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| True triaxial shear mechanical response and fracture surface evolution of granite under constant normal stiffness boundary |
| HU Liang1, 2, ZHAO Jun1, 2*, GUO Yue1, 2 |
| (1. National Key Laboratory of Intelligent Mining and Equipment for Deep Metal Mines, Northeastern University, Shenyang, Liaoning 110819, China; 2. Liaoning Provincial Key Laboratory of Deep Engineering and Intelligent Technology, Northeastern University, Shenyang, Liaoning 110819, China) |
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Abstract In deep true triaxial stress environments, the interaction between rock masses and support structures is intricate. Traditional constant normal load (CNL) tests, which neglect the effect of support stiffness, face challenges in characterizing the stress evolution paths and the genuine shear response governed by rock-support coupling. This study systematically compares the influence of constant normal stress (CNS) and CNL boundaries on the mechanical response of granite through true triaxial shear tests. The research focuses on analyzing the effects of varying lateral stresses (0–50 MPa) and normal stiffnesses (0–70 GPa/m) on true triaxial shear deformation, shear strength, shear failure modes, fracture surface morphology, and energy dissipation characteristics during shear fracture and friction sliding. The experimental results indicate that lateral stress primarily constrains lateral deformation, while its enhancement of normal deformation is an indirect effect. The CNS boundary effectively suppresses the normal dilatancy of granite. Under CNL conditions, increasing lateral stress exhibits a negative correlation with the rate of peak shear strength enhancement; specifically, the strength enhancement rate was 41.9% when lateral stress increased from 0 MPa to 10 MPa, but decreased to 11.36% when lateral stress further increased from 10 MPa to 50 MPa. The CNS boundary condition continuously suppresses normal dilation and enhances both peak and residual shear strength, with a maximum increase of 52.17%. Furthermore, under CNL conditions, lateral stress tends to induce feather-like secondary wing cracks and step-like fracture surfaces. Conversely, the coupling of dynamic normal stress and lateral confinement under the CNS boundary alters the energy dissipation mechanisms during fracture and friction sliding, resulting in a relatively smoother fracture surface morphology. This demonstrates the significant influence of boundary conditions on the failure mode. The study concludes that considering the CNS boundary provides a more realistic representation of the mechanical response of deep rock masses, offering crucial theoretical insights for support design and stability control.
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[1] YANG J P，CHEN W Z，ZHOU W S，et al. Geohazards of tunnel excavation in terbedded layers under high in situ stress[J]. Engineering Geology，2017，230：11–22.
[2] 谢和平. “深部岩体力学与开采理论”研究构想与预期成果展望[J].工程科学与技术，2017，49(2)：1–16.(XIE Heping. Research framework and anticipated results of deep rock mechanics and mining theory[J]. Advanced Engineering Sciences，2017，49(2)：1–16.(in Chinese))
[3] 佘诗刚，林 鹏. 中国岩石工程若干进展与挑战[J]. 岩石力学与工程学报，2014，33(3)：433–457.(SHE Sigang，LIN Peng. Some advances and challenges in rock engineering in China[J]. Chinese Journal of Rock Mechanics and Engineering，2014，33(3)：433–457. (in Chinese))
