Quasistatic Deformation of Solids with Pressure

The stress-strain behavior of several solids as a function of confining pressure to 4 kbar is determined by applying a fluid pressure of up to 5 kbar to the ends of cylindrical samples, thereby eliminating nonuniform stress fields that result from loading with a solid piston. The initial shear modulus μ of Pyrex glass is determined to be 255 kbar with δμ/δP=−2.15. Data are also presented on the deformation of Armco iron, polymethylmethacrylate, Westerly granite, and Solenhofen limestone. Hysteresis in the granite axial stress-strain data is attributed to the influence of elongate cracks that are closed with increasing confining pressure. The stress-strain curves for the limestone as a function of confining pressure show evidence of microfracturing from the distortion of the anisotropic calcite grains.