Analysis of rock mass classifications for safer infrastructures

Abstract

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.