910
Proceedings of the 18
th
International Conference on Soil Mechanics and Geotechnical Engineering, Paris 2013
From the centrifuge test a resultant earth pressure (sum of
passive and active pressure) distribution is obtained. By means
of numerical simulations it is possible to distinguish between
the different time dependent earth pressure components out- and
inside the system, as well as the pressure from the embankment
nsitivity of
.
Based on the results of the numerical investigations an
eveloped.
aterial is required to reach
al elements
geotextile and the vertical
t
performance of geogrid anchors for sheet pile walls or similar.
e
to the
r end
anchored back into the embankment. Also more flexible
connections are possible if large settlements are expected.
iour is required. It was concluded
tor is the
connection of the tension membrane to the vertical walls, which
lized in different applications.
Har
Och
Ada
Tan
Wa
. In
’88,
tions of
Geogrids as tie-back Anchors for Vertical Walls, 4th European
Geosynthetics Conference, Edinburgh, Scotland, UK
weight. It is also possible to identify and observe the different
origins of the tensile forces in the membrane.
With the numerical parametric study the se
different parameters and their impact on the stress and strain of
the different system components can be analyzed
analytical design approach will be d
4. CONSTRUCTION ASPECTS
For the system construction well established techniques such as
sheet pile wall installation can be used and the appropriate
machinery is generally available worldwide. Site preparation for
the equipment is reduced to two lateral “construction roads” for
the installation of only the vertical wall elements, compared to
full width working platforms which are required in the case of
conventional soil improvement techniques such as e.g. vibro
stone columns. The soft soil becomes part of the system and no
soil disposal is necessary. Less fill m
the final height of the embankment due to the reduced
settlement and lateral deformation.
Depending on the soft soil conditions and/or the lifetime of
the embankment it is possible to reclaim the vertic
with little effort. It is also possible to have a partly open wall
system by installing shorter sheet piles in-between.
From the practical point of few a key element of the system
will be the connection of the
elements. Large forces are to be transferred between the tension
membrane and the vertical walls.
The use of geogrids as an anchor element has already been
applied several times as shown in Detert et al. (2008). Differen
case studies demonstrate the applicability and the good
A possible connection detail is shown in figure 5. Th
connection consists here of u-shaped steel rings welded on
sheet pile wall and a steel pipe pushed through these rings.
Figure 5. Connection detail between sheet pile wall and geogrid anchor
The geogrid is wrapped around this steel pipe and the uppe
5. CONCLUSION
The paper describes the theoretical behaviour of a new
foundation system for embankments on soft soils. The system
consists of two parallel vertical walls, which are installed into
the soft subsoil and connected via a horizontal tension
membrane. The embankment is constructed on top of this
membrane. It was found that the understanding of the earth
pressure distribution along the walls, which is time and
deformation dependent, is a key factor for the design. Due to the
complex interaction between the system components a strategy
was developed to analyze the system. Numerical simulations
offer a very efficient method to perform comprehensive
parametric studies for analyzing the impact on the system
behaviour of the different system components. For the
validation and calibration of the numerical model measurement
data from the system behav
that centrifuge tests are the most beneficial technique for
gaining this required data.
From a practical point of view it was found that the
installation of the system is not difficult. A key fac
has been previously rea
6. REFERENCES
ata N, Otani J., Ochiai H., Onda K.. and Okuda Y. 2008.
Countermeasures against settlement of embankment on soft ground
with PFS (Partial Floatin Sheet-Pile) method.
Geotechnics of soft
soils: Focus on Ground Improvement: Proceedings of the Second
International Workshop on Geotechnics of Soft Soils, Glasgow,
Scotland, 3-5 September 2008
iai H., Hayashi S., Umezaki T. and Otani J. 1991.
Model test on
sheet-pile countermeasures for clay foundation under embankmen
t,
Developments in Geotechnical Aspects of Embankments,
Excavations and Buried Structures
lier K., Pamuk A. and Zimmie T.F. 2003.
Seismic Rehabilitation of
Coastal Dikes by Sheet-Pile Enclosures
, The Thirteenth
International Offshore and Polar Engineering Conference,
Honolulu, Hawai, USA, May 25-30, 2003
aka H., Murata H., Kita H. and Okamoto M. 2000.
Study of sheet
pile wall method as a remediation against liquefaction
, The
Twelfth World Conference on Earthquake Engineering, Auckland,
New Zealand, 2000
amal A., Parra E., Yang Z. and Adalier K. 2002.
N
Elg
umerical Analysis
of Embankment Foundation Liquefaction Countermeasures
, Jounral
of Earthquake Engineering, Vol. 6. No. 4 (2002)
Rowe, R.K. and Li, A.L. 2005.
Geosynthetic-reinforced embankments
over soft foundations
, No. 12, 2005, Geosynthetics International
ger, O. and Holtz, R.D. 1976.
Reinforcing Embankments by short
Sheet Piles and Tie Rods
. New Horizons in Construction Materials,
International Symposium, Lehigh University, Bethlehem,
Pennsylvania, November 1-3, 1976
ert O., König, D. and Schanz T. 2012.
Centrifuge
Det
modeling of an
adaptive foundation system for embankments on soft soils
,
Proceedings of Eurofuge 2012, Deflt, Netherlands
berger,H. and Güttler, U
Jess
. 1988.
Bochum geotechnical centrifuge
J. Cort (Ed.), Proc. Int. Conf. Geotech. Cent. Mod. - Centrifuge
Paris , 37 -44
Detert O, Wehrli E and Cejka, A. 2008. Innovative Applica
