Civil Engineering Reference
In-Depth Information
Figure 15.12
Determination of
c
v
from an oedometer test - Example 15.1.
From Eq. (15.10) the coefficient of permeability is given by
10
−
4
2.0
×
4.6
×
×
9.81
10
−
10
m/s
k
=
c
v
m
v
γ
=
=
2.9
×
w
60
2
×
×
24
365
Example 15.2: Settlement of an oedometer sample
In a stage of an oedometer test the
total stress was raised by 100 kPa. The sample was initially 20 mm thick and it was
drained from both ends. The properties of the soil were
c
v
2m
2
/year and
m
v
=
=
10
−
4
m
2
/kN.
From Eq. (15.1) the final settlement, after consolidation is complete, was
5
×
σ
z
=
10
−
4
ρ
=
m
v
z
5
×
×
20
×
100
=
1.0mm
(a) The time factor at which the settlement will be 0.25 mm (i.e. when
U
t
=
0.25) is
given by Eq. (15.26):
3
U
t
4
0.25
2
4
3
×
T
v
=
=
=
0.05
