An Investigation on the Fabric Type Dependency of the Crack Damage Thresholds in Brittle Rocks
An Investigation on the Fabric Type Dependency of the Crack Damage Thresholds in Brittle Rocks
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DOI：
10.1007/s10706-015-9909-1
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发表时间：
2015-12-01
影响因子：
1.7
通讯作者：
Martin, C. D.
中科院分区：
文献类型：
--
作者：
Ghazvinian, E.;Diederichs, M. S.;Martin, C. D.
脆性岩石中织物引导的微破裂现象及其对裂纹损伤阈值的影响仍有待于继续研究。岩石中的可用组构可以充当成核和/或延伸以及在优选方向上的微裂缝的相互作用的激励器，或者通过不同的机制（诸如矿物及其边界的顺应性（刚度对比）或优选方向）作为在给定方向上的微裂缝生长的抑制器。虽然各向异性的脆性岩石在其机械强度方面可以发挥重要的作用，在地下开口的稳定性，裂纹萌生（CI）和裂纹扩展（CD）阈值的依赖性的理解，在岩石中的可用织物可以提高预测的扩展和密度的微破裂在不同方向的地下开口的墙壁。为了更好地理解组构引导的微破裂现象，也为了研究脆性岩石中可用的组构类型对其各向异性行为的影响，本文研究了具有不同类型组构的四种类型的脆性岩石的裂纹损伤各向异性。本研究选择的岩石是来自科布尔组的石灰石、昆斯顿页岩、Olkiluoto云母片麻岩和邦纳湖花岗岩。对于每种岩石类型，CI和CD阈值确定从无侧限抗压强度测试数据。四种岩石类型的力学行为进行了研究，在每个损伤应力水平和各向同性或各向异性行为的岩石在不同的裂纹损伤阈值的影响因素进行了讨论。
Fabric-guided micro-fracturing phenomenon in brittle rocks and its effect on crack damage thresholds remains subject to continuing research. The available fabric in rocks can act as a motivator for nucleation and/or extension and interaction of micro-fractures in a preferred orientation, or as a suppressor for growth of micro-cracks in a given direction by different mechanisms such as compliance (stiffness contrast) or preferred orientation of minerals and their boundaries. While anisotropy of brittle rocks in terms of their mechanical strengths can play a significant role in the stability of underground openings, the understanding of the dependency of crack initiation (CI) and crack propagation (CD) thresholds on the available fabric in rocks can improve predictions of the extension and density of micro-fracturing in different directions in the walls of underground openings. To better understand the fabric-guided micro-fracturing phenomenon, and also to study the effect of fabric types available in brittle rocks on their anisotropic behaviour, four types of brittle rocks with different types of fabric are investigated in terms of crack damage anisotropy in this paper. The rocks that are chosen for this study are limestone from the Cobourg Formation, Queenston shale, Olkiluoto mica gneiss and Lac du Bonnet granite. For each rock type, CI and CD thresholds are identified from the unconfined compressive strength testing data. The mechanical behaviour of the four rock types are investigated at each damage stress level and the contributing factors to the isotropic or anisotropic behaviour of the rocks at different crack damage thresholds are discussed.