水射流切槽定向聚能爆破模型及数值模拟研究

Model of directional shaped blasting assisted with water jet and its numerical simulation

提出了基于高压水射流切槽的定向聚能护壁爆破新方法,理论上分析了护壁材料对冲击波的削弱作用并推导出其应力波传播公式,分析了射流缝附近冲击波的叠加效应,并结合热激活理论和微裂纹成核理论,得出爆炸初期微裂纹主要分布在射流缝附近及其端部,而在爆炸中后期,爆生气体的准静态压力场对裂纹的持续扩展起主导作用,并在护壁材料、炸药聚能槽和射流缝的激励机制作用下,根据裂纹扩展模型得出射流缝附近及其端部的裂纹扩展最长;最后,应用ANSYS/LS-DYNA软件并采用ALE算法对其进行数值模拟,其效果与理论模型基本相符:损伤区域在射流缝方向上明显大于护壁材料保护方向,裂纹在聚能和射流缝方向发育最长。

A new method of directional blasting was proposed with high pressure water jet,and the role of wall protecting materials for weakening shockwave impact and the additive effect in the area near jet joint were theoretically analyzed. The equation of wave propagation was derived. In the light of the heat activation theory and micro-crack nucleation theory,it is found micro-crack comes mainly in the vicinity of the jet seam in the initial stage of explosion and the quasi-static pressure of detonation gas dominates through the process of successive expansion of the crack in the medium-late stage. According to the crack propagation model,the expansion of crack near the jet seam or at the end will be the greatest owing to the incentive mechanism of wall materials,shaped-charge groove and jet joint. A numerical simulation was carried out by using ALE algorithm in ANSYS / LS-DYNA. The results are the same as those by the theoretical model. The damaged area in the direction of the jet seam is obviously greater than that under wall material protection and the crack develops to be the longest in jet joint＇s direction.