Creep and time-dependent damage in argillaceous rocks
Creep and time-dependent damage in argillaceous rocks
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DOI：
10.1016/j.ijrmms.2006.02.004
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发表时间：
2006-09-01
影响因子：
7.2
通讯作者：
Pellet, Frederic
中科院分区：
文献类型：
--
作者：
Fabre, Geraldine;Pellet, Frederic
本文介绍了对三种粘土颗粒含量高的岩石的时变行为进行实验室测试的结果。在单轴压缩的不同加载条件下研究了这些沉积岩的粘性：对结构面的不同方向进行了静态或循环蠕变试验以及准静态试验（低加载应变速率）。准静态试验表明这三种泥质岩的力学响应具有相似性：在不稳定裂纹扩展开始之前有一个后期的扩容阶段以及体积变形的线性发展。蠕变试验过程中二次和三次蠕变阶段的发展凸显了偏应力阈值的存在，低于该阈值时仅观察到一次蠕变。长期蠕变试验还表明，在粘塑性变形发展过程中体积变化不是恒定的。对试验后从试件上提取的薄片进行的微观结构分析，证明了碎裂蠕变和颗粒蠕变的存在。泥质基质发生损伤，在石英和碳酸盐颗粒中未观察到裂纹。在高应变速率加载的试验中也证明了这一点。最后，本研究强调了泥质岩显著的粘塑性。当裂纹扩展变得不稳定时，力学性能迅速恶化，粘塑性应变似乎是由于粘土颗粒滑移，即颗粒蠕变所致。（c）2006爱思唯尔有限公司。保留所有权利。
This paper presents the results of laboratory tests on the time-dependent behaviour of three rocks characterized by a high proportion of clay particles. The viscosity of these sedimentary rocks was studied under different loading conditions in uniaxial compression: static or cyclic creep tests and quasistatic tests (low-loading strain rate) were performed across various orientations of fabric planes.The quasistatic tests showed similarities in the mechanical response of these three argillaceous rocks: a late phase of dilation and a linear development of volumetric deformation before the beginning of unstable crack propagation. The development of secondary and tertiary creep phases during the creep tests highlighted the existence of a deviatoric stress threshold, below which only primary creep is observed. Long-term creep tests also showed that the volumetric variation is not constant during the development of viscoplastic deformations.A microstructural analysis of thin sections extracted from specimens after the tests, gave evidence of cataclastic and granular creep. Damage to the argillaceous matrix occurs and no cracks were observed in the quartz and carbonate grains. This evidence was also demonstrated for tests with loading at a high strain rate.Finally, this study highlights the significant viscoplasticity of argillaceous rocks. The mechanical properties deteriorate rapidly when crack propagation becomes unstable and the viscoplastic strains seem to be due to clay particle slips, known as granular creep. (c) 2006 Elsevier Ltd. All rights reserved.