Extended Iwan-Iai (3DXii) constitutive model for 1-Directional 3-Component seismic waves in liquefiable soils: application to the Kushiro site (Japan)-3C seismic wave propagation in liquefiable soils

Description

The influence of pore water pressure has to be taken into account when the propagation ofseismic waves in saturated soils is simulated, because it controls the strength decrease during thedynamic process and can induce phenomena such as cyclic mobility and liquefaction. Thedecrease of effective stresses leads to permanent deformation in the soil and damages to thesurface structures.This research aims at validating a 1-Directional propagation model of 3-Component seismicwaves (1D-3C) in a horizontally layered soil, in the case of saturated soil.A three-dimensional nonlinear elasto-plastic model for soils is used and the variation of the shearmodulus reduction curve with the pore water pressure is taken into account during the seismicevent. In the case of multiaxial stress states induced by a 3C seismic motion, if no additionalinformation is available, the modulus reduction curves in shear and compression, normalizedwith respect to the elastic moduli, are assumed identical, since the Poisson's ratio is supposed tobe constant during the process. The multiaxial stress state in saturated soils induced by a 3Cseismic motion is analyzed for various stress paths.The 1D-3C wave propagation model is used to compute the seismic response of the Kushiro soilprofile (Japan). The stratigraphy and geotechnical properties are deduced from in-situ andlaboratory tests provided by the PRENOLIN benchmark. Numerical results are in correctagreement with the records at the surface in terms of acceleration envelope

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