A parametric numerical study of the effect of interlayers and faults on the site amplification in cohesive soils

Autor: Mohammad Mohsen Olapour, Seyed Mohammad Reza Imam, Masoud Oulapour
Rok vydání: 2021
Předmět:
Zdroj: Arabian Journal of Geosciences. 14
ISSN: 1866-7538
1866-7511
DOI: 10.1007/s12517-021-08854-x
Popis: The lithology of Ahvaz city is very complex due to a combination of tectonic activities, flood plain sedimentation, and faulting. These features form subsoil of layers with different types and abrupt changes in stiffness. This lithology combined with a reverse fault may have significant effect on site amplification. This can be very destructive and may cost thousands of lives and needs to be investigated. In this research, the effect of abrupt changes in type and stiffness of material of layers and the variation of dip angle of faulting is studied numerically using finite element Plaxis software and finite difference Flac software. Based on the data from geotechnical studies in Ahvaz city area, some soil profiles and material properties are selected to perform the parametric study. It was concluded that the contrast in stiffness of material has a significant effect on the site amplification. In case of a soft interlayer embedded in dense layers with comparable thickness, the amplification ratio (AR) increases with increasing the stiffness of interlayer. But if its stiffness is higher than the surrounding layers, the AR decreases, as it cannot transmit the shear wave. Also, it was found that the AR increases as the thickness of the softer interlayer increases, due to the domination of the soft interlayer in soil profile. Moreover, it was concluded that in case of the presence of a fault in homogeneous silty clays, AR is not affected by the dip angle of the fault; however, the minimum amplification happens at a dip angle of 45°. Also, it was found that in case of a faulted stiff silty clay with a loose sandy interlayer, a dip angle of 30° yields an AR of 6.25 and a large displacement, which is destructive. But, in case of a faulted soft silty clay profile including a dense sandy interlayer, the maximum AR corresponds to a dip angle of fault of 45°.
Databáze: OpenAIRE
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