Geomechanics and Engineering

Techno-Press (테크노프레스)
권호 표지
DOI QR코드

DOI QR Code

Shear failure and mechanical behavior of flawed specimens containing opening and joints

  • Zhang, Yuanchao (Graduate School of Engineering, Nagasaki University) ;
  • Jiang, Yujing (Graduate School of Engineering, Nagasaki University) ;
  • Shi, Xinshuai (State Key Laboratory for Geomechanics and Deep Underground Engineering, China University of Mining and Technology) ;
  • Yin, Qian (State Key Laboratory for Geomechanics and Deep Underground Engineering, China University of Mining and Technology) ;
  • Chen, Miao (College of Energy and Mining Engineering, Shandong University of Science and Technology)
  • Received : 2020.04.29
  • Accepted : 2020.12.18
  • Published : 2020.12.25
⟨ Previous Next ⟩

Abstract

Shear-induced instability of jointed rock mass has greatly threatened the safety of underground openings. To better understand the failure mechanism of surrounding rock mass under shear, the flawed specimens containing a circular opening and two open joints are prepared and used to conduct direct shear tests. Both experimental and numerical results show that joint inclination (β) has a significant effect on the shear strength, dilation, cracking behavior and stress distribution around flaws. The maximum shear strength, occurring at β=30°, usually corresponds to a unifrom stress state around joint and an intense energy release. However, a larger joint inclination, such as β=90°~150°, will cause a more uneven stress distribution and a stronger stress concentration, thus a lower shear strength. The stress distribution around opening changes little with joint inclination, while the magnitude varys much. Both compression and tension around opening will be greatly enhanced by the 30°-joints. In addition, a higher normal stress tends to enhance the compression and suppress the tension around flaws, resulting in an earlier generation and a larger proportion of shear cracks.

Keywords

Acknowledgement

The research described in this paper was financially supported by the China Scholarship Council (201806420027), National Natural Science Foundation of China (51904290) and Natural Science Foundation of Jiangsu Province (BK20180663).

