Dipl.-Ing. Hans-Josef Kloubert,
BOMAG GmbH, Germany
Single drum roller with polygonal drum for deep compaction and
thick lift compaction applications
Introduction
Padfoot and smooth drum rollers are well known to projecting engineers, construction
supervisors and earth construction companies with respect to application and effect.
The compacting depth of this type of equipment is approx. 40 to max. 80 cm, whereby
lift heights of 30 - 40 cm, as typical for earth construction, are laid. Padfoot rollers are
thereby mostly used on cohesive loose ground, whereas the smooth drum roller is
employed for non-cohesive loose soils. On mixed particle soils either padfoot or
smooth drum rollers may be used, depending on the condition of the soil. A suitable
roller shape to enable deeper compaction and to cover a more wider soil spectrum
than the roller types available at this time, where not available in the market. Trying to
meet these requirements of earth construction companies resulted in the development
of a roller which, due to the wide ground contact area of the drum, achieves a high
depth effect and, due to the flexing and kneading effect, also achieves compaction in
mixed particle loose ground. These requirements are met by the polygonal drum.
The polygonal drum roller was developed by BOMAG in the early nineties and the 4th
generation of this roller type is available in the market since 6 years. The following
article describes the design and effect of the polygonal drum roller.
Fig. 1
26 t Polygonal drum roller
BW 226 DI – 4 BVC
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Dipl.-Ing. Hans-Josef Kloubert,
BOMAG GmbH, Germany
The polygonal drum developed by BOMAG consists of three octagonal elements
axially next to one another, each arranged offset to the neighbouring segment.
Laterally weld on rings prevent the drum from tipping when the central element is
standing exactly on the edge. Polygonal drums have 24 smooth areas and 24 edges.
With full ground contact these smooth areas generate a considerably higher pressure
cone, than comparable round drums. When the drums rolls on over the edges, these
edges generate a particularly effective kneading and shearing effect, as well as high
peak pressures, which are considerably higher than the ones achieved with padfoot
drums. The combination of this special drum shape with the high dynamic forces
provided by the directed vibrations of the BOMAG VARIOCONTROL system, enables
optimal introduction of forces into the ground (see Fig. 2a, 2b). The VARIOCONTROL
system is able to generate amplitudes of 2.85 mm and centrifugal forces of up to
530 KN.
Fig. 2 Compaction effect of the polygonal drum roller
The polygonal drum roller is always equipped with a compaction measuring device
(Terrameter), which measures continuously the soil stiffness modulus Evib ( MN/m²).
An additional documentation system (BCM05) can easily be installed in order to
collect, present and evaluate all data according to various criterions. This information
is very helpful for the economical use of the roller, the proof of maximum compaction
achieved, the proof of uniform stiffness, for weak spot analysis and proof rolling
purpose. It can also be applied as a continuous compaction control method based on
correlations between density and soil stiffness modulus. All standard BOMAG single
drum rollers (smooth drum / padfoot drum) can be equipped with the measuring and
documentation system.
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Dipl.-Ing. Hans-Josef Kloubert,
BOMAG GmbH, Germany
The BOMAG continuous compaction control systems (Terrameter and BCM05) are
already applied on many European highway, high speed rail link, airfield and huge
foundation areas projects.
Fig. 3:
BOMAG Compaction measuring and
documentation system
Over the last few years BOMAG conducted together with international geotechnical
consulting engineers extensive examinations concerning the compaction effect of the
polygonal drum roller in different soil materials and fields of application.
•
Post compaction of existing fills and natural grounds
•
Comparison of smooth / padfoot and polygonal drum rollers with different
operating weights
•
Increase of lift heights for embankments in motorway and dam construction
The result of these trials revealed that the polygonal drum roller in comparison to the
standard smooth and padfoot roller:
•
achieves higher degrees of compaction
•
deeper compaction depths
•
less permeability
•
higher load bearing capacities
•
substantial cost savings compared to the traditional cut and fill method using
traditional 10 – 12 t single drum rollers
3
Dipl.-Ing. Hans-Josef Kloubert,
BOMAG GmbH, Germany
Depth compaction trials
The depth compaction trials with the polygonal drum where conducted in testing and
calibration fields, following the test methods E3 and E4 of the German Earthwork
regulations TP BF StB. The significant parameters for compaction
•
degree of compaction
•
load bearing capacity
•
bonding of joints between the layers
were determined by direct and indirect testing methods. The tests concerning the
before mentioned parameters were carried out in the testing and calibration fields from
the top level of the terrain down to a depth of 5.0 m below the compaction level.
