Volume changes in grout used to fill up the tail void

air pressure
plate
grout
sand
d
Figure 1. Measurement principle.
Figure 2. Experimental setup.
valve
load
cell
water
collection
loaded mechanically with a constant load of 1–3 bar.
The expelled water is a measure of the consolidation
of the grout. After several minutes of consolidation
the sample was unloaded and the shear strength of
the grout was measured at different locations in the
grout. An example of results of such a test is shown
390
Weight expelled water (kg)
1.4
1.2
1.0
0.8
0.6
0.4
0.2
0.0
-0.2
350
300
250
200
150
100
0 10,000
Time (s)
-50
20,000
50
0
Applied air pressure (kPa)
Figure 3. Test result expelled water as a function of time
and applied pressure.
Height (cm)
20
18
16
14
12
10
8
6
4
2
10 min
20 min
30 min
0
0 2 4 6
Strength (kPa)
Figure 4. Strength development as measured with a vane.
in Figure 3 and Figure 4. Figure 4 shows the amount
of expelled pore water as a function of time and the
applied pressure. In this test a pressure of 300 kPa was
applied. Pressure was relieved several times to be able
to take the vane tests. Figure 4 shows the measured
shear strength after various times that pressure was
applied. In this test it was focused on the lower values
of the shear strength. Therefore only shear strengths
up to 6 kPa were measured and presented in the plot.
The type of grout tested here was tested before
at atmospheric pressure (Bezuijen et. al. 2002). In
that test it appeared that the measured shear strength
remained more or less constant until 5.5 hours and
after that time the hardening of the grout started.