GRLWEAP, SPECSHow do I know if plugging is going to occur?
During driving a soil column (or plug) is formed inside open ended piles or between flanges of H piles. If sufficient friction is developed between the soil column and the inside surface of the pile, and if the plug has become sufficiently stiff to no longer undergo significant compression, then the pile is said to be fully plugged, and it will tend to behave as if it were close ended. If these conditions are not met the pile is said to be unplugged. Partial plugging is also possible if these conditions are partially met. Whether or not plugging can occur for open pile profiles is a complex problem which depends on many factors relating to pile, soil and even hammer properties. Only very general suggestions can be made: In very dense sands or during restrike testing after a long waiting time, plugging may be expected in relatively small pipe piles (around 900 mm (30 inches) or less) unless the penetration into the dense bearing layer is very shallow (less than 3 diameters or so). For l
