岩石宏观裂纹分叉的加载率效应

Effect of Loading Rates on Macro-Crack Bifurcation of Rock

利用扫描电镜和光学显微镜，对静态和冲击（应力波）加载条件下断裂的辉长岩试件进行了剖面观察与分析．结果发现，静态加载时断裂面的剖面上几乎看不到宏观裂纹分叉现象；但在动态加载时，普遍发现剖面上有宏观裂纹分叉现象。随着加载率提高，分叉裂纹数量及其总长度也随之增加．基于以上实验结果，初步讨论了岩石动态断裂机理。

The longitudinal sections of the fractured surfaces of the gabbro specimens failured by static or dynamic load are observed and analysed with SEM and optical microscope. The results show that macro-crack bifurcation is hardly found on any section for static loading, but obvious macro-crack bifurcations are found for dynamic loading. And it shows that the number and the total length of the bifuraction cracks for a specimen increase with(dynamic) loading rates. Based on the experimental results, finally, the dynamic fracture mechanism of rock is discussed.