本文關(guān)鍵詞：海上風機桶形基礎安裝與支撐結(jié)構(gòu)動力特性研究　出處：《浙江大學》2014年博士論文　論文類型：學位論文

  更多相關(guān)文章： 海上風機 吸力桶安裝 粉土地基 沉貫阻力 反濾層 風機結(jié)構(gòu)自振頻率 相似理論 模型試驗 循環(huán)荷載 長期動力特性

【摘要】：海上風能是一種安全、清潔、穩(wěn)定的可再生能源,是緩解當前能源短缺、解決環(huán)境污染問題的戰(zhàn)略選擇。我國具有漫長的海岸線,海上風能儲量大,開發(fā)前景好。隨著風能開發(fā)從陸上走向海洋并逐漸向深海發(fā)展,特殊而惡劣的海洋環(huán)境對風機基礎和整體結(jié)構(gòu)的施工和運行提出了更高的要求。因此,海上風機建造的技術(shù)難度和經(jīng)濟成本也將顯著提高,并成為制約其快速發(fā)展的瓶頸。吸力式桶形基礎(簡稱吸力桶或桶形基礎),因其具有安裝簡便、抗傾覆承載力高、節(jié)約材料、可重復利用等優(yōu)點而將逐漸成為今后海上風機基礎形式之一。而海上風機支撐結(jié)構(gòu),因其高且柔的結(jié)構(gòu)特點和質(zhì)量與剛度的分布規(guī)律,決定了它是一種自身動力特性受環(huán)境荷載、基礎剛度等因素影響異常敏感的結(jié)構(gòu)物。 桶形基礎的吸力安裝和海上風機支撐結(jié)構(gòu)動力特性研究涉及到海洋工程和巖土工程的交叉領(lǐng)域,許多問題是在當前國內(nèi)大力發(fā)展海上風電背景下亟待解決的關(guān)鍵技術(shù)難題,具有重要的科學研究意義和工程應用價值。因此,本文針對這些問題,分別從理論分析、數(shù)值模擬和模型試驗等方面進行了系統(tǒng)的研究和探索,具體工作主要包括以下幾方面的內(nèi)容： 1.利用室內(nèi)桶形基礎安裝模型試驗平臺,開展了一系列粉土中吸力桶負壓安裝的模型試驗,結(jié)合桶體端部和桶內(nèi)土體中水力梯度變化趨勢,系統(tǒng)分析了桶內(nèi)吸力所引起的滲流對桶體沉貫阻力和土塞穩(wěn)定性的影響；針對試驗中觀察到的土塞失穩(wěn)現(xiàn)象并結(jié)合其失穩(wěn)機理,提出了吸力安裝中引入由土工織物和礫石組成的反濾裝置改善桶形基礎的吸力安裝質(zhì)量,并通過試驗結(jié)果評估了該反濾裝置的適用性,進而給出了相應的工程應用的建議。 2.基于考慮底部耦合剛度影響的風機結(jié)構(gòu)整體模型,系統(tǒng)研究了水平剛度、轉(zhuǎn)動剛度、耦合剛度和頂部豎向軸壓力等參數(shù)對支撐結(jié)構(gòu)前四階自振頻率的影響；并引入了考慮底端彈性約束的風機支撐結(jié)構(gòu)自振頻率近似計算理論；針對實際風機塔架“底部直徑大、頂部直徑小”的體型結(jié)構(gòu)特點,研究了風機支撐結(jié)構(gòu)動力特性中“錐化效應”影響；通過具體工程實例及本文模型試驗結(jié)果驗證了改進后的解析計算理論和近似計算方法的可靠性,并就相關(guān)參數(shù)對計算結(jié)果的敏感性做了分析。 3.基于無量綱化的相似性理論,在風機動力特性模型試驗平臺上,利用改進的循環(huán)加載裝置,系統(tǒng)研究了由單樁支撐的結(jié)構(gòu)模型,在不同特性循環(huán)荷載下的支撐結(jié)構(gòu)自振頻率和系統(tǒng)阻尼的變化規(guī)律；利用簡化的數(shù)學計算模型,并結(jié)合土體的微觀力學行為特性,解釋了試驗中所觀察到的支撐結(jié)構(gòu)自振頻率變化規(guī)律；在此模型試驗平臺上還研究了由重力式淺基礎、不同長徑比的吸力桶基礎、對稱與非對稱三腳架結(jié)構(gòu)及四腳導管架等“多足”基礎所支撐的模型結(jié)構(gòu)動力特性及在循環(huán)荷載下動力特性變化規(guī)律；并基于試驗結(jié)果給出了實際工程中有關(guān)風機基礎選型及支撐結(jié)構(gòu)設計上的相關(guān)建議。
[Abstract]:The sea wind is a safe, clean, stable and renewable energy, is to alleviate the energy shortage, the strategic choice to solve the problem of environmental pollution. China has a long coastline, offshore wind energy reserves, good development prospects. With the wind energy development from land to ocean, and gradually to the deep development, put forward higher the special requirements and the harsh marine environment construction and operation of the fan base and the overall structure. Therefore, the cost of technology and economy of offshore wind turbine construction will also be significantly improved, and become a bottleneck restricting its rapid development. The suction bucket foundation (referred to as the suction bucket or bucket Foundation), because of its easy installation, anti overturning and bearing capacity, material saving, using repeatedly etc and will become one of the offshore wind turbine foundation in the future. While the offshore wind turbine support structure, because of its high and soft structure and quality and stiffness The distribution rule determines that it is an abnormal sensitive structure which is influenced by environmental loads, basic stiffness and other factors.
