Crosshole Sonic Logging (CSL) is an accurate and reliable technique for assessing the integrity of deep foundation elements constructed on-site from concrete or grout. The Crosshole Sonic Logging method is normally applied as a quality assurance technique for newly placed drilled shafts and auger cast piles.
CSL testing provides assurance that the foundation concrete is sound and contains no defects, such as soil intrusions, necking, sand lenses, voids, foreign inclusions etc. The extent, depth, and approximate lateral location of defects can be determined with the CSL method. The CSL method is typically performed in steel access tubes tied to the rebar cage and cast into the shaft at the time of construction.