ, a borehole spacing of 3 m, and a burden of 2.7 m. These numerical simulation results provide a parameter selection basis and theoretical guidance for practical engineering applications.

     

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