Abstract
To investigate the stress path dependent of rock joints, a series of tangential loading tests and normal unloading tests were conducted using 32 cement mortar replicas of artificially split rock joints with 4 different joint roughness coefficients (JRC). The critical normal stresses of the unloading tests were recorded, and a comparative study was conducted by referencing the results under different loading paths and joints conditions. The test results indicate that the shear resistance has a distinct unloading effect, which is mainly influenced by the morphologic characteristics, normal stress levels and stress paths. By analyzing the results, it can be concluded that the variation trend of shear/normal stress ratio against the normal stress and JRC of the two test conditions were identical. However, under low normal stress condition, the stress ratio of the joints under normal unloading stress path is the higher one; while under higher normal stress, the relationship becomes converse. Compared to that of the tangential loading condition, shear/normal stress ratio of the unloading stress path reduces rapidly as the increasing of normal stress, and the influence of the morphology is masked under lower normal stress.
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References
Barton N (1978) Suggested methods for the quantitative description of discontinuities in rock masses. Int J Rock Mech Min Sci 15(6):319–368
Barton N (2013) Shear strength criteria for rock, rock joints, rockfill and rock masses: problems and some solutions. J Rock Mech Geotech Eng 5(4):249–261. https://doi.org/10.1016/j.jrmge.2013.05.008
Chen GQ, Liu D, Xu P et al (2018) True-triaxial test on unloading failure of jointed rock bridge. Chin J Rock Mech Eng 37(02):325–338. https://doi.org/10.13722/j.cnki.jrme.2017.0648
Diederichs M, Kaiser P, Eberhardt E (2004) Damage initiation and propagation in hard rock during tunnelling and the influence of near-face stress rotation. Int J Rock Mech Min Sci 41(5):785–812. https://doi.org/10.1016/j.ijrmms.2004.02.003
Duan SQ, Feng XT, Jiang Q et al (2017) Failure modes and mechanisms for rock masses with staggered zones of Baihetan underground caverns under high geostress. Chin J Rock Mech Eng 36(4):852–864. https://doi.org/10.13722/j.cnki.jrme.2015.1236
Fan PX, Li Y, Zhao YT et al (2018) Experimental study on unloading failure strength of red sandstone. Chin J Rock Mech Eng 37(04):852–861. https://doi.org/10.13722/j.cnki.jrme.2017.1368
Han GS, Jing HW, Jiang YJ et al (2020) Effect of cyclic loading on the shear behaviours of both unfilled and infilled rough rock joints under constant normal stiffness conditions. Rock Mech Rock Eng 53(1):31–57. https://doi.org/10.1007/s00603-019-01866-w
Hanson J, Bittencourt T, Ingraffea A (2004) Three-dimensional influence coefficient method for cohesive crack simulations. Eng Fract Mech 71(15):2109–2124. https://doi.org/10.1016/j.engfracmech.2003.12.008
Hu J, Li SC, Liu HL et al (2020) New modified model for estimating the peak shear strength of rock mass containing nonconsecutive joint based on a simulated experiment. Int J Geomech 20(7):04020091. https://doi.org/10.1061/(ASCE)GM.1943-5622.0001732
Huang D, Guo YQ, Cen DF et al (2020) Experimental investigation on shear mechanical behavior of sandstone containing a pre-existing flaw under unloading normal stress with constant shear stress. Rock Mech Rock Eng 53(8):3779–3792. https://doi.org/10.1007/s00603-020-02136-w
Jiang Q, Yang B, Liu C et al (2018) Manufacturing of natural rock joints by engraving and analysis of wearing damage of natural rock joints under shear tests. Chin J Rock Mech Eng 37(11):59–69. https://doi.org/10.13722/j.cnki.jrme.2018.0668
Lau J, Chandler N (2004) Innovative laboratory testing. Int J Rock Mech Min Sci 41(8):1427–1445. https://doi.org/10.1016/j.ijrmms.2004.09.008
Li J, Fan PX, Wang MY (2013) Failure behavior of highly stressed rocks under quasi-static and intensive unloading conditions. J Rock Mech Geotech Eng 5(4):287–293. https://doi.org/10.1016/j.jrmge.2013.03.004
Li A, Dai F, Xu N et al (2017) Failure mechanism and mode of surrounding rock of underground powerhouse at the right bank of Wudongde hydropower station subjected to excavation. Chin J Rock Mech Eng 36(4):781–793. https://doi.org/10.13722/j.cnki.jrme.2016.0691
Li J, Fan PX, Wang MY (2019) The stress conditions of rock core disking based on an energy analysis. Rock Mech Rock Eng 52(2):465–470. https://doi.org/10.1007/s00603-018-1634-7
Li B, Ye XN, Dou ZH et al (2020a) Shear strength of rock fractures under dry, surface wet and saturated conditions. Rock Mech Rock Eng 53(6):2605–2622. https://doi.org/10.1007/s00603-020-02061-y
