Small Diameter Piston Sampling with Cone Penetrometer Equipment
A small diameter piston sampler that can be operated by a cone penetrometer rig has been developed specifically for recovery of sand and clay samples under conditions where sample recovery using ordinary means is difficult. The 22-mm-diameter sample that is recovered in a polythene sheath is valuable for visual examination of the soil rather than for most laboratory testing purposes. Provided the soils are penetrable, the sampler may be pushed to any desired depth before the sampling operation; then the central 12-mm-diameter rod in the drill stem is held stationary while the sampling operation takes place. In initial tests when applied to soft, wet, interlayered sands and clays that could not be recovered in open tubes, essentially 100% recovery was obtained.