References

  1. Aksoy, C.O., Aksoy, G.G., Guney, A., Ozacar, V. and Yaman, H.E. (2020), "Influence of time-dependency on elastic rock properties under constant load and its effect on tunnel stability", Geomech. Eng., 20(1), 1-7. https://doi.org/10.12989/gae.2020.20.1.001.
  2. ASTM. (2008), Standard Test Method for Performing Laboratory Direct Shear Strength Tests of Rock Specimens under Constant Normal Force, ASTM International, U.S.A.
  3. Bahaaddini, M., Sharrock, G. and Hebblewhite, B.K. (2013), "Numerical investigation of the effect of joint geometrical parameters on the mechanical properties of a non-persistent jointed rock mass under uniaxial compression", Comput. Geotech., 49, 206-225. https://doi.org/10.1016/j.compgeo.2012.10.012.
  4. Cundall, P.A. and Strack, O.D.L. (1979), "A discrete numerical model for granular assemblies", Geotechnique, 29(1), 47-65. https://doi.org/10.1680/geot.1979.29.1.47.
  5. Fakhimi, A., Carvalho, F., Ishida, T. and Labuz, J.F. (2002), "Simulation of failure around a circular opening in rock", Int. J. Rock Mech. Min. Sci., 39(4), 507-515. https://doi.org/10.1016/S1365-1609(02)00041-2.
  6. Fan, X., Li, K., Lai, H., Xie, Y., Cao, R. and Zheng, J. (2018), "Internal stress distribution and cracking around flaws and openings of rock block under uniaxial compression: A particle mechanics approach", Comput. Geotech., 102, 28-38. https://doi.org/10.1016/j.compgeo.2018.06.002.
  7. Gay, N.C. (1976), "Fracture growth around openings in large blocks of rock subjected to uniaxial and biaxial compression", Int. J. Rock Mech. Min. Sci. Geomech. Abstr., 13(8), 231-243. https://doi.org/10.1016/0148-9062(76)91543-6.
  8. Hao, Y.H. and Azzam, R. (2005), "The plastic zones and displacements around underground openings in rock masses containing a fault", Tunn. Undergr. Sp. Tech., 20(1), 49-61. https://doi.org/10.1016/j.tust.2004.05.003.
  9. Hoek, E. and Brown, E.T. (1997), "Practical estimates of rock mass strength", Int. J. Rock Mech. Min. Sci., 34(8), 1165-1186. https://doi.org/10.1016/S1365-1609(97)80069-X.
  10. Jeon, S., Kim, J., Seo, Y. and Hong, C. (2004), "Effect of a fault and weak plane on the stability of a tunnel in rock-a scaled model test and numerical analysis", Int. J. Rock Mech. Min. Sci., 41, 658-663. https://doi.org/10.1016/j.ijrmms.2004.03.115.
  11. Jiang, Y., Xiao, J., Tanabashi, Y. and Mizokami, T. (2004), "Development of an automated servo-controlled direct shear apparatus applying a constant normal stiffness condition", Int. J. Rock Mech. Min. Sci., 41(2), 275-286. https://doi.org/10.1016/j.ijrmms.2003.08.004.
  12. Kim, J.S., Kim, G.Y., Baik, M.H., Finsterle, S. and Cho, G.C. (2019), "A new approach for quantitative damage assessment of in-situ rock mass by acoustic emission", Geomech. Eng., 18(1), 11-20. https://doi.org/10.12989/gae.2019.18.1.011.
  13. Lajtai, E.Z. (1969), "Strength of discontinuous rocks in direct shear", Geotechnique, 19(2), 218-233. https://doi.org/10.1680/geot.1969.19.2.218.
  14. Manouchehrian, A., Sharifzadeh, M., Marji, M.F. and Gholamnejad, J. (2014), "A bonded particle model for analysis of the flaw orientation effect on crack propagation mechanism in brittle materials under compression", Arch. Civ. Mech. Eng., 14(1), 40-52. https://doi.org/10.1016/j.acme.2013.05.008.
  15. Martin, C.D. (1997), "Seventeenth Canadian geotechnical colloquium: The effect of cohesion loss and stress path on brittle rock strength", Can. Geotech. J., 34(5), 698-725. https://doi.org/10.1139/t97-030.
  16. Matsuki, K., Nakama, S. and Sato, T. (2009), "Estimation of regional stress by FEM for a heterogeneous rock mass with a large fault", Int. J. Rock Mech. Min. Sci., 46(1), 31-50. https://doi.org/10.1016/j.ijrmms.2008.03.005.
  17. Muralha, J., Grasselli, G., Tatone, B., Blumel, M., Chryssanthakis, P. and Jiang, Y. (2014), "ISRM suggested method for laboratory determination of the shear strength of rock joints: revised version", Rock Mech. Rock Eng., 47(1), 291-302. https://doi.org/10.1007/s00603-013-0519-z.
  18. Park, K. (2017), "Simple solutions of an opening in elastic-brittle plastic rock mass by total strain and incremental approaches", Geomech. Eng., 13(4), 585-600. https://doi.org/10.12989/gae.2017.13.4.585.
  19. Sagong, M., Park, D., Yoo, J. and Lee, J.S. (2011), "Experimental and numerical analyses of an opening in a jointed rock mass under biaxial compression", Int. J. Rock Mech. Min. Sci., 48(7), 1055-1067. https://doi.org/10.1016/j.ijrmms.2011.09.001.
  20. Yang, S.Q., Yin, P.F., Zhang, Y.C., Chen, M., Zhou, X.P., Jing, H.W. and Zhang, Q.Y. (2019), "Failure behavior and crack evolution mechanism of a non-persistent jointed rock mass containing a circular hole", Int. J. Rock Mech. Min. Sci., 114, 101-121. https://doi.org/10.1016/j.ijrmms.2018.12.017.
  21. Zhang, Y., Jiang, Y., Asahina, D. and Wang, C. (2020), "Experimental and numerical investigation on shear failure behavior of rock-like samples containing multiple non-persistent joints", Rock Mech. Rock Eng., 53(10), 4717-4744. https://doi.org/10.1007/s00603-020-02186-0.
  22. Zhuang, X., Chun, J. and Zhu, H. (2014), "A comparative study on unfilled and filled crack propagation for rock-like brittle material", Theor. Appl. Fract. Mech., 72, 110-120. https://doi.org/10.1016/j.tafmec.2014.04.004.