RD&D-Programme 2004 - SKB

Programme
The Apse experiment is being conducted during 2004. A complete evaluation will be made in
2005.
The strategy for site-descriptive rock mechanical modelling is being applied and developed
within the framework of the site investigations (Deep Repository Project).
In-depth analysis will be carried out in connection with the evaluation of the Apse experiment
regarding calibration of the strategy for site-descriptive rock mechanical modelling, mainly
based on comparison between predicted properties and experimental results.
19.2.6 Thermal movement
Conclusions in RD&D 2001 and its review
General plans for construction of descriptive rock mechanical models were described in RD&D
2001. The risk of canister damage due to thermomechanical loading was addressed in RD&D
2001 under the process “reactivation” and can in practice be set equal to zero, provided that it
can be assumed that no canister holes will be intersected by fractures with a minimum length of
700 metres in the dip direction /19-36/.
The authorities note the absence of a reference in RD&D-Programme 2001 supporting the claim
that thermomechanical loading does not cause canister damage. SKI believes this remains to be
shown.
Newfound knowledge since RD&D 2001
Within the Decovalex project, the rock’s thermohydromechanical response to tunnel excavation
and heating has been analyzed with a number of different tools, including the commercially
available code Abaqus. The evaluation and reporting of the SKB work, i.e. simulation of the
Febex experiment, is under way.
Programme
The Apse experiment is continuing with updated analyses of the thermally generated movements
and stress changes.
Within the framework of the design process (stage D2 in SKB’s planning), thermomechanical
numerical analyses will be carried out using site data. General thermomechanical 3DEC
analyses may be done first as reference cases, where the rock is assumed to have continuum
properties equivalent to those obtained from the first versions of the site models. Other input
data, i.e. thermal loads, canister spacing etc, will be determined on the basis of the latest thermal
dimensioning analyses.
19.2.7 Reactivation – movements along existing fractures
Conclusions in RD&D 2001 and its review
In RD&D 2001 it was noted that the risks of induced fracture movements had been overestimated
in SR 97 due to the exaggerated safety margins that had been applied in the numerical
analyses. Furthermore, RD&D 2001 described plans to broaden the body of numerical data for
assessment of potential seismically induced fracture movements by defining and executing a
programme of dynamic calculations.
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