【作者】 彭艳菊；

【导师】 孟小红； 唐荣余；

【作者基本信息】 中国地质大学（北京） ， 固体地球物理， 2008， 博士

【摘要】 海洋平台是海洋油气资源开发的基础设施,属于可能产生严重次生灾害的工程,同时,我国近海海域的地震活动性较高,海洋平台的抗震问题受到广泛关注。但受海域研究程度的限制,我国尚未制定海洋平台的抗震设防规范。目前,一般是参照《建筑抗震设计规范》和美国石油协会制定的RP2A-WSD规范,依据地震安全性评价的技术规定,进行专门的地震动参数研究。但实际工作中发现,这些规范直接应用于海洋平台设计存在很多问题,如与平台设计原则不一致、概率水准比较保守等。渤海海域地震活动强度大、频度高,在我国海域中具有一定的代表性,而且这一地区地震活动特征和平台设计地震动参数的研究较深入,因此,本论文基于渤海地震环境研究海洋平台的抗震设防标准,确定设防原则和目标、设计基准期、设防水准、设防参数等。主要研究内容和技术途径可概括为:首先分析国内外工程抗震设防标准的研究现状及发展趋势、海洋平台的结构特征及其工程地震问题、渤海地震环境等,在此基础上,结合我国国情,确定海洋平台抗震设防标准的确定原则和方法;然后参照相关行业的经验,根据海洋平台的结构特征与地震破坏状态,确定设防目标;收集整理已有的平台设计地震动参数的研究成果,采用类比方法,标定抗震设防水准;分析渤海海域地震危险性特征,给出基于渤海地震环境的海洋平台的抗震设防参数;最后,通过工程实例的反应谱分析,论证平台结构的地震安全性。主要成果体现在:(1)从地震活动和地震危险性、社会经济状况、国内外抗震设计规范等方面,指出我国海洋平台抗震设防水准过于保守。(2)针对海洋平台的柔性和延性性质突出的特点,提出海洋平台抗震分析涉及的工程地震问题,如抗震设防标准、长周期地震动、地震动参数、设定地震等。(3)从历史地震记录、地震活动的时空特征等方面,研究了渤海海域地震环境。通过对比分析,指出南加州地区地震危险性远高于渤海地区,为本文结果与API规范的对比奠定了基础。(4)确定了海洋平台的两级设防目标,分别为正常使用极限地震和变形极限地震;基于已有平台的设计地震动参数,采用类比分析方法,确定正常使用极限和变形极限地震的重现期分别取200年和1000～3000年。(5)基于渤海地震危险性特征,给出海洋平台不同水准下的设防地震动参数;通过实例分析,证明结果的可靠性。创新性体现在:在我国首次确定海洋平台两级抗震设防目标及相应的设防水准,给出了海洋平台在不同地震危险性分区内、不同水准下的设防地震动参数。本研究成果为海洋平台的抗震设计提出了相应的设防标准和设防参数,为制定海洋平台行业抗震设计规范提供了基础资料和工作方法。同时,本研究填补了我国海洋工程抗震设防研究的空白,是对我国建设工程抗震设防研究的完善和提升。更多还原

【Abstract】 Offshore platform is the main facility for exploitation of ocean resources,and it is a kind of structure that could lead to severe subsequent disasters if destroyed. Moreover, the seismic activity is much intensive in seas of China. No specific seismic fortification design code has been drafted for offshore platforms in China because of insufficient knowledge on the seismic characteristics of the coastal waters. The related codes, such as <Code for seismic design of buildings (GB50011-2001)> and the RP2A-WSD constituted by the American Petroleum Institute, are taken as reference for the determination of seismic design parameters of offshore platforms. But the direct citation of these codes leads to many problems, the consistency of design rule and the applicability exceeding probabilities are challenged.Compared with the Yellow Sea, East China Sea and South China Sea, the seismic intensity and frequency of Bohai are much stronger, and accordingly much more investigations have been done in this area. The present study on seismic fortification of offshore platform is based on the seismic environment of Bohai, such as the design rule and objective, the design reference period, probability of exceedance and design parameters. The main contents and technical route are as follows. Firstly, the research status and development on seismic fortification of related industries home and abroad, the structural characteristics of offshore platform and related earthquake engineering problems, the seismic environment of Bohai are analyzed, simultaneously, considering the economic level, the design rule and technical idea. Then, the seismic fortification objectives are determined based on the related experiences and the structural characteristics and seismic damage states of offshore platforms. The research results of seismic design parameters of offshore platforms are collected and analyzed, and the seismic fortification levels of offshore platforms are calibrated using analogy method. The seismic risk characteristics of Bohai are delineated and the seismic design parameters of offshore platforms are presented based on the seismic environment of Bohai. Finally, the structural safety is demonstrated by a numerical model of a platform built in Bohai. The main results are as follows:(1) The comprehensive analysis of seismicity, economic status and related seismic codes home and abroad prove that the exceeding probabilities of seismic design currently used during the design of offshore platforms in China are too conservative.(2) In view of the special flexibility and ductility of offshore platforms, the related seismic problems are presented, such as seismic fortification objective, long-period of ground motion, ground motion parameters and scenario earthquake, et al.(3) The seismic environments of Bohai are investigated by the analysis of historical earthquakes, spatio-temporal distribution of earthquakes. The result shows that Bozhong, that is the central area of Bohai, is the crowded area of strong earthquakes, 4 earthquakes of magnitude above 7 took place in this area. By the comparison of intensity of seismicity and seismic risk with Southern California, the seismic risk in Bohai is much lower, this provides a basis for the comparison of seismic design level between this study and API code to demonstrate the rationality of the recommended exceeding probabilities.(4) The two-stage seismic design objectives are determined, that is the serviceability limited state and deformation limited state. According to the existing seismic design parameters, the return periods of the corresponding earthquakes are determined as 200a and 1000 to 3000a by the analog analysis method.(5) The seismic risk characteristic of Bohai is delineated, and the seismic design parameters of different exceeding probabilities are presented based on the seismic risk zonation. A numerical analysis of a platform proves the rationality and reliability under the recommended seismic design level.The innovation of this study is that the two-stage seismic fortification objectives and seismic design parameter are firstly presented, and the seismic design parameters of different exceeding probabilities based on seismic risk delineation are determined.The research results provide the seismic design level and parameter for the design of offshore platforms, and provide basic data and method for the determination of seismic code for offshore platforms. Simultaneously this study fills up the blank of seismic design on offshore platforms in China, and it is an improvement for the seismic design codes of different structures in China.更多还原