Shear-enhanced compaction and permeability reduction: Triaxial extension tests on porous sandstone

Triaxial extension experiments were conducted to investigate the influence of radial stress on porosity and permeability (for hydraulic flow along the axial direction) in three porous sandstones. The effective mean stresses were sufficiently high that the samples failed by cataclastic flow, with development of strain hardening and shear-enhanced compaction. Comparison of the new data with triaxial compression data from a previous study shows...