Stability analysis of large rock slopes for Sardasht dam hydraulic power plant trenches considering rock cleavage

Document Type : Original Article

Authors

1 Mining Engineering Department, Kashn University, Kashan-Iran

2 Rock Mechanics Department, Amirkabi University of Technology

Abstract

The site for Sardasht dam and its hydraulic power plant contains metamorphic slate rock masses with distinguished cleavage surface characteristics leading to reduced rock mass strength. Hence, stability analysis of the surrounding structures, underground spaces and slopes, is of great importance. Stability analysis of the slope, adjacent to the dam, was carried out for the three conditions of without cleavage, considering cleavage and inclusion of fractures zones, based on limit equilibrium and finite difference methods using SLIDE and FLACSLOPE 2D codes, respectively. The results indicate that the slope slide was not found safe in the presence of cleavage and fractured zones. For assurance, further statistical analysis was also carried out on the slope stability.  The accumulative distribution function indicated that the confidence coefficient for 68% of the data was found to be less than 1.7, which confirms the extreme influence of cleavage on the slate rock mass strength. Therefore, the 1:6 slope presented in the drilling map preliminary report is unstable.

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حسنی پاک، ع.الف.، 1377. زمین آمار. انتشارات دانشگاه تهران، چاپ اول.
خدابنده لو، ف.، بهادر بیگی، د.، 1390. نرم افزار FLAC. انتشارات جهاد دانشگاهی واحد صنعتی امیرکبیر, چاپ سوم.
مهندسی مشاور سپاسد – فراب.،1390. گزارش زمین شناسی مهندسی مطالعات مرحله دوم, تهران.
مهندسی مشاور مشانیر، 1390. گزارش بررسی، بازنگری و صحه گذاری مطالعات مرحله اول طرح سد ونیروگاه سردشت. تهران، فصل یازدهم.
Al-Harthi, A.A., 1998. Effect of planar structures on the anisotropy of Ranyah sandstone, Saudi Arabia. Engineering Geology, 50: 49–57.
Bromhead, E.N., 2002. The stability of slopes. Blackie Academic and Professional., 2nd edition, London and New York, 441p.
Giani, G.P., 1992.  Rock slope stability analysis. A.A.Balkema., United States of America, pp.47-73.
Goshtasbi, K., Ahmadi, M., Seyedi, J., 2006.  Anisotropic strength behavior of  slates in the Sirjan-Sanandaj zone. The Journal of the South African Institute of Mining and Metallurgy, 106: 71-76.
Hoek, E., Bray, J.W., 1981. Rock slope  engineering. 3rd Edition, London, Institute of mining and Metallurgy.
Johansson, L., Axelsson, K., 1992. Calculation of the slope stability using classical calculation methods, a comparison between different calculation programmes, Published in Swedish, the Swedish commission on slope stability, Report 2:91.
Kliche, C.A., 1999. Rock slope stability. Society for Mining, Metallurgy and Exploration, Inc. United States of America, 134p.
Nasseri, M.H.B., Rao, K.S., Ramamurthy, T., 2003. Anisotropic strength and deformational behavior of Himalayan schists. International Journal of Rock Mechanics and Mining Sciences, 40:  3–23.
Piteau, D.,  Martin, D., 1982. Mechanics of rock slope failure. Third International conference on Stability of Surface Mining, Vancouver ,British Columbia, Society of Mining Engineering, pp. 113-169.
Rocscience, Inc., 2003. 2D Limit Equilibrium Slope Stability for Soil and Rock Slope (SLIDE), A users manual, Version 5.
Sjoberg, J., 1999 .Analysis of  large scale rock slopes. Department of Civil and Mining Enginering, Sweden, pp.11-35.
Tien, Y.M., Kuo, M.Ch., Juang, Ch.H., 2006. An experimental investigation of the failure mechanism of simulated transversely isotropic rocks. International Journal of Rock Mechanics and Mining Sciences, 43:  1163–1181.
Tien, Y. M.,  Kuo,  M. C., 2001. A failure criterion for transversely isotropic rock. International Journal of Rock Mechanics and Mining Sciences, 38:  399–412.
Walsh, M.J., 2003. Engineering and design slope stability. US Army Corps of  Engineers, Washangton, DC, 205p.
Wyllie, D., 2005. Foundations on rock. E and FN Spon is an imprint of the Taylor and Francis Group.New York, 457p.
Wyllie, D., Mah, C., 2004. Rock slope engineering. Spon Press is an imprint of the Taylor and Francis Group. New York, 455p.
Xue-min, Z., Feng, Y., Jun-sheng, Y., 2010. Experimental study on anisotropic strength properties of sandstone. The Electronic Journal of Geotechnical Engineering, 15: 1325-1335.