Micromechanics of rock damage and its recovery in cyclic loading conditions
Micromechanics of rock damage and its recovery in cyclic loading conditions
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循环加载条件下岩石损伤的微观力学及其恢复
DOI：
10.1093/gji/ggac447
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发表时间：
2023
影响因子：
2.8
通讯作者：
Brantut N
中科院分区：
文献类型：
--
作者：
Brantut N
在压缩应力下，以拉伸微裂纹形式出现的岩石“损伤”与微观界面（如先前存在的裂纹和晶界）上的内部滑移相耦合。为了表征滑移对整体破坏过程的贡献，我们对westly花岗岩进行了三轴循环加载试验，并监测了体积应变、弹性波速和各向异性。循环加载试验表明，轴向应力-应变行为存在较大的迟滞，这完全可以用滑移来解释。弹性波速变化仅在超过屈服点时观察到，并且在卸载时表现出不完全可逆性的滞后。不可恢复的体积应变、弹性波速下降和各向异性随最大应力的增加而增加，在静水减压期间被放大，在变形周期后静水保持期间随时间呈对数递减。力学数据和弹性特性的变化被用来确定产生拉伸裂缝所需的机械功的比例，当岩石接近破裂时，这一比例会增加，但仍然很小，每个周期的净耗散功约为10%。岩石的破裂前变形行为与机翼裂纹力学性质在质量上是一致的。虽然拉伸裂缝是岩石物理性质发生巨大变化的原因，但它们与显著的能量耗散没有系统的联系，它们的孔径和增长主要受摩擦控制，而摩擦对岩石流变学在脆性状态下起主要控制作用。沿着预先存在的剪切界面的时间相关摩擦解释了拉伸裂缝如何在静态条件下关闭，并随着时间的推移产生弹性波速的恢复。
Under compressive stress, rock ‘damage’ in the form of tensile microcracks is coupled to internal slip on microscopic interfaces, such as pre-existing cracks and grain boundaries. In order to characterize the contribution of slip to the overall damage process, we conduct triaxial cyclic loading experiments on Westerly granite, and monitor volumetric strain and elastic wave velocity and anisotropy. Cyclic loading tests show large hysteresis in axial stress–strain behaviour that can be explained entirely by slip. Elastic wave velocity variations are observed only past a yield point, and show hysteresis with incomplete reversibility upon unloading. Irrecoverable volumetric strain and elastic wave velocity drop and anisotropy increase with increasing maximum stress, are amplified during hydrostatic decompression, and decrease logarithmically with time during hydrostatic hold periods after deformation cycles. The mechanical data and change in elastic properties are used to determine the proportion of mechanical work required to generate tensile cracks, which increases as the rock approaches failure but remains small, up to around 10 per cent of the net dissipated work per cycle. The pre-rupture deformation behaviour of rocks is qualitatively compatible with the mechanics of wing cracks. While tensile cracks are the source of large changes in rock physical properties, they are not systematically associated with significant energy dissipation and their aperture and growth is primarily controlled by friction, which exerts a dominant control on rock rheology in the brittle regime. Time-dependent friction along pre-existing shear interfaces explains how tensile cracks can close under static conditions and produce recovery of elastic wave velocities over time.
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DOI：
10.5860/choice.28-1579
发表时间：
2016
期刊：
--
影响因子：
--
作者：
Leon Bieber
通讯作者：
Leon Bieber
干岩剪胀定量模型及其在西风花岗岩中的应用
影响因子：
--
作者：
D. Holcomb
通讯作者：
D. Holcomb
裂纹面之间的部分接触对其对整体材料柔度和电阻率的贡献的影响
影响因子：
3.6
作者：
A. Trofimov;B. Drach;M. Kachanov;I. Sevostianov
通讯作者：
I. Sevostianov
影响因子：
3.9
作者：
Mitchell, T. M.;Faulkner, D. R.
通讯作者：
Faulkner, D. R.
影响因子：
--
作者：
I. Gupta
通讯作者：
I. Gupta