Rationalisation in the Design and Construction of Underground Structures

Based on many years of research focusing on a number of significant structures (bridges, tunnels, dams, high rock slopes, etc.) designed and realized in the Adriatic coastal area, we have collected a large quantity of engineering-geological and geotechnical information. To devise engineering-geological and geotechnical models, it is indispensable to conduct engineering rock-mass classification using one of the widely recognized methods. Starting from the existing RMR and Q classification, we have developed a new "n" classification which enables a more complete limestone classification and categorization, using a relatively simple procedure. These investigations served as a basis for establishing the correlation between the excavation and primary support unit price and the cross-sectional area or excavation volume. Finally, a complex correlation between the unit price and the cross-sectional area and excavation volume was established and presented in the form of diagrams to facilitate its use.