Macro and micro characteristics of jointed sandstone under cyclic loading and unloading
WANG Ruihong1，2，WEI Can2，LIU Jie1，2，LI Zhao2，TAN Yihong2
(1. Key Laboratory of Geological Hazards on Three Gorges Reservoir Area，Ministry of Education，China Three Gorges University，Yichang，Hubei 443002，China；2. College of Civil Engineering and Architecture，China Three Gorges University，Yichang，Hubei 443002，China)
Abstract：To study the macro and micro mechanical characteristics and failure mechanism of cumulative damage of jointed rock mass under fatigue loading，cyclic loading and unloading tests of jointed sandstone with different upper stress ratios were carried out. The experimental results show that：(1) With the increase of the upper limit stress ratio，the hysteretic cycle spacing of jointed sandstone changes from two-phase sparse-dense to three-phase sparse-dense-sparse. (2) When the upper limit stress ratio is less than 0.90，the uniaxial compressive strength of jointed sandstone increases to different degrees after cyclic loading and unloading，and the value increases first and then decreases with the increase of the upper limit stress ratio. When the upper limit stress ratio is 0.80，the uniaxial compressive strength reaches the maximum. When the upper limit stress ratio is greater than or equal to 0.90，the failure of jointed sandstone occurs during the cycle，and the fatigue times decrease with the rise of the upper limit stress ratio. (3) The fatigue times of sandstone with different inclination angles follow the principle of 90°＞60°＞0°＞45°. Through comparative analysis of failure modes of jointed sandstone after cyclic loading and unloading，the main effect of different upper limit stress ratios mainly affect is the failure degree of samples，the higher the upper limit stress ratio，the greater the degree of fracture，while the primary effect of joint dip angle mainly affects the failure mode of the samples. The shear failure is the main failure mode of the 60°and 45°jointed sandstone samples，with the tensile failure of the 90° and 0° jointed sandstone samples as the main failure mode. (4) After using nuclear magnetic resonance(NMR) and scanning electron microscope(SEM) to test cycle and unloading joint sandstone porosity change after fatigue damage and mesoscopic structure characteristic，it is found the sample fatigue damage can be divided into three stages，slow fatigue-stability-accelerated fatigue，characterized by gap pressure filling-crushing-matrix mineral crushing clay minerals content.
[1] 张吟钗. 水库地震和水–岩作用对库岸边坡动力响应特征的影响研究[硕士学位论文][D]. 宜昌：三峡大学，2019.(ZHANG Yinchai. Study on dynamic response characteristics of reservoir bank slope under the influence of reservoir earthquake and water-rock interaction[M. S. Thesis][D]. Yichang：China Three Gorges University，2019.(in Chinese))
[2] 罗 钧. 水库区库仑应力变化及地震活动机制研究[J]. 国际地震动态，2018，(2)：43–44.(LUO Jun. Study on coulomb stress change and seismic activity mechanism in reservoir area[J]. International Seismic Dynamics，2018，(2)：43–44.(in Chinese))
[3] 孙广忠. 岩体结构力学[M]. 北京：科学出版社，1988：217–218. (SUN Guangzhong. Rock mass structural mechanics[M]. Beijing：Science Press，1988：217–218.(in Chinese))
[4] 张 波，李术才，杨学英，等. 含交叉多裂隙类岩石材料单轴压缩力学性能研究[J]. 岩石力学与工程学，2015，34(9)：55–63.(ZHANG Bo，LI Shucai，YANG Xueying，et al. Mechanical property of rock-like material with intersecting multi-flaws under uniaxial compression[J]. Chinese Journal of Rock Mechanics and engineering，2015，34(9)：55–63.(in Chinese))
[5] 柯 炜. 循环动载作用下砂岩疲劳损伤特性及边坡稳定性动力影响因素研究[硕士学位论文][D]. 重庆：重庆大学，2018.(KE Wei. Study on the fatigue damage characteristics of sandstone under cyclic dynamic loading and dynamic influence factors of slope stability[M. S. Thesis][D]. Chongqing：Chongqing University，2018.(in Chinese))