[4] 韩观胜. 恒法向刚度条件下岩石多节理结构剪切力学特性研究[博士学位论文][D]. 徐州：中国矿业大学，2019.(HAN Guansheng. Study on shear mechanical Behaviours of multi-joint structure of rock under constant normal stiffness conditions[Ph. D. Thesis][D]. Xuzhou：China University of Mining and Technology，2019.(in Chinese))
[5] 沈明荣，张清照. 岩体结构面的剪切试验研究[J]. 地下空间与工程学报，2010，6(1)：38–43.(SHEN Mingrong，ZHANG Qingzhao. Study on shearing test of rock mass discontinuity[J]. Chinese Journal of Underground Space and Engineering，2010，6(1)：38–43.(in Chinese))
[6] 杜时贵，黄 曼，罗战友，等. 岩石结构面力学原型试验相似材料研究[J]. 岩石力学与工程学报，2010，29(11)：2 263–2 270.(DU Shigui，HUANG Man，LUO Zhanyou，et al. Similar material research of mechanics prototype test of rock structural plane[J]. Chinese Journal of Rock Mechanics and Engineering，2010，29(11)：2 263– 2 270. (in Chinese))
[7] 林志南，冯世宏，王家全，等. 石英砂岩三轴剪切力学特性及裂隙面形态特征[J]. 工程科学与技术，2024，56(4)：161–172.(LIN Zhinan，FENG Shihong，WANG Jiaquan，et al. Mechanical properties and fracture surface morphology of quartz sandstone under triaxial shear[J]. .Advanced Engineering Science，2024，56(4)：161–172.(in Chinese))
[8] 夏才初，宋英龙，唐志成，等. 粗糙节理剪切性质的颗粒流数值模拟[J]. 岩石力学与工程学报，2012，31(8)：1 545–1 552.(XIA Caichu，SONG Yinglong，TANG Zhicheng，et al. Particle flow numerical simulation for shear behavior of rough joints[J]. Chinese Journal of Rock Mechanics and Engineering，2012，31(8)：1 545–1 552.(in Chinese))
[9] MENG F Z，WONG L N Y，ZHOU H，et al．Shear rate effects on the post-peak shear behavior and acoustic emission characteristics of artificially split granite joints[J]. Rock Mechanics and Rock Engineering，2019，52(7)：2 155–2 174.
[10] 宋 洋，范 波，王贺平. 考虑法向应力与岩石强度的加锚节理岩体剪切力学模型研究[J]. 岩石力学与工程学报，2023，42(6)：1 325–1 335.(SONG Yang，FAN Bo，WANG Heping. Research on shear mechanics model of anchored-jointed rock mass considering normal stress and rock strength[J]. Chinese Journal of Rock Mechanics and Engineering，2023，42(6)：1 325–1 335.(in Chinese))
[11] LI Y C，WU W，LI B. An analytical model for two-order asperity degradation of rock joints under constant normal stiffness conditions[J]. Rock Mechanics and Rock Engineering，2018，51(5)：1 431–1 445.
[12] JING L，STEPHANSSON O，NORDLUND E. Study of rock joints under cyclic loading conditions[J]. Rock Mechanics and Rock Engineering，1993，26(3)：215–232.
[13] 周 辉，孟凡震，张传庆，等. 结构面剪切过程中声发射特性的试验研究[J]. 岩石力学与工程学报，2015，34(增1)：2 827–2 836. (ZHOU Hui，MENG Fanzhen，ZHANG Chuangqing，et al. Experimental study of acoustic emission characteristic of discontinuity under shearing condition[J]. Chinese Journal of Rock Mechanics and Engineering，2015，34(Supp.1)：2 827–2 836.(in Chinese))
[14] 崔国建，张传庆，韩华超，等. CNL及CNS条件下结构面剪切特性试验研究[J]. 岩石力学与工程学报，2019，38(增2)：3 384–3 392. (CUI Guojian，ZHANG Chuangqing，HAN Huachao，et al. Experimental study on shear behavior of artificial joint under CNL and CNS boundary conditions[J]. Chinese Journal of Rock Mechanics and Engineering，2019，38(Supp.2)：3 384–3 392.(in Chinese))
[15] 尹 乾，靖洪文，孟 波，等. CNL和CNS边界条件下砂岩宏细观剪切力学特性[J]. 采矿与安全工程学报，2021，38(3)：615–624. (YIN Qqian，JING Hongwen，MENG Bo，et al. Macroscopic and microscopic shear mechanical properties of sandstone under CNL and CNS boundary conditions[J]. Journal of Mining and Safety Engineering，2021，38(3)：615–624.(in Chinese))
[16] ZHANG C Q，CUI G J，DENG L，et al. Laboratory investigation on shear behaviors of bolt-grout interface subjected to constant normal stiffness[J]. Rock Mechanics and Rock Engineering，2020，53(3)，1 333–1 347.
[17] HAN G S，JING H W，JIANG Y J，et al. Effect of cyclic loading on the shear behaviours of both unfilled and infilled rough rock joints under constant normal stiffness conditions[J]. Rock Mechanics and Rock Engineering，2020，53(1)：31–57.
