Seismic site effects by an optimized 2D BE/FE method I. Theory, numerical optimization and application to topographical irregularities

Behrouz Gatmiri (1) , Chloé Arson (1) , K.V Nguyen

1 navier umr 8205 - Laboratoire Navier

This paper deals with the evaluation of seismic site effects due to the local topographical and geotechnical characteristics. The amplification of surface motions is calculated by a numerical method combining finite elements in the near field and boundary elements in the far field (FEM/BEM). The numerical technique is improved by time truncation. In the first part of this article, the accuracy and the relevance of this optimized method are presented. Moreover, parametric studies are done on slopes, ridges and canyons to characterize topographical site effects. The second part deals with sedimentary valleys. The complexity of the combination of geometrical and sedimentary effects is underlined. Extensive parametrical studies are done to discriminate the topographical and geotechnical effects on seismic ground movement amplifications in two-dimensional irregular configurations. Characteristic coefficients are defined to predict the amplifications of horizontal displacements. The accuracy of this quantitative evaluation technique is tested and discussed.

Mots clés: hybrid numerical technique; time truncation; convergence criterion; CPU time; mesh size; elastodynamics; seismic amplification; 2D site effects; topographical irregularities; parametric study

Domaines: Mécanique des matériaux [physics.class-ph]; Mécanique des matériaux [physics.class-ph]

Behrouz Gatmiri, Chloé Arson, K.V Nguyen. Seismic site effects by an optimized 2D BE/FE method I. Theory, numerical optimization and application to topographical irregularities. Soil Dynamics and Earthquake Engineering, 2008, 28 (8), pp.632-645. ⟨10.1016/j.soildyn.2007.09.001⟩. ⟨hal-00518975⟩