Slope Stability of an Earth Dam during Drawdown Conditions (KHASA-CHAI Dam) as a Case Study

 
 
 
  • Abstract
  • Keywords
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  • Abstract


    Aiming in this research was to have a clear view about the behavior of Khasa-Chai Dam during the draw down action taking into consideration the newly built of this dam which was filling during the time of this article, the upstream slope was investigated by taking drawdown of the water from the reservoir. This dam is consists of the zoned embankment with a total length of (2.36 km) with an upstream slope (1v:3h) and downstream slope (1v:2h). Slope stability was investigated during the drawdown of the water from the reservoir by considering the water in the reservoir to be at maximum water level and by taking two cases during the rapid and slow drawdown. SLOPE/W which is a sub program from Geo-Slope software was used in association with SEEP/W software to find the factor of safety of the upstream slip surface during the drawdown conditions. It was noticed from the drawdown conditions that the phreatic line falls almost at the same position for both cases. Also for both cases the factor of safety of the upstream slip surface falls above the value of (1.0) and that is mean the upstream slope is in a safe condition when the water drawdown. The exit gradient and the rate of flow at the downstream face decrease with time as the water in the reservoir drawdown which means the factor of safety against boiling increases with time.

     

     


  • Keywords


    Slope Stability analysis; Embankment Dams; Finite Elements; Khasa-Chai Dam; Drawdown conditions.

  • References


      [1] Abadjiev, C.B., (1994), “Safety Assessment and Stability Improvement of the Upstream Slope of Earth Dams”, Proc. Of the 18th ICOLD Congress. Durban, South Africa. 1:261-273.

      [2] An Engineering Methodology, (2007), "Slope Stability Modelling with SLOPE/W", GEO-SLOPE International Ltd.

      [3] Berilgen M., 2007,”Investigation of stability of slopes under drawdown condition”. Computers and Geotechnics 34:81-91.

      [4] Engemoen, B., (2014) “Embankment Dams”, U.S. Department of Interior Bureau of Reclamation 2014, DS-13(8)-4.1,Phase 4 (Final) January 2014 Chapter 8: Seepage.

      [5] Fattah, M.Y., (2015), “Behavior of an Earth Dam during Rapid Drawdown of Water in Reservoir”, International Journal of Advanced Research, 3(10):110-122.

      [6] Khassaf, S.I., Abdul-Hameed, M.R, Shams Al-deen, N.N., (2013), "Slope Stability Analysis under Rapid Drawdown Condition and Seismic Loads of Earth Dam (Case Study: Mandali Dam) ". International Journal of Innovative Research in Science, Engineering and Technology, 2(12):7114-7118.

      [7] Report of site investigation for Khasa Chai Dam, (2006), prepared by Andrea Engineering Tests Laboratory, Baghdad, Iraq.

      [8] Tran,X.T.(2004).“Stability Problems of an Earth Fill Dam in Rapid Drawdown Condition”, Ph.D.Dissertation, Slovak University of Technology.

      [9] Zomorodian, A. S.M., and Abodollahzadeh, M.S., (2010), "Effect of Horizontal Drains on Upstream Slope Stability during Rapid Drawdown Condition", International Journal of Geology, 4(4):85-90.


 

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Article ID: 23605
 
DOI: 10.14419/ijet.v7i4.37.23605




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