Iw. Yeo et al., EFFECT OF SHEAR DISPLACEMENT ON THE APERTURE AND PERMEABILITY OF A ROCK FRACTURE, International journal of rock mechanics and mining sciences & geomechanics abstracts, 35(8), 1998, pp. 1051-1070
Citations number
41
Categorie Soggetti
Engineering, Geological","Mining & Mineral Processing
The results of experiments ruing radial and unidirectional flow in a c
arefully described single rough aperture are reported and compared wit
h numerical predictions. Aperture replicas of a natural sandstone frac
ture were made at 0, 1 and 2 mm shear displacements using silicone rub
ber, with a reproducibility of better than 2%. The experimental arrang
ement permitted shear displacement to be obtained without causing dama
ge to the two displaced surfaces, which thus retained their original (
and essentially matching) geometry. Both the number of contact points
and the fractional contact area decreased with increasing shear displa
cement. With increasing shear displacement, mean aperture and standard
deviation increased and the ratio of standard deviation to mean apert
ure increased slightly. Semivariogram studies indicated that as shear
displacement increased in the direction normal to the roughness ridges
, the aperture distribution became more closely correlated in the dire
ction par allel to the roughness ridges than in the shear direction. F
low tests showed that,with increasing shear displacement, the fracture
became heterogeneous and anisotropic and became more permeable in the
direction perpendicular to the shear displacement than in the directi
on parallel to the displacement. Simulations were made of flow through
the fracture using the Reynolds equation and the actual aperture dist
ribution; the measured hydraulic apertures were generally about 20% lo
wer than those measured numerically. (C) 1998 Elsevier Science Ltd. Al
l rights reserved.