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Your search keyword '"Gélis, C."' showing total 3 results
Start Over Author "Gélis, C." Topic wave propagation
3 results on '"Gélis, C."'

1. In situ seismic measurements in claystone at Tournemire (France).

Author

Zillmer, M., Marthelot, J.-M., Gélis, C., Cabrera, J., and Druivenga, G.

Subjects
SEISMIC waves, TONSTEINS, SHEAR waves, EXCAVATION, VIBROSEIS
Abstract

Compressional and shear wave seismic measurements were performed in an old railway tunnel and in galleries excavated in a 250-m-thick Toarcian claystone formation in the Tournemire experimental station (France). Three component (3C) geophones and three orthogonal orientations of the vibroseismic force source were used. Additionally, vertical seismic profiling (VSP) measurements were recorded with a 3C borehole geophone, a hydrophone and a microphone in a 159 m deep borehole (ID180) in the tunnel. The seismic data show that Toarcian claystone has strong transverse isotropy (TI) with a vertical symmetry axis. The qP, SH and qSV wave propagation velocities in horizontal directions--the plane of isotropy of the TI medium--are measured as 3550, 1850 and 1290 m s-1, respectively. The zero-offset VSP reveals that only one shear wave propagates in the vertical (depth) direction and the P- and S-wave velocities are 3100 and 1375 m s-1, respectively. Four elastic moduli of the TI medium are determined from the seismic velocities and from the bulk density of 2.53 g cm-3: c11 = 31.9 GPa, c33 = 24.3 GPa, c44 = 4.5 GPa and c66 = 8.7 GPa. A walkaway VSP with the borehole geophone at 50 m depth in borehole ID180 and shot points in the galleries leads to oblique seismic ray paths which allow us to determine the fifth elastic modulus of the TI medium to c13 = 16 GPa. The tube wave recorded by a hydrophone in the water filled lower part of the borehole propagates with 1350 m s-1, which confirms the estimate of the elastic constant c66. The analysis of body wave and surface wave data from a seismic experiment in Galerie Est shows reflections from several fracture zones in the gallery floor. The thickness of the excavation damaged zone (EDZ) in the floor of Galerie Est is estimated to 0.7 m. [ABSTRACT FROM AUTHOR]

Published
2014
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2. Free and smooth boundaries in 2-D finite-difference schemes for transient elastic waves.

Author

Lombard, B., Piraux, J., Gélis, C., and Virieux, J.

Subjects
SEISMOLOGY, ELASTIC wave diffraction, ELASTIC wave scattering, FINITE differences, NUMERICAL analysis
Abstract

A method is proposed for accurately describing arbitrary-shaped free boundaries in finite-difference schemes for elastodynamics, in a time-domain velocity–stress framework. The basic idea is as follows: fictitious values of the solution are built in vacuum, and injected into the numerical integration scheme near boundaries. The most original feature of this method is the way in which these fictitious values are calculated. They are based on boundary conditions and compatibility conditions satisfied by the successive spatial derivatives of the solution, up to a given order that depends on the spatial accuracy of the integration scheme adopted. Since the work is mostly done during the pre-processing step, the extra computational cost is negligible. Stress-free conditions can be designed at any arbitrary order without any numerical instability, as numerically checked. Using 10 grid nodes per minimal S-wavelength with a propagation distance of 50 wavelengths yields highly accurate results. With 5 grid nodes per minimal S-wavelength, the solution is less accurate but still acceptable. A subcell resolution of the boundary inside the Cartesian meshing is obtained, and the spurious diffractions induced by staircase descriptions of boundaries are avoided. Contrary to what occurs with the vacuum method, the quality of the numerical solution obtained with this method is almost independent of the angle between the free boundary and the Cartesian meshing. [ABSTRACT FROM AUTHOR]

Published
2008
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3. International Benchmark on Numerical Simulations for 1D, Nonlinear Site Response (PRENOLIN): Verification Phase Based on Canonical Cases

