Assessment and mitigation of Crosshole Sonic Logging Anomalies in Large Diameter Bored Piles-PPT Presentation

PPT Presentation

Pdf Summary

The presentation describes an investigation into crosshole sonic logging (CSL) anomalies in large-diameter bored piles. The site had complex glacial and alluvial deposits, with artesian groundwater pressures, creating challenging construction conditions.<br /><br />The authors present a process for assessing piles with anomalous CSL results, including consideration of first-arrival time (FAT) and relative-energy measurements. Repeat testing showed that the CSL response changed over time: anomalies recorded at different test ages did not remain consistent, meaning that later results could obscure earlier indications of a potential problem.<br /><br />Pile load-test data also showed divergence between strain-gauge readings, interpreted as the onset of pile bending. The investigation highlights the importance of considering the full set of test results and their timing rather than relying on a single CSL profile. The authors conclude that coring would not have helped resolve the issues encountered in these piles.

Keywords

crosshole sonic logging

CSL anomalies

large-diameter bored piles

first-arrival time

relative-energy measurements

pile load testing

strain-gauge readings

pile bending

glacial deposits

artesian groundwater