An apparatus for measuring mechanical properties of a downhole material, including first and second fixtures each of the fixtures containing a force application fixture to apply a stress to a specimen of the downhole material. A confining sleeve wraps around portions of the first and second fixtures to form a sealed specimen chamber defined by an inner surface of the confining sleeve and ends of the first and second fixtures nearest the specimen. Wall of a confining chamber contain the first and second fixtures, the confining sleeve and the specimen therein. The confining chamber holds a hydraulic fluid therein such that the hydraulic fluid can exert a confining pressure on the confining sleeve to maintain the seal of the specimen chamber and to maintain contact between the inner surface of the confining sleeve and the specimen when the stress is applied to the specimen. First channels pass though one or more of the walls of the confining chamber to add and remove the hydraulic fluid to and from the confining chamber. Second channels pass though one or more of the walls of the confining chamber and through one of the first and second fixtures to add and remove a pore space fluid to and from specimen chamber ports open to the specimen chamber to maintain a pore pressure at the specimen chamber ports that is equal to or less than the confining pressure while the stress is applied to the specimen. A system and method are also disclosed.