Author

Gaetano Falcone, Fabrice Hollender, Alborz Ghofrani, Mahdi Taiebat, Michael Musgrove, Pierre-Yves Bard, Evangelia Garini, George Gazetas, Daniela Boldini, Luca Verrucci, Kohei Watanabe, Luis Fabian Bonilla, Aneta Richterova, Alex Nieto-Ferro, Peter Moczo, Annamaria di Lernia, Long Chen, Jian Shi, Boris Jeremić, Federico Pisanò, Stavroula Kontoe, Céline Gélis, Steve Kramer, James R. Gingery, Angelo Amorosi, Evelyne Foerster, Domniki Asimaki, Joseph Harmon, Julie Régnier, Sebastiano Foti, Jozef Kristek, Alessandro Pagliaroli, Giuseppe Tropeano, Anna Chiaradonna, Youssef M. A. Hashash, Silvana Montoya-Noguera, Maria Paola Santisi d'Avila, Francesco Silvestri, Susumu Iai, Florent Demartin, Nathalie Glinsky, Marco Ebrille, Fernando Lopez-Caballero, Suwal Sajana, Etienne Bertrand, Deborah Sicilia, Amalia Giannakou, Graeme McAllister, E. Diego Mercerat, Pedro Arduino, Hiroshi Kawase, Giuseppe Lanzo, Ahmed Elgamal, Marianne Marot, Régnier, Julie, Bonilla, Luis‐fabian, Bard, Pierre‐yve, Bertrand, Etienne, Hollender, Fabrice, Kawase, Hiroshi, Sicilia, Deborah, Arduino, Pedro, Amorosi, Angelo, Asimaki, Domniki, Boldini, Daniela, Chen, Long, Chiaradonna, Anna, Demartin, Florent, Ebrille, Marco, Elgamal, Ahmed, Falcone, Gaetano, Foerster, Evelyne, Foti, Sebastiano, Garini, Evangelia, Gazetas, George, Gélis, Céline, Ghofrani, Alborz, Giannakou, Amalia, Gingery, James R., Glinsky, Nathalie, Harmon, Joseph, Hashash, Youssef, Iai, Susumu, Jeremić, Bori, Kramer, Steve, Kontoe, Stavroula, Kristek, Jozef, Lanzo, Giuseppe, Lernia, Annamaria di, Lopez‐caballero, Fernando, Marot, Marianne, Mcallister, Graeme, Diego Mercerat, E., Moczo, Peter, Montoya‐noguera, Silvana, Musgrove, Michael, Nieto‐ferro, Alex, Pagliaroli, Alessandro, Pisanò, Federico, Richterova, Aneta, Sajana, Suwal, Santisi d'Avila, Maria Paola, Shi, Jian, Silvestri, Francesco, Taiebat, Mahdi, Tropeano, Giuseppe, Verrucci, Luca, Watanabe, Kohei, Centre d'Etudes et d'Expertise sur les Risques, l'Environnement, la Mobilité et l'Aménagement - Equipe-projet MOUVGS (Cerema Equipe-projet MOUVGS), Centre d'Etudes et d'Expertise sur les Risques, l'Environnement, la Mobilité et l'Aménagement (Cerema), Séismes et Vibrations (IFSTTAR/GERS/SV), Institut Français des Sciences et Technologies des Transports, de l'Aménagement et des Réseaux (IFSTTAR)-Communauté Université Paris-Est, Laboratoire de Géophysique Interne et Tectonophysique (LGIT), Observatoire des Sciences de l'Univers de Grenoble (OSUG), Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Laboratoire Central des Ponts et Chaussées (LCPC)-Institut des Sciences de la Terre (ISTerre), Université Grenoble Alpes (UGA)-Centre National de la Recherche Scientifique (CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-PRES Université de Grenoble-Institut de recherche pour le développement [IRD] : UR219-Institut national des sciences de l'Univers (INSU - CNRS)-Institut Français des Sciences et Technologies des Transports, de l'Aménagement et des Réseaux (IFSTTAR)-Université Joseph Fourier - Grenoble 1 (UJF)-Centre National de la Recherche Scientifique (CNRS)-PRES Université de Grenoble-Institut de recherche pour le développement [IRD] : UR219-Institut Français des Sciences et Technologies des Transports, de l'Aménagement et des Réseaux (IFSTTAR), Institut des Sciences de la Terre (ISTerre), Université Grenoble Alpes (UGA)-Centre National de la Recherche Scientifique (CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-PRES Université de Grenoble-Institut de recherche pour le développement [IRD] : UR219-Institut national des sciences de l'Univers (INSU - CNRS)-Institut Français des Sciences et Technologies des Transports, de l'Aménagement et des Réseaux (IFSTTAR)-Université Joseph Fourier - Grenoble 1 (UJF), CEA Cadarache, Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Disaster Prevention Research Institute, Kyoto University [Kyoto], Département de sismologie (DS (UMR_7580)), IPG PARIS-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Bureau de Recherches Géologiques et Minières (BRGM) (BRGM), Laboratoire de mécanique des sols, structures et matériaux (MSSMat), Centre National de la Recherche Scientifique (CNRS)-CentraleSupélec, Régnier, J., Bonilla, L.F., Bard, P.Y., Bertrand, E., Hollender, F., Kawase, H., Sicilia, D., Arduino, P., Amorosi, A., Asimaki, D., Boldini, D., Chen, L., Chiaradonna, A., Demartin, F., Ebrille, M., Elgamal, A., Falcone, G., Foerster, E., Foti, S., Garini, E., Gazetas, G., Gélis, C., Ghofrani, A., Giannakou, A., Gingery, J.R., Glinsky, N., Harmon, J., Hashash, Y., Iai, S., Jeremić, B., Kramer, S., Kontoe, S., Kristek, J., Lanzo, G., di Lernia, A., Lopez-Caballero, F., Marot, M., Mcallister, G., Mercerat, E.D., Moczo, P., Montoya-Noguera, S., Musgrove, M., Nieto-Ferro, A., Pagliaroli, A., Pisanò, F., Richterova, A., Sajana, S., Santisi d'Avila, M.P., Shi, J., Silvestri, F., Taiebat, M., Tropeano, G., Verrucci, L., Watanabe, K., Institut Français des Sciences et Technologies des Transports, de l'Aménagement et des Réseaux (IFSTTAR)-Institut national des sciences de l'Univers (INSU - CNRS)-Institut de recherche pour le développement [IRD] : UR219-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), Disaster Prevention Research Institute (DPRI), CentraleSupélec-Centre National de la Recherche Scientifique (CNRS), Institut de Radioprotection et de Sûreté Nucléaire (IRSN), Université Paris Diderot - Paris 7 (UPD7)-IPG PARIS-Centre National de la Recherche Scientifique (CNRS), Kyoto University, Université Paris Diderot - Paris 7 (UPD7)-Institut de Physique du Globe de Paris (IPG Paris)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'Etudes de Mécanique Sismique (EMSI), Service d'Etudes Mécaniques et Thermiques (SEMT), Département de Modélisation des Systèmes et Structures (DM2S), CEA-Direction des Energies (ex-Direction de l'Energie Nucléaire) (CEA-DES (ex-DEN)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-CEA-Direction des Energies (ex-Direction de l'Energie Nucléaire) (CEA-DES (ex-DEN)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Département de Modélisation des Systèmes et Structures (DM2S), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay

