Numerical investigation of the capacity and settlement of a thermo-active pile in saturated sand

R. Zhao, A. Leung, I. Anastasopoulos

In the proceedings of: GeoOttawa 2017: 70th Canadian Geotechnical Conference; 12th joint with IAH-CNC

Session: Renewable Energy Geotechnique

ABSTRACT: Finite element modeling has become a popular method to investigate the load transfer mechanisms between thermo-active piles and the surrounding soil upon pile heating/cooling. Sophisticated constitutive models that can capture soil thermo-elastoplasticity have been proposed to model the thermo-mechanical response of soil-pile systems, but their inherent complexity renders their application in practice rather difficult. This key scope of the present study is to explore whether a simple mechanical soil model, after proper calibration, could be adequate to capture some of the key features of soil-pile interaction. Such a model is developed herein and verified against centrifuge model tests. It is shown that the developed simplified model is capable of capturing the distribution of mobilized axial loading of a thermo-active pile in saturated sand. The pile heating/cooling effect is found to be significant only when the working load (WL) is lower than 60% of the ultimate pile bearing capacity. Under a large constant WL, irreversible pile settlement upon cyclic thermal loading is observed. The latter is associated with cyclic mechanical loading and plastic straining of the soil beneath the pile, due to pile expansion and contraction. Résumé La simulation numérique par la méthode des éléments finis est devenu populaire pour étudier le mécanisme de transfert de charge entre thermo-actif pieux et le sol entournant à chauffage / refroidissement. Le modèle sophistiqué qui pourrait capturer le sol thermo élastoplasticité est suggéré afin de modéliser le système thermo - mécanique de réponses entre le soil et pieux, mais le modèle est normalement très complexe qui est difficile à appliquer dans la pratique. Cette étude vise à déterminer si un modèle simple de sol mécaniques, après calibration, serait suffisant pour étudier certains aspects clés des interactions entre le soil et le pieux. En utilisant un modèle de sol mécanique simple se révèle d™être capable de capturer la répartition des actifs mobilisés charge axiale d'un pieu dans un essai des sables saturés dans une centrifugeuse. Chauffage / refroidissement pieux est importante seulement lorsque la charge de travail (wl) est inférieure à 60% de la capacité portante ultime. Sous une forte constante WL, la subsideuce de la tête du pieu wi, est irréversibles sous la charge thermique cyclique est permis en raison du chargement mécanique cyclique et la déformation plastique du sol sous la pile présenté par pile expansion et contraction.

Access this article:
Canadian Geotechnical Society members can access to this article, along with all other Canadian Geotechnical Conference proceedings, in the Member Area. Conference proceedings are also available in many libraries.

Cite this article:
R. Zhao; A. Leung; I. Anastasopoulos (2017) Numerical investigation of the capacity and settlement of a thermo-active pile in saturated sand in GEO2017. Ottawa, Ontario: Canadian Geotechnical Society.

@article{geo2017Paper454,author = R. Zhao; A. Leung; I. Anastasopoulos,title = Numerical investigation of the capacity and settlement of a thermo-active pile in saturated sand,year = 2017}