fundamentals_of_soil_behavior_(cha6)教材.pdf

CHAPTER 6
Soil–Water–Chemical
Interactions
INTRODUCTION Unbalanced force fields at the interfaces between
soil and water cause interactions between small soil
Saturated soils at void ratios greater than contain particles, dissolved ions, and water. If two particles are
more water volume than solid volume, and void ratios in close proximity, their respective force fields overlap
greater than are more the rule than the exception and influence the behavior of the system, especially
in fine-grained soils. Yet, the emphasis in the study of when the magnitudes of these forces are large relative
position and properties has traditionally been to the weights of the particles themselves. Clay parti-
almost entirely on the mineralogy and structure of the cles, because of their very small size, unique crystal
solid phase, with very little regard for the properties structure, and platy shapes, have very large specific
of the liquid phase. Perhaps this is because: surface areas and are especially influenced by these
forces.
1. Classical soil mechanics is founded on the con- Several types of interparticle attractive and repulsive
cept of effective stress, which postulates that forces determine the ulation–ulation be-
volume change and strength behavior depend on havior of clays in suspension and the volume change
the stresses carried by the solid grain structure and strength properties of soils at void mon
and the water phase is neutral. in natural deposits. The fabric at the time of formation
2. We all know that water is a clear, colorless, odor- may have a profound influence on the engineering
less, tasteless liquid that has a density very nearly properties of a soil deposit, so an understanding of
equal to unity. It freezes at a temperature of 0ЊC, factors influencing ulation–ulation behav-
boils at a temperature of 100ЊC, and it has quite ior is of considerable value. Furthermore, postdeposi-
well-defined viscosity and thermal properties.