Slippery slope doesn’t stop geophysics

Phase SI carried out a ground penetrating radar (GPR) survey at a site in Scotland to determine the depth to bedrock on a scree slope.

The site was in a sub-station and the slope was in close proximity to high voltage equipment and so the scope to carry out excavation was limited. New equipment needed to be installed near the base of the slope and the client needed to know the profile of the bedrock to ensure that there would be no risk of land slippage during or after the new installation.

GPR can detect a wide variety of sub-surface features and variations and was ideal for identifying the horizon between the scree and the solid bedrock. By attaching a survey wheel to the GPR antenna and rigging up a basic pulley system it was possible to pull the antenna up the slope from the level ground at the top without the need for an operative to walk up the uneven, slippery slope itself.

Using specialist processing software we were able to match the shape of the GPR profile to the topography of the slope and therefore obtain a truer indication of the sub-surface horizons.