地震危险性与核心电厂密闭可靠性的评价方法

本文就考虑地震危险性时，核电厂安全壳的防泄露可靠性的评价方法进行了理论研究，探讨了地震模型问题中的参数确定的一些方面，给出了可靠性评价的总体思路，分析方法及具体频骤，确定了要考虑的的不定参数及其描述，并进而利用概率断裂力学推导出可靠性计算的一般公式。     

核电厂混凝土安全壳的地震可靠性分析

本文给出了自重和地震作用下核电厂混凝土安全壳的可靠性分析方法。首先基于半解析有限环元法和随机振型分析法，用首超概率给出了给定系统参数时安全壳的条件极限状态概率，然后基于此概率用推广的一次二阶矩法求解了考虑系统参数不确定性的安全壳极限状态概率。一个预应力混凝土安全壳的实例分析表明，系统参数的不确定性对安全壳的可靠性有重要影响。     

考虑非线性场地效应地概率地震危险性分析

提出了一种改进的考虑非线性场地效应的概率地震危险性分析方法。文中应用实例展示了考虑吉尔罗伊2号场地土层非线性效应的危险性曲线。在卡拉韦拉斯断层上指定了震源参数和地震发生模型，假设该断层为影响该场地的主要震源。采用3次地震的记录经NONLI3程序（可计算土层对强地面运动的非线性响应）建立了该处地表和基岩加速之间的关系。对一定的基岩运动，估算出的地面峰值加速度（PGA）标准误差的不同值可作敏感性分析。实例研究包括一个可替换的非线性关系。除了非线性模型，在吉尔罗伊2号场地上的相同土壤剖面也采用了线性响应模型。结果显示，危险性曲线对估算的该处地表加速度峰值的标准误差非常敏感。如果对场地土壤的非线性程度考虑不足，危险性曲线将严重失真。得自回归分析的可替换的非线性模型和线性响应模型在考虑非线性场地效应的危险性评估是不适用的。     

时间相依的地震危险性概率分析

阐述了基于泊松模型以及时间相依的特征地震模型的地震危险性概率分析的基本原理与方法 .以祁连山中东段为例 ,对 2种不同模型的地震危险性概率分析结果做了对比研究 ,指出时间相依的地震危险性概率分析在理论上可能更为合理 ,并且可以应用于强震的短临预测研究 .     

多地震活动性参数在断裂带现今活动习性与地震危险性评价中的应用与问题

为了分析将地震活动性参数用于判定断裂带现今活动习性、进而评估长期地震危险性的可行性,文中介绍了沿断裂带进行b值扫描与填图的方法,以及进行断裂带分段的多参数值(—b、E、n和—a/—b)组合分析的资料处理、计算及分析步骤;提出了为进行多参数计算的、断裂带分段的参考判据,进而概括了根据计算的参数值、结合强震历史背景、现今地震分布综合分析断裂带现今活动习性空间差异的方法与思路。以5条地震活动水平和监测能力各异的断裂带为试验对象,基于归纳的方法综合分析了各断裂带现今活动习性的空间差异及潜在的地震危险段。文中还就断裂的震后调整运动与低b值的关系以及精定位的地震资料在参数计算中的合理使用等问题进行了讨论。主要认识为:以b值为主的若干地震活动性参数的空间分布可有效地用于断裂带现今活动习性及潜在强震危险段落的判定。沿断裂带b值扫描与填图以及断裂带分段多参数值组合分析两种方法,可分别应用于地震监测能力强和一般的地区;若在监测能力强的地区将两种方法结合起来使用,可获得更可靠的结果。晚期余震活跃或者大震后调整运动的断裂段也可表现出较低b或—b值的特点     

基于贝叶斯定理的地震危险性概率预测研究

由于地震孕育过程的复杂性和观测技术的局限性,不同地震观测资料表现出异常变化与后续较大地震的对应关系存在不确定性,因此对预测意见进行概率表达是一种科学恰当的做法。本文基于泊松分布的危险区背景地震概率预测和单项预测方法(包括测震、流体、形变、电磁等学科)的历史预测效能,采用贝叶斯定理计算得到单项预测方法的短期或年度地震危险概率预测结果,进而采用综合概率方法,给出基于多种单项预测方法的短期或年度地震危险概率预测结果。短期概率预测初步结果表明,2018年2～9月,中国大陆72%的5级以上地震都位于相对高概率预测区域。     

概率分配模型及其在地震危险性分析中的应用

本文提出了一种由地震区(带)的地震发生概率确定潜在震源区发震概率的概率分配模型。这一模型具有以下特点:1.地震区(带)的地震发生概率控制并确定了潜在震源区的发震概率,这一原则完全遵从概率论的基本原理;2.模型中用于描述地震发生过程的随机模型,对潜在震源区的发震概率不再起决定性作用,从而大大降低了由此而带来的不确定性。将概率分配模型与目前用于新的中国地震区划图编制工作中的地震平均年发生率分配方法进行了比较,结果表明,二者对华北地区的应用结果相差不大。但进一步的分析表明,当地震活动水平较高时,后一方法可能会低估潜在震源区的地震危险性。     

