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FP5

SELFRAC Résumé de rapport

Project ID: FIKW-CT-2001-00182
Financé au titre de: FP5-EAECTP C
Pays: Belgium

State of the art on fracturation and self-healing processes and characterisation

A review and reporting of the state of the art on basis of existing theoretical studies and in situ observations realised in underground laboratories has been performed.

A clear distinction has been proposed within the SELFRAC project, between the Excavation Damaged Zone (EDZ) and Excavation disturbed Zone (EdZ).

The definitions were established in the context of underground radioactive waste disposal, establishing a bridge between geomechanics and PA:
- The Excavation disturbed Zone (EdZ) is defined as a zone with hydro-mechanical and geochemical modifications, without major changes in flow and transport properties. Within the EdZ there are no negative effects on the long-term safety.

- The Excavation Damaged Zone (EDZ) is defined as a zone with hydro-mechanical and geochemical modifications inducing significant changes in flow and transport properties. These changes can, for example, include one or more orders of magnitude increase in flow permeability.

These definitions were internationally discussed and accepted at the conference "Impact of the excavation Disturbed or Damaged Zone on the performance of radioactive waste geological repositories" held in Luxembourg 3-5 November 2003. However the definitions should be deepened for each type of rock and each site. In particular, the terms significant and major should be quantified and the time effect should be determined for each particular site.

Reported by

Euridice
Boeretang
2400 Mol
Belgium
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