{"title":"Comminution-Induced Transient Frictional Behavior in Sheared Granular Halite","authors":"Chengrui Chang, Hiroyuki Noda, Yohei Hamada, Chao Huang, Tao Ma, Gonghui Wang, Tetsuo Yamaguchi","doi":"10.1029/2024GL109645","DOIUrl":null,"url":null,"abstract":"<p>Grain comminution is commonly observed in numerous geological settings. To elucidate the role of grain comminution in dry granular friction, we sheared breakable halite (NaCl) grains using a ring-shear configuration at a constant slip rate under various normal stresses. We observed transient frictional behaviors: a constant regime exhibiting a high friction coefficient at small slip displacements, and a weakening regime showing a substantial decay in friction at large slip displacements. The characteristic slip lengths for both regimes decreased with normal stress and were characterized by similar exponents. Micro-X-ray tomography revealed the evolution of microstructure from distributed grain comminution to progressive shear localization for these two regimes. We propose that the filling processes of comminuted fine particles, during which fine particles saturate and then overflow the shear zone, define transient frictional behaviors. This study may hold significant implications for natural shear systems, given the ubiquity of comminution and localization phenomena.</p>","PeriodicalId":12523,"journal":{"name":"Geophysical Research Letters","volume":null,"pages":null},"PeriodicalIF":4.6000,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024GL109645","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Geophysical Research Letters","FirstCategoryId":"89","ListUrlMain":"https://onlinelibrary.wiley.com/doi/10.1029/2024GL109645","RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"GEOSCIENCES, MULTIDISCIPLINARY","Score":null,"Total":0}
引用次数: 0
Abstract
Grain comminution is commonly observed in numerous geological settings. To elucidate the role of grain comminution in dry granular friction, we sheared breakable halite (NaCl) grains using a ring-shear configuration at a constant slip rate under various normal stresses. We observed transient frictional behaviors: a constant regime exhibiting a high friction coefficient at small slip displacements, and a weakening regime showing a substantial decay in friction at large slip displacements. The characteristic slip lengths for both regimes decreased with normal stress and were characterized by similar exponents. Micro-X-ray tomography revealed the evolution of microstructure from distributed grain comminution to progressive shear localization for these two regimes. We propose that the filling processes of comminuted fine particles, during which fine particles saturate and then overflow the shear zone, define transient frictional behaviors. This study may hold significant implications for natural shear systems, given the ubiquity of comminution and localization phenomena.
在许多地质环境中都能观察到晶粒粉碎现象。为了阐明晶粒粉碎在干粒状摩擦中的作用，我们在各种法向应力的作用下，以恒定的滑移率对可破碎的海泡石（氯化钠）晶粒进行了环形剪切。我们观察到了瞬态摩擦行为：在小滑移位移时，恒定机制表现为高摩擦系数；在大滑移位移时，削弱机制表现为摩擦力大幅衰减。两种状态下的特征滑移长度都随法向应力的增加而减小，并具有相似的指数。显微 X 射线层析技术揭示了这两种状态下微观结构从分布式晶粒粉碎到渐进式剪切局部化的演变过程。我们认为，粉碎细颗粒的填充过程，即细颗粒饱和后溢出剪切区的过程，决定了瞬态摩擦行为。鉴于粉碎和局部化现象无处不在，这项研究可能对自然剪切系统具有重要意义。
期刊介绍：
Geophysical Research Letters (GRL) publishes high-impact, innovative, and timely research on major scientific advances in all the major geoscience disciplines. Papers are communications-length articles and should have broad and immediate implications in their discipline or across the geosciences. GRLmaintains the fastest turn-around of all high-impact publications in the geosciences and works closely with authors to ensure broad visibility of top papers.
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