1D seismic response of soil: Continuously inhomogeneous vs equivalent homogeneous soil

George E. Mylonakis*, Emmanouil Rovithis, Haralambos Parashakis

*Corresponding author for this work

Research output: Chapter in Book/Report/Conference proceedingConference Contribution (Conference Proceeding)

2 Citations (Scopus)

Abstract

Equivalent homogeneous soils are investigated as simplified approximations of continuously inhomogeneous soils. The examined system comprises of an inhomogeneous surface layer over a homogeneous one of higher stiffness. Five alternative definitions are adopted for the representative shear wave velocity (Vhom) in the inhomogeneous layer: (i) Vhom1 at the base of the inhomogeneous layer (ii) Vhom2 in the middle of the inhomogeneous layer (iii) Vhom3 equal to the mean shear wave velocity within the inhomogeneous layer (iv) Vhom4 providing equal travel time from base to surface between homogeneous and inhomogeneous soil and (v) Vhom5 corresponding to an equivalent homogeneous soil having the same fundamental frequency as the inhomogeneous profile. Seismic response between inhomogeneous and equivalent homogeneous soils is compared by means of exact analytical solutions for single- and two-layer inhomogeneous soils. Fundamental frequencies and resonant peak amplitudes are examined, as affected by salient model parameters such as inhomogeneity factor, surface-to-base shear wave velocity ratio in the inhomogeneous layer, shear wave velocity contrast between the inhomogeneous and the homogeneous layer and relative layer thickness. It is observed that resonant frequencies of a smoothly-to-moderately inhomogeneous soil may be adequately captured by an equivalent homogeneous soil of either equal shear wave propagation velocity at the mid depth of the inhomogeneous layer, or of equal mean shear wave velocity within the whole layer. On the contrary, resonant amplitudes of a moderately-tostrongly inhomogeneous soil may be significantly underestimated or overestimated when an equivalent homogeneous soil is adopted, especially at higher resonances. The response of inhomogeneous soils with vanishing shear wave velocity near soil surface is explored.

Original languageEnglish
Title of host publicationECCOMAS Thematic Conference - COMPDYN 2011: 3rd International Conference on Computational Methods in Structural Dynamics and Earthquake Engineering: An IACM Special Interest Conference, Programme
Publication statusPublished - 26 Oct 2011
Event3rd International Conference on Computational Methods in Structural Dynamics and Earthquake Engineering, COMPDYN 2011 - Corfu, Greece
Duration: 25 May 201128 May 2011

Conference

Conference3rd International Conference on Computational Methods in Structural Dynamics and Earthquake Engineering, COMPDYN 2011
Country/TerritoryGreece
CityCorfu
Period25/05/1128/05/11

Keywords

  • Equivalent homogeneous soil
  • Inhomogeneous soil
  • Seismic response
  • Transfer function
  • Wave propagation

Fingerprint

Dive into the research topics of '1D seismic response of soil: Continuously inhomogeneous vs equivalent homogeneous soil'. Together they form a unique fingerprint.

Cite this