Browse > Article
http://dx.doi.org/10.18770/KEPCO.2022.08.01.31

Confinement Effect Analysis Of Suction Pile In Ground Soil On The Basis Of Natural Frequency Measurement  

Ryu, Moo Sung (KEPCO Research Institute, Korea Electric Power Corporation)
Lee, Jun Shin (KEPCO Research Institute, Korea Electric Power Corporation)
Lee, Jong Hwa (KEPCO Research Institute, Korea Electric Power Corporation)
Seo, Yun Ho (KEPCO Research Institute, Korea Electric Power Corporation)
Publication Information
KEPCO Journal on Electric Power and Energy / v.8, no.1, 2022 , pp. 31-36 More about this Journal
Abstract
This paper presents the measuring process of dynamic properties of offshore wind power foundation and provides consideration of each step. This Guideline enables to maintain consistent measuring procedure and therefore increase the reliability of test results. Small scaled suction bucket foundation was fabricated to represent the commercial support structure installation mechanism and two cases(free-free, free-fixed) of dynamic tests were performed at workshop. From the tests, the importance of dynamic properties of connection part between suction bucket and tower was figured out. More over, types and configuration of measuring devices are recommended which can help find the natural frequency of wind turbine foundation correctly. In field test, it was found that the natural frequency of suction bucket foundation was increased linearly with the penetration depth due to the confining effect of ambient soil. Meanwhile, it was not easy to get an enough excitation force with normal impact hammer because the N.F of suction bucket model was in the lower range of 0 Hz ~ 5 Hz. Therefore, new excitation method which has enough force and can excite lower frequency range was devised. This study will help develop safety check procedure of suction bucket foundation in field at each installation stage using the N.F measurement.
Keywords
Offshore wind power; Suction pile; Excitation force; Frequency Response Function; Confinement Effect;
Citations & Related Records
연도 인용수 순위
  • Reference
1 GWEC, 2019, Global Wind Report update 2018, Available from http://www.gwec.net
2 Senpere, D. and Auvergne, G. A., 1982, "Suction Anchor Piles-A Proven Alternative to Driving or Drilling," Offshore Technology Conference, Paper No. 4206.
3 Clukey, E. C. and Morrison, M. J., 1995, "The response of Suction Caissons in Normally Consolidated Clays to Cyclic TLP Loading Conditions," Offshore Technology Conference, Paper No. 7796.
4 Larsen, P., 1989, "Suction Anchors as an Anchoring System for Floating Offshore Constructions," Offshore Technology Conference, Paper No. 6029.
5 MIL-STD-740-2, Structureborne Vibratory Acceleration Measurements and Acceptance Criteria of Shipboard Equipment.
6 D.J. Ewins, Modal Testing : Theory, Practice and Application 2nd Edition, Research Studies Press LTD, 2000.
7 EEA, 2009, Europe's onshore and offshore wind energy potential..
8 Cottrill, A., 1992, "Skirt Plate to Support Europipe Jacket," Offshore Engineering.
9 ISO 4866, Mechanical Vivration and Shock-Vibration of BuildingsGuidelines for the Measurement of Vibrations and Evaluation of their Effects on Buildings.