基于地震带细致划分为地震构造区的概率地震危险性分析

在我国当前地震安全性评价中,普遍使用考虑地震活动时空不均匀性的概率地震危险性分析方法(CP-SHA),它规定以地震带为统计区域计算地震活动性参数b值和v4值。正在编制的中国地震动区划图(五代图)提出了针对潜在震源区进行三级划分原则:划分地震带、地震带上划分地震构造区、地震构造区内再划分潜在震源区。本文提出以地震构造区为统计区域回归统计方法计算b值和v4值,然后进行概率危险性分析计算,这样得到的结果可能更为合理。     

累积绝对速度在核电厂地震危险性分析中的应用研究

指出了运用我国现行的考虑时空非均匀性的地震危险性分析计算方法对核电厂等设计精良的设施进行地震危险性分析时所存在的问题.介绍了累积绝对速度（CAV）的概念,并将其引入到我国现行的考虑时空非均匀性的地震危险性分析计算方法之中,用以排除厂址周围小震对核电厂地震危险性分析的影响,并选取实际工程场点进行了试算.试算结果表明,此方法能明显排除厂址周围小震对地震危险性分析结果的影响.     

核电站抗震研究综述

核电站抗震性一直是核电站设计的主要问题之一。随着此问题各方面研究的深入和研究手段的进步,核电站的抗震计算理论也在不断发展,本文试图根据已有的资料,在核电站抗震问题的一些主要方面（地震输入参数的确定,抗震计算理论,结构与地基的相互作用,支加速度谱及反应谱的确定,建筑物及设备的抗震计算,地基,基础及地下建筑的抗震计算等）研究状况作一些综述,并在此基础上展望一下需要解决的问题。     

Regional variation of spectral parameters for seismic design from broadband probabilistic seismic hazard analysis

The characterisation of the seismic hazard input is a critical element of any seismic design code, not only in terms of the absolute levels of ground motion considered but also of the shape of the design spectrum. In the case of Europe, future revisions of the seismic design provisions, both at a national and a pan‐European level, may implement considerable modifications to the existing provisions in light of recent seismic hazard models, such as the 2013 European Seismic Hazard Model. Constraint of the shape of the long‐period design spectrum from seismic hazard estimates on such a scale has not been possible, however, owing to the limited spectral period range of existing ground motion models. Building upon recent developments in ground motion modelling, the 2013 European Seismic Hazard Model is adapted here with a new ground motion logic tree to provide a broadband Probabilistic Seismic Hazard Analysis for rock sites across a spectral period range from 0.05 seconds to 10.0 seconds. The resulting uniform hazard spectra (UHS) are compared against existing results for European and broadband Probabilistic Seismic Hazard Analysis and against a proposed formulation of a generalised design spectrum in which controlling parameters can be optimised to best fit the uniform hazard spectra in order to demonstrate their variability on a European scale. Significant variations in the controlling parameters of the design spectrum are seen both across and within stable and active regions. These trends can help guide recalibrations of the code spectra in future revisions to seismic design codes, particularly for the longer‐period displacement spectrum.     

基于改进云图法的结构概率地震需求分析

概率地震需求分析是美国太平洋地震工程研究中心(Pacific Earthquake Engineering ResearchCenter,PEER)提出的新一代"性能化地震工程(Performance-Based Earthquake Engineering,PBEE)"理论框架的重要一环。传统的概率地震需求分析方法称为"云图法",这种方法针对确定性结构进行一系列地震动作用下的非线性动力分析,从而得到地震动强度参数与结构地震需求的"云图"。然而,传统的云图法只能考虑地震动的不确定性,而无法考虑结构的不确定性。为此,结合拉丁超立方体抽样技术,提出一种能综合考虑地震动不确定性和结构不确定性的改进云图法,并将传统的概率地震需求分析内容拓展为概率地震需求模型、概率地震需求易损性分析、概率地震需求危险性分析三个层次。以一榀五层三跨钢筋混凝土框架结构为例,分别采用传统云图法和改进云图法对其进行概率地震需求分析,得到了该结构的概率地震需求模型、地震需求易损性曲线和地震需求危险性曲线。分析结果表明:提出的方法可以有效地考虑地震动与结构的不确定性,避免不考虑结构的不确定性而低估结构的地震风险性。     

Recognition of the zones of seismic hazard in Polish Coal mines by using a seismic method

In the Upper Silesian Coal Field the seismic hazard induced by mining operations in collieries is closely related to the rockburst hazard. A seismic method is used for premonitory recognition of the zones of seismic hazard. It takes advantage of the relationship between the velocity of propagation of seismic waves and the state of stress existing in the rock. It consists of the determination of the velocity field of artificially induced seismic waves in a studied fragment of the rock, and of locating the velocity anomaly. The position of the velocity anomaly zones and their intensity are the basis for estimating the seismic hazard in advance of mining works.     

