The application of seismic methods for dynamic characterization of soils in earthquake engineering

Jongmans, Denis

doi:10.1007/bf02595035

Cited by 21 publications

(13 citation statements)

References 6 publications

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“…Shear wave velocity (Vs) can be measured by various methods including active source techniques (borehole tests, SH refraction tests, surface wave inversion) and ambient vibration techniques (Jongmans, 1992;Socco and Jongmans, 2004). In this study we applied the SH seismic refraction method and the surface wave (SW) inversion for deriving Vs values along the cross-section ZZ'.…”

Section: S-wave Velocity Measurementsmentioning

confidence: 99%

Geophysical investigation of a large landslide in glaciolacustrine clays in the Trièves area (French Alps)

Jongmans

Bièvre

Renalier

et al. 2009

Engineering Geology

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113

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Slope movements in clay deposits are world widespread and result from complex deformation processes, including internal strains in the landslide body and slipping along rupture surfaces. Such mass movements are likely to generate changes in the geophysical parameters characterizing the ground, which can be used to map the landslide body. In the last decade, geophysical techniques have been increasingly used for landslide investigation purposes. However, the success of any geophysical technique is overall controlled by the existence of a geophysical contrast differentiating the body to be mapped. For landslides affecting thick clay materials (from soft clay to shale or marl), electrical and seismic techniques have been mainly applied in the past. In this study, we attempt to physically characterize the deformation within a large slide (Avignonet) affecting laminated clays which were deposited in a glacially dammed lake during the Würm period. Clay deposits, which cover an area of 300 km 2 south of Grenoble (French Alps) and have a maximum thickness of 200 m, overlay compact alluvial layers and marly limestone of Mesozoic age. Piezometric data at Avignonet show that the water table is very shallow, implying that the slide developed in saturated clay. Several seismic and electrical profiles were performed in order to tentatively correlate the variations of P-wave velocity, S-wave velocity and electrical resistivity with geotechnical data and morphological observations. In such saturated and fine material, it turned out that only the S-wave velocity (Vs) exhibits significant variations with the displacement rates and the morphological features. Vs values at shallow depth were found to be inversely correlated with displacement rates measured by GPS, with a division by at least a factor of 2 between the zones unaffected and strongly deformed by the landslide. These results suggest that Vs mapping could provide valuable information on the deformation state of the clay material and that the evolution of Vs with time could be used as an indicator for characterizing the landslide activity at depth, including the evolution into a flow.

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Section: S-wave Velocity Measurementsmentioning

confidence: 99%

Geophysical investigation of a large landslide in glaciolacustrine clays in the Trièves area (French Alps)

Jongmans

Bièvre

Renalier

et al. 2009

Engineering Geology

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113

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“…When, d=0.025 m is substituted in eqn (11) (12), (13) Similarly, the modulus of elasticity of the soil, E, under the foundation within a layer of thickness H, as shown in Fig. 1, is obtained from eqn ( …”

Section: Coefficient Of Subgrade Reactionmentioning

confidence: 99%

“…The use of geophysical methods in foundation engineering has been extensively studied also by Imai and Yoshimura [6], Tatham [7], Willkens et al [8], Phillips et al [9], Keçeli [10], Jongmans [11], Sully and Campanella [12], and Pyrak-Nolte et al [13]. Campanella and Stewart [14] determined various soil parameters by digital signal processing, while Butcher and Powell [15] supplied practical geophysical techniques to assess various soil parameters related to ground stiffness.…”

Section: Introductionmentioning

confidence: 99%

Seismic technique to determine the allowable bearing pressure in soils and rocks

Tezcan¹,

Özdemir²,

Keçeli³

2009

WIT Transactions on the Built Environment

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Based on a variety of case histories of site investigations, including extensive bore hole data, laboratory testing and geophysical prospecting, an empirical formulation is proposed for the rapid determination of the allowable bearing capacity of shallow foundations. The proposed expression corroborates consistently with the results of the classical theory and is proven to be rapid, reliable and safe. It consists of only two soil parameters, namely the in situ measured shear wave velocity, and the unit weight. The unit weight may also be determined, with sufficient accuracy, by means of another empirical expression, using the P-wave velocity. It is indicated that once the shear and P-wave velocities are measured in situ by an appropriate geophysical survey, the allowable bearing pressure, as well as the coefficient of subgrade reaction and many other elasticity parameters, may be determined rapidly and reliably.

