Civil Engineering Reference
In-Depth Information
Fig. 12.21
Equivalent radius: triangular system.
hence:
2
1
2 2
2 3
a
a
a
Area of triangle ABC
= × ×
=
8 3
So that:
2
a
Total area of the hexagon
= ×
12
=
0 865
.
a
2
8 3
Radius of the equivalent circle, R
=
0.525a
Determination of consolidation rates from curves
Barron has produced curves which give the relationship between the degree of consolidation due to radial
flow only, U
r
, and the corresponding radial time factor, T
r
.
c t
R
h
T
=
4
r
2
where t
=
time considered.
These curves are reproduced in Fig.
12.22
and it can be seen that they involve the use of factor n. This
factor is simply the ratio of the equivalent radius to the sand drain radius.
R
r
n
=
and should lie between to
5
100
To determine U (for both radial and vertical drainage) for a particular time, t, the procedure becomes:
c t
H
v
T
=
where H vertical drainage path
=
z
2
(ii) Determine U
r
from Barron's curves of U
r
against (ii)
r
.
