In the construction of land transport infrastructures such as roads, highways, or railways,
one of the factors that determine their design most is the characteristics of the terrain
through which they run. Additionally, tunnels have become one of the most adopted
solutions to reduce environmental impact. The characteristics of the rock mass are a key
point to decide the layout of the tunnel and its construction method. However, the rock
masses are discontinuous, anisotropic, and heterogeneous media, so their classification and
knowledge are needed for a safer design of these infrastructures.
The rock mass is not an industrial material with “pre-established” properties and
behaviours, but rather a natural material that needs to be analyzed, understood, and
standardized. The need to understand the behaviour of the rock mass has led throughout
modern history to the use of different standards, which lead to the development of
geomechanical classifications, with the aim of establishing a common language that
translates the very advanced geological language in the macro and microgeological
behaviour, which is needed for applications in civil engineering. In the last decades of the
20th century, and in the present 21st, the efforts in the process of understanding the intact
rock and the rock mass has been constantly increasing because a better understanding of
the rock mass behaviour implies a better result in reached in projects involving affection to
rock masses. This paper briefly reviews the history of rock mass classifications, their
implications in rock mechanics and their applicability in the definition of behaviours as a
function of natural conditions and human action, as well as their direct implication in some
fields of the transport infrastructures management with regard to hazard and risk
assessment.
