花岗岩中强爆炸形成的应力封闭壳及其与爆炸当量的关系

Formation of stress containment cage and its relation with explosive yield for strong explosion in granite

以应力封闭壳理论为基础,对花岗岩介质中地下强爆炸产生的应力封闭壳效应进行了数值模拟。以100 t TNT当量的强爆炸为例,模拟了爆后空腔的回弹和封闭壳的动态形成过程,给出了形成稳定封闭壳后的径向应力、环向应力和爆心距的关系。计算了不同爆炸当量形成的应力封闭壳尺寸及其形成时间与爆炸当量的关系。计算结果表明,当空腔膨胀到最大尺寸之后,空腔开始回弹,此时开始形成应力封闭壳;当空腔回弹结束即形成稳定的空腔尺寸时,稳定的应力封闭壳也在该时刻形成;爆炸当量越大,形成的应力封闭壳的范围越大,当爆炸当量低于10 t TNT时,不能形成应力封闭壳。

Based on the theory of stress containment cage, the effects of stress containment cage of underground strong blast in granite are studied by numerical simulation. A numerically simulated example of strong explosion with yield of 100 t TNT demonstrated the phenomena of cavity rebound and the dynamic formation process of stress containment cage. The relationships between radial stress and hoop stress with distance from explosive point after the formation of stable stress containment cage are given. The relationships between the size of stress containment cage and the formation time with serial explosive yields are analyzed. Nnmerical results indicate that： cavity begins to rebound and the stress containment cage begins to form when the cavity radius expending to maximum; stable cavity and stable stress containment cage are formed when the progress of cavity rebound ended; the bigger of explosive yield is, the larger of the formed stress containment cage region is; stress containment cage could not form when the explosive yield is lower than 10 t TNT.