Li YC, Tang CA, Li DQ et al (2020b) A new shear strength criterion of three-dimensional rock joints. Rock Mech Rock Eng 53(3):1477–1483. https://doi.org/10.1007/s00603-019-01976-5
Liu GF, Feng XT, Jiang Q et al (2016) Failure characteristics, laws and mechanisms of rock spalling in excavation of large-scale underground powerhouse caverns in Baihetan. Chin J Rock Mech Eng 35(5):865–878. https://doi.org/10.13722/j.cnki.jrme.2015.0933
Magsipoc E, Zhao Q, Grasselli G (2020) 2D and 3D roughness characterization. Rock Mech Rock Eng 53:1495–1519. https://doi.org/10.1007/s00603-019-01977-4
Manouchehrian A, Cai M (2015) Simulation of unstable rock failure under unloading conditions. Can Geotech J 53(1):22–34. https://doi.org/10.1139/cgj-2015-0126
Meng FZ, Wong LNY, Zhou H et al (2019) Shear rate effects on the post-peak shear behaviour and acoustic emission characteristics of artificially split granite joints. Rock Mech Rock Eng 52(7):2155–2174. https://doi.org/10.1007/s00603-018-1722-8
Pusch R, Standfors R (1992) The zone of disturbance around blasted tunnels at depth. Int J Rock Mech Min Sci Geomech Abstr 29(5):447–456. https://doi.org/10.1016/0148-9062(92)92629-Q
Tse R, Cruden DM (1979) Estimating joint roughness coefficients. Int J Rock Mech Min Sci Geomech Abstr 16(5):303–307. https://doi.org/10.1016/0148-9062(79)90241-9
Tu GX, Deng H (2021) Unloading depth of rock masses and its relations with river downcutting in deep valleys in Southwest China. Eng Geol 288:106161. https://doi.org/10.1016/j.enggeo.2021.106161
Xing WZ, Wang S, Fan PX et al (2021) Experimental study on direct shear behavior of split rock joints. J Cent South Univ (sci Technol) 52(8):2933–2944
Yin ZM, Liu XR, Yang ZP et al (2021) Shear behavior of Marlstone containing parallel fissure under normal unloading. KSCE J Civ Eng 25(4):1283–1294. https://doi.org/10.1007/s12205-021-0959-z
You MQ (2002) Strength and deformation of rock under complex loading path. Chin J Rock Mech Eng 21(1):23–28
Zhang QZ, Shen MR, Zhang LB (2009) Study on mechanical properties of rock discontinuity during unloading. Chin J Undergr Sp Eng 5(06):1126-1130+1137
Zhang CQ, Feng XT, Zhou H et al (2012) Case histories of four extremely intense rockbursts in deep tunnels. Rock Mech Rock Eng 45(3):275–288. https://doi.org/10.1007/s00603-011-0218-6
Zhang CQ, Feng XT, Zhou H et al (2013) Rockmass damage development following two extremely intense rockbursts in deep tunnels at Jinping II hydropower station, southwestern China. Bull Eng Geol Environ 72(2):237–247. https://doi.org/10.1007/s10064-013-0470-y
Zhu Z, Huang D, Zhang YF et al (2020) Experimental study on the effects of unloading normal stress on shear mechanical behaviour of sandstone containing a parallel fissure pair. Rock Mech Rock Eng 53(4):1647–1663. https://doi.org/10.1007/s00603-019-01997-0
Zhou XP, Zhang YX, Ha QL (2003) Study on the stress intensity factor for the crack tips under unloading and loading. Undergr Sp 23(2):277–280
Zhou H, Meng FZ, Zhang CQ et al (2016) Investigation of the acoustic emission characteristics of artificial saw-tooth joints under shearing condition. Acta Geotech 11(4):925–939. https://doi.org/10.1007/s11440-014-0359-3
Zhou H, Cheng GT, Zhu Y et al (2019) Experimental study of shear deformation characteristics of marble dentate joints. Rock Soil Mech 40(3):852–860. https://doi.org/10.16285/j.rsm.2017.0964
Zhu TT, Huang D (2019) Experimental investigation of the shear mechanical behavior of sandstone under unloading normal stress. Int J Rock Mech Min Sci 114:186–194. https://doi.org/10.1016/j.ijrmms.2019.01.003
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The authors gratefully acknowledge the support of the National Natural Science Foundation of China (no. 51979280).
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Partial financial support was received from the National Natural Science Foundation of China (no. 51979280).
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PF, JY and SW contributed to the study conception and design. Material preparation, data collection and analysis were performed by JY, SW, QW, WX. The first draft of the manuscript was written by PF and all authors commented on previous versions of the manuscript. All authors read and approved the final manuscript.
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Yang, J., Wang, S., Wang, Q. et al. Unloading effect of the shear resistance of rock joints. Environ Earth Sci 81, 292 (2022). https://doi.org/10.1007/s12665-022-10415-8
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DOI: https://doi.org/10.1007/s12665-022-10415-8