When do you need a "site pile"

This is an SOS service case. SOS is the Piletest Second Opinion Support service. One of our customers has sent an email stating. "I am writing you because I need your support in the analysis of some PET reflectograms that we made for some piles on one of our sites! We are using your wireless PET BT equipment! I am waiting for your response on how to contact one of your technicians so that I can explain my issue.

PET reflectogram from 3 piles at the construction site

As you can see above, it looks like all the piles have a similar issue

This is a classic case for creating a "site pile". This is an average reflectogram of all or a group of piles on a specific construction site. "Calc and add average pile" is a standard tool on the PET Tools tab. This adds another pile to the list, which is not a real pile, but an average of a group of piles.

This is a reflectogram representing the average of the reflectograms of all piles on site

As you can see, all piles show a reflection that repeats every ~2.5m

Nevertheless, the toe reflection is visible

(The Filter and Sharp values have been increased to get a clearer picture)

Since this indicates a consistent reflection pattern across all piles, it is reasonable to assume that the reason is not specific to any one pile, but rather related to the construction method or soil profile.

The low and consistent over-poring volume also suggests that the piles are regular

One possible explanation is the construction method: recoverable casing

The casing is placed in a larger diameter of ~2.5m, and then the drilling continues in the normal pile diameter

This creates a step in the pile that reflects the wave

This anomaly is not usually an indication of a flaw or a defect

The Piletest PileWave simulator can demonstrate it well - See the simulation here