[18] 刘日成，尹 乾，杨瀚清，等. 恒定法向刚度边界条件下三维粗糙节理面循环剪切力学特性[J]. 岩石力学与工程学，2021，40(6)：1 092– 1 109.(LIU Richeng，YIN Qian，YANG Hanqing，et al. Cyclic shear mechanical properties of 3D rough joint surfaces under constant normal stiffness(CNS) boundary conditions[J]. Chinese Journal of Rock Mechanics and Engineering，2021，40(6)：1 092–1 109.(in Chinese))
[19] 蒋宇静，张孙豪，栾恒杰，等. 恒定法向刚度边界条件下锚固节理岩体剪切特性试验研究[J]. 岩石力学与工程学报，2021，40(4)：663–675.(JIANG Yujing，ZHANG Shunhao，LUAN Hengjie，et al. Experimental study on shear characteristics of bolted rock joints under constant normal stiffness boundary conditions[J]. Chinese Journal of Rock Mechanics and Engineering，2021，40(4)：663–675.(in Chinese))
[20] FENG X T，WANG G，ZHANG X W，et al. Experimental method for direct shear tests of hard rock under both normal stress and lateral stress[J]. International Journal of Geomechanics，2021，21(3)：04021013.
[21] WANG G，FENG X T，YANG C X，et al. Effect of lateral stress on shear strength of jointed hard rocks in true triaxial single-shear test[J]. Bulletin of Engineering Geology and the Environment，2023，82(12)：463–480.
[22] ZHENG Z，LI R H，PAN P Z，et al. Shear failure behaviors and degradation mechanical model of rockmass under true triaxial multi-level loading and unloading shear tests[J]. International Journal of Mining Science and Technology，2024，34(10)：1 385–1 408.
[23] 刘汉祥. 真三轴加卸载条件下粗糙节理岩体剪切破坏及锚固控制演化规律研究[博士学位论文][D]. 徐州：中国矿业大学，2024.(LIU Hanxiang. Research on shear failure and anchorage control evolution law of rough jointed rock mass under true triaxial loading and unloading conditions[Ph. D. Thesis][D]. Xuzhou：China University of Mining and Technology，2024.(in Chinese))
[24] ZHAO J，HU L，FENG X T，et al. Shear failure mechanisms of standstone subjected to direct，true triaxial and confining shear test conditions[J]. Rock Mechanics and Rock Engineering，2023，56(9)：6 889–6 903.
[25] 中华人民共和国行业标准编写组. T/CSRME 007—2021岩石真三轴试验规程[S]. 北京：中国标准出版社，2021.(The Professional Standards Compilation Group of People?s Republic of China. T/CSRME 007—2021 Technical specification for true triaxial test of rock specimen[S]. Beijing：Standards Press of China，2021.(in Chinese))
[26] ZHAO J，FENG X T，WANG J R，et al. A multifunctional shear apparatus for rocks subjected to true triaxial stress and high temperature in real-time[J] Journal of Rock Mechanics and Geotechnical Engineering，2024，16(9)：3 524–3 543.
[27] LI H P，HE B G，FENG X T，et al. Mechanism of axial chain rockbursts in deep tunnels：structural plane-induced stress concentration triggered by drilling and blasting[J]. Rock Mechanics and Rock Engineering，2025，58(12)：13 977–13 998.
[28] 侯公羽. 岩石力学高级教程[M]. 北京：科学出版社，2018：152–154.(HOU Gongyu. Advanced rock mechanics[M]. Beijing：Science Press，2018：152–154.(in Chinese))
[29] LOCKNER D. The role of acoustic emission in the study of rock fracture[J] International Journal of Rock Mechanics and Mining Sciences and Geomechanics Abstracts，1993，30(7)：883–899.
[30] BIENIAWSKI Z T. Mechanism of brittle fracture of rock：Part I—theory of the fracture process[J]. International Journal of Rock Mechanics and Mining Sciences & Geomechanics Abstracts，1967，4(4)：395–406.
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2026, Vol. 45 
