Alessandro F. Rotta Loria

Numerical Study on the Suitability of Centrifuge Testing for Capturing the Thermal-Induced Mechanical Behavior of Energy Piles

AbstractCurrently, the suitability of centrifuge testing for capturing the thermal-induced mechanical behavior of full-scale energy piles has not been established, yet, despite their increasing worldwide development. Looking at this challenge, this paper investigates through thermomechanical numerical analyses the capability of centrifuge tests to reproduce fundamental aspects of the response of full-scale energy piles in dry sand when subjected to thermal and mechanical loads. The analysis proves the appropriateness of centrifuge tests for the considered goal and comments on crucial points that have to be considered when modeling energy pile-related problems.

Thermo-mechanical Schemes for Energy Piles

Currently, schemes based on seminal empirical knowledge about energy piles subjected to mechanical and thermal loads are available to describe the response of such foundations. However, schemes based on theoretical principles may more closely reflect the predictions made for the analysis and design of energy piles. Looking at such challenge, this paper presents thermo-mechanical schemes based on thermo-elasticity theory to address the response of single energy piles to mechanical and thermal loads. The proposed schemes highlight a number of key aspects associated with the modelling of energy pile response to loading and may be considered in analysis and design.

Impact of Thermally Induced Soil Deformation on the Serviceability of Energy Pile Groups

This paper expands on the impact of the thermally induced deformation of the soil on the serviceability mechanical performance (i.e., deformation-related) of energy pile groups. The work is based on the results of a full-scale in-situ test that was performed on a group of energy piles at the Swiss Tech Convention Centre, Lausanne, Switzerland, and on a series of 3-D thermo-mechanical finite element analyses that were carried out to predict the considered experiment. This study proves that the serviceability mechanical performance of energy pile groups crucially depends on the relative thermally induced deformation of the soil to that of the energy piles. The relative thermally induced deformation of the soil to that of the energy piles is governed by (i) the thermal field characterising the energy pile group and (ii) the relative thermal expansion coefficient of soil to pile. Considering these aspects in the analysis and design of energy pile groups is key because they profoundly characterise the deformation of such foundations.