Macroscopic and microscopic shear mechanical properties of sandstone under CNL and CNS boundary conditions

被引：0

作者：

Yin Q. ^{[1
,2
]}

Jing H. ^{[1
]}

Meng B. ^{[1
]}

Liu R. ^{[1
]}

Wu J. ^{[1
]}

Wu Y. ^{[1
]}

机构：

[1] State Key Laboratory for Geomechanics and Deep Underground Engineering, China University of Mining and Technology, Xuzhou, 221116, Jiangsu

[2] State Key Laboratory of Geohazard Prevention and Geoenvironment Protection, Chengdu University of Technology, Chengdu, 610059, Sichuan

来源：

Jing, Hongwen (hwjing@cumt.edu.cn) | 1600年 / China University of Mining and Technology卷 / 38期

关键词：

Boundary condition; Crack development; Initial normal stress; PFC[!sup]2D[!/sup] particle flow; Shear stress; Shear velocity;

D O I：

10.13545/j.cnki.jmse.2020.0203

中图分类号：

学科分类号：

摘要：

The shear mechanical properties and deformation and fracture mechanisms of rock mass are of great significance tostability control of surrounding rock mass. In this paper, the effects of initial normal stress on peak shear strength, normal stress, dilatancy deformation and acoustic emission response of sandstone were first revealed through macroscopic shear tests of sandstone under constant normal load (CNL) and constant normal stiffness (CNS) conditions, respectively. Then, the microscopic crack growth, particle displacement filed evolution, deformation and fracture process, and the shear rate effects of sandstone were investigated through numerical simulations with PFC2D particle flow. The results have shown that as the initial normal stressincreases, both the peak shear strength and residual shear strength of sandstone increase linearly, and compared with the CNL boundary condition, the peak shear strength increases by 46.57%-307.84%, the cohesive force increases by 85.09%, while the internal friction angle shows a decrease of 10.38% for the CNS boundary condition. The normal displacement generally undergoes the process of shear shrinkage, rapid shear expansion and slow shear expansion, and with crack growth and coalescence to formation of the shear slip surface, the acoustic emission activity is extremely intense. The evolution process of micro cracks and the fracture mechanisms of sandstone under various boundary conditions are significantly different. During the shear process, the total crack number presents the variation characteristics of "calm - rapid increase - decreasing growth rate - tending to be stable", and compared with the CNL boundary condition, the total crack number increases by 19.66%-89.20% under CNS boundary condition. As the shear velocity increases, the peak shear strength of sandstone decreases exponentially, and the shear rate effects are more significant for the CNS boundary condition. © 2021, Editorial Board of Journal of Mining & Safety Engineering. All right reserved.

引用

页码：615 / 624

页数：9

共 21 条

[1] ZHOU Hui, CHENG Guangtan, ZHU Yong, Et al., Experimental study of shear deformation characteristics of marble dentate joints, Rock and Soil Mechanics, 40, 3, pp. 852-860, (2019)
[2] HUANG Jingzhu, FENG Xiating, ZHOU Yangyi, Et al., Analysis of collapse process and mechanism of complex lithologic compressive rupture zone in deep buried hard rock tunnel: a case study ofJinping underground laboratory, Chinese Journal of Rock Mechanics and Engineering, 36, 8, pp. 1867-1879, (2017)
[3] CUI Guojian, ZHANG Chuanqing, HAN Huachao, Et al., Experiment study on shear behavior of artificial joint under CNL and CNS boundary conditions, Chinese Journal of Rock Mechanics and Engineering, 38, pp. 3384-3392, (2019)
[4] XU Jiang, LU Lifeng, YANG Hongwei, Et al., Study of evolution law of microfracturing progress of sandstone under shear loading, Chinese Journal of Rock Mechanics and Engineering, 30, 5, pp. 944-950, (2011)
[5] CHENG Lichao, XU Jiang, FENG Dan, Et al., Quantitative analysis on development of surface cracks of rocks upon shear failure, Chinese Journal of Rock Mechanics and Engineering, 34, 1, pp. 31-39, (2015)
[6] LI Xiaozhao, QI Chengzhi, SHAO Zhushan, Et al., Micromechanics-based model study of shear properties of brittle rocks, Rock and Soil Mechanics, 40, 4, pp. 1358-1367, (2019)
[7] WANG Xiaoqing, KANG Hongpu, GAO Fuqiang, Numerical investigation on the shear behavior of jointed coal mass, Computers and Geotechnics, 106, pp. 274-285, (2019)
[8] MENG Bo, JING Hongwen, YANG Shengqi, Et al., Experimental study on shear behavior of bolted cement mortar blocks under constant normal stiffness, KSCE Journal of Civil Engineering, 23, 8, pp. 3724-3734, (2019)
[9] LI Yingchun, WU Wei, LI Bo, An analytical model for two-order asperity degradation of rock joints under constant normal stiffness conditions, Rock Mechanics & Rock Engineering, 51, pp. 1431-1445, (2018)
[10] HAN Guansheng, JING Hongwen, JIANG Yujing, Et al., Effect of cyclic loading on the shear behaviours of both unfilled and infilled rough rock joints under constant normal stiffness conditions, Rock Mechanics & Rock Engineering, 53, pp. 31-57, (2020)

← 1 2 3 →