中文摘要：

利用单轴压缩试验,研究了裂纹应变随加载速率的变化规律,得到了不同加载速率下黄龙灰岩的起裂应力。黄龙灰岩的起裂应力约为峰值强度的95%以上,裂纹起裂应力随加载速率增加而增加,而且加载速率越高,破坏后的岩石碎块的尺寸越小。根据岩石黄龙灰岩单轴压缩过程的声发射特征,得到了岩石内部微裂纹演化特征。随着裂纹的不断扩展,岩样出现了明显的损伤局部化现象。最后,利用滑移裂纹模型,分析了黄龙灰岩动态损伤演化机制,得到了加载速率与裂纹起裂应力的关系,同时获得了临界裂纹长度与加载速率的关系。

英文摘要：

Based on the uniaxial compression test of Huanglong limestone,the initial cracking stress of rock specimens under different loading rates can be obtained by studying the crack strain curves.The initial cracking stress of Huanglong limestone is more than 95 percent of the peak strength,and increases with loading rate increase.The fragment size of Huanglong limestone gets smaller as the loading rate increases.Crack initiation and propagation process of Huanglong limestone is monitored by using the acoustic emission technique.It is found that damage localization occurs in the rock specimens as the cracks propagate.The sliding crack model is adopted to analyze the mechanism of dynamic damage evolution of Huanglong limestone.The dependence of initial cracking stress of Huanglong limestone on the loading rate and the relationship between critical length of crack and loading rate are obtained.