8.5 One-dimensional compression and swelling
In the ground the stresses are not generally isotropic as the horizontal and vertical
stresses are different. A common case where a relative wide load from an embankment
or spread foundation is on a relatively thin layer of clay sandwiched between stiff
sand is illustrated in Fig. 8.8. In this case the horizontal strains below most of the
embankment are approximately zero, as shown, and the loading is one-dimensional.
In the laboratory one-dimensional conditions occur in oedometer tests and in shear
box tests before the shear stresses are applied. Although here we are concerned with
one-dimensional loading, the conditions below the foundation illustrated in Fig. 8.8
and in the one-dimensional laboratory tests correspond to one-dimensional drainage
as well.