[6] 杨小彬，程虹铭，裴艳宇，等. 不同加载方式下岩石变形及峰后能量演化特征研究[J]. 岩石力学与工程学报，2020，39(增2)：3 229–3 236.(YANG Xiaobin，CHENG Hongming，PEI Yanyu，et al. Study on the evolution characteristics of rock deformation and post-peak energy under different loading methods[J]. Chinese Journal of Rock Mechanics and Engineering，2020，39(Supp.2)：3 229–3 236.(in Chinese))
[7] 俞 缙，刘泽瀚，林立华，等. 变幅循环加卸载作用下大理岩扩容特性试验研究[J]. 岩土力学，2021，42(11)：1–9.(YU Jin，LIU Zehan，LIN Lihua，et al. Characteristics of dilatancy of marble under variable amplitude cyclic loading and unloading[J]. Rock and Soil Mechanics，2021，42(11)：1–9.(in Chinese))
[8] 赵 军，郭广涛，徐鼎平，等. 三轴及循环加卸载应力路径下深埋硬岩变形破坏特征试验研究[J]. 岩土力学，2020，41(5)：1 521– 1 530.(ZHAO Jun，GUO Guangtao，XU Dingping，et al. Experimental study of deformation and failure characteristics of deeply-buried hard rock under triaxial and cyclic loading and unloading stress paths[J]. Rock and Soil Mechanics，2020，41(5)：1 521–1 530.(in Chinese))
[9] MENG Q B，LIU J F，REN L，et al. Experimental study on rock strength and deformation characteristics under triaxial cyclic loading and unloading conditions[J]. Rock Mechanics and Rock Engineering，2021，54(2)：777–797.
[10] 徐 颖，李成杰，郑强强，等. 循环加卸载下泥岩能量演化与损伤特性分析[J]. 岩石力学与工程学报，2019，38(10)：2 084–2 091.(XU Ying，LI Chengjie，ZHENG Qiangqiang，et al. Analysis of energy evolution and damage characteristics of mudstone under cyclic loading and unloading[J]. Chinese Journal of Rock Mechanics and engineering， 2019，38(10)：2 084–2 091.(in Chinese))
[11] 苗胜军，刘泽京，赵星光，等. 循环加卸载下北山花岗岩能量耗散与损伤特征[J]. 岩石力学与工程学报，2021，40(5)：928–938.(MIAO Shengjun，LIU Zejing，ZHAO Xingguang，et al. Energy dissipation and damage characteristics of Beishan granite under cyclic loading and unloading[J]. Chinese Journal of Rock Mechanics and engineering，2021，40(5)：928–938.(in Chinese))
[12] 李欣慰，姚直书，黄献文，等. 循环加卸载下砂岩变形破坏特征与能量演化研究[J]. 岩土力学，2021，42(6)：1 693–1 704.(LI Xinwei，YAO Zhishu，HUANG Xianwen，et al. Investigation of deformation and failure characteristics and energy evolution of sandstone under cyclic loading and unloading[J]. Rock and Soil Mechanics，2021，42(6)：1 693–1 704.(in Chinese))
[13] 蔡燕燕，唐 欣，林立华，等. 疲劳荷载下大理岩累积损伤过程的应变速率响应[J]. 岩土工程学报，2020，42(5)：827–836.(CAI Yanyan，TANG Xin，LIN Lihua，et al. Strain rate response of damage accumulation of marble under fatigue loading[J]. Chinese Journal of Geotechnical Engineering，2020，42(5)：827–836.(in Chinese))
[14] 张慧梅，陈 敏，孟祥振，等. 不同倾角节理岩体损伤模型及力学特性[J]. 哈尔滨工程大学学报，2022，43(6)：801–808.(ZHANG Huimei，CHEN Min，MENG Xiangzhen，et al. Damage model and mechanical characteristics of jointed rock mass with different joint dip angles[J]. Journal of Harbin Engineering University，2022，43(6)：801–808.(in Chinese))
[15] 邓华锋，齐 豫，李建林，等. 水–岩作用下断续节理砂岩力学特性劣化机制[J]. 岩土工程学报，2021，43(4)：634–643.(DENG Huafeng，QI Yu，LI Jianlin，et al. Degradation mechanism of intermittent jointed sandstone under water-rock interaction[J]. Chinese Journal of Geotechnical Engineering，2021，43(4)：634–643.(in Chinese))
[16] 潘 博，汪旭光，徐振洋，等. 节理角度对岩石材料的动态响应影响研究[J]. 岩石力学与工程学报，2021，40(3)：566–575.(PAN Bo，WANG Xuguang，XU Zhenyang，et al. Research on the effect of joint angle on dynamic responses of rock materials[J]. Chinese Journal of Rock Mechanics and Engineering，2021，40(3)：566–575.(in Chinese))
[17] 包 含，裴润生，兰恒星，等. 基于循环加卸载的矿物定向排列致各向异性岩石损伤演化规律——以黑云母石英片岩为例[J]. 岩石力学与工程学报，2021，40(10)：2 015–2 026.(BAO Han，PEI Runsheng，LAN Hengxing，et al. Damage evolution of Biotite quartz schist caused by mineral directional arrangement under cyclic loading and unloading[J]. Chinese Journal of Rock Mechanics and engineering，2021，40(10)：2 015–2 026.(in Chinese))
[18] LIU Y，DAI F，DONG L，et al. Experimental investigation on the fatigue mechanical properties of intermittently jointed rock models under cyclic uniaxial compression with different loading parameters[J]. Rock Mechanics and Rock Engineering，2018，51(1)：47–68.
