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TitleExperimental and analytical study of seismic site response of discontinuous permafrost
AuthorDadfar, B; El Naggar, M H; Nastev, M
SourceCanadian Geotechnical Journal issue 9, 2016 p. 1363-1375, (Open Access)
Alt SeriesEarth Sciences Sector, Contribution Series 20150319
PublisherCanadian Science Publishing
Mediapaper; on-line; digital
File formatpdf; html
ProgramQuantitative risk assessment project, Public Safety Geoscience
Released2016 04 25
AbstractSeismic site response of discontinuous permafrost is discussed. The presence of frozen portions in soil deposits can significantly affect their dynamic response due to stiffer conditions characterized by higher shear wave velocities compared to unfrozen soils. Both experimental and numerical investigations were conducted to examine the problem. The experimental program included a series of 1g shaking table tests on small-scale models. Nonlinear numerical analyses were performed employing the FLAC software. The numerical model was verified using the obtained experimental results. Parametric simulations were then conducted using the verified model in order to study the variations of the free-field spectral accelerations (on top of the frozen and unfrozen soil blocks) with the scheme of frozen/unfrozen soil, and to determine the key parameters and their effects on the seismic site response. The results showed that spectral accelerations were generally higher in frozen soils than in unfrozen soils. It was found that the shear wave velocity of the frozen soil, the assumed geometry of the blocks and their spacing have significant impact on the site response.
Summary(Plain Language Summary, not published)
Knowledge of the seismic response of discontinuous permafrost soils during earthquakes is important for the security of energy pipelines in the Canadian North. It was investigated with laboratory experiments and numerical simulations. The results showed that the seismic shaking is higher in frozen soils than in unfrozen soils and that the pipelines are most sensitive in the transition zone between frozen and unfrozen soils.