砂岩冲击岩爆实验碎屑研究

Study on sandstone fragments from impact rockburst experiments

冲击岩爆是在地下工程形成以后,岩体受静荷载和动荷载共同作用所致。改变静载和改变动载幅值是两种不同的冲击岩爆实验,收集实验后的砂岩碎屑,并选取只施加静载的相似破坏实验后砂岩碎屑进行对比。测量每块碎屑的质量、长度、宽度和厚度,并对粗粒、中粒、细粒以及微粒等不同粒径范围内的碎屑数量、质量及粒度分布进行分析,得到碎屑的破碎程度和形状特征,并计算碎屑的分形维数。结果表明,冲击岩爆碎屑的破碎程度更高,片状特征明显;动静载的组合方式对冲击岩爆碎屑的破碎程度和尺度特征影响小;冲击岩爆比静载破坏产生碎屑耗能更多。

Impact rockburst is induced by the combined static and dynamic loads after excavation. There are two types of impact rockburst experiments,one is induced by changing the static load and another is induced by changing the amplitude of dynamic load. The sandstone fragments after these two experiments were collected. Meanwhile,the sandstone fragments generated from the similar compression experiment under static load were collected too. And the mass,length,width and thickness of each fragment has been measured respectively. The quantities and mass distribution of fragments with coarse,medium,fine and micro grains in different size ranges,and size distribution were further analyzed. The crushing level and shape characteristic of fragments were obtained. Then the fractal dimensions were calculated. The results show that the degree of crushing level of fragments from impact rockburst is higher and with obvious slice shape; the ways of combined static and dynamic loads have a little effect on the crushing level and scale characteristic of fragments from impact rockburst experiments; energy dissipation from impact rockburst experiments is higher than that of similar compression experiment.