1225
Five years of Impact Compaction in Europe – successful implementation of an
innovative compaction technique based on fundamental research and field
experiments
Cinq ans de compactage par impact en Europe – mise en œuvre avec succès d'une technique
de compactage novatrice basée sur la recherche fondamentale et expériences sur le terrain
Adam D., Paulmichl I.
Vienna University of Technology, Austria
Adam C., Falkner F.-J.
University of Innsbruck, Austria
ABSTRACT: In the year 2007, the innovative Impact Compactor was widely introduced in Central Europe on the initiative of an
Austrian company to compact and improve the ground. At the beginning, the application of the novel impact-like compaction
technique was based on empirical data and experience gained on several construction sites. Soon after, a funded research project was
initiated including both fundamental research and field experiments. The outcomes of the research work provided the basis for the
optimized and economic application of this novel compaction method on-site. Since 2007, in numerous applications the Impact
Compactor has been successfully employed for ground improvement for industrial, administrative and apartment buildings, bridges,
bridge abutments, embankments, dams and dikes, and other civil engineering structures.
RÉSUMÉ : Le compacteur par impact pour l'amélioration des sols a été introduit en Europe Centrale en 2007, sur l'initiative d'une
société Autrichienne. Au début de son utilisation cette technique novatrice de compactage et fondée sur des données empiriques et
l'expérience acquise sur plusieurs chantiers. Peu de temps après, un projet de recherche a été lancé en se focalisant sur la recherche
fondamentale et les expériences sur le terrain. Les résultats de ces travaux de recherche ont fournit la base d'une application optimisée
et économique de ce procédé novateur de compactage sur site. Dans de nombreux projets, le compacteur à impact a été mis en œuvre
avec succès pour l'amélioration des sols pour des projets des bâtiments industriels, administratifs et appartements, ponts, culées de
ponts, remblais, barrages et digues et autres travaux de génie civil.
KEYWORDS: Impact Compactor, dynamic compaction, soil dynamics, ground improvement, earth works.
1 INTRODUCTION
1.1
Background and history of the Impact Compactor
The Impact Compactor was developed for the British military
forces to compact and improve the ground. In the year 2007 the
Austrian company TERRA-MIX introduced this device in
Central Europe.
In the early days after implementation the application of the
novel impact-like compaction technique was based on empirical
data and experience gained on several construction sites. Later,
a basic research project funded by the Austrian Research
Promotion Agency (FFG) was initiated to quantify the effect of
this innovative device, and to optimize its application. At the
same time, a GPS-based data recording system for the
documentation of the compaction process including stop codes
as indication for maximum possible compaction was developed.
Since implementation, the Impact Compactor has proven to
improve efficiently the ground for industrial, administrative and
apartment buildings, bridges, bridge abutments, embankments,
dams and dikes, and other civil engineering structures.
1.2
Basic principle and setup of the Impact Compactor
The Impact Compactor is a dynamic compaction device based
on the piling hammer technology that is used to increase the
load-bearing capacity of soils through controlled impacts. The
general idea of this method is to drop a falling weight from a
relatively low height onto a special foot assembly at a fast rate
while the foot remains permanently in contact with the ground.
The lately introduced compaction equipment aims at closing the
gap between the surface compaction methods and the deep
compaction methods, and permitting a middle-deep
improvement of the ground up to a depth of 4.5 to 7.5 m (10 m)
(Adam and Paulmichl 2007).
The Impact Compactor consists mainly of three impact
components: the impact foot, the driving cap, and the hammer
with the falling weight. The impact foot made of steel has a
diameter of 1.5 m. Since the driving cap is connected loosely to
the foot, only compression forces load the subsoil, which allows
an efficient energy transfer. Impact foot, driving cap, and falling
weight are connected to the so-called hammer rig. Falling
weights of mass 5,000, 7,000, 9,000 or 12,000 kg are dropped
from a falling height up to 1.2 m at rate 40 to 60 repetitions per
minute. For further details see (Falkner et al. 2010).
Gravels, sands, silts, industrial byproducts, tailings material,
and landfills can be successfully compacted by the Impact
Compactor to increase the load-bearing capacity of foundations,
to improve the ground bedding conditions for slabs, to reduce
the liquefaction potential of soils, and to stabilize waste
materials.
2 FUNDAMENTAL RESEARCH
2.1
Numerical simulations
Theoretical investigations comprised numerical computer
simulations of the impact-type compaction effect, energy
transfer into the soil, and wave propagation.
A theoretical study of the dynamic impact of the Impact
Compactor on its environment was performed employing a
simple mechanical model of the Impact Compactor-subsoil
interaction system. Thereby, the falling weight was modeled as
