【作者】 吴健；

【导师】 高孟潭；

【作者基本信息】 中国地震局地球物理研究所 ， 固体地球物理学， 2013， 博士

【摘要】 概率地震危险性分析方法目前广泛应用于工程结构设计地震动参数确定工作中,其优点在于能够全面的表现场点周边所有可能的地震对于场点的地震动影响。但同时也带来一个明显的缺点,即地震概念的缺失,简单说就是没有一个地震能够产生概率地震危险性分析方法得到的反应谱。这导致一些需要考虑与地震相关地震动特性的工作难以开展。因此需要在概率地震危险性分析方法的理论框架下和具体的地震构造环境中,识别出能够体现区域地震构造特点并具有构造含义的设定地震,来确定与地震相关的一系列地震动参数用于后续的定性或定量的分析工作。本文的目的是在我国的地震危险性分析方法的理论框架下,系统分析概率地震危险性分析方法和工程结构动力反应分析原理,结合国内外关于设定地震确定方法的已有研究成果,建立适合我国方法体系和工程应用目的的基于概率地震危险性分析方法的设定地震参数的确定原则和计算方法,使得到的设定地震参数能够用于工程结构等对象的最不利地震反应分析,并分析地震活动性参数和地震动离散等因素对设定地震参数的不确定性影响。在此基础上,研究分析与我国新一代地震动参数区划图相匹配的设定地震参数分布特征,服务于工程结构抗震设防与地震反应分析、地震灾害损失预测、工程场地地基失效评价、地震地质灾害评价与防治、地震预警系统设计等工作。为达到上述目的,本文从系统分析了我国现有概率地震危险性分析方法理论体系、地震构造模型构建方法及地震动参数计算方法,以及工程结构动力学分析原理及常见工程结构的弹性及弹塑性动力反应特征,提出基于我国的概率地震危险性分析方法的设定地震参数确定一般性原则,并提出了适用于设定地震参数确定和今后复杂地震构造模型及衰减关系模型的完整的地震活动性空间离散-衰减关系逐点校正算法。为考虑地震动参数的不确定性对于设定地震参数确定的影响,本文从理论分析、案例分析和地震动离散分析三个方面开展工作,.提出了概率地震危险性分析算法中对衰减关系不确定校正的原则和方法。为考虑地震活动性参数的不确定性对于设定地震参数确定的影响,本文计算分析了四代图五套潜在震源区方案在华北地震区接近1.6万个场点上四个超越概率水平下四个反应谱值的总体设定地震参数,并进行了不确定性分析,同时验证了提出的设定地震确定原则与计算方法的合理性。在此基础上,基于五代图潜在震源区划分方案、地震活动性参数方案和衰减关系模型,计算了全国大陆地区接近11万个场点上四个超越概率水平下四个反应谱值的总体设定地震和基于构造设定地震参数,并对这些设定地震参数的分布特征和影响因素进行了分析。基于全新数据得到的全国范围内的设定地震参数与新一代全国地震动参数区划图计算方案完全匹配,能够满足今后十年内的防震减灾相关工作的需求。在上述工作的基础上,本文在以下四个主要方面获得了新的成果和认识：1.首次提出了在我国概率地震危险性分析理论框架下的考虑地震动参数不确定性、工程结构弹性及弹塑性动力反应特性、工程结构地震反应分析目的要求的设定地震确定原则和计算方法。根据该原则,设定地震分为总体设定地震和基于构造的设定地震两种,总体设定地震用于描述整个地震环境对场址的地震危险性影响特征,基于构造的设定地震描述特定地震构造对场址的地震危险性影响特征。2.首次同时在理论分析、案例分析和地震动离散分析三个方面系统分析了概率地震危险性分析方法中衰减关系不确定性校正范围对地震危险性评价结果的影响特征,并明确建议计算较低超越概率(年超越概率小于等于10-4)地震动参数时地震动不确定性校正范围应不小于4倍标准差。3.在全面分析概率地震危险性分析原理的基础上,首次完整系统的提出了地震活动性空间离散-衰减关系不确定性逐点校正的概率地震危险性分析算法,并通过与经典的CPSHA90算法的比较分析,认为新算法能够满足设定地震参数确定和今后采用复杂地震构造模型及衰减关系模型进行概率地震危险性分析时的需要。4.首次给出了我国大陆地区四个主要反应谱值的在四个不同超越概率水平下的设定地震参数分布图,并分析了分布特征及主要影响因素。该项工作完全基于全新的地震活动性模型和地震动衰减关系模型,与新一代全国地震动参数区划图所依据的基础数据和参数模型完全一致,能够满足今后十年时间内一般建设工程和重大建设工程及各类规划对于设定地震参数的一般性需求。更多还原

