Mechanical properties of soft tailings from different depths of a Swedish tailings dam: Results from triaxial tests

Document Type : Article

Authors

1 Department of Civil Engineering, Quaid-e-Awam University of Engineering Science and Technology, Nawabshah, Pakistan

2 Department of Civil, Environmental and Natural Resources Engineering, Luleå University of Technology, SE-97187 Luleå, Sweden

Abstract

In an upstream tailings dam, loose layers might occur at different depths due to melting of frozen layers deposited during freezing temperature in Sweden. Reduced shear strength of such layers in a tailings dam might cause stability problems. Due to slow consolidation process, it is unknown, whether self-weight of a high tailings dam could have influence on strength and stiffness of soft tailings located at different depths. For numerical modelling, appropriate strength and stiffness properties of soft tailings are needed. For this purpose, loose layers in an upstream tailings dam were identified based on results of cone penetration tests. Consolidated Drained (CD) triaxial tests were conducted on undisturbed soft tailings collected from different depths of the dam. The results indicated that depth did not have considerable influence on strength and stiffness of tailings. Hardening Soil Model (HSM), at high confining pressures and axial strains underestimated stiffness of soft tailings under CD triaxial state. This study shows that: (i) proper care is needed in evaluating strength and stiffness parameters for soft tailings, and (ii) use of the HSM is likely to predict more deformations which could give an early warning before an actual failure of a tailings dam.

