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Analysis of an adaptive foundation system for embankments on soft soils by means
of physical and numerical modelling
Analyse d'un système de fondation adaptatif pour les remblais sur sols compressibles par
modélisation physique et numérique
Detert O., Alexiew D.
HUESKER Synthetic GmbH & Ruhr-Universität Bochum, Germany
Schanz T., König D.
Ruhr-Universität Bochum, Germany
ABSTRACT: A new innovative foundation system for embankments on soft soil is currently being analyzed at the Ruhr-Universität
Bochum, Germany, in cooperation with the company HUESKER Synthetic GmbH. The system consists of two parallel vertical walls
(e.g. sheet pile walls), which are installed into the soft subsoil and connected at their top via a horizontal tension membrane (e.g.
geotextile). The embankment is then constructed on top of this tension membrane. The aim of this research project is to demonstrate
the applicability of the system and to develop an analytical calculation algorithm for serviceability and ultimate limit state of the
system. To study the complex interactive system behaviour a strategy is followed using geotechnical centrifuge technology and
numerical modelling. Measurement data from the centrifuge wall tests will be used for the validation and calibration of the numerical
model.
RÉSUMÉ : Un système de fondation pour les remblais sur sol mou, innovant est actuellement analysé à l’université de la Ruhr à
Bochum, Allemagne, en coopération avec l’entreprise HUESKER Synthetic GmbH. Le système consiste en deux palplanches
verticales et parallèles, ancrées dans le sol mou et reliées par une membrane horizontale résistante à la traction. Le remblais est ensuite
construit par-dessus cette membrane. Le but de ce projet de recherche est de démontrer la pertinence du système et de développer un
algorithme analytique de calcul pour les états limites de service et ultimes. Pour étudier le comportement complexe du remblai, on
comparera un modèle en centrifugeuse et une modélisation numérique. Les résultats des mesures des essais seront utilisés pour la
validation et la calibration du modèle numérique.
KEYWORDS: soft soils, embankment, foundation system, geotextile, self-regulating, centrifuge tests, numerical modelling
1 INTRODUCTION
The construction of embankments on soft soils (e.g. for
transportation, as break-waters or stockpiles) is a challenge due
to their low shear strength, low permeability, high
compressibility and high water content. The surcharge by the
embankment can not only result in a local or total loss of
stability (failure, see Figures 1 and 2) but also in unacceptable
settlements or horizontal deformations, which could endanger
structures nearby. The subsoil below the middle of the
embankment will be loaded under approximately oedometric
conditions, whereas the subsoil below the embankment
shoulders will experience compressive as well as shear stresses.
Figure 1. Slope stability failure of an embankment directly founded on
soft soil and numerical illustrated shear failure zone (foto: HUESKER)
To overcome these issues different solutions such as a
phased construction of the embankment with a basal
reinforcement, prefabricated vertical drains and consolidation
phases or the use of (geotextile encased) granular columns or
rigid inclusions, e.g. prefabricated concrete piles, with a
horizontal geotextile reinforcing layer, are available. Each
system has its limitations however, which can be related to the
thickness of the soft soil layer, height of the embankment, time
and also economic, ecological or technical reasons.
Figure 2. Soil extrusion below an embankment (sand filled geotextile
tube) with basal reinforcement (sand mattress), system sketch and
numerical illustrated shear failure zone (foto: HUESKER)
A new self-regulating foundation system for the
construction of embankments on soft soils is presented in this
