Granular Materials in Civil Engineering: Recent Advances in the Physics of Their Mechanical Behavior and Applications to Engineering Works - Multiscale Geomechanics: From Soil to Engineering Projects - page 78

the description of their internal structure, leading to the formation of failure lines.
Thisastonishingphysicsofgranularassembliesopensnewfieldsofresearchandhas
already produced many results that are useful for practical applications. This is
particularly the case for the material scale effects and their implication on structural
stability in terms of both static equilibrium and the kinetics of deformation, as
observedinmajorcivilengineeringworks.
Several key elements of practical applications have been highlighted in this
chapter, such as the central tendency in the shear strength (section 3.2.2.2), that
deserve wider investigation in order to enlarge the data bank, to confirm the
statistical tendencies and to determine their limits. This is one of the objectives of
the joint ECHO (scale effects in civil engineering embankment works) research
projectthatiscurrentlyin progressand isfinancedbytheANR(theFrench National
ResearchAgency).
These results also show the major relevance of introducing a better
representation of the physics of these materials within constitutive models. In the
present study, these results were obtained through a multiscale approach starting
from the local scale rather than through the usual macroscopic phenomenological
approaches. The latter have produced numerous constitutive models that often
containmultipleparametersandsometimeslackclearground.
Along this path, we expect to be able to develop simple, clear and efficient
representations of some sort of “ideal granular material”, with a small number of
physical parameters. Such a representation would be a continuation of the typical
models of standard material behaviors in engineering sciences, which have been
provedtobeveryusefulinhydraulics,thephysicsofgas,structuralanalysis,etc.
The sequence of results obtained on the energy dissipation by friction
(section3.1), grain breakage (section 3.2), and their practical applications
(section3.3)demonstratethatsucharepresentationisnowpossible.
3.5.Bibliography
[BAR 81] B ARTON N., K JAERNSLI B., “Shear strength of rockfill”, J. Geotechn. Eng. Div. ,
vol.107,no.Gt7,pp.873-891,1981.
[BOL 98] B OLTON M.R., M C D OWELL G.R., “On the micromechanics of crushable
aggregates”, Géotechnique ,vol. 48,no.5,pp.667-679,1998.
[CHA 80] C HARLES J.A., W ATTS K.S., “The influence of confining pressure on the shear
strengthofcompactedrockfill”, Géotechnique ,vol.30,no.4,pp.353-367,1980.