Roughness characterization and JRC estimation have been made on rock joints of the Monte Seco tunnel. The authors have adapted field profiling of discontinuity surfaces to be able to estimate JRC using 3D laser scanner images. Results indicate similarity between traditional and laser scanning methods. The data also confirms the JRC size effect and the importance of evaluating field scale roughness.
The 905 km long Vitória–Minas Railway contains 44 tunnels. The majority of these tunnels are constructed in rock mass without any lining. In recent years, some tunnels have been presenting sporadic block falls, which have not represented generalized risk. The TUNELCON Project, partnership between Vale Company and Escola Politécnica da Universidade de São Paulo – EPUSP, seeks to study the geomechanical behaviour of these tunnels by the laboratory test, geological geotechnical mapping and numerical analyses.
The Monte Seco tunnel is located near to the cities of João Neiva and Ibiraçu in the state of Espírito Santo, where in the recent years, the block fall mechanism has been studied in detail (Cacciari et al., 2016; Cacciari, 2014).