A long time ago, Pusch (1983) reported that the
penetration rate of the bentonite into a fractured rock is a
function of the density and the fracture width, while an
erosion of the bentonite gel depends on its shear strength
as well as on the flow rate of the water in the fractures. A
few years ago, Pusch (1999a) performed a study on the
colloid formation from compacted MX-80 buffer that
had penetrated into fractures although this work actually
was focused on colloids with a relatively larger size
between 2 and 50 μm. Grindrod et al. (1999) investigated
a mechanical interaction between a compacted clay and a
fractured rock, and the possible generation of clay colloids. In this study, a limited model for the penetration
mechanism of the swelled bentonite gel into a rock fracture
was suggested and the mass loss of the bentonite by
erosion was also estimated. Furthermore, Pusch (1999b)
and Sjöblom et al. (1999) investigated the applicability
of a general microstructure model to a bentonite erosion.