单轴压缩岩石相似材料损伤特性及时空演化规律

Damage characteristics and space-time evolution law of rock similar material under uniaxial compression

  • 摘要: 为了研究岩石相似材料的损伤特性和损伤时空演化规律,利用自主研发的YYW-Ⅱ应变控制式无侧限压缩仪及PCIE-8型声发射(AE)监测系统,监测了岩石相似材料试样在单轴压缩过程中的应力应变变化和AE事件活动,建立了基于AE事件累计数的单轴压缩岩石相似材料损伤模型,进一步分析了岩石相似材料在单轴压缩过程中的损伤发展阶段,研究了单轴压缩下岩石相似材料的损伤时空演化过程。结果表明:岩石相似材料试样在单轴压缩过程中,AE事件活动大致经历了初始压密少量段、弹性变形稳定增长段、塑性变形和破坏剧烈增长段3个阶段;损伤过程可分为初始损伤阶段、损伤稳定发展阶段和损伤加速发展阶段;损伤时空演化过程较好地反映了损伤特性,以1号试样为例:损伤由试样底部开始发展集中,而后中部和上部出现损伤并向底部和顶部稳定发展,随后中部和上部损伤迅速增多并与底部损伤区连通,最终试样发生破坏。研究成果可为相似材料模型损伤演化规律的研究提供一定的参考。

     

    Abstract: In order to study the damage characteristics and space-time evolution law of rock similar material, using the self-developed YYW-Ⅱ strain controlled unconfined compression apparatus and the PCIE-8 acoustic emission (AE) monitoring system, the active procedure of AE events and change of stress and strain of rock similar material sample in the process of uniaxial compression were monitored, the damage model of rock similar material under the condition of uniaxial compression based on accumulative AE events was established, the stages of damage development of rock similar material in the process of uniaxial compression were further analyzed, and the process of space-time evolution of damage of rock similar material under the condition of uniaxial compression was studied.The results show that the AE events activities are roughly experienced three stages of small amount in the period of initial compression, stable growth in the period of elastic deformation, and dramatic growth in the period of plastic deformation and damage; the process of damage can be divided into three stages of initial damage, stable damage and accelerated damage; the process of space-time evolution of damages better reflects the damage characteristics.For instance, in the case of No.1 sample, the damages start to develop and focus at the bottom of the sample in the first place, then damages appear in the middle and upper of the sample and stably extend to the bottom and top of the sample, and then damages rapidly grow in the middle and upper of the sample and connect the damage zone at the bottom of the sample, then the damage of the sample happens eventually.The research result can provide certain reference to the study of damage evolution law of similar material model.

     

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