Assessing foundation stability and soil-structure interaction through integrated geophysical techniques: a case history in Rome (Italy)

We present a case history in which several geophysical methods were used to investigate a five-floor residential building, constructed from reinforced concrete, which has been seriously damaged by differential settlement. The results from various geophysical methods (electrical resistivity tomography, seismic refraction, multichannel analysis of surface waves, cross-hole seismic surveys) were integrated and correlated to give an overall picture of the subsoil geometry and characteristics in the area under investigation, with particular regard to the stiffness properties and the degree of saturation. The ability of geophysics to investigate non-invasively has proven successful for dealing with buildings affected by foundation instability. The resolution of the results obtained from experimental data provides additional insight into the geological scenario and the causes of the settlement. Moreover, geophysical data may be used as a guide to optimize borehole locations for coring and soil specimen collection, which are necessary steps in designing the restoration intervention.