The need for deep compaction of submerged granular soils has led to
improvements in this area. In 1971, L.B. Foster Company personnel patented a
method of deep compaction using a vibratory pile hammer and pile probe. The
technique had some success, but did not produce consistent results and thus
found its way to obscurity. Other patents attempted to modify the technique by
various probe modifications, but again without measurable improvement from a
practical point of view. Solutions to economical deep compaction up to 100 foot
depths particularly in saturated granular soils would have a great impact on the
construction industry and new bulkhead structures being developed, thus PND was
prompted into related research and development. The advent of higher
horsepower vibratory hammers, coupled with PND engineers’ experiments,
observations and measurements, led to an “H” pile probe design which has
produced measured soil density improvements up to 250% using SPT “N60” values
as a measure.
Author: Dennis Nottingham, PND Incorporated
Publisher: DFI