Geology, basics and application to civil engineering

The civil engineer who plans or builds a structure is necessarily confronted with the "terrain" that forms the support or material for the structure. It is important for them to have a basic understanding of geology, so as to be able to dialogue with the geologist from whom they are requesting work.

Geology as a science (also known as "Earth Sciences") involves studying the parts of the Earth accessible to observation, and making hypotheses aimed at reconstructing their history and layout. The geology of a region is also referred to as its geological characteristics.

Thus, all activities aimed at exploiting, using or developing the soil and subsoil have to do with geology. A good knowledge of the geology of our subsoil and its past or potential evolution is beneficial or necessary to the development of mankind.

However, geologists face a twofold difficulty: the difficulty of accessing the underground, which is by nature hidden, and the difficulty of understanding processes that take place over a very long period of time, "geological time". In geology, therefore, interpretation is inevitably a major factor. This makes it particularly important to understand and pass on basic knowledge of the earth's constituents, their various known or possible arrangements, and the main geological phenomena and processes.

This article begins by presenting the different types of rock in our subsoil, what constitutes and characterizes them, what affects and deforms them (geological structures), and their relationship to the earth's history and, more generally, to time. The article goes on to describe the geological issues in civil engineering and the methodology for studying the subsoil for construction purposes on or in it.