Caratterizzazione Geotecnica dei Terreni Mediante l’Uso di Tecniche Geofisiche

The objective of this work is to illustrate the use of some of the most important geophysical techniques for geotechnical site characterization. Most of the interest is focused to the seismic methods because of their relevance to the applications in geotechnical engineering. The description of these methods is preceded by two brief sections dedicated to recall the definitions of soil mechanical properties and some important concepts of seismic wave propagation in soil deposits. The main purposes of these sections are a) to put in evidence, in relation to the quantities measured during geophysical testing, of the dependence of the geotechnical parameters from the constitutive model used to represent soil mechanical behaviour, and b) to recall the attention on some of the difficulties that are inherent to geophysical methods and which are related to the complexity of soils when considered as media where the propagation phenomena take place. These introductory sections are then followed by a brief description of some of the most commonly used seismic methods in geotechnical engineering and also of some advanced techniques. In the second part of the paper are then illustrated the principles and capabilities of some electromagnetic methods that have recently expanded their use in geotechnical engineering. Finally, the article is ended with a brief section dedicated to a problem affecting most geophysical problems which is that of ill-posedness.