Civil Engineering Reference
In-Depth Information
Fig. 11.8
Example
11.4.
The values of e at the end of each consolidation can be calculated from this
expression.
Pressure (kPa)
H (mm)
dH (mm)
de
e
0
20.0
0.727
+
0.75
+
0.065
50
19.65
0.697
+
0.40
+
0.035
100
19.52
0.685
+
0.27
+
0.023
200
19.35
+
0.10
+
0.009
0.671
400
19.15
−
0.10
−
0.009
0.653
800
18.95
−
0.30
−
0.026
0.636
0
19.25
0
0
0.662
From the e-p curve in Fig.
11.8a
:
e at 250 kPa
=
0.666
e at 350 kPa
=
0.658
0 666 0 658
100
0 000 08
.
−
.
a
=
=
.
m /kN
2
a
0 000 08
1 666
.
⇒
m
=
=
v
1
+
e
.
1
5
2
=
4 8 10
.
×
−
m /kN
Alternative method for determining m
v
m
v
can be expressed in terms of thicknesses:
dH
H dp H
1
1
dH
dp
m
v
=
=
1
1
dH/dp is the slope of the curve of thickness of sample against pressure. Hence m
v
can
be obtained by finding the slope of the curve at the required pressure and dividing by
the original thickness. The thickness/pressure curve is shown in Fig.
11.8b
; from it:
