Calculation of Dynamic Deformation Modulus of Rock Masses Using Rock Mass Classification Systems and Laboratory Tests

Deformation Modulus of Rock Masses is one of the most important rock mass parameters that is used to measure the displacement of rocks under loading. Dynamic loads such as earthquakes and explosions are also important in rock engineering, as are static loads. Therefore, it is necessary to consider dynamic parameters as much as static properties. Dynamic deformation Modulus of Rock Masses is determined using Tomography and seismic refraction tests, which are time-consuming and cost-effective. Therefore, in this study, indirect methods based on the combinations of engineering classification systems and laboratory results were used to estimate the dynamic deformation modulus of rock masses. Due to the easy and comprehensive measurement of the Geological Strength Index (GSI) classification system and ultrasonic tests in the laboratory, the data of the five large dams in Iran were gathered and analyzed. The multivariate regression analysis showed that the dynamic deformation modulus of the rock masses can be estimated by an acceptable approximation with combination of GSI and the ultrasonic tests results.