[19] 宋勇军，张磊涛，任建喜，等. 基于核磁共振技术的弱胶结砂岩干湿循环损伤特性研究[J]. 岩石力学与工程学报，2019，38(4)：825–831.(SONG Yongjun，ZHANG Leitao，REN Jianxi，et al. Study on damage characteristics of weak cementation sandstone under drying-wetting cycles based on nuclear magnetic resonance technique[J]. Chinese Journal of Rock Mechanics and engineering，2019，38(4)：825–831.(in Chinese))
[20] 张 强，王军保，宋战平，等. 循环荷载作用下盐岩微观结构变化及经验疲劳模型[J]. 岩土力学，2022，43(4)：995–1 008.(ZHANG Qiang，WANG Junbao，SONG Zhanping，et al. Microstructure variation and empirical fatigue model of salt rock under cyclic loading[J]. Rock and Soil Mechanics，2022，43(4)：995–1 008.(in Chinese))
[21] NING Z，XUE Y，LI Z，et al. Damage characteristics of granite under hydraulic and cyclic loading–unloading coupling condition[J]. Rock Mechanics and Rock Engineering，2022，55(3)：1 393–1 410.
[22] 苗胜军，王 辉，黄正均，等. 不同循环上限荷载下泥质石英粉砂岩力学特性试验研究[J]. 工程力学，2021，38(7)：75–85.(MIAO Shengjun，WANG Hui，HUANG Zhengjun，et al. Experimental study on mechanical properties of argillaceous quartz siltstone under different upper limit cyclic loading[J]. Engineering Mechanics，2021，38(7)：75–85.(in Chinese))
[23] 苗胜军，王 辉，杨鹏锦，等. 近疲劳强度循环加卸载对泥质石英粉砂岩力学特性影响研究[J]. 岩土力学，2021，42(8)：2 109– 2 119.(MIAO Shengjun，WANG Hui，YANG Pengjin，et al. Effect of cyclic loading near fatigue strength on mechanical properties of argillaceous quartz siltstone[J]. Rock and Soil Mechanics，2021，42(8)：2 109–2 119.(in Chinese))
[24] 席道瑛，刘小燕，张程远，等. 由宏观滞回曲线分析岩石的微细观损伤[J]. 岩石力学与工程学报，2003，22(2)：182–187.(XI Daoying，LIU Xiaoyan，ZHANG Chengyuan，et al. Analysis of microscopic damage of rock by macroscopic hysteresis curve[J]. Chinese Journal of Rock Mechanics and engineering，2003，22(2)：182–187.(in Chinese))
[25] 席道瑛，刘小燕，张程远，等. 应力控制疲劳载荷作用下循环硬化的应变响应[J]. 岩石力学与工程学报，2003，22(11)：1 807– 1 810.(XI Daoying，LIU Xiaoyan，ZHANG Chengyuan，et al. Strain response of cyclic hardening under fatigue loading on saturated rock[J]. Chinese Journal of Rock Mechanics and engineering，2003，22(11)：1 807–1 810.(in Chinese))
[26] 葛修润，蒋 宇，卢允德，等. 周期荷载作用下岩石疲劳变形特性试验研究[J]. 岩石力学与工程学报，2003，32(10)：1 581–1 585.(GE Xiurun，JIANG Yu，LU Yunde，et al. Experimental study on fatigue deformation characteristics of rock under cyclic loading[J]. Chinese Journal of Rock Mechanics and Engineering，2003，32(10)：1 581–1 585.(in Chinese))
2023, Vol. 42 
