A Study of Young's Modulus on Rocks

There are several reports that the static Young's modulus of rocks differs from the dynamic one. In this study, the relation between static Young's modulus and dynamic Young's modulus of rocks is examined. First, static Young's modulus was obtained by the uni-axial compression test, and dynamic Young's modulus was obtained by the ultrasonic transmission method. Secondly, their relationship was examined from the viewpoint of the strain level. In addition, the value of the Poisson's ratio for calculation of dynamic Young's modulus was examined. As a result, it was clarified that the dynamic Young's modulus becomes almost equal to the static one determined from the region of small strain if the Poisson's ratio used to calculate the dynamic Young's modulus is the appropriate value which is measured at the strain level without effect of crack closure.