碩士 / 國立中央大學 / 土木工程學系 / 102 / The mono-pile supported offshore wind turbine usually subjected to cyclic lateral loadings induced by wind, ocean current, sea wave etc. It would cause the shear failure of surrounding soil for rigid pile foundation or the plastic yield of pile by bending moment, leading to the instability of wind turbine system. Therefore, it is very important to estimate the ultimate lateral bearing capacity of monopole foundation, and to predict the inclination and permanent horizontal displacement of pile under cyclic lateral loadings.
In this study, 8 models were conducted in 80 g acceleration field by using the NCU geotechnical centrifuge and rigid container. The lateral load for each test was applied at the elevation of 34 m above the ground surface. A-series tests were designed to have different water level and subjected to the same cyclic loadings. B-series tests were dry sand models and the different amplitude of cyclic lateral loadings were applied to the mono-pile. From the test results, the following conclusions can be drawn. (1) The natural frequencies of mono-pile and sand bed did not change with different water level. (2) The maximum bending moment occurred at the depth of 1.6 m under the ground surface while the lateral load was 1383 kN. The place of maximum bending moment would move upward along the pile with increasing lateral loads. (3) When the maximum cyclic lateral loading is 230 kN, the bending moment of pile is almost zero under the ground surface of 11.2 m, which is about 5 times of pile diameter. (4) Under the same amplitude of cyclic lateral loadings, the increase of cycles leads to the increasing of permanent lateral displacement, rotation angle and bending moment of pile, but the increments decrease with more number of cycles.
| Identifer | oai:union.ndltd.org:TW/102NCU05015153 |
| Date | January 2014 |
| Creators | Hsin-hao Liu, 呂昕澔 |
| Contributors | 李崇正 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | zh-TW |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 217 |
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