Cable Percussion Drilling
Cable percussion drilling (otherwise known as shell and auger) is utilised where deeper ground conditions need to be assessed alongside in situ strength testing and sample recovery. It is dependent upon access limitations and favourable ground conditions. Boreholes up to 60m depth can be achieved.
Standard light-cable percussion boring uses a winch driven by an engine and tripod. In areas where there is limited access a modular percussive rig is used.
The borehole is made using a ‘clay cutter’ for cohesive soils or a ‘shell’ (or bailer) for non-cohesive materials. If the exploratory hole is formed in loose sands / gravels, steel casing will be driven into position to support the borehole sides. This method allows for the easy installations of standpipes / gas monitoring tubes within the borehole.