Abstract

This work compares the results of expensive and time-consuming destructive tests and cheap non-destructive ultrasonic analyses for the assessment of rock parameters (i.e. uniaxial compressive strength, Young's modulus, Poisson's ratio, etc.), with the aim to geologically characterize the site and to find correlations between the mechanical and acoustic properties of rocks for applications in the field of the monitoring of CO2 leakage. The assessment considers 60 samples, 10 per each of the six formations of the Sulcis Miocene volcanic sequence. Samples have been initially subjected to non-destructive tests for the measurement of density and compressional and shear wave velocity and then mechanically tested to determine the uniaxial strength. As it happens for other kinds of rock, a linear direct correlation has been found between uniaxial compressive strength and compressional wave velocity, as well as between dynamic and static Young's moduli and for the dynamic and static Poisson's ratios, with a correlation coefficient R2 significantly affected by the nature of the pyroclastic formation. Helpful information on the pyroclastic rocks have been obtained, collecting parameters currently not available in the literature for this kind of geological formations.