A new laboratory test for shear fracture formation and its permeability measurement

摘要

We propose a new testing method which allows us to create a single shear fracture and measure its permeability sequentially under confining pressure, once a specimen is set to an apparatus. Then the shear sliding of fracture occurs while keeping contact of the fracture surfaces, as expected to occur in subsurface rocks subjected to compressive stresses. We constructed the apparatus and applied it to the tests using Kimachi sandstone as a rock sample. Results show that permeability of the rock increased with existence of a shear fracture, however the increment was not so significant compared with the original permeability and there was no clear correlation between the permeability increment and shear displacements of the fracture surfaces.