Shear mechanical properties and fracturing responses of layered rough jointed rock-like materials  

作　　者：Xinxin Nie Qian Yin Manchao He Qi Wang Hongwen Jing Bowen Zheng Bo Meng Tianci Deng Zheng Jiang Jiangyu Wu 

机构地区：[1]State Key Laboratory for Geomechanics&Deep Underground Engineering,China University of Mining and Technology,Xuzhou 221116,China [2]State Key Laboratory for Geomechanics&Deep Underground Engineering,China University of Mining and Technology(Beijing),Beijing 100083,China [3]Key Laboratory of Shale Gas and Geoengineering,Institute of Geology and Geophysics,Chinese Academy of Sciences,Beijing 100029,China [4]Department of Materials,University of Oxford,Oxford OX13PH,UK

出　　处：《International Journal of Minerals,Metallurgy and Materials》2024年第11期2417-2434,共18页矿物冶金与材料学报（英文版）

基　　金：financial support from the National Natural Science Foundation of China(Nos.52174092,51904290,52004272,52104125,42372328,and U23B2091);Natural Science Foundation of Jiangsu Province,China(Nos.BK20220157 and BK20240209);the Fundamental Research Funds for the Central Universities,China(No.2022YCPY0202);Xuzhou Science and Technology Project,China(Nos.KC21033 and KC22005);Yunlong Lake Laboratory of Deep Underground Science and Engineering Project,China(No.104023002);the Graduate Innovation Program of China University of Mining and Technology(No.2023WLTCRCZL052)。

摘　　要：This study aims to investigate mechanical properties and failure mechanisms of layered rock with rough joint surfaces under direct shear loading.Cubic layered samples with dimensions of 100 mm×100 mm×100 mm were casted using rock-like materials,with anisotropic angle(α)and joint roughness coefficient(JRC)ranging from 15°to 75°and 2-20,respectively.The direct shear tests were conducted under the application of initial normal stress(σ_(n)) ranging from 1-4 MPa.The test results indicate significant differences in mechanical properties,acoustic emission(AE)responses,maximum principal strain fields,and ultimate failure modes of layered samples under different test conditions.The peak stress increases with the increasingαand achieves a maximum value atα=60°or 75°.As σ_(n) increases,the peak stress shows an increasing trend,with correlation coefficients R² ranging from 0.918 to 0.995 for the linear least squares fitting.As JRC increases from 2-4 to 18-20,the cohesion increases by 86.32%whenα=15°,while the cohesion decreases by 27.93%whenα=75°.The differences in roughness characteristics of shear failure surface induced byαresult in anisotropic post-peak AE responses,which is characterized by active AE signals whenαis small and quiet AE signals for a largeα.For a given JRC=6-8 andσ_(n)=1 MPa,asαincreases,the accumulative AE counts increase by 224.31%(αincreased from 15°to 60°),and then decrease by 14.68%(αincreased from 60°to 75°).The shear failure surface is formed along the weak interlayer whenα=15°and penetrates the layered matrix whenα=60°.Whenα=15°,as σ_(n) increases,the adjacent weak interlayer induces a change in the direction of tensile cracks propagation,resulting in a stepped pattern of cracks distribution.The increase in JRC intensifies roughness characteristics of shear failure surface for a smallα,however,it is not pronounced for a largeα.The findings will contribute to a better understanding of the mechanical responses and failure mechanisms of the layered rocks subjected

关 键 词：layered samples anisotropic angle joint roughness coefficient mechanical properties acoustic emission response fracturing evolution failure modes 

分 类 号：TD315[矿业工程—矿井建设]