Page 234 - Analysis and Design of Energy Geostructures

CHAPTER 5

Thermohydromechanical behaviour

of soils and soil structure interfaces

5.1 Introduction
The ground represents the medium through which loads arising from energy geostruc-
tures are to be equilibrated by means of a transfer through the interfaces with such
structures (i.e. soil structure interfaces). Because of the multifunctional role of energy
geostructures, thermal and mechanical loads are applied to soils and soil structure
interfaces. In this context, the multiphysical nature of the applied loads, together with
the couplings that govern the behaviour of materials, makes the thermohydromechani-
cal behaviour of soils and soil structure interfaces paramount for the analysis and
design of energy geostructures. Not only does this behaviour influence the deforma-
tion and capacity of energy geostructures depending on the material properties, but it
also characterises the heat that can be exchanged via such structures. Understanding
the behaviour of soils and soil structure interfaces is thus critical to address the analysis
and design of energy geostructures.
This chapter focuses on the experimental analysis of the thermohydromechanical
behaviour of soils and soil structure interfaces based on the results of laboratory tests.
The behaviour of soils and soil structure interfaces is expanded with a focus on their
deformation and strength under nonisothermal conditions, and the influence of aspects
that govern such behaviour are highlighted.
To address the aforementioned aspects, idealisations and assumptions are presented
first: in this context, the objective is to propose a summary of the conceptual descrip-
tions and hypotheses that are employed for describing the behaviour of soils and

soil structure interfaces under nonisothermal conditions. Second, the characterisation of
soils is treated: the objective of this part is to summarise concepts for the characterisa-
tion of the behaviour of fine- and coarse-grained soils. Third, the deformation and
strength of soils under nonisothermal conditions is discussed: in this context, the purpose is
to address the influence of thermal and mechanical loads on the response of the con-
sidered materials. Next, the thermally induced effects on soil parameters are treated: in this
framework, the purpose is to discuss the influence of thermal loads on parameters that

describe the thermohydromechanical behaviour of soils. Afterward, the characterisation
of soil structure interfaces is discussed: the purpose of this part is to expand on features of
interfaces with soils that can be employed to describe the related response to loading.

r 2019 Elsevier Inc.
Analysis and Design of Energy Geostructures
DOI: https://doi.org/10.1016/B978-0-12-816223-1.00005-9 All rights reserved. 209