Dear Mr. Donze,

are you refering to the creep characteristics of a shale or to its shear deformation (like in a triaxial test)? And what is the range of the confining pressures you want to apply?

Best Regards

Try to sée this paper: http://www.sciencedirect.com/science/article/pii/S0264817200000271

Good luck 

Dear Christian and Mansour,

Thanks for your replies. I am referring to direct shear tests with a confinement higher than 5 MPa. Most of the experiments, like the one you refer to Mansour, show a decrease of permeability as the shear deformation increases. But these tests often neglect the very beginning of the shear deformation process, i.e. before reaching 0.5-1 mm of displacement.  In this range of displacement, does the permeability increase? And what happens if a shear loading cycle is applied in this range of displacement? Frederic