Assessment of the Upstream Slope Stability of Darbandikhan Rockfill Dam during Drawdown

Sirwan Gh. Salim; Krikar M. G. Noori

doi:10.14500/aro.10678

Sirwan Gh. Salim 1Department of City Planning, Technical College of Engineering, Sulaimani Polytechnic University, Sulaymaniyah, Kurdistan Region – F.R. Iraq http://orcid.org/0000-0002-1093-6166
Krikar M. G. Noori Department of Petroleum Technology, Control and Operation, Koya Technical Institute, Erbil Polytechnic University, Erbil, Kurdistan Region – F.R. Iraq http://orcid.org/0000-0001-8192-2776

Keywords: Drawdown rate, Earth/Rockfill dam, Factor of safety, GeoStudio 2012, Pore water pressure

Abstract

Earth and rockfill dams face a variety of loading conditions during lifetime. One of the most critical loading conditions is the rapid drawdown of water level after steady state conditions. Rapid drawdown may cause instability of upstream slope of the dam. The present work examines the stability of a rockfill dam under different drawdown rates in terms of factor of safety for the upstream slope of the dam. For this purpose, a computer software named GeoStudio 2012 SEEP/W and SLOPE/W has been used for the numerical analysis. The results showed that the drawdown rate has a significant effect on stability of rockfill dam in which increasing the drawdown rate from 1 m/day to 10 m/day decreases the stability of the dam by 33%. Based on the outcomes, for the studied case the drawdown rate (1 m/day) can be recommended.

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Author Biographies

Sirwan Gh. Salim, 1Department of City Planning, Technical College of Engineering, Sulaimani Polytechnic University, Sulaymaniyah, Kurdistan Region – F.R. Iraq

Sirwan Ghafoor Salim is an Assistant Lecturer at the Department of City Planning, Technical College of Engineering, Sulaiamni Polytechnic University, Kurdistan region, Iraq. He got the B.Sc. degree from the University of Sulaimani, Kurdistan region, Iraq, and the M.Sc. degree from Nottingham University, UK. His research interests are in dam engineering, foundation engineering and soil&rock mechanics.

Krikar M. G. Noori, Department of Petroleum Technology, Control and Operation, Koya Technical Institute, Erbil Polytechnic University, Erbil, Kurdistan Region – F.R. Iraq

Krikar M. Gharrib Noori is a Lecturer at the Koya Technical Institute, Erbil Polytechnic University, Kurdistan region, Iraq. He got the BSc degree in Koya University, Kurdistan region, Iraq, and the MSc degree in Nottingham University, UK. His research interests are in earth and rockfill dam, tunnelling, ground improvement, soil&rock mechanics and foundation engineering.

References

Abbas, J.M., Aljanabi, Q.A. and Mutiny, Z.A., 2017. Slope stability analysis of an earth dam. Diyala Journal of Engineering and Science, 10(1), pp.106-117.

Alonso, E. and Pinyol, N., 2009. Slope Stability Under Rapid Drawdown Conditions, Barcelona.

Bishop, A.W. and Morgenstern, N., 1960. Stability coefficients for earth slopes. Geotechniques, 4(10), pp.164-169.

Bishop, A.W., 1955. The use of slip circle in the stability analysis of slopes. Geotechniques, 1(5), pp.7-17.

Davis, C.V. and Asce, M., 1958. Rockfill Dam, the Derbandi Khan Dam, Portland, Oregon.

Duncan, J.M., Wright, S.G. and Wong, K.S., 1990. Slope Stability during Rapid Drawdown.

Fattah, M.Y., Omran, H.A. and Hassan, M.A., 2015. Behavior of an earth dam during rapid drawdown of water in reservoir-case study. International Journal of Advanced Research, 3(10), pp.110-122.

Fellenius, W., 1936. Calculation of Stability of Earth Dams, pp.445-463.

Gao, Y.F., Zhang, F., Lei, G.H. and Li, D.Y., 2013. An extended limit analysis of three-dimensional slope stability. Geotechnique, 6(63), pp.518-524.

Janbu, N., 1954. Applications of Composite Slip Surfaces for Stability Analyses, Stockhol, pp.39-43.

Janbu, N., 1968. Slope Stability computations. Technical University of Norway, Trondheim.

Morgenstrern, N.R. and Price, V.E., 1965. The analysis of the stability of general slip surfaces. Geotechnique, 1(15), pp.79-93.

Novak, P., Moffat, A., Nalluri, C. and Narayanan, R., 2001. Hydraulic Structures. Spon Press, London.

Pinyol, N.M., Alonso, E.E. and Olivella, S., 2008. Rapid drawdown in slopes and embankments. Water Resources Research, 44, pp.1-22.

Rulon, J.J. and Freeze, R.A., 1985. Multiple seepage faces on layered slopes and their implications for slope stability analysis. Canadian Geotechnical Journal, 22, pp.347-356.

SEEP/W, 2012. GEO-SLOPE International Ltd., Seepage Modeling with SEEP/W 2012: An Engineering Methodology. 6th ed. GEO-SLOPE International Ltd., Alberta.

Siacara, A.T., Beck, A.T. and Futai, M.M., 2020. Reliability analysis of rapid drawdown of an earth dam using direct coupling. Computers and Geotechnics, 118, pp.1-16.

Sica, S., Pagano, L. and Rotili, F., 2019. Rapid drawdown on earth dam stability after a strong earthquake. Computers and Geotechnics, 116, p.103187.

SLOPE/W, 2012. GEO-SLOPE International Ltd., Stability Modelling with SLOPE/W 2012: An Engineering Methodology. 6th ed. GEO-SLOPE International Ltd., Alberta.

Souliyavong, T., Gallage, C., Egodawatta, P. and Maher, B., 2012. Factors Affecting the Stability Analysis of Earth Dam Slopes Subjected to Reservoir Drawdown, Kuala Lampur, pp.507-512.

Tatewar, S.P. and Pawade, L.N., 2012. Stability analysis of earth dam by geo-studio software. International Journal of Civil Engineeringand Technology, 3(1), pp.437-446.

Tourism of Kurdistan, 2020. Official Site of General Board of Tourism of Kurdistan-Iraq. Available from: http://www.bot.gov.krd/sulaimaniya-province/ darbandikhan. [Last accessed on 2020 Apr 01]