Estimation of RQD by digital image analysis using a shadow ...
1. Introduction. Rock Quality Designation (RQD) 1 is a rock quality index used in tunnel support/reinforcement design, prediction of insitu modulus1., 2., 3. finding allowable foundation contact pressures and fracture frequency, and as a parameter of RMR, 4 Q, 5 and Geological Strength Index (GSI) 6 rock mass classification systems. Hence, determination of RQD .