Civil Engineering Reference
In-Depth Information
e =
H H
H
−
s
Pressure (kPa)
Thickness, H (mm)
s
20 11 58
11 58
−
.
0
20
=
0 727
.
.
50
19.65
0.697
100
19.52
0.685
200
19.35
0.671
400
19.15
0.653
800
18.95
0.636
Note:
Such close agreement between the two methods for determining the e-p rela-
tionship could only happen in a theoretical example. In practice one often finds large
discrepancies between the two methods.
11.3.6 The virgin consolidation curve
Clay is generally formed by the process of sedimentation from a liquid in whisch the soil particles were
gradually deposited and compressed as more material was placed above them. The e-p curve correspond-
ing to this natural process of consolidation is known as the virgin consolidation curve (Fig.
11.9a
).
This curve is approximately logarithmic. If the values are plotted to a semi-log scale (e to a natural scale,
p to a logarithmic scale), the result is a straight line of equation:
p
+
dp
0
e
= −
e
C
log
0
C
10
p
0
Fig. 11.9
e-p and e-log p curves for natural consolidation and for a normally consolidated clay.
