Advances in acquisition and processing of near-surface seismic tomographic data for geotechnical site assessment

Characterization of an earth-filled dam through the combined use of electrical resistivity tomography, P- and SH-wave seismic tomography and surface wave data

“…Non destructive testing of existing infrastructures is an emerging trend in engineering geophysics: depending on the size and the complexity of the structure to be investigated, the geophysical investigation must be properly designed to match the required depth target and resolution. As far as geotechnical design is concerned, seismic methods are found particularly useful to integrate geotechnical data (Paasche et al, 2013), which are generally obtained under static loading and up to permanent deformation. In fact, since the compressional (P-wave) and shear (S-wave) seismic velocities are linked to the elastic (small strain) stiffness, it is reasonable that variations in seismic velocities coincide with analogous variations in shear strength and soil stiffness, although this association is typically non-linear and dependent on the strain level (Vucetic, 1994).…”

“…The applicability of High Resolution (HR) shallow reflection to engineering problems is strictly related to the possibility of obtaining good S/N ratio for shallow reflections either for P-wave (Steeples and Miller, 1998) or SH-wave (Haines and Ellefsen, 2010;Krawczyk et al, 2013) investigation. Conversely, it is well known that seismic refraction works only when seismic velocity is continuously increasing with depth (Pelton, 2005); because of this limitation, conventional refraction interpretation has now been superseded by first arrival tomography in most engineering applications (Paasche et al, 2013). In recent years, surface wave methods (Socco and Strobbia, 2004) have gained attention for the estimation of the S-wave profile for geotechnical applications (Park, 2013) and in the safety assessment of existing embankments (Karl et al, 2011;Pérez-Santisteban et al, 2011) although they provide 1-D shear wave profiles.…”