石灰岩冲击损伤实验与破碎特性研究

利用一级轻气炮对石灰岩试件进行冲击损伤实验，采用锰铜压力计对冲击波作用过程进行压力测试，对冲击后的试件进行声波探测和剖切观察，研究石灰岩冲击损伤与破碎特征。实验与分析结果表明，在飞片直径小于试件直径、试件自由面条件较好、碰撞压力在1~1.7 GPa的实验条件下，岩石试件的冲击损伤存在头部核心区、环状裂隙区、中部损伤区、底部破坏区的分区特性，且各区的损伤原理不同。软回收装置为试件的侧向和底部创造了良好的自由面条件，以致拉应力对岩石损伤起到了主导作用。最后用有限元软件LS-DYNA对岩石冲击过程进行数值模拟，分析岩石试件的冲击损伤作用，验证了实验结果的正确性。

Study on shock-damaged rock experiment and numerical simulation

Impact-damage experiments on limestone specimens were carried out on one-stage light-gas gun.Pressure in specimens during shock wave action process was tested by manganin gauge.Impact-damaged and fragmentation properties of lime rock were analyzed by acoustic sounding and splitting cut observation on specimens after shock experiments. Test and analyzed results show that if flyer plate diameter is smaller than that of specimen,the freedom surface of specimen is better,and colliding pressure is 1.0~1.7 GPa,specimen damage has divisional characters with different mechanisms,including head-core space,ring-shape crack area,central section damage space and empennage failure zone.Soft reclaim installation provided a good freedom surface for the side and empennage of specimens,and pull stress made the dominant function for rock damage.Impact-damaged process of rock was numerically simulated using LS-DYNA finite element code to analyze impact-damaged properties of limestone specimens and to validate experimental results.