Civil Engineering Reference
In-Depth Information
(a)
2
r
(b)
Equilibrium water
level,
t
= infinite
h
2
h
2
h
1
h
1
h
0
h
0
t
=0
D
t
=0
L
2
R
2
R
(c)
1.0
0.5
h
1
h
t
h
0
h
2
0.2
t
1
t
2
0
2
4
6
8
10
12
Elapsed time,
t
Figure 5.14
Method of calculating hydraulic conductivity for variable head test: (a) piezometer with
completion length
L
; (b) open hole to depth
D
below water table; (c) typical plot of head increase (recovery)
against time.
hydraulic conductivity,
K
, is the mean hydraulic
conductivity given by
√
(K
v
×
length (Figure 5.15). Packer tests can be made
during diamond drilling using a triple packer sys-
tem that is lowered through the rods so that the
test is conducted in a portion of the hole below
the drill bit. The packer system consists of three
inflatable rubber packers, each 1 m long that is
K
h
)
.
Packer tests.
Where conductivity tests are
required at specific locations within a drill hole, a
test zone can be isolated using packers positioned
at any location in the hole, and over any required