考虑土-结构相互作用和岩土参数不确定性的核电厂结构地震响应分析

针对核电厂结构,在考虑土-结构相互作用(SSI)的情况下进行随机地震反应分析,探讨地基岩土参数的不确定性对反应堆厂房楼层反应谱(FRS)的影响。运用ANSYS软件模块建立核电厂(NPP)结构有限元模型,通过设置边界弹簧单元和阻尼装置来考虑SSI效应;并且通过设置具有概率意义的弹簧刚度和阻尼系数,来模拟土特性参数的不确定性。随机响应分析与确定性分析的结果对比,揭示了岩性地基条件下SSI效应对核电厂FRS的影响以及地基岩土参数不确定性对FRS的影响程度。研究表明,在岩性地基条件下,亦不应忽略SSI效应;考虑SSI效应的随机分析模型同确定性模型相比,二者的分析结果较为接近,两方法都可用于NPP的FRS敏感性分析评估之中,并可进行相互比照。     

A probabilistic framework for quantification of aftershock ground‐motion hazard in California: Methodology and parametric study

This paper presents a proposed method of aftershock probabilistic seismic hazard analysis (APSHA) similar to conventional ‘mainshock’ PSHA in that it estimates the likelihoods of ground motion intensity (in terms of peak ground accelerations, spectral accelerations or other ground motion intensity measures) due to aftershocks following a mainshock occurrence. This proposed methodology differs from the conventional mainshock PSHA in that mainshock occurrence rates remain constant for a conventional (homogeneous Poisson) earthquake occurrence model, whereas aftershock occurrence rates decrease with increased elapsed time from the initial occurrence of the mainshock. In addition, the aftershock ground motion hazard at a site depends on the magnitude and location of the causative mainshock, and the location of aftershocks is limited to an aftershock zone, which is also dependent on the location and magnitude of the initial mainshock. APSHA is useful for post‐earthquake safety evaluation where there is a need to quantify the rates of occurrence of ground motions caused by aftershocks following the initial rupture. This knowledge will permit, for example, more informed decisions to be made for building tagging and entry of damaged buildings for rescue, repair or normal occupancy. Copyright © 2008 John Wiley & Sons, Ltd.     

The Grandori model: Anisotropic formulation and its application in the plotting of seismic hazard maps

The seismic hazard for the Calabro-Sicilian area is evaluated using an anisotropic formulation of the Grandori attenuation law. For each macroseismic field two main directions are identified: minimum and maximum attenuation of the macroseismic intensity. The results of the investigation show that the anisotropic formulation improves the compatibility level of the model (with respect to the isotropic one) with the intensities observed and produces probabilistic expected intensities which compare favourably with the values of seismic history in the investigated area when the zonation defined by the Messina University research group was used.     

Accounting for source location errors in the bayesian analysis of seismicity and seismic hazard

A method is presented for incorporating the uncertainties associated with hypocentral locations in the formulation of probabilistic models of the time and space distributions of the activity of potential seismic sources, as well as of the resulting seismic hazard functions at sites in their vicinity. For this purpose, a bayesian framework of analysis is adopted, where the probabilistic models considered are assumed to have known forms and uncertain parameters, the distribution of the latter being the result of an a priori assessment and its updating through the incorporation of the direct statistical information, including the uncertainty associated with the relations between the actual hypocentral locations and the reported data. This uncertainty is incorporated in the evaluation of the likelihood function of the parameters to be estimated for a given sample of recorded locations. For the purpose of illustration, the method proposed is applied to the modelling of the seismic sources near a site close to the southern coast of Mexico. The results of two alternate algorithms for the incorporation of location uncertainties are compared with those arising from neglecting those uncertainties. One of them makes use of Monte Carlo simulation, while the other is based on a closed-form analytical integration following the introduction of some simplifying assumptions. For the particular case studied, accounting for location uncertainties gives place to significant changes in the probabilistic models of the seismic sources. Deviations of the same order of magnitude can be ascribed to differences in the mathematical and/or numerical tools used in the uncertainty analysis. The resulting variability of the seismic hazard at the site of interest is less pronounced than that affecting the estimates of activity of individual seismic sources.     

Probabilistic seismic hazard assessment for Romania and sensitivity analysis: A case of joint consideration of intermediate-depth (Vrancea) and shallow (crustal) seismicity

The earthquake risk on Romania is one of the highest in Europe, and seismic hazard for almost half of the territory of Romania is determined by the Vrancea seismic region, which is situated beneath the southern Carpathian Arc. The region is characterized by a high rate of occurrence of large earthquakes in a narrow focal volume at depth from 70 to 160 km. Besides the Vrancea area, several zones of shallow seismicity located within and outside the Romanian territory are considered as seismically dangerous. We present the results of probabilistic seismic hazard analysis, which implemented the “logic tree” approach, and which considered both the intermediate-depth and the shallow seismicity. Various available models of seismicity and ground-motion attenuation were used as the alternative variants. Seismic hazard in terms of macroseismic intensities, peak ground acceleration, and response spectra was evaluated for various return periods. Sensitivity study was performed to analyze the impact of variation of input parameters on the hazard results. The uncertainty on hazard estimates may be reduced by better understanding of parameters of the Vrancea source zone and the zones of crustal seismicity. Reduction of uncertainty associated with the ground-motion models is also very important issue for Romania.