Civil Engineering Reference
In-Depth Information
Figure 16.1
One-dimensional consolidation and swelling of soil in the ground due to deposition
and erosion.
used to estimate
K
0
is
K
0nc
Y
0
K
0
=
(16.2)
φ
c
is the value
where
Y
0
is the yield stress ratio defined in Sec. 8.3 and
K
0nc
=
1
−
sin
of
K
0
for normally consolidated soil.
In previous chapters I showed that many aspects of soil behaviour (but not the critical
states) depend on the state which arises as a consequence of the history of loading and
unloading. This means that reconstituted samples should be compressed and swelled
one-dimensionally in the apparatus before shearing and intact samples of natural soil
should be recompressed to the estimated state in the ground.
The state of an element of soil in the ground depends on the current stresses (i.e. on
the depth) and on the overconsolidation (i.e. on the current depth and on the depth
of erosion). Figure 16.2 illustrates the variations of water content with depth for a
deposit which is lightly eroded (i.e. the depth of erosion
z
e
is small) or heavily eroded
(i.e. the depth of erosion is large). For the lightly eroded soil the difference between
the water contents at A and B is relatively large, while for the heavily eroded soil
