Improved Equal-K Method for Evaluation of Stability of Gravity Dams against Sliding along Deep-Failure Surfaces in Foundation: Case Study in China
Publication: International Journal of Geomechanics
Volume 16, Issue 3
Abstract
A newly built roller-compacted concrete gravity dam is located on the Yalongjiang River in southwest China. Complex geological conditions greatly puzzled the designers of the project. There are abundant joints within the riverbed that form the double-inclined wedge foundation. This is a typical mode of instability of concrete gravity dams. The equal-K method, which falls into the category of conventional limit-equilibrium methods, is provided in the design codes of gravity dams to evaluate the stability of a dam against sliding along deep failure surfaces. The factor of safety calculated by the equal-K method is determined by the angle of the force acting on the interface of the two inclined wedges, denoted by , which is unspecified in the design codes. On the basis of Sarma’s assumption, this study proposes an algorithm for the determination of , which needs only slight improvement of the algorithm in the existing codes. The justification of the proposed procedure is demonstrated by showing that the results from the proposed procedure are very close to those from a rigorous limit-equilibrium method in which all equilibrium conditions are satisfied.
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Acknowledgments
The authors are grateful for the support of the National Basic Research Program of China (973 Program, Grant Nos. 2011CB013505 and 2014CB047100) and the National Natural Science Foundation of China (Grant No. 11202223).
References
Bishop, A. W. (1955). “The use of the slip circle in the stability analysis of slopes.” Géotechnique, 5(1), 7–17.
Bretas, E. M., Lemos, J. V., and Lourenco, P. B. (2010). “Masonry gravity dams: A numerical application for stability analysis.” Proc., 8th Int. Masonry Conf., International Masonry Society, Shermanbury, U.K., 1963–1972.
Chen, S., Qiang, S., Shahrour, I., and Egger, P. (2008). “Composite element analysis of gravity dam on a complicated rock foundation.” Int. J. Geomech., 275–284.
Chen, Z. Y. (2002). “Discussion of the wedge stability analysis method specified in the gravity dam design code.” J. Hydroelectric Eng., 2(2), 101–107 (in Chinese).
COE (Corps of Engineers). (1995). “Engineering and design: Gravity dams design.” EM1110-2-2200. Washington, DC.
Duncan, J. M. (1996). “State of the art: Limit equilibrium and finite-element analysis of slopes.” J. Geotech. Eng., 577–596.
Goodman, R. E. (1988). Introduction to rock mechanics, John Wiley & Sons, New York.
Guo, L. N., Li, T. C., Lu, S. S., and Guo, Y. J. (2011). “Deep sliding stability analysis of gravity dam based on FEM strength reduction.” Adv. Mater. Res., 243–249, 4608–4613.
Larese, A., Rossi, R., Oñate, E., Toledo, M., Morán, R., and Campos, H. (2015). “Numerical and experimental study of overtopping and failure of rockfill dams.” Int. J. Geomech., 04014060.
Léger, P., Bretas, E. M., and Lemos, J. V. (2012). “3D stability analysis of gravity dams on sloped rock foundations using the limit equilibrium method.” Comput. Geotech., 44(6), 147–156.
Léger, P., Tinawi, R., Bhattacharjee, S. S., and Leclerc, M. (1997). “Failure mechanisms of gravity dams subjected to hydrostatic overload: Influence of weak lift joints.” ICOLD XIX Congress on Large Dams, R. B. Jansen, ed., Van Nostrand-Reinhold, New York, 11–38.
Pan, J. Z. (1987). Gravity dam design, Water Resources and Electric Power Press, Beijing (in Chinese).
Ren, X. H., Shu, J. Q., Ben, N. H., and Ren, H. Y. (2008). “Stability analysis of concrete gravity dam on complicated foundation with multiple slide planes.” Water Sci. Eng., 1(3), 65–72.
Sarma, S. K. (1979). “Stability analysis of embankments and slopes.” J. Geotech. Engrg. Div., 105(12), 1511–1524.
Su, H., Hu, J., Li, J., and Wu, Z. (2013). “Deep stability evaluation of high-gravity dam under combining action of powerhouse and dam.” Int. J. Geomech., 257–272.
PSCGPRC (Professional Standards Compilation Group of People’s Republic of China). (2000). “Design specification for concrete gravity dams.” DL 5108-1999, China Power Press, Beijing (in Chinese).
PSCGPRC (Professional Standards Compilation Group of People’s Republic of China). (2005). “Design specification for concrete gravity dams.” SL 319-2005, Chinese Water Conservancy and Electric Power Press, Beijing (in Chinese).
Wang, H., Chang, X. L., Zhou, W., and Deng, J. H. (2010). “Distinct element method for analyzing the stability of gravity dam against deep sliding based on fluid-solid coupling.” J. Sichuan Univ., 42(1), 48–53 (in Chinese).
Wang, J. H., Zhou, X. L., and Lu, J. F. (2003). “Dynamic response of pile groups embedded in a poroelastic medium.” Soil Dyn. Earthquake Eng., 23(3), 235–242.
Zheng, H., and Tham, L. G. (2009). “Improved Bell’s method for the stability analysis of slopes.” Int. J. Numer. Anal. Methods Geomech., 33(14), 1673–1689.
Zhou, W., Chang, X. L., Zhou, C. B., and Liu, X. H. (2008). “Failure analysis of high-concrete gravity dam based on strength reserve factor method.” Comput. Geotech., 35(4), 627–636.
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Published In
International Journal of Geomechanics
Volume 16 • Issue 3 • June 2016
Copyright
© 2015 American Society of Civil Engineers.
History
Received: Dec 8, 2014
Accepted: May 7, 2015
Published online: Oct 20, 2015
Discussion open until: Feb 17, 2016
Published in print: Jun 1, 2016
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