【作者】 王胜永；

【导师】 岳前进；

【作者基本信息】 大连理工大学 ， 工程力学， 2013， 博士

【摘要】 寒区抗冰平台结构的设计一直存在诸多具有挑战性的课题。特别是近年来,随着海洋油气资源开发的日益追求经济性效益,抗冰平台结构的设计越来越趋于经济性设计。然而这些抗冰平台结构在运行中普遍存在冰激振动问题,致使平台结构存在多种失效模式,甚至严重冰激振动下会导致平台结构的性能丧失。因而,如何满足各种性能需求的抗冰平台结构设计是值得深入研究的课题。寒区抗冰平台结构的性能是由多种性能需求共同构成的。抗冰平台结构的设计过程包含概念设计、初步设计和详细设计三个阶段,其中概念设计和初步设计是决定抗冰平台结构性能的设计阶段,很有必要开展深入的研究分析工作。因而本文在平台结构现场测量数据分析及相关研究成果的基础上,开展了抗冰平台结构性能设计理论、隔振锥体减冰振策略以及简易混凝土平台结构抗冰振性能设计等方面的研究分析工作。寒区平台结构现场测量数据是抗冰平台结构性能设计研究的基础,其中渤海冰区已经开展了数年的现场测量工作,并取得了很多有价值的测量数据。本文介绍了渤海海冰信息及平台结构冰激振动响应的现场测量体系,以及测量方法、原理及技术等最新研究进展。在海冰荷载形成机理、冰力计算模型以及平台结构冰振失效机理等最新研究成果的基础上,给出了抗冰平台结构的性能评估指标。根据平台结构现场测量数据及性能评估指标,对JZ20-2海域的三座抗冰平台结构进行了性能评估比较分析。油气资源特点、开发模式和平台结构静、动力性能需求是抗冰平台结构性能设计的主要影响因素。阐述了抗冰平台结构性能设计是满足安全性能、适用性能及经济性能要求的结构设计方法。讨论了抗冰平台结构性能设计应该满足的设计控制限值,包括安全性能的强度设计限值、适用性能的冰振失效限值以及构件截面几何尺寸设计限值等。通过平台结构冰振失效和减冰振策略分析,给出了抗冰平台结构基于性能的动力设计流程。以JZ20-2油气田为例,进行了适合该油气田开发的抗冰平台结构概念设计、平台结构选型等分析。抗冰平台应用隔振锥体减冰振是利用了海冰物理力学特性和隔振原理。即海冰弯曲破碎强度低于压缩强度以降低冰力,同时,动冰荷载作用下隔振锥体发生主要的冰激振动响应,以减少传递给平台结构的冰激振动能量。计算分析了弹簧刚度和阻尼对隔振锥体设计的影响。结果表明弹簧刚度是影响隔振锥体设计的主要因素,同时适当的阻尼能够吸收冰激振动能量,有利于降低平台结构的冰激振动响应。以JZ20-2MUQ平台结构为例,应用数值仿真分析方法验证了隔振锥体的减冰振效果。以JZ20-2油气田为例,应用实例推理方法进行了基于性能的抗冰平台结构初步设计分析。包括平台结构主桩腿及支撑杆件布置方案选择,隔振锥体设计参数计算以及各性能设计限值控制条件下的平台构件截面几何尺寸参数设计。对基于性能的抗冰平台与JZ20-2MUQ原型平台的结构设计参数及结构性能参数的进行了对比分析表明,基于性能的抗冰平台结构初步设计达到了性能设计要求,从而也验证了抗冰平台结构性能设计理论及动力设计流程的正确性和可行性。最后,混凝土平台与钢质平台进行经济性比较分析表明,混凝土平台结构在建造成本、安装就位及维护费用等方面比钢质平台更具经济性。本文分析了适用于寒区浅海边际油气田开发的抗冰平台结构应具有简易经济性、可移动性以及抗冰振等性能,并提出了满足这些性能要求的单立柱桶型基础混凝土平台型式。以JZ9-3WHPB单立柱桶型基础钢质平台结构为例,进行了将其钢质中央立柱设计为混凝土中央立柱的初步设计分析。计算分析表明,在同等冰况下,该单立柱桶型基础混凝土平台与JZ9-3WHPB单立柱桶型基础钢质平台相比,具有更好的抗冰振性能。同时,为寒区边际油气田开发提供了一种可以选择的平台结构型式。更多还原

