This paper concerns both in situ measurements of permeability and numerical
modelling of changes in permeability induced by microcrack growth. Hydraul
ic experiments including pulse tests with the SEPPI probe are in progress.
These tests are a part of the tunnel sealing experiment (TSX) at the 420 m
level of Canada's Underground Research Laboratory, whose aim is to estimate
the in situ hydraulic properties of Lac du Bonnet granite. Based on labora
tory investigations, the anisotropic damage model developed by Homand et al
. (Comput. Geotech. 22 (1998) 135) and recently reviewed by Shao et ar. (In
t. J. Rock Mech. Min. Sci. 36 (1999) 1001) has been extended in order to ac
count for changes in permeability induced by microcrack growth. We have imp
lemented this extension in the three-dimensional code (FLAC(3D)). Triaxial
compression tests, with permeability measurements carried out on two differ
ent granites, provide a verification of the numerical implementation with a
good agreement between experiments and predictions. Comparison between in
situ measurements of permeability and predictions indicates that both the r
esults of numerical modelling and observations are globally in agreement. F
inally, numerical modelling as well as the in situ measurements indicate th
at a depth of 50-70 cm is a good estimation of the extent of excavation dis
turbed zone in the TSX tunnel. (C) 2001 Elsevier Science Ltd. All rights re
served.