摘要
基于一组实验结果 ,讨论了岩石标本的非均匀性 (预存微裂纹和宏观裂纹 )对声发射时空分布的影响 .对比分析表明 ,预存微裂纹的存在使得破裂成核前声发射率快速增加、b值表现出一种短期异常现象 ,即在下降背景上出现起伏 ,从而增加了破裂时间的可预报性 .宏观结构 (节理、层面等 )的存在对声发射率和b值的影响与微裂纹相同 ,而且宏观结构对声发射的空间分布具有控制作用 ,声发射丛集的宏观构造通常控制着未来的主破裂 .这意味着宏观构造的存在使得主破裂的时间和位置预报成为可能 .
Based on a set of experimental results, the effects of heterogeneity (pre existing microcracks and macrostructures) in rock sample on spatial and temporal distribution of acoustic emission (AE) were discussed. The comparative analysis indicates that the existence of pre existing microcracks makes AE occurrence rate rapidly increase prior to the fracture nucleation. In addition, the b value shows a short term anomaly, i.e . fluctuation on a decreasing background, which increases the predictability of the fracturing time. The effects of pre existing macrostructures, such as joint, bedding plane on AE occurrence rate and b value are the same as that of microcracks. AE spatial distribution is controlled by the pre existing macrostructures and the macrostructure clustered by AE events usually controls the coming final fracture. This means that the existence of macrostructures makes prediction of the time and location of the final fracture possible.
出处
《地球物理学报》
SCIE
EI
CAS
CSCD
北大核心
2004年第1期127-131,I006,I007,共7页
Chinese Journal of Geophysics
基金
国家"十五"科技攻关项目 (2 0 0 1BA60 1B0 2 )
国家重点基础研究发展规划项目 (G19980 40 70 4)
