Abstract Shear induced asperity degradation and gouge formation significantly affect the mechanical and fluid flow behaviors of single rough fractures, but the asperity damage process during shear has not been entirely understood and requires further investigation. In this study, direct shear tests were performed on the artificial and natural fractured granite specimens, respectively. The evolution of asperity damage during shear was monitored using acoustic emission (AE) technique, and the asperity degradation zones and damage volumes caused by shear were evaluated with the 3D blue light scanner. The correlation between the asperity damage volume and AE energy was examined. The results show that there is a strong correlation between shear stress and cumulative AE energy in both artificial and natural fractures. AE events are scattered in the pre-peak stage but are localized around the fracture surface in the post-peak stage. The shear induced asperity damage is represented well by the clusters of AE events with large amounts of energy, which initially occur after the shear entering the post-peak stage. Their distribution conforms to the destruction locations of surface asperities. The proposed new method of calculating AE b-values based AE energy is more suitable to predict the surface damage characteristics in the artificial and natural granite fractures. The consistency between AE energy and shear induced damage volume of asperities is found when the detection area increases up to a certain larger range of about 25 mm.

中文翻译：

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单条花岗岩裂隙剪切诱导粗糙度与声发射能量的相关性

摘要 剪切引起的粗糙退化和泥浆形成显着影响单个粗糙裂缝的力学和流体流动行为，但剪切过程中的粗糙破坏过程尚未完全了解，需要进一步研究。在这项研究中，分别对人造和天然断裂花岗岩试样进行了直剪试验。使用声发射 (AE) 技术监测剪切过程中粗糙损伤的演变，并使用 3D 蓝光扫描仪评估剪切引起的粗糙退化区域和损伤体积。检查了粗糙损伤体积和 AE 能量之间的相关性。结果表明，在人工裂缝和天然裂缝中，剪应力与累积声发射能量之间存在很强的相关性。AE 事件分散在峰前阶段，但在峰后阶段集中在断裂表面周围。剪切引起的粗糙损伤由具有大量能量的 AE 事件簇很好地表示，这些事件最初发生在剪切进入峰值后阶段之后。它们的分布符合表面凹凸不平的破坏位置。提出的基于AE能量计算AE b值的新方法更适合预测人工和天然花岗岩裂缝中的表面损伤特征。当检测区域增加到大约 25 mm 的某个较大范围时，发现 AE 能量与粗糙的剪切诱导损伤体积之间存在一致性。剪切引起的粗糙损伤由具有大量能量的 AE 事件簇很好地表示，这些事件最初发生在剪切进入峰值后阶段之后。它们的分布符合表面凹凸的破坏位置。提出的基于AE能量计算AE b值的新方法更适合预测人工和天然花岗岩裂缝中的表面损伤特征。当检测区域增加到约 25 mm 的某个较大范围时，发现 AE 能量与粗糙的剪切诱导损伤体积之间存在一致性。剪切引起的粗糙损伤由具有大量能量的 AE 事件簇很好地表示，这些事件最初发生在剪切进入峰值后阶段之后。它们的分布符合表面凹凸不平的破坏位置。提出的基于AE能量计算AE b值的新方法更适合预测人工和天然花岗岩裂缝中的表面损伤特征。当检测区域增加到大约 25 mm 的某个较大范围时，发现 AE 能量与粗糙的剪切诱导损伤体积之间存在一致性。提出的基于AE能量计算AE b值的新方法更适合预测人工和天然花岗岩裂缝中的表面损伤特征。当检测区域增加到大约 25 mm 的某个较大范围时，发现 AE 能量与粗糙的剪切诱导损伤体积之间存在一致性。提出的基于AE能量计算AE b值的新方法更适合预测人工和天然花岗岩裂缝中的表面损伤特征。当检测区域增加到大约 25 mm 的某个较大范围时，发现 AE 能量与粗糙的剪切诱导损伤体积之间存在一致性。