A history of vibratory deep compaction 9
one compaction point took 22 : 8 h for boring, 12 h for compaction and
backfilling, and 2 h to move the gantry to the next position. He proposed avoiding the extraordinarily time-consuming drilling operation
by making use of the liquefaction effect of the vibrations on the in-situ
sand, enabling the vibrator to sink into the ground under its own weight
to the required depth from where the compaction work was to begin
by extracting the vibrator slowly back up from the ground. The necessary modifications of the vibrator were made in the same year, so that
by 1937 the first foundation works on loose sand with the new vibro
flotation method were carried out. Figure 2.3 shows this new method
of operation, and Figure 2.4 shows the depth vibrator while executing a
trial compaction.
Understandably little was published about the vibrator—the key precondition for the method—and little survived the war in the archives of the
Keller Company. After a patent was granted on the method in 1933, the
vibrator together with other additional features of the method were also
patented in 1936.
Figure 2.3 Working sequences of the new vibro compaction method. Note: Einspülen
des….—flushing down of vibrator and extension tubes, Beginn der….—start of
compaction work, Verdichtung….—working stage, Zustand …— completed
compaction, Wasseraustritt—water exit, Bodenzugabe—addition of soil.
(Courtesy of Degebo, Berlin, Germany.)
V e rd ic h tu n g i m
fo rtg e s c h ritte n e n
' Z u s ta n d
Z u sta n d nach
abgeschl ossener
V e rd ic h tu n g
Bodenzuqabe
Wasser o u s t r i t t
I
1
1
S ä
■&>
'S
W a s s e ra u s tritt
■ W a s s e ra u s trrtt'
Begi nn d e r
V e rd ic h tu n g s a rb e it
E in s p i ite n des R ü ttle rs
m it dem anschl ießenden
• A Gestänge
one compaction point took 22 : 8 h for boring, 12 h for compaction and
backfilling, and 2 h to move the gantry to the next position. He proposed avoiding the extraordinarily time-consuming drilling operation
by making use of the liquefaction effect of the vibrations on the in-situ
sand, enabling the vibrator to sink into the ground under its own weight
to the required depth from where the compaction work was to begin
by extracting the vibrator slowly back up from the ground. The necessary modifications of the vibrator were made in the same year, so that
by 1937 the first foundation works on loose sand with the new vibro
flotation method were carried out. Figure 2.3 shows this new method
of operation, and Figure 2.4 shows the depth vibrator while executing a
trial compaction.
Understandably little was published about the vibrator—the key precondition for the method—and little survived the war in the archives of the
Keller Company. After a patent was granted on the method in 1933, the
vibrator together with other additional features of the method were also
patented in 1936.
Figure 2.3 Working sequences of the new vibro compaction method. Note: Einspülen
des….—flushing down of vibrator and extension tubes, Beginn der….—start of
compaction work, Verdichtung….—working stage, Zustand …— completed
compaction, Wasseraustritt—water exit, Bodenzugabe—addition of soil.
(Courtesy of Degebo, Berlin, Germany.)
V e rd ic h tu n g i m
fo rtg e s c h ritte n e n
' Z u s ta n d
Z u sta n d nach
abgeschl ossener
V e rd ic h tu n g
Bodenzuqabe
Wasser o u s t r i t t
I
1
1
S ä
■&>
'S
W a s s e ra u s tritt
■ W a s s e ra u s trrtt'
Begi nn d e r
V e rd ic h tu n g s a rb e it
E in s p i ite n des R ü ttle rs
m it dem anschl ießenden
• A Gestänge