【Abstract】 There has been a lot of challenging research about ice-resistant platform structures design in cold regions. In recent years, the economic design of the platform structures is considered increasingly with the pursuit of the maximum economic benefits in oil/gas resource developments. However, the ice-induced vibrations are prevalent phenomenon in those ice-resistant platform structures, resulting in multiple structure failure modes, and even severe ice-induced vibrations may cause performances failure. Therefore, how to meet the performance requirements of ice-resistant platform structures design is worthy of further study.The performances of ice-resistant platform structure constitute a variety of performance requirements.The design process of the ice-resistant platform structures inclues conceptual design, preliminary design and detailed design, and the conceptual design and the preliminary design are to determine the performances of the ice-resistant platform structures, which is necessary to carry on in-depth research. A systematic research on the ice-resistant performance design theory of the platform structures, the local-oscillator theory of the isolation cones and the concrete platform structure with economic performance is presented based on in-situ results of ice-induced vibration and the current progress of ice load.Based on the field test data, the performance design of the ice-resistant platform structures is studied. There has been carried out field tests for many years, and has gained a lot of valuable measurement data. For Bohai Sea as an example, the full-scale field test system of ice conditions and ice-induced vibration responses are introduced, and the recent research progress about monitoring methods, principle and technology is summarized. Based on ice-force mechanism, ice loading model and ice-induced vibration failure, the evaluation index of ice-resistant performances is developed for the platform structures in cold regions. A general analysis about ice-resistant performances evaluation for three typical platform structures is processed according to the performance evaluation index and the field test data in the JZ20-2Seas.The main influence factors of performances design for ice-resistant platform structures are the characteristics and development model of oil/gas resources, static and dynamic properties of platform structures. The performances design theory is met the requirements of security, serviceability and economic performance for ice-resistant platform structures. And the performance design control limits of ice-resistant platform structures are discussed, including the strength design limits of security performance, the ice-induced vibration failure limits of serviceability performance, structure member section design limits etc. Based on the analysis of ice-induced vibration failure and reducing ice-induced vibration methods, the performance-based dynamical design process is proposed for ice-resistant platform structures. A general analysis about conceptual design and structure type for ice-resistant platform structure is processed in the JZ20-2oilfield.The ice-induced vibration reduction of isolation cones is the application of ice mechanical properties and isolation theory. That is, the ice forces is reduced by flexural strength less than compressive strength, and the isolation cones have a major vibration response in order to reduce the ice-induced vibration energy transferred to the platform structure under the dynamic ice forces. The main parameters of the isolation cones are the spring stiffness and the damping coefficient, and the results show that the spring stiffness is the main influencing factor for isolation cone design, the appropriate damping could absorb the ice-induced vibration energy, which is useful for reducing ice-induced vibrations of the platform structures. For JZ20-2MUQ platform as an example, the ice-induced vibration reduction effect of isolation cones is verified by simulation computations.The initial design of the ice-resistant platform structure is studied by case-based reasoning method for JZ20-2oil field, which including the layout design of piles and supporting members for the platform structure, the parameters design of the isolation cones. The comparison of structure parameters and performances is conducted between initial design platform and JZ20-2MUQ prototype platform. The results show that the initial design platform structure meets the ultimate strength limits, and the correctness and feasibility is verified for the performance design theory and process.Finally, the economic comparison between steel platforms and concrete platforms shows that the concrete platform structures are more economic on construction costs, installation and service costs. The ice-resistant platform structures should have the simplicity, mobility and ice-resistant performances during the marginal oil/gas field developments in cold regions. Then a single concrete pile platform with bucket foundations is proposed. Taking JZ9-3WHPB platform as an example, the initial design of the single concrete pile platform instead of the single steel pile is conducted and its ice-resistant performance is verfied. This is also provided a reference for platform structure types during the marginal oil/gas field development.更多还原