Seismic response analysis of loess site under far-field bedrock ground motion of the Wenchuan earthquake

In this paper, considering the far-field seismic input, an accelerogram recorded in the bedrock at Wuquan Mountain in Lanzhou city during the 2008 Wenchuan Ms8.0 earthquake was selected, and numerical dynamic analyses were conducted. The one-dimensional equivalent linear method was implemented to es...

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Bibliographic Details
Published in:PloS one 2021-07, Vol.16 (7), p.e0254871-e0254871
Main Author: Chen, Tuo
Format: Article
Language:English
Subjects:
Amplification
Analysis
Bedrock
China
Civil engineering
Computer and Information Sciences
Dynamic response
Earth Sciences
Earthquake accelerograms
Earthquakes
Engineering and Technology
Far fields
Finite element analysis
Finite element method
Free surfaces
Ground motion
Laboratories
Loess
Mathematical models
Motion effects
Mountains
Physical Sciences
Refraction
Seismic activity
Seismic response
Seismic surveys
Seismic waves
Shear strain
Slopes
Soil dynamics
Soil layers
Soils
Spectrum analysis
Thickness
Topographic effects
Topography
Viscoelasticity
Wave reflection
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Summary:In this paper, considering the far-field seismic input, an accelerogram recorded in the bedrock at Wuquan Mountain in Lanzhou city during the 2008 Wenchuan Ms8.0 earthquake was selected, and numerical dynamic analyses were conducted. The one-dimensional equivalent linear method was implemented to estimate the ground motion effects in the loess regions. Thereafter, slope topographic effects on ground motion were studied by applying the dynamic finite-element method. The results revealed the relationship between the PGA amplification coefficients and the soil layer thickness, which confirmed that the dynamic response of the sites had obvious nonlinear characteristics. The results also showed that there was an obvious difference in the dynamic magnification factor between the short-period and long-period structures. Moreover, it was found that the amplification coefficient of the observation point at the free surface was greater than the point inside the soil at the same depth, which mainly occurred in the upper slope. Through this study, the quantitative assessment of ground motion effects in loess regions can be approximately estimated, and the amplification mechanism of the far-field ground motion mechanism can be further explained. In addition to the refraction and reflection theory of seismic waves, the resonance phenomenon may help explain the slope topographic effect through spectrum analysis.
ISSN:1932-6203
1932-6203
DOI:10.1371/journal.pone.0254871