Experimental Study on the Effects of Unloading Normal Stress on Shear Mechanical Behaviour of Sandstone Containing a Parallel Fissure Pair

  • Zhu Zhong
  • Da HuangEmail author
  • Yongfa Zhang
  • Guowei Ma
Original Paper


To gain deeper insight into the effects of unloading normal stress on shear mechanical behaviour, laboratory tests are carried out on the red-sandstone specimens containing a parallel fissure pair under the constant shear stress and the unloading normal stress. The results reveal that the trace of the entire rupture surface is mainly controlled by the rock bridge, and the impacts of the rupture surfaces of the unloading tests are narrower than those of the direct shear tests. Tensile failure, tension–shear failure, shear failure, and two-stage failure are observed, the failure rules of rock bridges are further summarized according to the ranges of the length and inclination of the rock bridge. The shear strength of the normal unloading test has a slight increase compared with that of the direct shear test. With an increase in the initial normal/shear stress, the shear strength of rock specimens increase; under the low to medium initial stress conditions, the shear strength increment has a linear growth tendency, but under the medium to high initial stress conditions, the growth trend slows down. The ratio of shear deformation on rupture surface increases with the increase of the initial shear stress but decreases with the increase of the initial normal stress. The ratio of shear deformation on rupture plane increases with the increase of the initial shear stress, and decreases with the increase of the initial normal stress, There is a little difference in the deformation ratio (shear damage deformation divided by tensile damage deformation, ΔDrs/ΔDrn) between the observed tensile failure and tension–shear failure. The dominate damage deformation under different geometric conditions is closely related to the failure patterns.


Unloading normal stress Failure pattern Rock bridge Fissure pair Shear strength Deformation behaviour 



This work is supported by the National Natural Science Foundation of China (No. 41672300). The authors would like to thank Dr. Duofeng Cen in Hebei University of Technology, China, for his suggestions on the revision.


