Evolution of P-wave anisotropy as an indicator of pre-failure deformation in shale

Description of the dataset This dataset contains experimental measurements acquired during a uniaxial compression test performed on a clay-rich rock sample.The file is provided in NumPy .npy format and contains a Python dictionary with the following entries: sample_size_v : vertical sample dimension (m) sample_size_h : horizontal sample dimension (m) sample_size_h_bis : second horizontal dimension (m) sample_size_45_corrected : corrected path length for the 45° ultrasonic measurement (m) time : time of each acquisition axial_strain : axial strain (%) axial_stress : applied axial stress (mechanical load) in MPa v_0, v_90, v_45 : P-wave velocities (m/s) along the three propagation directions t_0, t_90, t_45 : time of each acquisition of P-wave