Experimental study of heterogeneous water flow in a sheared fracture

We developed an experimental system that can be used to conduct a shear-flow test under a constant normal stress using a flat-jack-type true triaxial compressive test apparatus. A shear flow test was carried out on a cubic specimen with a single tensile fracture with this experimental system. A comparison of the results of the numerical experiment and the shear-flow test suggest that the heterogeneity of fracture permeability may be governed by the spatial distribution of large and small apertures, which can form channels. Thus, continuity between localized passes formed by apertures of various sizes can contribute to the appearance of channels, along with merely large passes. The contact regions of the fracture surfaces enlarged and localized with an increase in shear displacement, and the flow of water in the fracture was blocked. Additionally, gouged material that was produced by contact of the fracture surfaces may have affected the fracture permeability.