  1. Bahaaddini M, Hagan PC, Mitra R, Khosravi MH (2016) Experimental and numerical study of asperity degradation in the direct shear test. Eng Geol 204:41–52CrossRefGoogle Scholar
  2. Bobet A (2000) The initiation of secondary cracks in compression. Eng Fract Mech 66(2):187–219CrossRefGoogle Scholar
  3. Bobet A, Einstein HH (1998) Fracture coalescence in rock-type materials under uniaxial and biaxial compression. Int J Rock Mech Min Sci 35(7):863–888CrossRefGoogle Scholar
  4. Cai M, Kaiser PK (2005) Assessment of excavation damaged zone using a micromechanics mode. Tunnel Undergr Space Technol Inc Trenchless Technol Res 20(4):301–310CrossRefGoogle Scholar
  5. Eberhardt E, Stead D, Coggan JS (2004) Numerical analysis of initiation and progressive failure in natural rock slopes-the 1991 Randa rockslide. Int J Rock Mech Min Sci 41(1):69–87CrossRefGoogle Scholar
  6. Gong QM, Yin LJ, Wu SY, Zhao J, Ting Y (2012) Rock burst and slabbing failure and its influence on TBM excavation at headrace tunnels in Jinping II hydropower station. Eng Geol 124(1):98–108CrossRefGoogle Scholar
  7. Gu DM, Huang D, Yang WD, Zhu JL, Fu GY (2017) Understanding the triggering mechanism and possible kinematic evolution of a reactivated landslide in the three gorges reservoir. Landslides 14(10):1–15Google Scholar
  8. Habib P (1987) The Malpasset dam failure. Eng Geol 24(1–4):331–338CrossRefGoogle Scholar
  9. He MC, Miao JL, Feng JL (2010) Rock burst process of limestone and its acoustic emission characteristics under true-triaxial unloading conditions. Int J Rock Mech Min Sci 47(2):286–298CrossRefGoogle Scholar
  10. Huang R (2008) Geodynamical process and stability control of high rock slope development. Chin J Rock Mech Eng 27(8):1525–1544 (in Chinese) Google Scholar
  11. Huang R (2009) Some catastrophic landslides since the twentieth century in the southwest of China. Landslides 6(1):69–81CrossRefGoogle Scholar
  12. Huang R (2012) Mechanisms of large-scale landslides in China. Bull Eng Geol Environ 71(1):161–170CrossRefGoogle Scholar
  13. Huang RQ, Huang D (2014) Evolution of rock cracks under unloading condition. Rock Mech Rock Eng 47(2):453–466CrossRefGoogle Scholar
  14. Huang RQ, Wang XN, Chan LS (2001) Triaxial unloading test of rocks and its implication for rock burst. Bull Eng Geol Environ 60(1):37–41CrossRefGoogle Scholar
  15. Huang D, Cen D, Ma G, Huang R (2015) Step-path failure of rock slopes with intermittent joints. Landslides 12(5):911–926CrossRefGoogle Scholar
  16. Huang D, Zhong Z, Gu DM (2019) Experimental investigation on the failure mechanism of a rock landslide controlled by a steep-gentle discontinuity pair. J Mt Sci 16(6):1258–1274CrossRefGoogle Scholar
  17. Jelínek R, Wagner P (2007) Landslide hazard zonation by deterministic analysis (veľká Čausa landslide area, Slovakia). Landslides 4(4):339–350CrossRefGoogle Scholar
  18. Jiang Q, Feng XT, Hatzor YH, Hao XJ, Li SJ (2014) Mechanical anisotropy of columnar jointed basalts: an example from the Baihetan hydropower station, China. Eng Geol 175(3):35–45CrossRefGoogle Scholar
  19. Karu AE, Belk ED (1982) 886337 Malpasset dam failure: londe, p engng geol v24, n1–4, Dec 1987, pp 295–329 (Proc international workshop on dam failures, Purdue University, Indiana, 6–8 august 1985). Int J Rock Mech Min Sci Geomech Abstr 25(2):275–282Google Scholar
  20. Kilburn CRJ, Petley DN (2003) Forecasting giant, catastrophic slope collapse: lessons from Vajont, Northern Italy. Geomorphology 54(1):21–32CrossRefGoogle Scholar
  21. Krahn J, Morgenstern NR (2014) Mechanics of the Frank slide. In: Rock engineering for foundations and slopes. ASCEGoogle Scholar
  22. Li Y, Huang D, Li X (2014) Strain rate dependency of coarse crystal marble under uniaxial compression: strength, deformation and strain energy. Rock Mech Rock Eng 47(4):1153–1164CrossRefGoogle Scholar
  23. Liu EL (2012) Deformation mechanisms of crushable blocky materials upon lateral unloading for a biaxial stress state. Rock Mech Rock Eng 45(3):439–444CrossRefGoogle Scholar
  24. Manouchehrian A, Cai M (2015) Simulation of unstable rock failure under unloading conditions. Can Geotech J 53(1):22–34CrossRefGoogle Scholar
  25. Marschalko M, Yilmaz I, Bednárik M, Kubečka K (2012) Influence of underground mining activities on the slope deformation genesis: Doubrava Vrchovec, Doubrava Ujala and Staric case studies from Czech Republic. Eng Geol 147–148(15):37–51CrossRefGoogle Scholar
  26. Mei S, Poncos V, Froese C (2008) Mapping millimetre-scale ground deformation over the underground coal mines in the frank slide area, Alberta, Canada, using spaceborne INSAR technology. Can J Remote Sens 34(2):113–134CrossRefGoogle Scholar
  27. Park CH, Bobet A (2009) Crack coalescence in specimens with open and closed flaws: a comparison. Int J Rock Mech Min Sci 46(5):819–829CrossRefGoogle Scholar
  28. Park JW, Song JJ (2009) Numerical simulation of a direct shear test on a rock joint using a bonded-particle model. Int J Rock Mech Min Sci 46(8):1315–1328CrossRefGoogle Scholar
  29. Suwa H, Mizuno T, Suzuki S, Yamamoto Y, Ito K (2008) Sequential processes in a landslide hazard at a slate quarry in Okayama, Japan. Nat Hazards 45(2):321–331CrossRefGoogle Scholar
  30. Ventisette CD, Gigli G, Bonini M, Corti G, Montanari D, Santoro S et al (2015) Insights from analogue modelling into the deformation mechanism of the Vaiont landslide. Geomorphology 228:52–59CrossRefGoogle Scholar
  31. Xie HQ, He CH (2004) Study of the unloading characteristics of a rock mass using the triaxial test and damage mechanics. Int J Rock Mech Min Sci 41(3):366CrossRefGoogle Scholar
  32. Yamaguchi U, Shimotani T (1986) 10. A case study of slope failure in a limestone quarry. Int J Rock Mech Min Sci Geomech Abstr 23(1):95–104CrossRefGoogle Scholar
  33. Yin Y, Sun P, Zhang M, Li B (2011) Mechanism on apparent dip sliding of oblique inclined bedding rockslide at Jiweishan, Chongqing, China. Landslides 8(1):49–65CrossRefGoogle Scholar
  34. Zeng B, Huang D, Ye S, Chen F, Zhu T, Tu Y (2019) Triaxial extension tests on sandstone using a simple auxiliary apparatus. Int J Rock Mech Min Sci 120:29–40CrossRefGoogle Scholar
  35. Zhang K, Cao P, Ma G, Wang W, Fan W, Li K (2016) Strength, fragmentation and fractal properties of mixed flaws. Acta Geotech 11(4):901–912CrossRefGoogle Scholar
  36. Zhou XP (2005) Localization of deformation and stress–strain relation for mesoscopic heterogeneous brittle rock materials under unloading. Theor Appl Fract Mech 44(1):27–43CrossRefGoogle Scholar
  37. Zhou X, Ha Q, Zhang Y, Zhu K (2004) Analysis of deformation localization and the complete stress–strain relation for brittle rock subjected to dynamic compressive loads. Int J Rock Mech Min Sci 41(2):311–319CrossRefGoogle Scholar

Copyright information

© Springer-Verlag GmbH Austria, part of Springer Nature 2019

Authors and Affiliations

  1. 1.School of Civil and Transportation EngineeringHebei University of TechnologyTianjinChina
  2. 2.State Key Laboratory of Coal Mine Disaster Dynamics and ControlChongqing UniversityChongqingChina

Personalised recommendations