A Study of Young's Modulus on Rocks
Yuichi KOHMURA
Abstract:There are several reports that the static Youngfs modulus of rocks differs from the dynamic one. In this study, the relation between static Youngfs modulus and dynamic Youngfs 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 Poissonfs ratio for calculation of dynamic Youngfs 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 Poissonfs ratio used to calculate the dynamic Youngfs modulus is the appropriate value which is measured at the strain level without effect of crack closure. Key Words:Rocks, Static Young's modulus, Dynamic Young's modulus, Strain level, Poisson's ratio