【Abstract】 The probabilistic seismic hazard analysis (PSHA) is widely used to determine design-based ground motion parameters. The primary advantage of PSHA over alternative representations of the earthquake threat is that PSHA integrates over all possible earthquake occurrences and ground motions to calculate a combined probability of exceedence that incorporates the relative frequencies of occurrence of different earthquakes and ground-motion characteristics. A disadvantage of PSHA is that the concept of "earthquake" is lost. This disadvantage results directly from the integrative nature of PSHA, and it means that other characteristics of the ground motion (e.g., the duration or non-stationary) must be estimated in an ad hoc fashion if these characteristics are important for analysis or design. So one or more "scenario earthquakes" should be identified based on PSHA method to estimate the characteristics of the ground motion those cannot be obtained by PSHA directly.The total purpose of this study is to establish a systematic methodology which can identify scenario earthquakes and determine the parameters of these earthquakes such as magnitude, distance and discreteness characteristics of ground motions under Chinese PSHA theoretical framework. The scenario earthquakes determined by this method should have explicit geology background and can induce the most unfavorable dynamics reaction of target engineering structures.To achieve this purpose, this study analysis the theory of Chinese PSHA and structure dynamics, summarize the dynamics response characteristics of critical projects in China, propose the general principles and calculation method can be used in the determination of scenario earthquakes, and a new algorithm (can be called "seismic activity spatial discretization-attenuation uncertainty pointwise correction ", abbrev. SASD-APC) is presented. To analysis the influence of attenuation uncertainty on determination of scenario earthquakes parameters, the calculation principles and method are presented based on mathematical analysis, case studies of sites and distribution analysis of ground motion. To analysis the influence of seismic activity parameters uncertainty on determination of scenario earthquakes parameters, the scenario earthquakes of four response spectra values on different periods with four probabilities of exceedence on about16,000sites of North China are calculated and compared based on five sets potential source models. Finally, the scenario earthquakes of four response spectra values on different periods with four probabilities of exceedence on about110,000sites of China mainland based on the potential source model and attenuation relationship used in5th generation Seismic ground motion parameters zonation map of China.Based on the studies above mentioned, four aspects new understandings of scenario earthquake and PSHA are obtained:1. The general principles and calculation method of scenario earthquake are first put forward. The new principles and calculation method considered uncertainty of seismic activity and ground motion parameters, the elasticity and elastoplastic dynamics response characteristics of typical critical projects, the purposes of dynamics response analysis of engineering structures. According to the principals proposed in this study the scenario earthquake can be divided two type:overall scenario earthquake which describes the influence of whole seismotectonic settings on target ground motion parameters on specific site, and scenario earthquake based on seismogenic structure which describes the influence of single seismogenic structure on target ground motion parameters on specific site.2. A mathematical analysis of the influence of the truncation level on PSHA, case studies of sites in different seismotectonic settings, and a distribution analysis of ground motion residuals are conducted in this study. It is concluded that ε=4is the minimum acceptable value for engineering applications for APEs within0.002to10-4. The three aspects analysis and the conclusion are all first put forward.3. Based on the analysis of theory of PSHA, the complete SASD-APC algorithm is first put forward. Compared to the classical CPSHA90algorithm, the new algorithm is more suitable for calculation of scenario earthquake parameters and PSHA with complex seismogenic model and attenuation relationship model.4. It is first put forward that the distribution of scenario earthquake parameters of four response spectra values on different periods with four probabilities of exceedence of China mainland. The main factors which affect the distribution of scenario earthquake parameters are studied in this work. This analysis are based on the potential source model and attenuation relationship used in5th generation Seismic ground motion parameters zonation map of China, so the result can meet general demanding of dynamics analysis of engineering structures and different types of planning.更多还原