Experience in the application of geophysical techniques to the geotechnical characterization of rock massifs in the madrid-zaragoza section of the AVE railroad line

Carrying out geophysical techniques as a part of geotechnical studies for the characterization of rock massifs in public works is a more and more frequent and systematic task in Spain. Up to very recent dates, the application of geophysical techniques to the civil engineering field were relatively unknown for many Geotechnics professionals and were limited to the solution of a few specific problems through resistivity or refraction seismic methods. Progressively, this situation has changed toward an increasingly more frequent and professional use of geophysical methods. One example would be the geotechnical studies for the Madrid- Barcelona AVE railway Project, which has included the generalized application of geophysical techniques as a complement to other classic methods for the geomechanical characterization of rock massifs. In this Project, a great variety of geological patterns and problems has been found in a layout of hundredths of Km. This has made it necessary to use a considerable number of geophysical techniques, which have been applied with the aim of solving a series of specific problems established from the detailed geological mapping. We have exclusively recurred to the experience of INTERNATIONALGEOPHYSICAL TECHNOLOGY, S.A., which has taken part in the study as a geophysical consultant in ten of the twelve subsections of the Project, thus using the following methods: Georadar, D.C. resistivity (VES and profiles), TEM soundings (TEMS), seismic refraction and down-hole seismic. The aim of this communication is to carry out a summarized assessment of the role played by the geophysical techniques based in the results obtained byeach of the techniques used.