文献类型：期刊文献

英文题名：Three-dimensional discrete element simulation on mechanical response and failure characteristics of composite rock under triaxial unloading condition

作者：Yang, Sheng-Qi[1];Song, Yu[2];Du, Shi-Gui[3];Yong, Rui[3];Wang, Su-Sheng[1];Hu, Yun-Jin[1];Zhao, Jiang[4]

机构：[1]Shaoxing Univ, Key Lab Rock Mech & Geohazards Zhejiang Prov, Shaoxing 312000, Peoples R China;[2]China Univ Min & Technol, State Key Lab Intelligent Construction & Hlth Oper, Xuzhou 221116, Peoples R China;[3]Ningbo Univ, Inst Rock Mech, Ningbo 315211, Peoples R China;[4]China Univ Min & Technol, Sch Mech & Civil Engn, Xuzhou 221116, Peoples R China

年份：2024

卷号：176

外文期刊名：COMPUTERS AND GEOTECHNICS

收录：SCI-EXPANDED(收录号：WOS:001312253600001)、、EI(收录号：20243717017857)、Scopus(收录号：2-s2.0-85203266166)、WOS

语种：英文

外文关键词：Composite rock; Discrete element method; Unloading confining pressure; Unloading rate; Mechanism of crack evolution; Moment tensor analysis

外文摘要：The significance of various unloading conditions on the strength and deformation characteristics of transverse isotropic rocks cannot be overstated. In this paper, we utilized a discrete element numerical method to simulate unloading pressures on composite rocks featuring laminated dips of 0 degrees, 30 degrees, 45 degrees, 60 degrees, and 90 degrees. We analyzed the effects of various initial confining pressures, degrees of initial damage, and unloading rates on the strength and deformation of these composite rocks. Real-time acoustic emission event monitoring was conducted on the composite rocks, and we investigated the internal damage deterioration mechanism under different unloading conditions based on the moment tensor theory. The findings indicated that the peak strength of all dipping composite rocks exhibited a positive correlation with the initial envelope pressure and a negative correlation with the unloading rate. Moreover, the strains including axial, lateral and volumetric demonstrated an increase with initial confining pressure and initial damage, while they decreased with the unloading rate. The final damage of the composite rock, quantified by the number of cracks, displayed a positive correlation with the initial confining pressure and initial damage, and a negative correlation with the unloading rate. Analysis of the moment tensor of acoustic emission events for each isotropy/deviation ratio revealed that the number of acoustic emission events associated with compression-dominated failure increased proportionally with increasing confining pressure, while the number of acoustic radiation events linked with tensile damage decreased. Furthermore, with the increase in the unloading rate, shear-dominated acoustic emission events escalated while compression-dominated acoustic radiation events decreased.