Mechanical and Fracture Behavior of Sedimentary Rocks under Uniaxial Compression

Energy-related characterizations can provide important information regarding mechanical behavior of rocks. A series of uniaxial compression tests were carried out on intact rock samples obtained from Wyoming, USA. The physical properties of the samples (i.e., porosity and grain size) were first examined. To investigate the fracture behavior of sedimentary rocks, a compilation of published dataset and our experimental data were employed to develop a new approach for estimating uniaxial compressive strength (UCS) based on the amount of energy released during rock deformation, which is known as the rock toughness. The energy release is calculated as the area under the stress-strain curve until the peak stress is reached. This energy shows a strong correlation with the density of the rock. Moreover, a predictive empirical model was proposed to estimate the rock UCS based on the rock toughness. The proposed empirical model was validated by comparing the predicted and measured UCS values of experimentally tested rocks, and the comparison showed a good agreement with a mean bias (the ratio of measured to the predicted compressive strength) of 1.002.