Evaluation et réduction des risques sismiques liés à la liquéfaction : modélisation numérique de leurs effets dans l’ISS (original) (raw)
16th European Conference on Earthquake Engineering, Thessaloniki, Greece, 2018
Kruiver, P.P., De Lange, G., Korff, M., Wiersma, A., Harting, R., Kloosterman, F.H., Stafleu, J., Gunnink, J.L., Van Elk, J. & Doornhof, D., 2018. Parameterization of Geological Models for Regional Site Response and Liquefaction Potential Indicators (Extended Abstract, 12 pp). 16th European Conference on Earthquake Engineering, June 18 – 21, 2018, Thessaloniki, Greece. We have built two regional geological models-covering over 1,000 km 2-that serve as input for the seismic hazard and risk analysis of the onshore gas field of the Groningen region, the Netherlands. The first model describes the liquefaction potential indicators and the second model contains the layer model and parameterization for site response analysis. Earlier published papers focused on the construction of the models. The emphasis of the current paper is on the parameterization of both models. The liquefaction potential indicator consists of the cumulative thickness of loosely, moderately and densely packed sand in the top 40 m. This parameter was derived from the cone resistance values in the database of ~ 5,700 Cone Penetration Test (CPT) soundings. The geological model for site response consists of vertical voxel stacks corresponding to the GeoTOP model and extended to ~ 800 m depth using scenarios. These voxel stacks serve as input for site response calculations which requires information about shear wave velocity, unit weight, overconsolidation ratio, plasticity index, undrained shear strength, median grain size and coefficient of uniformity. These parameters were either derived based on local data from Seismic CPTs, CPTs or grainsize analyses. The empirical relations from literature were modified to fit the local Groningen characteristics of the soil. The parameterization was derived for the combinations of stratigraphy and lithology that are present in the region. Although our approach to schematize geology and to parameterize the geological models was developed for the region of Groningen, the general approach can be applied to other regions.
Assessment and mitigation of liquefaction seismic risk : numerical modeling of their effects on SSI
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Influence of Liquefaction and Adjacent Structures on Seismic Response
2016
During past decades the destructive potential and the complexity of soil liquefaction phenomenon associated with strong earthquakes has been widely documented. However, current structural seismic design generally neglects the influence of the subsoil. Design codes that deal with liquefaction usually focus the settlements that can affect the structural foundations. Additionally, most studies related to soil-structure interaction have focused on the response of an isolated structure. In reality, especially in urban areas, this assumption rarely can be justified. The omission of adjacent structures can lead to inaccurate results, especially when nonlinear behaviour of soil, e.g. resulting from liquefaction, takes place. The aim of this work was to implement a holistic approach to the study of liquefaction. The influence of an existing structure on the liquefaction potential will be presented. Also, the effects of adjacent structures on the seismic response will be investigated under co...