Stability Control of Narmab Dam and Sensitivity Analysis of Reliability Coefficients

Atanaz Bahrami Balfeh Teimouri, Ahad Bagherzadeh Khalkhali


Static and quasi-static stability analysis of embankment dams is of vital importance in different stages of dam’s design, construction and operation. The stability can be studied using different techniques which are generally analyzed through Limit Equilibrium Method. Base on this main method, the critical slip surface is selected and the shear strength required to counter the slip at the selected surface is obtained and compared with shear strength of the soil at that surface in order to obtain confidence coefficient. In the present research, the Geo-studio Slope/w software that is a geotechnical software based on finite element method and is widely used in geotechnical field, is employed in order to analyze the stability of the body and foundation of Narmab dam in Golestan province. Narmab dam is a homogeneous embankment dam with a height of 60 m, crest length of 807 m and reservoir volume of 115 million cubic meters. The confidence coefficients provided by the software are compared to the permissible confidence coefficients. Moreover, the sensitivity of the confidence coefficients values to the changes in the effective factors, adhesion and internal friction coefficient, is analyzed. The analyses were performed on 8 values (±5, ±10, ±15, ±20) of c and φ and the obtained values of confidence coefficients were compared. In addition, a comparison was made between different methods of stability analysis. According to the static and quasi-static conditions, Narmab dam is stable in all loading stages (End of Construction, First Impounding and Steady State Seepage and In general, only for the static conditions of the end of construction stage, the sensitivity of adhesion is greater than the angle of internal friction, but, in other conditions and stages, the sensitivity of friction angle has more effects.


Stability; Coefficient of Confidence; Finite Element; Sensitivity Analysis; Geo-Studio Slope/W.


Ghanbary- A, Principles of Soil Dams Engineering, Tehran, Kharazmi University Press, 2015.

Rahardjo, H, K.J Hritzuk, E.C Leong, and R.B Rezaur. “Effectiveness of Horizontal Drains for Slope Stability.” Engineering Geology 69, no. 3–4 (June 2003): 295–308. doi:10.1016/s0013-7952(02)00288-0.

Report "Geological studies of Narmab reservoir site - second phase studies - Narmab Reservoir Dam", 2004, Water and Sustainability Development Engineers.

Report of the Narmab Dam Project, Regional Water Company of Golestan Province, (2003).

Rahimi-H, Principles of Soil Dams Engineering, Tehran, Tehran University Press, 671, 2006.

Askaripour-V, Soltani-F, Investigating the effect of deviations of measured values of shear soil parameters on the stability of dams, 2015, 5th, Jihad University of Kerman.

Taghizadeh-M-h. and Vafaiean-M. Investigation of the stability of the slopes of the soil by changing the shear parameters of the soil. National Electronic Conference of New Achievements in Engineering and Basic Sciences, Tehran, Center for Earthquake Research, (2015).

Alonso, E. E. “Risk Analysis of Slopes and Its Application to Slopes in Canadian Sensitive Clays.” Géotechnique 26, no. 3 (September 1976): 453–472. doi:10.1680/geot.1976.26.3.453.

Kamanbedast, A., and A. Delvari. "Analysis of earth dam: Seepage and stability using ansys and geo-studio software." World Applied Sciences Journal 17, no. 9 (2012): 1087-1094.

Hasani, H., J. Mamizadeh, and H. Karimi. "Stability of slope and seepage analysis in earth fills dams using numerical models (Case Study: Ilam Dam-Iran)." World Applied Sciences Journal 21, no. 9 (2013): 1398-1402. doi: 10.5829/idosi.wasj.2013.21.9.1313.

Arshad, Imran, Muhammed Muneer Babar, and Natasha Javed. "Numerical Analysis of Seepage and Slope Stability in an Earthen Dam by Using Geo-Slope Software." PSM Biological Research 2, no. 1 (2017): 13-20.

Devi, D. Durga Naga Laxmi, and R. Anbalagan. "Study on Slope Stability of Earthen Dams by using GEOSTUDIO Software." International Journal of Advance Research, Ideas and Innovations in Technology 3, no. 6 (2017): 408-414.

Report "Borrowing Resources and Building Materials of the Second Phase of the Dam Control Study of Normab", July 2005, Water and Sustainable Development Engineers.

Zhang, Lianyang. Engineering properties of rocks. Butterworth-Heinemann, 2016.

SLOPE/W for Slope Stability Analysis, User’s Guide, Geoslope international limited, Calgary, Canada, Version 2016.

Seed H.B, Idriss I. M. Soil module and damping factors for dynamic response analysis, University of California,Berlely, Rep. EERC 70-10,1970.

U.S. Army Corps of Engineers, “Stability of Earth and Rock-Fill Dams”, EM 110-2-1902, (1970).

Mirzaie Gamchi- Gh. and Parivashi-A. “Sensitivity Analysis of Parameters Effecting on Gate Hassanloo Dam Sustainability”. 2th International Conference on Geotechnics and Seismic Engineering, (2014).

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DOI: 10.28991/cej-03091150


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