2358
Proceedings of the 18
th
International Conference on Soil Mechanics and Geotechnical Engineering, Paris 2013
Figure 10. Load – displacement curves for different internal friction
angles and dilation angles of the silty sand layer
The resistance was affected by the cohesion of the
surrounding soil (Figure 11).
Figure 11. Load – displacement curves for different cohesions of the
silty sand layer
Figure 12 shows the result when the elastic modulus and
cohesion were decreased from the reference values. The curve is
closer to the centrifuge test result than others. However, this
does not mean that this set of parameters are the actual
properties, but provides a guide on which parameters are more
influential than others and how the numerical model can be
improved. Further researches are needed to model the
nonlinearity and the dependency on confining stress of elasticity
of the silty sand layer.
Figure 12. Comparison of load – displacement curves for the centrifuge
test result and numerical model
4 CONCLUSIONS
The load – displacement behaviour of a monopod suction
bucket foundation was studied by a centrifuge test and
numerical modeling. The centrifuge model test was performed
with a model soil which represented key soil characteristics of
the target site. Horizontal load combined with overturning
moment was applied according to the preliminary design of an
offshore wind tower. In the centrifuge test, the foundation and
soil behaviour was observed for a wide load range from the
initial to the post-yield load, so that the foundation design be
verified and improved based on the test result. A series of
numerical modeling were performed to validate the centrifuge
test condition and study the effects of soil parameters on the
load-displacement curves. It was found that the increased
weight and vertical load provided slight increase in the
resistance. The effect of the limited horizontal boundary
distance in the tested centrifuge model was analysed to be
minimal. Soil parameters such as elastic modulus and cohesion
were found to have significant impacts than other factors in this
study on the load – displacement behaviour of the monopod
foundation in the silty sand layer. Refinement of the numerical
model related to these parameters and elaborate estimation of
them are important for realistic modeling of the foundation
behaviour.
5 ACKNOWLEDGEMENTS
This study was supported by a grant from the Offshore Wind-
energy Foundation System (OWFS) R&D program (10 CTIP
E04) of Korea Institute of Construction & Transportation
Technology Evaluation and Planning funded by Ministry of
Land, Transport and Maritime Affairs and Hyundai Engineering
and Construction, Co., Ltd.
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