Seismic reflection profiling applied for the construction of the Acerenza Genzano hydraulic tunnel in South Italy

The Authors discuss the results of seismic reflection profiling, borings and geotechnical, hydrogeological and mineralogical tests carried out to set up a geologic-structural model of clayey sediments crossed by a hydraulic tunnel. An appropriate survey campaign was impelled by the research of useful parameters for the choice of a suitable method of the tunneling works (boring and first face lining methods). The survey results allow to define: a) the tectonic conditions of the clayey sediments; b) the nature and the percentage distribution of clay minerals; c) the swelling characters of clay minerals; d) the correlation between mineralogy and geotecnical parameters; e) the hydrogeologic model. Besides traditional processing, reflection tomography was applied using some good reflecting layers to study the distribution of tectonic unconformity and to detect week or faulted zones.