Despite the fact that CPT penetrometer rigs are not designed for drilling, one can though use the direct push force of the rig for drilling holes up to a depth of 20 meter fast and efficiently by applying the lost tip drilling method.
The lost tip is pushed into the ground by means of 55 mm casing tubes using the pushing force of the CPT penetrometer rig.
The lost tip assures a very straight bore hole that is slightly larger in diameter than the casing in order to reduce lateral friction on the string of tubes. This makes it possible to reach greater depths.
On reaching the desired depth a filter tube / piezometer standpipe can be lowered through the string of casing tubes. Subsequently the string of casing tubes can be retracted using the pulling force of the CPT penetrometer rig.
