Geoscience Reference
In-Depth Information
Thus, Biarez found a fundamental representation for undrained tests, in this case
for sands, but also valid for remolded clays. This is an example of his unified view
of materials without “glue”.
It is our hope that these six planes can be fruitfully adopted by the international
community of soil mechanics and that mathematical modeling of the
overconsolidated paths will appear in the near future.
5.8. The triaxial behavior of “lumpy” sands
In the section below we broach the rather peculiar subject of how Biarez
attempted to show by experimental means that lumpy sand is indeed a granular
material with the particular feature of containing “glue”, i.e. capillary forces.
5.8.1. “Lump” sands
In preparing a sample of sand in moist conditions, we observe that a lumpy
structure is created. With an electronic scanning microscope, Benhamed [BEN 01]
produced images of sands with a moist deposit, showing a geometric arrangement of
grains with lumps and lacunae (see Figure 5.16), i.e. two void ratio classes: an intra-
lump class and an inter-lump class.
Figure 5.16. “Lumpy sands” observations with scanning electron microscope [BEN 01]
On the drained triaxial path, we can assume that the large strains have effaced
the history of the material. Therefore, the same perfect plasticity line as for the dry
 
Search WWH ::




Custom Search