Coupled Hydro-Mechanical Analysis of Excavation Damaged Zones around an Underground Opening in Sedimentary Rock

H. Abdi[1], E. Evgin[1], M. Fall[1], T.S. Nguyen[2], and G. Su[2]
[1]University of Ottawa, Ottawa, ON, Canada
[2]Canadian Nuclear Safety Commission, Ottawa, ON, Canada
Published in 2010

A large amount of research work has been carried out in many countries to determine the viability of radioactive waste disposal in deep geological repositories. It is well known that excavation can cause damage around underground openings. On the other hand, the mechanical damage can influence the stability of the opening and the flow characteristics of the rock mass. In addition, all physical and chemical processes involved are time dependent. The main objective of the present study is to determine the extent of the excavation damage zone and the intensity of damage as a function of time. The Hoek-Brown failure criterion is implemented into COMSOL Multiphysics. The relation between the changes in the effective plastic strains and the permeability of the rock mass is used in the hydro-mechanical analysis. The coupled finite element analysis is performed for a deep geological repository which is in its planning stage.