Euradwaste '08 - EU Bookshop - Europa

3. Results
3.1 Laboratory experiment
The laboratory experiment was constructed without using the original lining from the PRACLAY
project (SCK-CEN Mol, Belgium). The lining used differed both in terms of its inner span, the
thickness of the segments and the quality of the concrete used. The principal objective of this experiment
was to gain experience in the construction of this type of model and to test both the
REVEL heating system and the instrumentation, Pacovský et al. (2007)[3].
From the very beginning, the heating system was set at a temperature of 90 o C i.e. the maximum
loading temperature. Due to effective thermal insulation, temperature equilibrium was soon
achieved. Individual deformations and displacements within the individual lining segments measured
to date do not exceed 3mm, which is less than had been assumed. Figure 5 shows a typical result
from the deformation measurement.
Displacement [mm]
1
0.75
0.5
0.25
0
-0.25
01 Nov 07
30 Jan 08
29 Apr 08
28 Jul 08
Date
26 Oct 08
Figure 5: Measurement of deformation of joints between individual segments of the lining
3.2 “In situ” experiment
The “in situ” experiment is being performed in accordance with a precisely specified procedure.
Due to the requirement for the temperature difference between the inside and outside lining surfaces
(temperature gradient) never to exceed 30 o C, thermal loading must be increased on a step-by-step
basis (60 o C, 75 o C, 90 o C).
Instrumentation provides accurate, sometimes very surprising results one of which was the discovery
of a steep increase in stress where the physical model comes into contact with the rock mass
(Fig.6). Measured values are continuously evaluated. The stress measured inside the lining segments
reaches values of up to 10MPa.
432
24 Jan 09
107
108
109
24 Apr 09