【摘要】 利用自制的与CT系统和声发射系统配套的加载装置,研究了泥岩在破坏过程中裂纹、孔隙等变化规律及与声发射事件之间的关系.研究表明:从CT图像可以观测到不同加载阶段试件中微裂纹闭合、扩展、分叉等细观损伤活动,声发射事件的空间分布规律很好地反映了内部微破裂、微裂纹的演化过程,定位结果与裂纹发育区域较一致.破坏模式不同反映了破坏过程和破坏机理的不同,破坏从规模较大的原生微裂纹处起裂,起裂载荷约为峰值载荷的80%,无原生裂纹区域和含坚硬夹层区域发生突发性脆性破坏,坚硬夹层对破坏模式起控制作用.声发射事件主要来源于加载初期新生裂纹的形成、原生裂纹的压密及裂纹的稳定扩展,此时声发射信号为突发型.裂纹的起裂和非稳定扩展过程不能形成声发射事件,此时声发射信号为连续型.能量累积陡增是裂纹起裂、分叉及宏观破坏的标志.更多还原

【Abstract】 The self-developed loading device which matches with CT system and Acoustic Emission system is used to study the relationship between the mudstone change(cracks and poles)and acoustic emission during the failure process.Results show that mesoscopic damages(closure,extension and branching)in samples under different loading stages can be observed from CT images,and the evolution process of internal micro-fracture and micro-cracks can be well reflected by spatial distribution of acoustic emission events,which is consistent with crack development area.Different failure mode indicates different failure process and failure mechanism.Failure initiates from the large-scale original micro-cracks and the initial load of crack initiation is approximately eighty percent of the peak load.The sudden brittle failure occurs in the area with no original crack and the area with hard interlayer,of which the latter plays a role in controlling failure mode.Acoustic emission events mainly derive from the formation of newborn cracks in the initial loading stage,the consolidation of original cracks and the stable exten-sion of cracks.At this time,the acoustic emission signals are sudden.The initiation and unstable extension process of cracks can’t form acoustic emission events,and at this time acoustic emission signals are continuous.The sharp energy accumulation heralds the initiation,branching and macroscopic failure of cracks.更多还原