Factors affecting the stability analysis of earth dam slopes subjected to reservoir drawdown

Souliyavong, T., Gallage, Chaminda, Egodawatta, Prasanna, & Maher, B (2012) Factors affecting the stability analysis of earth dam slopes subjected to reservoir drawdown. In Hossain, Md. Zakaria & Huat, Bujang B.K. (Eds.) Proceedings of the Second International Conference on Geotechnique, Construction Materials and Environment, The GEOMATE International Society, Kuala Lumpur, Malaysia, pp. 507-512.


The drawdown of reservoirs can significantly affect the stability of upstream slopes of earth dams. This is due to the removal of the balancing hydraulic forces acting on the dams and the undrained condition within the upstream slope soils. In such scenarios, the stability of the slopes can be influenced by a range of factors including drawdown rates, slope inclination and soil properties. This paper investigates the effects of drawdown rate, saturated hydraulic conductivity and unsaturated shear strength of dam materials on the stability of the upstream slope of an earth dam. In this study, the analysis of pore-water pressure changes within the upstream slope during reservoir drawdown was coupled with the slope stability analysis using the general limit equilibrium method. The results of the analysis suggested that a decrease in the reservoir water level caused the stability of the upstream slope to decrease. The dam embankment constructed with highly permeable soil was found to be more stable during drawdown scenarios, compared to others. Further, lower drawdown rates resulted in a higher safety factor for the upstream slope. Also, the safety factor of the slope calculated using saturated shear strength properties of the dam materials was slightly higher than that calculated using unsaturated shear strength properties. In general, for all the scenarios analysed, the lowest safety factor was found to be at the reservoir water level of about 2/3 of drawdown regime.

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ID Code: 58170
Item Type: Conference Paper
Refereed: Yes
Keywords: Reservoir Drawdown, Earth Dam, Slope Stability, Hydraulic Conductivity, Unsaturated Shear Strength
ISBN: 978-4-9905958-1-4
Divisions: Current > Schools > School of Earth, Environmental & Biological Sciences
Current > QUT Faculties and Divisions > Science & Engineering Faculty
Copyright Owner: Copyright 2012 (please consult the authors).
Deposited On: 13 Mar 2013 02:56
Last Modified: 18 Mar 2013 14:45

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