Hydro-mechanical response of a bedded argillaceous rock formation to excavation and water injection

Abstract of the journal article published in Canadian Geotechnical Journal: March 2014

Author(s):
Son Nguyen

Abstract:

In many countries, including Canada, sedimentary rock formations are being considered as candidates for the long-term management of radioactive wastes. These formations possess desirable characteristics (such as very low permeability) that would limit the movement of radionuclides from the wastes. However, the digging of a repository results in an excavation damage zone (EDZ) with higher permeability than the undisturbed rock around it. The ability to predict the extent and characteristics of the EDZ is important, to allow for the inclusion of mitigation measures in the design of the repository.

The authors use experimental data from the excavation and water injection in a test tunnel (inside an underground research laboratory in Switzerland) to develop a mathematical model. The model can predict the extent and characteristics of the EDZ and successfully simulate the flow pattern inside it. This work provides CNSC staff with a tool to independently assess future proposals for geological disposal repositories.