An integrated approach to excavation design - A project within Canada's used fuel disposal program

A project to develop an excavation design process for potential application in construction of a nuclear fuel waste disposal vault is being undertaken in Canada. Towards this end, fundamental issues in rock mechanics are being addressed. Issues include increasing the understanding of the micro-mechanical phenomena leading to time-dependent cracking in situ;quantifying rock mass damage through field measurements; coupling mechanical rock fracture analyses with thermal and hydraulic numerical tools; presenting the results from field measurements, numerical simulations and analytical calculations in terms that are relevant to excavation design; and calibrating properties related to time-dependent strength degradation using resultsof laboratory long-term loading tests. As such, the project encompasses a wide range of geotechnical skills and technologies.