Fig. 4:
30 –35 cm of soil settlement after 10
passes with BW 226 DI-4 polygonal
drum
Initial tests for determining the depth effect of the polygonal drum roller were
conducted in 2003 (WEINGART et al 2003). Here parameter changes down to 5 m
under the ground surface were detected after compaction with a 26 tonne polygonal
drum roller. The degree of compaction increased by 5 % over a depth range of approx.
2.0 m. The sounding resistance of the light ram penetrometer increases by 10 blows
per 10 cm penetration and the peak resistance of the static pressure tube increases by
5 MN/m², always across a depth range of approx. 3.0 m. The surface settlement on
average was 30 – 35 cm (see Fig. 4).
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Dipl.-Ing. Hans-Josef Kloubert,
BOMAG GmbH, Germany
German highway embankment A 20
The A 20 motorway construction required the construction of a subbase in the form of
an dam layer with a thickness of up to 1.5 m. For this dam construction it was
examined whether the previous layer thickness of 0.3 m could be increased when
using the polygonal drum roller. For this purpose a wedge shaped testing field with a
maximum layer thickness of 2.0 m and 9 compaction tracks side by side was
prepared. Always three compaction tracks were compacted in 3, 6 or 9 passes of the
polygonal drum roller with an operating weight of 26 tonnes. The middle track of these
three tracks were examined in 4 transverse profiles (per 0.5 m increase in layer
thickness).
Fig. 5
Preparation of the
compaction trial area
The examination revealed the required compaction of 95 % of the degree of
compaction over a height of 1.5 m had already been reached after 3 passes. The
compaction was examined over the layer thickness by calibrating the compaction
against the ram penetration resistance. After testing and approval of the testing field
the company DEGES constructed the A 20 motorway over a length of 20 km with a
layer thickness of max. 1.5 m and used the polygonal drum roller for compaction.
Dubai seaport extension
Apart from extensive experiences on constructions sites in Germany, excellent results
were also achieved with the polygonal drum roller in international backfilling, dam
construction and land reclamation projects. There are currently 10 machines involved
in land reclamation measures in the Persian Gulf.
For the extension of the Jebel Ali seaport in Dubai the area of the container terminal is
extended as the first of 14 project phases by using the dredging/flushing method. The
offshore dredging vessels dredge gravelly, sandy soils, which are partly heavily loaded
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Dipl.-Ing. Hans-Josef Kloubert,
BOMAG GmbH, Germany
with rock material, from the bottom of the sea and flush these to the shore. According
to the original plan the new container area was to be built up in layers of 30 cm,
starting from 1.5 m above seal level to a height of 3.80 m above seal level, and
compacted with 12 t single drum rollers. For the existing terrain, which has already
been flushed up to a height of 1.50 m, subsequent compaction to 90 % of the modified
Proctor density is required. For the layers on top of this terrain up to a height of 3.80 m
above sea level a compaction of 95 % modified Proctor density is specified.
Fig. 6: Compaction of soil to 1.50m with BW 226 DI-4 BVC and compaction tests at
various depths on trial area
Extensive compaction trials including a BW 226 DI-4 BVC with polygonal drum
revealed that a subsequent compaction on the terrain level was possible down to a
depth of 1,50 m and that the following build up can be made in two layers of 1.35 m
each.
Two testing fields, 20 m in width x 50 m in length, were prepared to measure the
density with an isotope gauge and the sand replacement method at depths of 0.30m,
0.80m and 1.50 m after 6, 8, 10 and 12 passes with water contents in the range of 6 %
≤ Wn ≤ Wopt ~ 10 %.
