The Concept of Effective Stress in Unsaturated Soils - Multiscale Geomechanics: From Soil to Engineering Projects - page 161

Figure 6.6. Relation between capillary cohesion and stresses in Mohr plane
Figure 6.7. (a) Geometrical representation of the liquid bridge between two grains
of different diameters and (b) detail of the liquid bridge [SOU 06]
6.3. Material and methods
6.3.1. Material and preparation of samples
The tests were carried out on a residual silty sand, called “Perafita sand”, mainly
composed of decomposed granite, which was used for the construction of a road in
the north of Portugal. Its geotechnical properties are shown in Table 6.2 and its grain
size distribution in Figure 6.8. The soil contains approximately 2% particles smaller
than 2 µm and nearly 20% smaller than 80 µm. Standard and modified Proctor
curves are plotted in Figure 6.9. Photographs of the material taken with a scanning