Study on the dynamic characteristics of the structure involved in the field of marine engineering and geotechnical engineering support and installation of suction bucket foundation for offshore wind turbines, a lot of problems is a key technical problem to be solved urgently in the current domestic development of offshore wind power under the background, has important scientific significance and engineering application value. Therefore, this paper focuses on these the problem, from the theoretical analysis, the research and exploration of the system of numerical simulation and model test, the main work includes the following aspects:
1. using the model test platform for indoor installation of bucket foundation, model tests were carried out in a series of negative pressure suction bucket installed in silt, according to the change trend of hydraulic gradient barrel end and the barrel in the soil, analyzed the influence of seepage caused by the barrel suction penetration resistance and stability of soil plug barrel; according to the observed soil instability and the instability mechanism, put forward the suction filtration device of suction installation introduced by geotextile and gravel composition improvement of bucket foundation installation quality, and applicability of the filter device was evaluated by the test results, and the corresponding engineering application the suggestions are given.
2. based on the overall model of fan structure considering the effect of bottom coupling stiffness and horizontal stiffness system, rotational stiffness coupling, vertical stiffness and the top shaft pressure parameters on the supporting structure of four natural frequencies; and considering the bottom end of the elastic constraint fan support structure vibration approximation the frequency calculation theory; according to the actual wind turbine tower bottom diameter, top shape structure characteristics of small diameter ", on the fan supporting structure dynamic characteristics of" taper effect "; reliability analysis, the improved calculation theory and approximate calculation method is verified by engineering examples and the model test results, and the relevant parameters on the results of the sensitivity analysis is made.
3. based on similarity theory of dimension in the model test platform of wind power characteristics, cyclic loading device the improved system was investigated by single pile support structure model, change law of supporting structure in different characteristics under cyclic loading frequency and the damping of the system; using a simplified mathematical model and, combined with the microscopic mechanical behavior of soil, explained the support structure observed in the test of natural frequency changes; this model test platform is also studied by gravity shallow foundation, different length diameter ratio of the suction bucket foundation, dynamic characteristics of the model structure is supported by a symmetric and asymmetric structure and three tripod legs jacket "multiped" foundation and under the cyclic load dynamic characteristics; and based on the test results are given in the actual project on the foundation of fan selection and design of the supporting structure Relevant suggestions.

【學位授予單位】：浙江大學
【學位級別】：博士
【學位授予年份】：2014
【分類號】：TU476;TM315

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