文献类型：期刊文献

英文题名：Experimental investigation on frictional properties of stressed basalt fractures

作者：Zhong, Zhen[1,2];Xu, Congqiang[1];Wang, Lei[1];Hu, Yunjin[1,2];Zhang, Fengshou[3,4]

机构：[1]Shaoxing Univ, Sch Civil Engn, Shaoxing 312000, Peoples R China;[2]Shaoxing Univ, Key Lab Rock Mech & Geohazards Zhejiang Prov, Shaoxing 312000, Peoples R China;[3]Tongji Univ, Dept Geotech Engn, Coll Civil Engn, Shanghai 200092, Peoples R China;[4]Tongji Univ, Minist Educ, Key Lab Geotech & Underground Engn, Shanghai 200092, Peoples R China

年份：2023

卷号：15

期号：6

起止页码：1457

外文期刊名：JOURNAL OF ROCK MECHANICS AND GEOTECHNICAL ENGINEERING

收录：SCI-EXPANDED(收录号：WOS:001070901300007)、、Scopus(收录号：2-s2.0-85148341299)、WOS

基金：We thank Changrong He and two anonymous reviewers for their thorough reviews and constructive comments. This work was funded by National Natural Science Foundation of China (Grant Nos. 51509154 and 42077247), and Natural Science Foundation of Zhejiang Province (Grant No. LGJ20E090001). All of the supports are gratefully acknowledged.

语种：英文

外文关键词：Rock friction; Basalt fracture; Gouge; Velocity-strengthening behavior; Frictional healing

外文摘要：The frictional strength and sliding stability of faults are crucial in interpreting earthquake mechanisms and cycles. Herein, we report friction experiments on basalt fractures, using a self-designed triaxial apparatus that allows direct shear of samples under coupled hydro-mechanical conditions. Velocity-stepping (VS) and slide-hold-slide (SHS) experiments are performed on both bare and gouge-bearing surfaces of Xiashan basalt subjected to cyclic shear velocities at 1-30 mm/s, effective normal stresses of 1-5 MPa, and pore pressures of 70-300 kPa. The measured basalt friction coefficients are in the range of 0.67-0.74, which is sensitive to gouge thickness, normal stress, and water. Specifically, a reduction in friction coefficient is observed with an increment in gouge thickness, normal stress, and pore pressure. Based on the microscopic observation of the pre- and post-shearing sliding surfaces, this weakening effect in friction coefficient can be attributed to powder lubrication. Furthermore, the VS test results reveal predominantly velocity-strengthening behavior at investigated slip velocities, and this velocity strengthening behavior does not appear to be influenced by variations in normal stress, gouge thickness, and water. However, changes in sliding velocity and normal stress can lead to a shift between stable and unstable sliding. Specifically, stable sliding is favored by high sliding velocities and low normal stress applied in this study. Finally, we analyze the experimental data by calculating the rate-and-state parameters using the rate- and state-dependent friction (RSF) theory. Importantly, the calculated friction rate parameter (a-b) supports the velocity-strengthening behavior. Both frictional relaxation (Dmc) during hold periods and frictional healing (Delta mu) upon re-shearing are linearly proportional to the logarithmic hold time, which may be attributed to the growth in true contact area with hold time. This study sheds light on the roles of sliding velocity, and gouge thickness in controlling frictional strength and stability of basalt fractures. (C) 2023 Institute of Rock and Soil Mechanics, Chinese Academy of Sciences. Production and hosting by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).