Zur dimensionierung der monopile-gründungen von offshore-windenergieanlagen
Başlık çevirisi mevcut değil.
- Tez No: 402370
- Danışmanlar: PROF. DR. YURI PETRYNA
- Tez Türü: Doktora
- Konular: Deniz Bilimleri, Denizcilik, Marine Science, Marine
- Anahtar Kelimeler: accumulation, ANSYS, cyclic, deflection, design method, extended-strain-wedge- model, finite element method, geotechnic, hypoplasticity, lateral load, monopile, monopile test, multi-stage loading, non-linear, number of cycle, numeric, offshore wind energy, one-stage loading, permanent deformation, pile, pore water pressure, p-y method, strain-wedge- model, subgrade reaction method, triaxial test, two-phase-element, two-phase-model
- Yıl: 2011
- Dil: Almanca
- Üniversite: Technische Universität Berlin
- Enstitü: Yurtdışı Enstitü
- Ana Bilim Dalı: Belirtilmemiş.
- Bilim Dalı: Belirtilmemiş.
- Sayfa Sayısı: 174
Özet
Özet yok.
Özet (Çeviri)
Monopiles are a suitable foundation type for offshore wind energy converters. They are single open-ended steel pipe piles, which are driven in the prevailing sandy saturated soil of the seabed. The monopiles are often subjected to high lateral loads due to the harsh conditions of the offshore enviroment, especially arising from the action of wind and water waves. The prognosis of accumulated deformations due to cyclic horizontal loading with monopile foundations is a real challenge. Adequate predictions require profound knowledge about the soil-monopile interaction behaviour. In the frame of the present doctoral work, a number of monopile tests have been carried out in the geotechnical testing pit of TU Berlin in order to investigate that interaction behaviour in more detail. Short, intermediate and long open ended steel pipe piles have been jacked into water saturated sand after instrumentation and subsequently subjected to cyclic horizontal loading with varying load amplitude and a simultaneously acting static vertical load. Final vertical jacking pressure and sand plugging inside the pile were measured during pile installation. Not only the pile head displacements, but also the pile deformations, horizontal soil displacements close to the pile shaft, pore pressures, settlement of the soil surface as well as the ultimate lateral load capacity of the piles were measured during the tests. The conception, preparation and execution of the pile tests is presented here, and subsequently the main findings are discussed. Due to the high cyclic lateral loads, in general a monopile diameter of up to 8 m will be necessary to maintain serviceability of the wind energy converter over several years. However a huge monopile diameter under unfavorable drainage, deformational behaviour and loading conditions can lead to a pore water pressure accumulation which can affect considerably the behaviour of monopiles. The interaction behaviour of monopile-soil-systems subjected to extreme loading is here analyzed using a finite element model. A fully coupled two-phase model and a hypoplastic constitutive model for the sandy soil are used in the numerical analyses. Results from the parametrical studies are presented, including the variation of loading amplitude, frequency, number of cycles and loading type, as well as the diameter of the monopile and the initial density and permeability of the sand. The obtained numerical results are then compared with several design approaches for cyclic horizontally loaded piles from the literatur. A new criterion for soil-monopile systems is proposed here. It permits a prediction of the possibilities for pore water pressure accumulation during the whole cycling loading based alone on the pore water pressure development of the first loading cycle. Taking the presented criteria as a basis, the results of the parameter studies are discussed and the possibilities for pore water pressure accumulation of soil-monopile-systems are evaluated. These investigations demonstrate the importance and relevance of the consideration of pore water pressure accumulation for the analysis of soil-monopile-systems subjected to offshore loading conditions. The accumulation of soil deformations and pile displacements due to cyclic lateral loads cannot be reliably calculated based on the current design methods. This thesis presents a practical design approach for the prediction of monopile displacements due to irregular cyclic horizontal loads which can be suitably calibrated by means of static and cyclic triaxial test results. The design approach has been validated with results from monopile load tests in the laboratory. The practical application of the proposed method demonstrates its usefulness for the prediction of monopile displacements over the service lifetime of an offshore wind power turbine.
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Başlık çevirisi yok
HACI YILDIZ
- Zur aequivalenz der literarischen betitelung aus dem Deutschen ins Türkische
Almancadan Türkçeye edebi başlık çevirisinin eşdeğerliği
AYHAN AKGÜLLÜ
Yüksek Lisans
Almanca
1999
Alman Dili ve EdebiyatıHacettepe ÜniversitesiAlman Dili ve Edebiyatı Ana Bilim Dalı
DR. ARMAĞAN ETHEMOĞLU