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Dipl.-Ing. Hans-Josef Kloubert,
BOMAG GmbH, Germany
Compaction Trials Bomag BW 226 DI-4 Polygon Drum on gravely sand
% of MDD
85,0
0
90,0
95,0
100,0
105,0
110,0
0,2
depth below surface (m)
0,4
0,6
0,8
1
1,2
1,4
R2bund 8 passes
R2bund 10 passes
R2bund 12 passes
1,6
Fig. 7: Compaction test with BW 226DI- BVC polygonal at Dubai seaport extension
The tests revealed that successful subsequent compaction of the dredged and flushed
terrain down to a depth of 1.50 m after 8 passes is assured. For the additional build up
in two layers of 1.35 m each a total of 12 passes was found to be adequate to achieve
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Dipl.-Ing. Hans-Josef Kloubert,
BOMAG GmbH, Germany
a compaction of 95 % modified Proctor density. With the use of the polygonal drum
roller from BOMAG the entire construction process – application of soil by dredging /
flushing, distribution by bulldozer, compaction with roller – could be significantly
accelerated and executed more economically, because of the roller's higher depth
effect when compared with conventional single drum rollers.
Singapore Jurong Island
Two units with BW 226 DI-4 BVC polygonal drum machines were delivered to
Singapore in 2007 for post compaction, backfilling and proof rolling purpose of a mid
size land reclamation project. Around 500.000 m² of the area was to be developed for
heavy industrial installations . The existing ground, mainly brown sand with at least 30
% of sea shell content and a density of around 85 – 90 % MDD, had to be compacted
to a depth of 2,0m in one layer with at least 95 % MDD at a depth of 1,0 m. Uniform
compaction had to be achieved.
Fig.8 Post compaction of existing ground on Jurong Island at depths of > 1,5m with
BW 226 DI –4 BVC equipped with BCM05
On the Jurong Island project compaction trials were set up and it was found that
compaction requirements were achieved after 14-16 passes at an operating speed of
2,0-2,5 km / h.
The documentation of the soil stiffness data measured by the roller itself provide very
useful information about compacted soil quality and uniformity of compaction (Fig. 9).
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Dipl.-Ing. Hans-Josef Kloubert,
BOMAG GmbH, Germany
Fig. 9: Mapping of soil stiffness Evib, right for one track, left for an area of 3000m²
showing uniform compaction on a high bearing capacity level
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Dipl.-Ing. Hans-Josef Kloubert,
BOMAG GmbH, Germany
Conclusion:
For the construction practice the available results from the testing fields and the
practical applications mean that the polygonal drum roller in comparison to traditional
single drum rollers:
•
deep compaction capability of > 1 m
•
Thick lifts application
•
high compaction performance (500 - 1500 m³/h)
•
considerable reduction of construction time
•
the on board compaction measuring system together with the BCM05
documentation system provide continuous proof rolling documentation
•
suitable for granular , mixed and cohesive soils
With the polygonal drum roller the market offers a machine which, apart from the
original requirements – higher depth effect, compaction of sandy, gravely, silty, mixed
and cohesive soils – can be universally and economically used in earth and dam
construction.
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Dipl.-Ing. Hans-Josef Kloubert,
BOMAG GmbH, Germany
Literature
Floss, R. (2001):
Compaction Technology in Earthwork, Highway and
Transportation Engineering Volume 1, BOMAG GmbH, Boppard
Weingart, W.; Körner, M.; Saal, S. (2003):
Investigation into the compaction in depth effect of a vibratory
roller with polygonal drum .
German version published in Strasse und Autobahn , 2003,
Kirschbaum Verlag GmbH, Bonn, Germany
BOMAG (2004):
Company documents Polygonal Drum Roller
FUGRO (2004):
Technical test report - Examination of the compaction effect of
various BOMAG single drum rollers by means of direct and
indirect testing methods Construction: Testing field BOMAG
Thiele, R. (2005):
Experience with the use of a single drum roller with polygonal
drum for in-depth compaction, Expert Meeting Road
Construction, Civil Engineering and Earthwork 2005
ZTV-E-StB (1994 / 1997): German Earthwork Regulations
FGSV (1994):
German technical testing instructions for soils and field in TP
BF-StB, part E 3, Examination and compaction by test
compaction and work instructions
Kloubert, H.-J. (2006) Construction site report about the use of a polygonal drum roller
BW 226 DI-4 BVC in the Jebel Ali harbour extension project in
Dubai, BOMAG GmbH, Boppard, not published
Ong, K.L. (2008)
Experience report with polygonal drum roller BW 226 DI-4 BVC
on Jurong Island Project , Singapore; BOMAG GmbH, not
published
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