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 56

authors for this peculiar property; therefore, curve B2 should be located below the
range of usual rockfill properties.
Figure 3.10. Charles &Watts compilation of rockfill shear strength envelopes (1980)
3.2.2.2. Evidence of scale effect
In another study, Barton [BAR 81] displayed a very peculiar set of large triaxial
test results. The tests have been performed on granular materials issued from the
same mineral stock, with homothetic grain size distributions, and tested at the same
density. In Figure 3.11a, the results obtained on two different groups show a clear
size effect: the shear strength is lower when the grain size is coarser.
These two groups having parallel grain size distribution curves, a comparison of
their properties may be examined in light of the grain strength resulting from the
probabilistic approach with the central trend distribution (see section 3.2.1.3):
− for homothetic grain size distributions, the grain resistance is in principle
inversely proportional to the square root of a given characteristic diameter, for
example equal to D Max ;
− therefore, to obtain in a granular material 1 with characteristic grain size D 1 ,
the same amount of grain breakage and, then, the same shear strength as in material