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Dynamic Properties of Seepage and Stability on Upstream Slope of an Unsaturated Homogeneous Earth Dam Subjected to Rapid Drawdown | ||
| تحقیقات مهندسی صنایع غذایی | ||
| Article 2, Volume 16, Issue 1, June 2015, Pages 19-36 PDF (2.81 M) | ||
| Document Type: Research Paper | ||
| DOI: 10.22092/jaer.2015.101248 | ||
| Abstract | ||
| Analysis of seepage from an earth dam helps determine water loss and is very important for analysis of the stability of these structures. The present study examined the effect of material hydraulic properties and drawdown rate and ratio on the position and form of the phreatic line, pore water pressure and the stability of the shoulder of a homogeneous earth dam. For this purpose, the materials used in the homogeneous earth dam were selected from the unsaturated soil hydraulic database. Seepage and stability analysis were performed using the Geostudio sub-programs of seep/w and slope/w (based on the finite element and limit equilibrium methods, respectively). Seepage and stability analysis were performed in steady and transient states by applying four different drawdown rates. The results showed that the lack of significant differences in safety factors means that application of constant or function conductivity does not affect downstream slope stability of a homogeneous earth dam and the phreatic line was independent of conductivity. Results from the numerical model shows the noticeable impact of the soil water characteristic curve and slope () on the rate of drainage and subsequent pore water pressure and shear strength. The safety factors and critical states changed as the degree of saturation decreased or increased. With rapid drawdown of the reservoir at constant volumetric water content, the state of the upstream shoulder became critical when the drawdown ratio (L/H) reached about 0.5. As the water content of the unsaturated zone and the capacity of drainage decreased, stability reached the minimum FOS at a reservoir water level of about 2/3 of the total drawdown height. | ||
| Keywords | ||
| Earth Dam; Rapid Drawdown; Seepage; Slope Stability; Soil Water Characteristic Curve | ||
| References | ||
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Alinezhad. H. and Zomorodian, S. M. A. 2010. Optimal horizontal and oblique drainage in homogeneous earth dam. Proceedings of the 5th National Congress on Civil Engineering. May. 4-6. Mashhad. Iran. (in Farsi) Anon. 1996. The UNSODA Unsaturated Soil Hydraulic Database. User Manual. Vol. 1. National Service Center for Environmental Publications (NSCEP). United State Environmental Protection Agency. Washington D. C. Anon. 1980. Earth Manual. 2nd Ed. United States Bureau of Reclamation (USBR). Department of Interior, Washington D. C. Anon. 1987. Design of Small Dams. United States Bureau of Reclamation (USBR). Department of Interior, Col., USA. Berilgen, M. M. 2007. Investigation of stability of slope under drawdown condition. Computers and Geotechnics, 81-91. Childs, E. C. and Collis-George, N. 1950. The permeability of porous materials. Proc. Royal Society. London. 201(1066): 392–405. Chu-Agor, M., Fox, G. A., Cancienne, R. M. and Wilson, G. V. 2008. Seepage caused tension failures and erosion undercutting of hillslopes. J. Hydrol. 359, 247-259. Fredlund, D. G. and Rahardjo, H. 1993. Soil Mechanics for Unsaturated Soils. John Wiley & Sons Inc. New York. Griffiths, D. V. and Lane, P. A. 2000. Assessment of stability of slopes under drawdown condition. J. Geotech. Geoenviron. Eng. 126(5): 443-450. Krahn, J. 2004. Seepage Modeling with seep/w. Geo-Slope International LTD. Calgary, Alberta, Canada. Lopez-Acosta, N. P., Fuente de la, H. A. and Auvinet, G. 2013. Safety of a protection levee under rapid drawdown conditions. Coupled analysis of transient seepage and stability. Proceedings of the 18th International Conference on Soil Mechanics and Geotechnical Engineering. September 2-6. Paris. 3305-3308.
Mahdavi, E., Ghorbanbeygi, S. and Sadatibaladehi, S. H. 2010. Evaluation of methods for determining the safety factors of slope stability in slope/w software. Proceedings of the 3rd National Congress on Urban Management and Construction Stability. May. 20. Arak. Iran. (in Farsi) Montaseri, M., Deiminiat, A. and Ghezelsofloo, A. A. 2010. Optimization of Clay Core Dimensions in Earth Dams Using Genetic Algorithm. Water. Soil Science (Agric. Sci.). 20(3): 73-86. (in Farsi) Moradi, G. H., Azadi, A. and Hoseinzadeh, Y. 2011. Investigation effective parameters on upstream slope stability of earth dam subjected to rapid drawdown. Proceedings of the 6th National Congress on Civil Engineering. Apr. 26-27. Morgenstern, N. 1963. Stability charts for earth slopes during rapid drawdown. Geotechnique. 13, 121-131. Nian, T., Jiang, J., Wan, Sh. and Luan, M. 2011. Strength reduction FE analysis of the stability of bank slopes subjected to transient unsaturated seepage. Electronic J. Geotech. Eng. 16, 165-177. Paronuzzi, P., Rigo, E. and Bolla, A. 2013. Influence of filling-drawdown cycles of the Vajont reservoir on Mt. Toc slope stability. Geomorphology. 191, 75-93. Souliyavong, T., Gallage, C., Egodawatta, P. and Maher, B. 2012. Factors affecting the stability analysis of earth dam slopes subjected to reservoir drawdown. Proceedings of the 2nd International Conference on Geotechnique, Construction Materials and Environment. Nov. 14-16. Kuala Lumpur. Malaysia. Vafaeiyan, M. 2006. Excute Information of Earth Dam. 2nd ED. Semnan. Iran. (in Farsi) Vanapalli, S. K., Fredlund, D. G., Pufahl, D. E. and Clifton, A. W. 1996. Model for the prediction of shear strength with respect to soil suction. Canadian Geotech. J. 33(3): 379-392. | ||
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