摘要
动静加载下煤的破坏特性及机制是研究动载冲击地压机制的基础问题,利用改进的霍普金森杆对该问题进行试验研究。首先,通过试验结果的回归分析发现煤在动静加载下有其不同于均质致密岩石的独特的破坏特性。然后,通过对试验结果的讨论对动静加载煤的破坏机制进行分析,发现较多裂隙的存在是导致独特破坏特性的主要原因。破坏模式以裂隙脆性扩展为主;动载的作用主要是使裂隙扩展,进而发生破坏;而静载的作用主要是改变原生裂隙的数量和裂隙尖端的蓄能。最后,基于试验结果对动静加载下煤的冲击危险性进行分析,得出动静加载下煤具有临界静载和最优动载;并将动静载荷下煤的强度作为动载抵抗指数,用来反映抵抗动载能力的强弱;将碎片的分维值作为动载冲击能量指数,用来衡量动载冲击破坏的剧烈程度。
Failure characteristics and mechanism of coal are the foundation of studying mechanism of rockburst under impact disturbance,which is investigated by the improved split Hopkinson pressure bar(SHPB) in the laboratory. First,based on the regression analysis of experimental data,there are the unique failure characteristics of coal,as fracture half-hard brittle rock,under coupled static and dynamic loads. Then,though the discussion of experimental result,the failure mechanism is analyzed. It is found that the main reason of the unique failure characteristics is the existence of much crack. Main failure mode is brittle expansion of fracture;the dynamic loading leads to crack propagation until to destruction,meanwhile,the static loading mainly changes the number of existing fractures and the size of the elastic energy in the fissures tip. At last,based on the result of the experiment,the rockburst hazad of coal under coupled static and dynamic loads is discussed. We know that there are the critical static loading and the optimal dynamic loading under coupled static and dynamic loads. The strength under the static and dynamic loads of the coal,as a dynamic load resistance index,can reflect the capacity of the resistance to dynamic loads. Fractal dimension,as a dynamic loading energy index,can be used to measure the intensity of dynamic loads damage.
出处
《岩石力学与工程学报》
EI
CAS
CSCD
北大核心
2013年第S2期3749-3759,共11页
Chinese Journal of Rock Mechanics and Engineering
基金
国家重点基础研究发展计划(973)项目(2010CB226806)
关键词
岩石力学
动载冲击地压
动静加载
破坏特性
裂隙
分维
弹性能释放率
rock mechanics
rockburst under impact disturbance
static and dynamic loading
failure characteristics
crack
fractal dimension
release rate of elastic energy
