Correlation of in situ modulus of deformation with degree of weathering, RMR and Q-system

Geotechnical investigation projects in Korea produced data on the in situ modulus of deformation of rock masses (E _M) measured with the borehole test, rock mass rating (RMR), and Q-system. The modulus of deformation of rock masses was correlated with the degree of weathering, RMR, and Q values. Determination of E _M for each degree of weathering allows for the results to be used to classify the degree of weathering or to predict E _M. The relation between E _M and RMR is represented by \( E_{\text{M}} = 10^{{\frac{{{\text{RMR}} - 16}}{50}}} \), which returns values 2–3 times lower than those reported in previous studies. Despite scatter in the values, due to larger dataset used in this study, the proposed equation may be used to predict the in situ modulus of deformation from RMR values. In addition, the relation between modulus of deformation and Q values is \( E_{\text{M}} = 10^{{0.32{ \log }Q + 0.585}} \).