State-of-the-art compaction

Engineering projects today are characterised by the need of increasing output, a strong weighting of economical aspects and high quality demands. One of the technically indispensable construction technologies is compaction. What are the recent developments in this technology? How can it speed up construction progress?

“The secret of modern, highly efficient compaction is the variation of the effective direction of vibration, the so-called directed vibration”
-Hans-Josef Kloubert

The sophisticated art of compaction is not just measured in machine mass. Static compaction has long since given way to dynamic compaction. The secret of modern, highly efficient compaction is the variation of the effective direction of vibration, the so-called directed vibration. Weights are positioned on the exciter shaft that rotate counter-directionally and adjust themselves to the level of force required. These forces can be adjusted progressively and fully automatically between vertical (maximum compaction energy) and horizontal (minimum compaction energy).

The compaction result is more even, quicker and more specific. Being able to vary the effective force means you can operate the machine at considerably higher amplitudes. And higher amplitudes mean higher compaction performance and improved depth effect. Amplitude can also be reduced for the compaction of surfaces or when compacting in vibration-sensitive zones such as inner-city areas. Consequently, a single drum roller with directed vibration will achieve a compaction result comparable to conventional single drum rollers in a higher weight class and you can still operate it in sensitive zones. This is how you get increasing output from one machine.

For the economical aspects and high quality demands, you need to monitor your compaction results, for example, on BOMAG single drum rollers with VARIOCONTROL, the BOMAG system for the direction, variation and controlling of vibration, the Terrameter BTM prof measuring system monitors compaction results. It allows precise and surface covering detection of soil stiffness in MN/m2 during the compaction process itself. The EVIB value (described as a vibration module) is calculated from the interaction between the acceleration of the vibrating drum and the dynamic stiffness of the soil; this value increases with further compaction. The EVIB also stands in direct relation to the deformation modules produced in static plate bearing tests.

A Compaction Management System BCM 05 supplements these measuring systems by providing a convenient way to manage measured data, as well as comprehensive options for documentation and evaluation. A graphic display signals when maximum compaction is achieved, so the roller driver is continually up-dated about the area being worked.

The advantages of this technology really come to the fore in major projects. For example, BOMAG single drum rollers were able to put their efficiency to the test during the development of the Jebel Ali container port in Dubai. Originally, this project intended to do follow-up compaction on an embankment 1.5 m above sea level using conventional 12 ton single drum rollers. The rollers were to be used to install layers of just 30 cm to a level of 3.80 m above sea level and to compact these layers to 95 percent proctor density. However, a BW 226 DI- BVC single drum roller with polygonal drum and VARIOCONTROL achieved the same measure by installing and compacting layers of just 1.35 m each – a gain in productivity of 450 percent. In addition to this, follow-up compaction of the 1.5 m high embankment was finished in just eight passes.

If you talk about state-of-the-art technology in the field of compaction, you have to talk about directed vibration combined with control and measurement systems, it is these kind of techniques that really speed up construction progress.

Hans-Josef Kloubert, Head of Application Technology at BOMAG is a renowned
expert in compaction techniques