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Main Subjects


1. Vick, S., Planning, Design, and Analysis of Tailings Dams, BiTech Publishers, Vancouver (1990). 2. Owolagba, J. and Azam, S. Geotechnical properties of centrifuged oil sand _ne tailings", Envir. Geotech., 2(5), pp. 309{316 (2014). 3. Lee, J.K. and Shang, J.Q. Evolution of thermal and mechanical properties of mine tailings and y ash mixtures during curing period", Can. Geotech. J., 51(5), pp. 570{582 (2014). 4. Bhanbhro, R., Knutsson, R., Edeskar, T., and Knutsson, S. Mechanical properties of soft tailings from a Swedish tailings impoundment: Results from direct shear tests", Elec. J. of Geotech. Eng., 19(Z), pp. 9023{9039 (2014). 5. Jia, Y., Stenman, D., Makitalo, M., Maurice, C., and  Ohlander, B. Use of amended tailings as mine waste cover", Waste Biomass Valori, 4(4), pp. 709{ 718 (2013). 6. Bhanbhro, R., Knutsson, R., Rodriguez, J., Edeskar, T., and Knutsson, S. Basic description of tailings from Aitik focusing on mechanical behaviour", Int. J. Emerg. Tech. Adv. Eng., 3(12), pp. 65{69 (2013). 7. Rodriguez, J.M. and Edeskar, T. Case of study on particle shape and friction angle on tailings", J. Adv. Sci. Eng. Res., 3(4), pp. 373{387 (2013). 8. Dimitrova, R.S. and Yanful, E.K. Factors a_ecting the shear strength of mine tailings/clay mixtures with varying clay content and clay mineralogy", Eng. Geol., 125, pp. 11{25 (2012). doi.org/10.1016/j.enggeo.2011.10.013. 9. Liu, H.M., Yang, C.H., Zhang, C., and Mao, H.J. Study on static and dynamic strength characteristics of tailings silty sand and its engineering application", Saf. Sci., 50(4), pp. 828{834 (2012). 10. Dimitrova, R.S. and Yanful, E.K. Undrained strength of deposited mine tailings beds: e_ect of water content, e_ective stress and time of consolidation", Geotech. Geol. Eng., 29(5), pp. 935{951 (2011). 11. Villavicencio, A.G., Breul, P., Bacconnet, C., Boissier, D., and Espinace, A.R. Estimation of the variability of tailings dams properties in order to perform probabilistic assessment", Geotech. Geol. Eng, 29, pp. 1073{ 1084 (2011). 12. Wickland, B.E., Wilson, G.W., and Wijewickreme, D. Hydraulic conductivity and consolidation response of mixtures of mine waste rock and tailings", Can. Geotech. J., 47(4), pp. 472{485 (2010). 13. Shamsai, A., Pak, A., Bateni, S.M., and Ayatollahi, S.A.H. Geotechnical characteristics of copper mine tailings: a case study", Geotech. Geol. Eng., 25(5), pp. 591{602 (2007). 14. Guo, P. and Su, X. Shear strength, interparticle locking, and dilatancy of granular materials", Can. Geotech. J., 44(5), pp. 579{91 (2007). 15. Qiu, Y. and Sego, D. Laboratory properties of mine tailings", Can. Geotech. J., 38(1), pp. 183{90 (2001). 16. Zardari, M.A., Mattsson, H., Knutsson, S., and Ormann, L. Comparison of three dimensional and two dimensional axisymmetric _nite element analyses of a corner section of a tailings dam", Sci. Iran., 24(5), pp. 2320{2331 (2017). 17. Ormann, L., Zardari, M.A., Mattsson, H., Bjelkevik, A., and Knutsson, S. Numerical analysis of strengthening by rock_ll embankments on an upstream tailingsdam", Can. Geotech. J., 50(4), pp. 391{399 (2013). doi: 10.1139/cgj-2012-0255 18. Yu, S.Y., Shao, L.T., and Liu, S.Y. Stability analysis of tailings dam based on _nite element limit equilibrium method", Rock. Soil. Mech., 34(4), pp. 1185{1190 (2013). 1074 R. Bhanbhro et al./Scientia Iranica, Transactions A: Civil Engineering 27 (2020) 1066{1074 19. Rout, S., Sahoo, T., and Das, S. Design of tailing dam using red mud", Open. Eng., 3(2), pp. 316{328 (2013). 20. Ozcan, N.T., Ulusay, R., and Isik, N.S. A study on geotechnical characterization and stability of downstream slope of a tailings dam to improve its storage capacity (Turkey)", Environ. Earth Sci., 69(6), pp. 1871{1890 (2013). 21.  Ozer, A.T. and Bromwell, L.G. Stability assessment of an earth dam on silt/clay tailings foundation: A case study", Eng. Geol., 151, pp. 89{99 (2012). 22. Ormann, L., Zardari, M.A., Mattsson, H., Bjelkevik, A., and Knutsson, S. Numerical analysis of curved embankment of an upstream tailing dam", Elec. J. of Geotech. Eng., 16/I, pp. 931{944 (2011). 23. Pak, A. and Nabipour, M. Numerical study of the e_ects of drainage systems on saturated/unsaturated seepage and stability of tailings dams", Mine. Water. Environ., 36(3), pp. 341{355 (2017). 24. Saad, B. and Mitri, H. Hydromechanical analysis of upstream tailings disposal facilities", J. of Geotech. and Geoenviron. Eng., 137(1), pp. 27{42 (2011). 25. Psarropoulos, P.N. and Tsompanakis, Y. Stability of tailings dams under static and seismic loading", Can. Geotech. J., 45(5), pp. 663{675 (2008). 26. Pirulli, M., Barbero, M., Marchelli, M., and Scavia, C. The failure of the Stava Valley tailings dams (northern Italy): numerical analysis of the ow dynamics and rheological properties", Geoenviron., Disas., 4(3), pp. 1{15 (2017). 27. Pastor, M., Quecedo, M., Fern_andez Merodo, J.A., Herrores, M.I., Gonzalez, E., and Mira, P. Modelling tailings dams and mine waste dumps failures", Geotechnique, 52(8), pp. 579{591 (2002). 28. Hassellund, L., Knutsson, R., Mattsson, H., and Knutsson, S. Numerical simulations of stability of a gradually raised upstream tailings dam in northern sweden", Elec. J. of Geotech. Eng., 21(13), pp. 4699{ 4720 (2016). 29. Knutsson, R. Tailings dam performance: Modeling and safety analysis of a tailings dam", Licentiate of Engineering Thesis, Lulea University of Technology, Lulea, Sweden (2015). 30. Schanz, T., Vermeer, P., and Bonnier, P. The hardening soil model: formulation and veri_cation", Beyond 2000 in Computational Geotechnics-10 Years of PLAXIS, Balkema, Rotterdam, pp. 281{296 (1999). 31. Head, K.H., Manual of Soil Laboratory Testing, E_ective Stress Tests, 3, Whittles Publishing (2014). 32. Jantzer, I. Critical hydraulic gradients in tailings dams: comparison to natural analogies", Licentiate of Engineering Thesis, Lulea University of Technology, Lulea, Sweden (2009). 33. Surarak, C., Likitlersuang, S., Wanatowski, D., Balasubramaniam, A., Oh, E., and Guan, H. Sti_ness and strength parameters for hardening soil model of soft and sti_ Bangkok clays", Soils and Foundations, 52(4), pp. 682{697 (2012). 34. Brinkgreve, R.B.J., Kumarswamy, S., and Swolfs, W.M., PLAXIS 2D Reference and Material Models Manuals, PLAXIS bv, the Netherlands (2016). 35. Lade, P.V., Yamamuro, J.A., and Bopp, P.A. Significance of particle crushing in granular materials", J. Geotech. Eng., 122(4), pp. 309{316 (1996).