Effect of loading rate on mechanical properties of anisotropic sandstone under compressive loading

An experimental investigation was carried out on the Hawkesbury sandstone to study effects of loading rate on the peak strength and deformability during uniaxial monotonic compressive testing. Axial load and axial and lateral deformations were measured precisely from start of loading until post-peak state. To predict properties of anisotropic Hawkesbury sandstone samples, a methodology to conduct monotonic testing was devised including the development of an innovative peak strength prediction method. The strength of the sandstone was increased with an increase in loading rate. The Tangent Young's modulus was found to increase slightly with increase of loading rate. Poisson's ratio of samples were also affected by loading rate, however, no conclusive trend was observed. A preliminary model was developed to predict variations of the Hawkesbury sandstone peak strength under different loading rates.