Description: Das Projekt "Non - Linear Threshold for amplification analyses in moderate earthquakes in alpine valleys (NLT)" wird vom Umweltbundesamt gefördert und von Eidgenössische Technische Hochschule (ETH) Zürich, Institut für Geotechnik durchgeführt. The project Non-Linear Threshold for amplification analyses for moderate earthquakes in alpine valleys (NLT) aims to enhance the use of non-linear soil models in amplification analyses. Due to the complexity of the non-linear soil models, especially when incorporated in 2 or 3 dimensional dynamic calculations, the knowledge of threshold conditions need to be studied in detail to reduce computational efforts. The so-called non-linear soil behaviour is governed by the change of stiffness of soils under loading, deformation and in case of high water table levels by an increase in porewater pressure, which can reach values equivalent to the effective stress (liquefaction). Whereas studies exists on the threshold for stress and strain to consider nonlinearity in dry conditions (e.g. Vucetic, 1994), no such value exists for the interaction between earthquake loading causing porewater pressure build-up and subsequently softening of the material and a change of the stress state. The increase in porewater pressure depends on the incoming stresses and strains as well as the length of an earthquake. As long as particle reorientation is involved, porewater pressures increase already under low loading states, even though liquefaction might only be reached after significant numbers of load cycles. The influence of pore pressure increase, change in directivity and elongated earthquakes, as shown by Faeh et al. 2006 due to topographical effects, will be studied with a series of cyclic laboratory experiments using advanced triaxial and a hollow cylinder apparatus. These tests will be accompanied by field experiments, which have been partially funded with matching funds from the Competence Centre for Environment and Sustainability (CCES) in the project COGEAR . This study is absolutely essential for countries like Switzerland, where big earthquakes are rare whereas moderate earthquakes occur quite frequently and valley effects amplify and lengthen an earthquake in time. To be able to study the amplification further, different material models developed to describe non-linear soil behaviour in the last decades need to be judged to which extent the non-linearity caused by an increase of pore pressures can be covered with these models. While the judgment will be based on one-dimensional calculations and on the existing codes, the most promising model(s) will be transferred into a hybrid calculation building on the developments from the Swiss Seismological Survey (SED). The area of non-linearity can be separated from the linear equivalent calculations. For specific valley conditions (Visp, VS), a model is in preparation to incorporate topographical effects into the study. The Valais, and specifically the area of Visp, has been selected for its high seismic hazard and their well reported non-linear effects observed after the 1855 event. In the past, the Valais has experienced a magnitude 6 or larger event every 100 years, the last in 1946, and the region of (...).
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Origin: /Bund/UBA/UFORDAT
Tags: Zürich ? Brunnen ? Schweiz ? Seismizität ? Material ? Erdbebengefährdung ? Gebäude ? Stress ? Wirkung ? Bewässerung ? Bodenuntersuchung ? Geodäsie ? Geotechnik ? Rechtsverfahren ? Grundwasserstand ? Staat ? Stoffgemisch ? Studie ? Erdbeben ? Laborversuch ? Wasser ? Boden ? Hochgebirge ? Bodenwert ? Belastung ? Wirkung ? REACH ? Einkommen ? Nachhaltigkeit ? Abdeckung ? Bedarf ? Berechnung ? Finanzierung ? Forschungseinrichtung ? Freilandversuch ? Partikel ? Fahrradfahren ? Schwellenwert ? Umwelt ? Zuständigkeit ? Tal ? Gebiet ? Eintrittswahrscheinlichkeit ? FORTSCHRITTLICH ? BEWERTEN ? BESTEHEND ? DNA-Amplifikation ? EXPERIMENT ? FOERDERN ? Aufladung ? Geotechnical Earthquake Engineering ? DRUCK ? Ground Amplification ? EIN ? INITIATIVE ? LAENDER ? EINSATZ ? LAND ? Liquefaction ? ENTWICKLUNG ? Non Linear Soil Behaviour ? PROJEKT ? SAEULE ? SPEZIFISCH ? Soil Dynamics ? UNTER ? UNTERSUCHUNG ? VERHAELTNIS ? VERHALTEN ? AUSGEWAEHLT ? Vermehrung ? Vorgang ? WERT ?
License: cc-by-nc-nd/4.0
Language: Deutsch
Time ranges: 2010-01-01 - 2012-06-30
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