Three-dimensional seismic response of earth dams subjected to spatially varying earthquake ground motion

نوع مقاله : مقاله پژوهشی‌

نویسندگان

1 Ph.D. Candidate, Department of Civil Engineering, Science and Research Branch, Islamic Azad University, Tehran, Iran

2 Associate Professor, Geotechnical Engineering Research Center, International Institute of Earthquake Engineering and Seismology (IIEES), Tehran, Iran

3 Professor, International Institute of Earthquake Engineering and Seismology, Tehran, Iran

4 Assistant Professor, Department of Structural Engineering, Science and Research Branch, Islamic Azad University, Tehran, Iran

چکیده

For extended structure, the seismic load has a spatiotemporal variation that simultaneously changes with time and space. The incorporation of the seismic wave spatial random variability effect is
especially important when large structures such as long bridges, dams, and large buildings are
analyzed. The effect of spatially varying earthquake ground motion (SVEGM) on the seismic
response of earth dams is analyzed in this paper. To this end, a parametric study is conducted to investigate the effects of length to height ratio ( ) on the 3D seismic response of the studied dams. Ground motions, consistent with the three-directional lagged coherency model, are generated at
different discretized cells at the base of the dam. The dams are assumed to sit on trapezoidal and
V-shaped canyons and vibrate in all three directions, upstream-downstream, vertical, and
longitudinal. The average coherency of different frequencies is calculated and used for the generation of SVEGM. The time histories are simulated using a spectral representation-based method. The
separation distance between the cells is determined in such a way that 90% of correlation between seismic input motions can be captured. For each case of  ratio, a numerical model of the dam and its foundation is constructed using the finite difference numerical method. The 3D seismic
behavior of the earth dams is evaluated under the artificially generated three-directional components of SVEGM. Generally, it is concluded that with increasing  ratio, at the midpoint of the dam crest, the difference between maximum of acceleration values obtained by applying uniform and SVEGM excitations decreases. In all cases of analyses, SVEGM has decreasing effect on the vertical displacement of dam crest.

کلیدواژه‌ها

موضوعات

عنوان مقاله [English]

Three-dimensional seismic response of earth dams subjected to spatially varying earthquake ground motion

نویسندگان [English]

  • Amir Ghalyanchi Langroudi 1
  • Mohammad Davoodi 2
  • Mohammad Kazem Jafari 3
  • Masoud Nekooei 4
1 Ph.D. Candidate, Department of Civil Engineering, Science and Research Branch, Islamic Azad University, Tehran, Iran
2 Associate Professor, Geotechnical Engineering Research Center, International Institute of Earthquake Engineering and Seismology (IIEES), Tehran, Iran
3 Professor, International Institute of Earthquake Engineering and Seismology, Tehran, Iran
4 Assistant Professor, Department of Structural Engineering, Science and Research Branch, Islamic Azad University, Tehran, Iran
چکیده [English]

For extended structure, the seismic load has a spatiotemporal variation that simultaneously changes with time and space. The incorporation of the seismic wave spatial random variability effect is
especially important when large structures such as long bridges, dams, and large buildings are
analyzed. The effect of spatially varying earthquake ground motion (SVEGM) on the seismic
response of earth dams is analyzed in this paper. To this end, a parametric study is conducted to investigate the effects of length to height ratio ( ) on the 3D seismic response of the studied dams. Ground motions, consistent with the three-directional lagged coherency model, are generated at
different discretized cells at the base of the dam. The dams are assumed to sit on trapezoidal and
V-shaped canyons and vibrate in all three directions, upstream-downstream, vertical, and
longitudinal. The average coherency of different frequencies is calculated and used for the generation of SVEGM. The time histories are simulated using a spectral representation-based method. The
separation distance between the cells is determined in such a way that 90% of correlation between seismic input motions can be captured. For each case of  ratio, a numerical model of the dam and its foundation is constructed using the finite difference numerical method. The 3D seismic
behavior of the earth dams is evaluated under the artificially generated three-directional components of SVEGM. Generally, it is concluded that with increasing  ratio, at the midpoint of the dam crest, the difference between maximum of acceleration values obtained by applying uniform and SVEGM excitations decreases. In all cases of analyses, SVEGM has decreasing effect on the vertical displacement of dam crest.

