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A study on the behaviour of the weathered crust in the Perniö failure test

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Original languageEnglish
Title of host publicationProceedings of the XVI ECSMGE 2015
Subtitle of host publication13-17 September 2015 - Edinburgh, Geotechnical Engineering for Infrastructure and Development
PublisherICE Publishing
Number of pages6
ISBN (Print)9780727760678
Publication statusPublished - 2015
Publication typeA4 Article in a conference publication
EventEuropean conference on soil mechanics and geotechnical engineering -
Duration: 1 Jan 1900 → …


ConferenceEuropean conference on soil mechanics and geotechnical engineering
Period1/01/00 → …


A full-scale embankment failure test was done in Finland in 2009 in Perniö. The test was conducted in order to gather data to
enhance stability calculation methods on soft soils in railway environment. A shallow embankment with loading structure was built on top
of an existing fill layer over a stiff and overconsolidated clay crust followed by a soft sensitive clay layer and brought to failure in two
days. The soft clay has been thoroughly studied and modeled over the last years based on high quality laboratory and field tests as well as
measurements from the experiment. In this paper, the effect of the weathered clay crust on the stability of the embankment is studied. Ac-
cording to La Rochelle (1974), the field vane tends to overestimate the undrained shear strength of the dry crust since measurements are
affected by uncertainties due to soil structure and test conditions. For this reason a parametric study on stiffness and strength parameters of
Perniö dry crust is done through comparison of experimental data with predictions from finite element method. In particular, three differ-
ent models are used in this study: the isotropic Mohr-Coulomb and Hardening Soil model and the anisotropic NGI-ADP model. The anal-
ysis is carried out with PLAXIS 2D. Finally, FE analysis of the Perniö failure test is done using different soil models and the failure load
is predicted. Results are discussed in order to evaluate the most suitable model for the realistic prediction of undrained behaviour of Perniö
weathered crust.

Publication forum classification

Field of science, Statistics Finland