炮孔内爆炸荷载非均匀性对激发动应力场的影响

由于炸药爆轰波的传播以及炮孔堵塞物冲出后爆生气体的非定常逸出过程,柱状炮孔内的爆炸荷载压力沿炮孔轴向呈不均匀分布。采用LS-DYNA动力有限元软件计算探讨了爆炸荷载分布不均匀性对岩体内激发动应力场的影响。计算结果表明,激发的径向压应力和环向拉应力在孔底段最大、在孔口段最小,且应力波在孔底段持续时间最长;爆炸荷载分布的不均匀性对环向应力影响更大;但荷载的非均匀分布对激发动应力场的影响仅局限在炮孔近区岩体内,且应力差值较小,非均布爆炸荷载与均布爆炸荷载在远区的计算结果是一致的。

Study on effect of non-uniform blast loading in a cylindrical blast-hole on induced dynamic stress field

Due to propagation of explosion wave and non-constant flow of blast-induced gas after the ejection of blast-hole blockage, the blasting load in column blast hole is non-uniform distributed in the axis direction. By using the dynamic finite el-ement software LS-DYNA, the influence of the non-uniformity of the blast loading on the induced dynamic stresses is studied. The results show that blast-induced radial compression stress and circumferential tension stress are the largest at the section of blast-hole bottom and the duration is the longest, while the stresses at the section of blast-hole orifice are the smallest. It is al-so found that the circumferential stress is more affected by the non-uniformity of the blast loading. However, the affected stress field is only restricted in rock mass near the blast-hole and the stress difference is small;the computational stress results of non-uniform and uniform loading are the same in far area from the blast-hole.