کلیدواژه‌ها [English]

  • SVEGM
  • earth dam
  • coherency model
  • finite-difference numerical method
  • dynamic analysis

مراجع

Chen, M. T., and Harichandran, R. S., 2001, Response of an earth dam to spatially varying earthquake ground motion: Journal of Engineering Mechanics, 127(9), 932-939.
Dakoulas, P., and Hashmi, H., 1991, Response of earth dams in canyons subject to asynchronous base excitation: Proceeding of Second International Conference of Geotechnic, Earthquake Engineering & Soil Dynamics: St. Louis, II, 1105-1112.
Davoodi, M., Jafari, M. K., and Sadrolddini, S. M. A., 2013, Effect of multi-support excitation on seismic response of embankment dams: International Journal of Civil Engineering, 11(1), 19-28.
Davoodi, M., and Sadreddini, A., 2010, Seismic behavior of a large embankment dam under incoherent ground motions: 4th International Conference on Geotechnical Engineering and Soil Mechanics (ICGESM), Tehran, Iran.
Efthymiou, E. A., 2019, The effect of multi-angle spatially variable ground motions on the seismic behaviour of cable-stayed bridges: City, University of London.
Haroun, M. A., and Abdel-Hafiz, E. A., 1987, Seismic response analysis of earth dams under differential ground motion: Bulletin of the Seismological Society of America, 77, 1514-1529.
Itasca Consulting Group, Inc., 2002, FLAC3D — Fast Lagrangian Analysis of Continua in Three-Dimensions, User's manual: Itasca, Minneapolis.
Liu, T., and Hong, H., 2015, Simulation of horizontal ground motions with spatial coherency in two orthogonal horizontal directions: Journal of Earthquake Engineering, 19(5), 752-769.
Liu, T., and Hong, H., 2016, Assessment of spatial coherency using tri-directional ground motions: Journal of Earthquake Engineering, 20(5), 773-794.
Luco, J., and Wong, H., 1986, Response of a rigid foundation to a spatially random ground motion: Earthquake Engineering & Structural Dynamics, 14(6), 891-908.
Nippon Koei Group, Moshanir, Lahmeyer, 1999, Masjed-E-Soleiman HEEP report on dynamic analysis for the Masjed-E-Soleiman dam.
Sadreddini, A., and Davoodi, M., 2010, Response of a rockfill dam to spatially varying earthquake ground motion: 14th European Confrence on Earthquake Engineering, Ohrid, Macedonia.
Sadreddini, S. M. A., 2012, Evaluation of the effect of spatially varying earthquake ground motion on the seismic behavior of earth dams: PhD thesis, Science and Research Branch, Islamic Azad University, Tehran, Iran, 2012.
Sadrolddini, S. M. A., Davoodi, M., and Jafari, M. K., 2013, Effects of different frequency content of multi-support excitations on seismic response of a large embankment dam: Iranian Journal of Science and Technology, Transactions of Civil Engineering, 37(C2), 243-256.
Sawada, Y., and Takahashi, T., 1975, Study on the material properties and the earthquake behaviors of rockfill dams: Proceeding of 4th Japan Earthquake Engineering Symposium.
Shih, J. Y., Thompson, D., and Zervos, A., 2016, The effect of boundary conditions, model size and damping models in the finite element modelling of a moving load on a track/ground system: Soil Dynamics and Earthquake Engineering, 89, 12-27.
Swaisgood, J., 2003, Embankment dam deformations caused by earthquakes: Pacific conference on earthquake engineering.
مجله ژئوفیزیک ایران
دوره 17، شماره 3
مهر و آبان 1402
صفحه 1-12

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