Investigation of the earthquake ground motion coherence in heterogeneous non-linear soil deposits

F Gatti (1, 2, 3) , Luciano de Carvalho Paludo (1, 2, 3) , Angkeara Svay (1, 2, 3) , Fernando Lopez-Caballero (1, 2) , Régis Cottereau (1) , Didier Clouteau (1, 2, 3)

1 MSSMat - Laboratoire de mécanique des sols, structures et matériaux
2 Université Paris-Saclay
3 CentraleSupélec

The physics-based numerical simulation is a reliable tool to build-up source-to-site strong ground motion earthquake scenarios. In this paper, we enhance those forward simulations by including (1) the hysteretic non-linear behaviour of geomaterials and (2) the heterogeneous nature of soils. Scattering-induced damping, ground motion spatial incoherence and de-amplification may therefore be reproduced. A classical case study is considered herein: a seismic wave generated by a localized double-couple earthquake propagating towards the surface through layered elastic homogeneous bedrock, underlying a heterogeneous non-linear soil stratum. 3D numerical simulations were performed by means of a Spectral Element Method (SEM) code. The latter was coupled with a highly scalable random field generator to reproduce the media heterogeneity. Moreover, an extension to J 2 elasto-plasticity numerical integration was introduced. Time-histories and lagged-coherency curves at the surface show the ground motion de-amplification (mainly related to soil non-linearity) and loss of coherency (due to the wave-scattering caused by soil heterogeneity).

Mots clés: Spectral Element Method; Non-linear; Heterogeneous; Wave-Propagation

Domaines: Géotechnique; Géophysique [physics.geo-ph]; Mécanique des solides [physics.class-ph]; Dynamique, vibrations; Génie civil nucléaire

F Gatti, Luciano de Carvalho Paludo, Angkeara Svay, Fernando Lopez-Caballero, Régis Cottereau, et al.. Investigation of the earthquake ground motion coherence in heterogeneous non-linear soil deposits. X International Conference on Structural Dynamics (EURODYN 2017), Sep 2017, Rome, Italy. pp.2354-2359, ⟨10.1016/j.proeng.2017.09.232⟩. ⟨hal-01586963⟩