Shear sliding of rough-walled fracture surfaces under unloading normal stress
作者机构：State Key Laboratory for Geomechanics and Deep Underground EngineeringChina University of Mining and TechnologyXuzhou221116China School of Earth Sciences and EngineeringHohai UniversityNanjing210098China State Key Laboratory of Geohazard Prevention and Geoenvironment ProtectionChengdu University of TechnologyChengdu610059China State Key Laboratory for Geomechanics and Deep Underground EngineeringChina University of Mining and Technology(Beijing)Beijing100083China College of Civil EngineeringFuzhou UniversityFuzhou350108China
出 版 物：《Journal of Rock Mechanics and Geotechnical Engineering》 (岩石力学与岩土工程学报（英文版）)
年 卷 期：2023年第15卷第10期
页 面：2658-2675页
核心收录：
学科分类：08[工学] 080104[工学-工程力学] 0815[工学-水利工程] 0801[工学-力学（可授工学、理学学位）]
基 金：support from the National Natural Science Foundation of China(Grant Nos.52174092 and 52104125) the Fundamental Research Funds for the Central Universities,China(Grant No.2022YCPY0202)is gratefully acknowledged
主 题：Unloading normal stress Rough fracture surface Shear sliding Normal displacement Shear wear characteristics
摘 要：Through high-precision engraving,self-affine sandstone joint surfaces with various joint roughness coefficients(JRC=3.21e12.16)were replicated and the shear sliding tests under unloading normal stress were conducted regarding various initial normal stresses(1e7 MPa)and numbers of shearing cycles(1 e5).The peak shear stress of fractures decreased with shear cycles due to progressively smooth surface morphologies,while increased with both JRC and initial normal stress and could be verified using the nonlinear Barton-Bandis failure *** joint friction angle of fractures exponentially increased by 62.22%e64.87%with JRC while decreased by 22.1%e24.85%with shearing *** unloading normal stress,the sliding initiation time of fractures increased with both JRC and initial normal stress due to more tortuous fracture morphologies and enhanced shearing resistance *** surface resistance index(SRI)of fractures decreased by 4.35%e32.02%with increasing shearing cycles due to a more significant reduction of sliding initiation shear stress than that for sliding initiation normal stress,but increased by a factor of 0.41e1.64 with *** sliding initiation,the shear displacement of fractures showed an increase in power *** defining a sliding rate threshold of 5105 m/s,transition from“quasi-staticto“dynamicsliding of fractures was identified,and the increase of sliding acceleration steepened with JRC while slowed down with shearing *** normal displacement experienced a slight increase before shear sliding due to deformation recovery as the unloading stress was unloaded,and then enhanced shear dilation after sliding initiation due to climbing effects of surface *** was positively related to the shear sliding velocity of *** characteristics of the fracture surfaces after shearing failure were evaluated using binary calculation,indicating an increasing shear area ratio by 45.24%e91.02%with normal stress.
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