Subjects
Geochemistry & Geophysics, Peak ground acceleration, Earthquake, Wave propagation, Computation, 0211 other engineering and technologies, 0404 Geophysics, 02 engineering and technology, Seismic, 010502 geochemistry & geophysics, Civil Engineering, 01 natural sciences, 0905 Civil Engineering, Viscoelasticity, Ground response analysis, Geochemistry and Petrology, Applied mathematics, Boundary value problem, seismic response analysis, numerical modelling, ComputingMilieux_MISCELLANEOUS, 021101 geological & geomatics engineering, 0105 earth and related environmental sciences, Mathematics, Geophysics, Computer simulation, business.industry, [SPI.GCIV.GEOTECH]Engineering Sciences [physics]/Civil Engineering/Géotechnique, Structural engineering, Dissipation, Nonlinear system, geophysics, geochemistry and petrology, [SPI.GCIV.DV]Engineering Sciences [physics]/Civil Engineering/Dynamique, vibrations, business
Abstract

© 2016 Seismological Society of America. All rights reserved. PREdiction of NOn-LINear soil behavior (PRENOLIN) is an international benchmark aiming to test multiple numerical simulation codes that are capable of predicting nonlinear seismic site response with various constitutive models. One of the objectives of this project is the assessment of the uncertainties associated with nonlinear simulation of 1D site effects. A first verification phase (i.e., comparison between numerical codes on simple idealistic cases) will be followed by a validation phase, comparing the predictions of such numerical estimations with actual strongmotion recordings obtained at well-known sites. The benchmark presently involves 21 teams and 23 different computational codes. We present here the main results of the verification phase dealing with simple cases. Three different idealized soil profiles were tested over a wide range of shear strains with different input motions and different boundary conditions at the sediment/bedrock interface. A first iteration focusing on the elastic and viscoelastic cases was proved to be useful to ensure a common understanding and to identify numerical issues before pursuing the nonlinear modeling. Besides minor mistakes in the implementation of input parameters and output units, the initial discrepancies between the numerical results can be attributed to (1) different understanding of the expression “input motion” in different communities, and (2) different implementations of material damping and possible numerical energy dissipation. The second round of computations thus allowed a convergence of all teams to the Haskell–Thomson analytical solution in elastic and viscoelastic cases. For nonlinear computations, we investigate the epistemic uncertainties related only to wave propagation modeling using different nonlinear constitutive models. Such epistemic uncertainties are shown to increase with the strain level and to reach values around 0.2 (log10scale) for a peak ground acceleration of 5 m=s2at the base of the soil column, which may be reduced by almost 50% when the various constitutive models used the same shear strength and damping implementation.

Published
2016
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