摘要
依据声发射测试原理,建立了微裂纹成核时声发射率与应力,晶粒直径、位错数目的定量表达式,表明晶粒大小对声发射有较强的控制作用。晶粒断裂时,声发射参数与单轴应力、断裂指数有关,即声发射与材料的性质及应力状态有关。对于有预制裂纹的试样,低脆性岩石声发射与裂纹尖端塑性区大小有关,指数b取决于材料的强度特性;高脆性岩石声发射主要受裂纹扩展速率控制。
A relationship of acoustic emission (AE) rate to stress, crystal grain size and number of dislocations is expressed for microcrack nucleation on the principle of AE testing. It is shown that AE is relatively dependent on crystal grain size. The AE parameter is proved relating to uniaxial stress and fracture index, i.e., AE depends material's properties and stress level. As to pre-cracked specimens, the low-brittleness rocks relate to the dimension of crack-tip plastic zone and index b depends on mechanical properties, whereas the high-brittle-ness rock are mainly controlled by the crack propagation rate.
关键词
岩石
破裂
声发射
裂纹
破坏机理
acoustic emission, deformation, fracture, crack.
