Purpose This paper aims to present the investigation of the linear and nonlinear seismic site response of a saturated inhomogeneous poroviscoelastic soil profile for different soil properties, such as pore-water saturation, non-cohesive fines content FC, permeability k, porosity n and coefficient of uniformity Cu. Design/methodology/approach The inhomogeneous soil profile is idealized as a multi-layered saturated poroviscoelastic medium and is characterized by the Biot’s theory, with a shear modulus varying continuously with depth according to the Wichtmann’s model. Seismic response analysis has been evaluated through a computational model, which is based on the exact stiffness matrix method formulated in the frequency domain assuming that the incoming seismic waves consist of inclined P-SV waves. Findings Unlike the horizontal seismic response, the results indicate that the vertical one is strongly affected by the pore water saturation. Moreover, in the case of fully saturated soil profile, the same vertical response spectra are found for the two cases of soil behavior, linear and nonlinear. Originality/value This research is a detailed study of the geotechnical soil properties effect on the bi-directional seismic response of saturated inhomogeneous poroviscoelastic soil profile, which has not been treated before; the results are presented in terms of the peak acceleration ratio, as well as the free-field response spectra and the spectral ratio (V/H).

This paper deals with empirical spectral amplification function for a reference site (STK) near Keddara dam in Algeria using local strong ground motion of earthquakes of magnitudes Mw 4.0-6.8. Amplification function is obtained as the 5% damped mean spectral ratio of surface observed and the rock predicted ground motions and it is compared to the ambient vibration HVSR which shows a good agreement in terms of fundamental frequency and curve tendency. In addition, recorded ground motions are compared to surface predicted motion with modified GMPE, the site term of the local ground motion prediction equation is adjusted based on the obtained amplification function of the free field STK site. Examples of the M 6.8, M5.4 and M4.7 earthquakes show clearly the advantage of using the adjusted Ground Motion Prediction Equations (GMPE) for predicting surface ground motion. Site effect characterization and the adjusted GMPE presented in this study provide the basis elements toward partially non ergodic site specific-Probabilistic seismic hazard assessment (PSHA) application based on local strong motion data in Algeria.

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Influence of soil properties on amplification of saturated inhomogeneous poroviscoelastic soil profileThe influence of local geotechnical site conditions on the soil profile amplification is analysed in this paper by assuming that the incoming seismic waves consist of inclined P-SV waves. The inhomogeneous soil profile is idealized as a multi-layered saturated poroviscoelastic medium and characterized by the Biot's theory with a shear modulus varying continuously in depth according to the Wichtmann's model. The results are presented in terms of horizontal and vertical soil profile amplification with linear and nonlinear soil behaviour, for different values of incidence angle, pore-water saturation, porosity, permeability, coefficient of uniformity, and non-cohesive fines content.