Evaluation of Geometric Effect on the Pseudo-Static Seismic Coefficient in Embankment Dams

Year 2012, Volume: 25 Issue: 3, 707 - 719, 19.07.2012

Mahdi Shırdel , Ali Ghanbarı Mohammad Davoudı

Abstract

Selection of appropriate seismic coefficients considering the geometry, stiffness and damping of materials is the foremost part of analysis in Pseudo-static approach. So Masjed Soleiman dam for a case study has been selected. Finite Element model of Masjed Soleiman dam has been constructed in GeoStudio-Geoslope software. Also in constructing of finite element model, has been used of Mohr-Coulomb failure criterion for body of dam. For analyses of finite element model, first a layer analysis has been carried out considering 12 layers in end of construction stage. Then, this analysis has been continued considering water table and weight of dam reservoir. 2 earthquake records in the far field condition have been applied horizontally to the bedrock as the input for dynamic analysis. In this study, to perform stability analysis and calculate the factor of safety, critical sliding surface on downstream that was reported by the consultant engineers have been considered. The semi empirical Newmark method for estimating permanent earthquake-related deformation of slopes is based on the sliding block framework. This conceptual framework approximates the potential sliding mass as a rigid body resting on a rigid sloping base. Assuming the allowable permanent deformations to be 300mm, a new perspective on dynamic factor of safety is proposed in this research. Also, in order to investigate the variations of pseudo-static acceleration coefficient along the height of dam, all analyses have been carried out in static, pseudo-static and dynamic conditions for the Masjed Soleiman dam assuming various geometrical properties. The results demonstrate a decrease in acceleration with increase in the height of dam and also an increase in the acceleration with steepening the slopes.

Keywords: Embankment dams, Pseudo-static method, Dynamic analysis, Masjed Soleiman dam

Keywords

Embankment dams, Pseudo-static method, Dynamic analysis, Masjed Soleiman dam

References

• Terzaghi, K., “Mechanism of landslides”. Berkeley, Geological Society of America. 83–123, (1950).
• Baker, R., Shukha, R., Operstein, V., Frydman, S., “Stability charts for pseudo-static slope stability analysis”. Soil Dynamics and Earthquake Engineering, 26 (9):813-823, (2006).
• Shukha, R., Baker, R., “Design implications of the vertical pseudo-static coefficient in slope analysis”. Computers and Geotechnics, 35 (1):86-96 (2008).
• Siad, L., “Seismic stability analysis of fractured rock slopes by yield design theory”, Soil Dynamics and Earthquake Engineering, 23(3): 21-30, (2003).
• Li, A.J., Lyamin, A.V., Merifield, R.S., “Seismic rock slope stability charts based on limit analysis methods”. Computer and Geotechnics, 36( 1- ):135-148 (2009).
• Ausilio, E., Conte, E., Dente, G., “Seismic stability analysis of reinforced slopes”,Soil Dynamics andEarthquake Engineering, 19(3): 159-172, (2000).
• Nouri, H., Fakher, A., Jones, C.J.F.P., “Evaluating the effects of the magnitude and amplification of pseudo-static acceleration on reinforced soil slopes and walls using the limit equilibrium Horizontal Slices Method”. Geotextiles and Geomembranes, (3): 263-278, (2008).
• Azad, A., Yasrobi, S.Sh., Pak, A., “Seismic active pressure distribution history behind rigid retaining walls”, Engineering, 28(5): 365-375, (2008).
• Shekarian, S., Ghanbari, A., Farhadi, A., “New seismic parameters in the analysis of retaining walls with reinforced backfill”. Geotextiles and Geomembranes, 26(4): 350-356, (2008).
• Tokimatsu, K., Suzuki, H., Sato, M., “Effects of inertial and kinematic interaction on seismic behavior of pile with embedded foundation”. Soil Dynamics and Earthquake Engineering, 25, (7- ): 753-762, (2005).
• Park, D., Sagong, M., Kwak, D.Y., Jeong, Ch.G., “Simulation of tunnel response under spatially varying ground motion”. Soil Dynamics and Earthquake Engineering, 29(11-12):1417-1424 (2009).
• Seed, H.B., Martin, G.R., “The seismic coefficients in earth dam design”. ASCE, Journal of Soil Mechanic and Foundation, Div, SMC, (1966).
• Makdisi, F.I., Seed, H.B., “A simplified procedure for estimating earthquake-induced deformation in dams and embankments”. J, Geotech Eng, (12): 1427-1434, (1978).
• Seed, H.B., “Consideration in the earthquake resistant design of earth dams”. Geotechnique,29:215-263, (1979).
• Hynes-Griffin, M.E., Franklin, A.G., “Rationalizing the seismic coefficient method”. US Army Corp of Engineers. Waterways Experiment Station, Vicksburg, MS, GL-84-13, (1984).
• Yanagisawa, E., “Dynamic behavior of rock fill dams”, Advanced in rock fill structures. E.Marahha das neves, Academic publishers, Netherlands, (1984).
• U.S.Army corps of Engineers,. “Geologic hazards evaluation”. Appendix F, (1992).
• IITK-GSDMA., “Guidelines for seismic design of earth dams and embankments”. Indian Institute of Technology Kanpur, (2005).
• Ghanbari, A., Davoodi, M. Ahmadi, B., “Pseudo- static analysis for the masjed soleiman dam”. International Water Power and Dam Construction, Dam Engineering, XIX ( 2): 123- , (2008).
• Eisenstein, Z., “Computer analyses in earth dam engineering”, Computers in soil mechanics: present and future, R. L, (1979).
• Elgamal, A. W. M., Abdel-Ghaffar, A. M., Prevost, J. H., “2-D Elasto-plastic Seismic Shear Response of Earth Dam”, ASCE, Journal of the Engineering Mechanics, 113 (5): 702-719, (1987).
• Davoodi, M., “Evaluating dynamic characteristics of embankment dams using ambient and forced vibration tests”. PhD thesis, International Institute of Earthquake Engineering and Seismology, (2003). www.peer.berkeley.edu
• Kuhlemeyer, R., Lysmer, J., “Finite element method accuracy for wave propagation problems”, Journal of Soil Mechanic and Foundation, Div, ASCE, 99, 421-427, (1973).
• Kavazanjian. E., Matasovic, N., Hadj-Hamou, T., Sabatini, P.J., “Design guidance, geotechnical earthquake engineering for highways”. Vol.1, Design Principles, Geotechnical Engineering Circular 3, Publication FHWA-SA-97-076, Federal Highways Administration, U.S. Department of Transportation, Washington, DC, (1997).
• Bray, J.D., Rethie, E.M., Augello, A.J., Merry, S.M., “Simplified seismic designs procedure for geosynthetic lined”. Soil-waste landfills, Geosynthetics International, 5(1-2), 203-235, (1988).
• “Earthquake Resistant Design Codes in Japan”, Japan Society of Civil Engineers(2000).
• Indian Standard IS., 1893-1984, “Criteria for earthquake resistant design of structure”.
• Earthquake Resistant Regulations, a Word List , International Association for Earthquake Engineering, Tokyo, (1988).