为了探究能兼顾计算效率与力学合理性的爆破块度的精细化数值仿真方法,首先比较了不同类型方法在爆破块度预测方面的优劣与工程适应性,并通过开展现场试验揭示爆破块度的形成特性,并阐明不同级配范围内的爆破块度数值模拟方法选择必要性,进而提出一种基于LS-DYNA+DDA耦合的连续-非连续爆破块度数值模拟方法。在炮孔近区采用基于LS-DYNA的连续介质数值模拟,提高粉碎区计算效率,中远区采用基于DDA的非连续方法进行模拟,实现爆破块度的非连续表征,并比选了将应力和速度分量作为耦合参量的准确性。最后基于舟山绿色石化矿山的开采爆破实践,对耦合方法进行了验证,结果表明:小粒径块度主要集中于炮孔附近很小的范围内,使用连续方法可以高效地模拟小粒径块度的分布;采用DDA方法模拟中大粒径块度的破碎更加合理,采用峰值速度作为不同方法之间的耦合分量可以减少计算传递时的压力亏损;所提的新方法预测爆破块度的准确性有所提高,在兼顾爆破块度力学机理的合理性和计算效率方面有其优越性。研究成果对于工程技术人员在爆破块度的精细化数值仿真方面有一定参考价值。

[Objective] Among numerical simulation methods for blasting fragmentation, the continuous medium simulation method has high efficiency, but its mechanical mechanisms are not rigorous and errors are significant when dealing with discontinuous problems; the discontinuous deformation analysis (DDA) method performs well for discontinuous problems, but when the fragment size becomes too small, excessively long computation time and non-convergence are likely to occur. This study aims to propose a numerical simulation method for blasting fragmentation that considers both computational efficiency and mechanical rationality. [Methods] Field tests were conducted to reveal the formation characteristics of blasting fragmentation, and the necessity of selecting appropriate numerical simulation methods for different fragment size ranges of blasting fragmentation was clarified. A continuous-discontinuous numerical simulation method for blasting fragmentation based on LS-DYNA+DDA coupling was proposed. In the near-field region of the blast hole, a continuous medium numerical simulation based on LS-DYNA was used to improve the computational efficiency of the crushing zone. In the middle- and far-field regions, a discontinuous method based on DDA was used to achieve discontinuous characterization of blasting fragmentation. The accuracy of using stress and velocity components as coupling parameters was compared. Finally, the LS-DYNA+DDA coupling method was validated based on the mining and blasting practice of Zhoushan Green Petrochemical Mine. [Results] Through field experiments and numerical simulation, it was determined that small-sized fragments were mainly concentrated within a very small range near the blast hole. The continuous medium method could efficiently simulate the distribution of small-sized fragments while ensuring accuracy. It was more reasonable to use DDA method to simulate the fragmentation of medium- and large-sized fragments. Using peak velocity as the coupling parameter between different methods could reduce the pressure loss during computation transmission. [Conclusion] Based on the measured results, comparison and validation between existing numerical simulation methods and the proposed LS-DYNA+DDA coupling method show that the proposed method improves the accuracy of blasting fragmentation prediction and has advantages in balancing the mechanical rationality of fragmentation mechanisms and computational efficiency. However, this method is currently applied in limited engineering scenarios, and its prediction efficiency needs further summary and optimization for different lithologies and blasting parameters.