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“…Various geophysical noninvasive methods, such as surface wave tests combined with inversion techniques (Rix et al 2000;Lai et al 2002;Foti 2003) and borehole seismic methods involving various kinds of post-data processing (Hoar and Stokoe 1984;Jongmans 1992;Gibbs et al 1994), have been implemented to characterize in situ damping ratios. Among these measurement techniques, using borehole seismic tests together with the spectral-ratio method seems to be the most simple and direct approach (Hauge 1981;Mok et al 1988;Pujol and Smithson 1991;Jongmans 1992;Campanella et al 1994;Gibbs et al 1994;Liu et al 1994). However, the accuracy of this method and the associated signal processing require systematic examination, which is the first objective of this study.…”

Section: Introductionmentioning

confidence: 99%

Damping-ratio measurements by the spectral-ratio method

Wang¹,

Yan²,

Lo³

2006

Can. Geotech. J.

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In this paper, bender elements are used as sensors to measure the damping ratio of soil by the spectral-ratio method. The results of numerical and physical experiments suggest that adequate measurement precision can be achieved by reducing the two types of inherent biases arising from (i) the near-field effect and (ii) the different transfer functions of the two receiver bender elements. The first bias can be avoided by setting sensors to r 1 /λ ≥ 2.0 and r 1 /r 2 ≥ 2.0, where r 1 and r 2 are the distances between the source and the first and second receivers, respectively; and λ is the wavelength. The second bias can be minimized by modifying the original spectral-ratio method to accommodate the self-healing technique. The damping ratios, measured by this modified method, obtained from the experiment conducted in a tailor-made, true-triaxial apparatus are very similar to those obtained from resonant column tests under the same state of stress.Key words: bender element, damping ratio, spectral-ratio method, near-field effect, true-triaxial apparatus.Résumé : Dans cet article, des languettes piézocéramiques ont été utilisées comme capteurs pour mesurer le rapport d'amortissement du sol par la méthode du rapport spectral. Les résultats des expériences numériques et physiques suggèrent qu'on peut atteindre une précision de mesure en réduisant les deux types de déviations inhérentes provenant de (i) l'effet du champ rapproché et (ii) les différentes fonctions de transfert des deux éléments piézocéramiques récep-teurs. La première déviation peut être évitée en fixant les capteurs à r 1 /λ ≥ 2,0 et r 1 /r 2 ≥ 2,0, où r 1 et r 2 sont les distances entre la source et les premier et deuxième récepteurs respectivement, et λ est la longueur d'onde. La deuxième déviation peut être minimisée en modirfiant la méthode originale de rapport spectral pour accommoder la technique d'autocorrection. Les rapports d'amortissement mesurés par cette méthode modifiée, obtenus à partir de l'expérience réalisée dans un appareil vrai triaxial construit spécialement pour cette tâche, sont très semblables à ceux obtenus par des essais à la colonne résonnante sous le même état de contraintes.

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The application of seismic methods for dynamic characterization of soils in earthquake engineering

Cited by 21 publications

References 6 publications

Geophysical investigation of a large landslide in glaciolacustrine clays in the Trièves area (French Alps)

Geophysical investigation of a large landslide in glaciolacustrine clays in the Trièves area (French Alps)

Seismic technique to determine the allowable bearing pressure in soils and rocks

Damping-ratio measurements by the spectral-ratio method

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