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General Report for TC104
Physical Modelling in Geotechnics
Rapport général du TC104
Modélisation physique en géotechnique
White D.J., Gaudin C.
Centre for Offshore Foundation Systems, University of Western Australia
Take W.A.
Geo-Engineering Centre, Queen’s University, Canada
ABSTRACT: The session of the 18th ICSMGE on physical modelling in geotechnics, held by Technical Committee 104, provides an
opportunity to reflect on the varied contributions that physical modelling makes to our profession – in both research and practice. The
27 papers contributed within this theme span many different applications of physical modelling. These range from simple small-scale
laboratory tests to reveal mechanisms of soil-structure interaction – particularly where simulation by numerical methods is
problematic – through to scaled-down versions of field constructions, performed outdoors, to validate the performance of new
monitoring technology. These examples show physical modelling in action across the entire spectrum of geotechnics, from the
validation of fundamental analysis principles, to the assurance of construction technology. In all cases, physical models – defined here
as physical idealisations of all or part of an envisioned geotechnical system – provide a more convenient method of gaining
knowledge than observing or simulating the full geotechnical system.
RÉSUMÉ : La session de la 18
e
ICSMGE sur la modélisation physique en géotechnique est l’opportunité de faire le point sur les
différentes contributions que cette dernière a apporté à notre profession, dans le domaine de la recherche et des applications pratiques.
Les 27 articles retenus dans les comptes rendus de la conférence couvrent un champ varié d’applications de la modélisation physique.
Ils incluent notamment des expériences de laboratoire menées à échelle réduite pour révéler les mécanismes d’interaction sol-structure
(notamment dans des cas ou la modélisation numérique peut s’avérer inadaptée), ainsi que des expériences de terrain réalisées sur des
versions réduites d’ouvrage réels pour développer et valider de nouvelles techniques d’instrumentation et de suivi. Ces différents
exemples démontrent la variété des applications de la modélisation physique, de la validation de principes fondamentaux, à
l’évaluation des performances de technologie de construction. Dans tous les cas, la modélisation physique, définie ici comme
l’idéalisation d’un system physique réel, permet d’accéder de manière rapide, économique et rigoureuse à une connaissance élargie du
problème étudié.
KEYWORDS: Physical modelling. Centrifuge modelling. Field monitoring.
1 INTRODUCTION
The papers submitted to the TC104-organised session on
Physical Modelling in Geotechnics illustrate a range of
applications of physical models to support geotechnical research
and practice.
Physical modelling can serve a variety of purposes in
geotechnical engineering. It can provide (Gaudin et al. 2010):
1.
Insights into soil-structure interaction and geotechnical
behaviour
– qualitative and quantitative. Given the
complexity of soil constitutive behaviour and the complex
deformations and processes in some construction
technologies, physical modelling provides a basis to assess
fundamental modes of behaviour in controlled conditions.
2.
Performance data to calibrate analytical or numerical
models
. Physical models use well-characterized soil and
known boundary conditions, providing reliable performance
data for a given idealized problem.
3.
Specific performance data for design and operation
.
Physical modelling can be used directly to design
geotechnical systems or tools. For example, site-specific
soil and loading conditions can be replicated in a centrifuge
model, to validate a foundation design. Or, the shape of a
geotechnical tool – such as a novel form of ground
improvement device or a proprietary anchoring system –
can be optimised using performance data from physical
models.
4.
Soil characterisation data
– through testing of samples
using miniature versions of conventional in situ testing
tools. Using physical models in this way can be more cost-
effective than full scale in situ tests.
Physical modelling, in its various forms, contributes across
the entire proceedings of the 18
th
ICSMGE, not only the 27
papers that were allocated to this session. Physical modelling is
a technique that cuts across the traditional categories of ground
engineering. The majority of the sessions at the ICSMGE are
defined by type of geotechnical system – foundations, slopes,
ground improvement and so forth. These are the traditional
groupings that our profession forms, pooling expertise and
specialist knowledge from experiences in design and
construction.
The physical modelling community within geotechnical
engineering pools a different type of specialist expertise. The
TC104 activity focuses on the technology and principles that
allow physical modelling facilities to flourish and provide
capabilities that can be applied across all geotechnical topics.
When the ICSMGE was last held in Paris, in 1961, the
ISSMFE did not have Technical Committees and there was no
session dedicated to physical modelling. However, physical
modelling featured heavily in the presented papers. The
Proceedings of the Paris conference feature classic physical
modelling studies of retaining walls by Rowe and Schofield, as
well as model pile tests in the field performed by De Beer,
Kerisel and Meyerhof. Many papers show film photographs of
