基于可靠度和性能的结构整体地震易损性分析

地震风险分析包括地震危险性分析、地震易损性分析和地震灾害损失评估3个方面，其中，地震易损性分析可以预测结构在不同等级地震作用下发生各级破坏的概率，因此对结构的抗震设计、加固和维修决策具有重要的应用价值。传统的结构地震易损性分析主要采用经验方法或蒙特卡洛模拟法绘制地震易损性曲线。首先介绍地震风险分析的基本原理，然后提出结构整体地震易损性的概念，针对传统方法存在的问题，将结构的可靠度方法与基于性能的抗震设计理论结合起来，提出了基于可靠度和性能的结构整体地震易损性分析方法，并采用有限元可靠度方法进行了结构地震易损性的计算。以结构的最大层间相对变形作为整体性能指标，对某5层2跨钢框架结构进行了地震易损性分析，绘制了其在不同地震作用下对应不同性能水准要求的地震易损性曲线。     

石羊河流域生态脆弱性评价研究

综合分析自然条件和人类活动对区域生态系统的两方面影响，建立了生态脆弱性评价指标体系，运用层次分析法和综合指数法计算了石羊河流域9县（区）的生态脆弱度分值。根据计算结果，将石羊河流域划分为4级生态脆弱区，分别为极强度脆弱区、强度脆弱区、中度脆弱区和轻度脆弱区。在此基础上，对各脆弱区提出生态治理对策，为今后流域开展生态经济功能区划提供依据。     

黑河流域生态环境的脆弱性及其对地下水的依赖性

本文通过翔实的素材阐述了河西走廊黑河流域生态环境的脆弱性及其对地下水环境的依赖性,根据野外实地考察实料揭月了适合西北生态脆弱区的地下水可持续利用模式,并指出了生态环境保护与水资源利用协调发展的国土安全意义.     

贵州普定后寨河流域岩溶生态脆弱性的模糊综合评价

本文介绍了基于模糊数学理论的岩溶生态脆弱性评价方法，选取了平均坡度、森林覆盖率、石山裸露、耕地面积、水土流失、人口密度、．人均耕地、人均粮食、人均收入9个主要因素作为评价因素，并以贵州省普定县后寨河流域为例进行了具体计算与分析。评判结果表明：该研究区生态脆弱形势较为严重，在13个典型喀斯特村中有7个属于强度脆弱或极强度脆弱区，2个属于中度脆弱，属于轻度脆弱的有4个，因而需大力加强生态环境保护和重建工作。     

三峡库区次级河流流域生态脆弱性评价——以重庆市小安溪流域为例

文章以重庆市小安溪流域为例，根据流域的生态环境特点，对导致流域生态环境脆弱程度恶化的主要因素——地质、资源、经济等因素进行统计分析并做出综合评价，最后再根据综合评价指数进行结果分析与讨论，为缓解小安溪流域生态环境脆弱程度的进一步恶化提出合理化建议。     

Humanitarian governance and the consequences of the state‐fragility discourse in the Democratic Republic of Congo's health sector

This paper examines how the discourse on state fragility affects the preferences of key actors in humanitarian governance for different types of health‐sector interventions in the Democratic Republic of Congo. It argues that, instead of focusing on the actual meaning of state fragility, attention should be paid to interactive processes around the discourse among stakeholders in the health sector. The lack of consensus on state fragility influences humanitarian governance, especially the perceptions of and interactions between the host government, donors, and international non‐governmental organisations. The latter have legitimised the persistence of vertical, emergency‐based interventions by emphasising state fragility, whereas state officials have preferred to assert political statehood and a higher degree of control. Nevertheless, they agree that donors’ financial contributions ensure the survival of the public health sector. Looking ahead, a policy coalition based on harmonised views about addressing fragility is necessary for effective engagement and the sustainability of interventions, but this is unlikely to happen any time soon.     

我国主要煤炭基地的生态脆弱性评价与类型分析

针对我国绝大多数煤炭基地生态环境脆弱的局面,研究在文献分析和实地调研的基础上,建立生态脆弱性评价指标体系,对我国主要煤炭基地的生态脆弱性进行评价和类型分析.研究发现,我国大多数煤炭生产基地处于生态环境脆弱区,其中陕北和神东基地的生态环境极度脆弱,黑东、鲁西的生态环境较好.根据不同基地各生态要素对生态脆弱性总体得分的贡献率,判断不同基地的主要生态约束因素与约束程度,可以将我国煤炭基地分为水土因素交互作用型、地质不稳定和地面塌陷约束型以及生态功能约束型三种类型.最后针对不同的生态约束类型区,提出未来我国煤炭基地的生态建设措施.     

Seismic fragility analysis of a coupled tank-piping system based on artificial ground motions and surrogate modeling

The catastrophic consequences of recent NaTech events triggered by earthquakes highlighted the inadequacy of standard approaches to seismic risk assessment of chemical process plants. To date, the risk assessment of such facilities mainly relies on historical data and focuses on uncoupled process components. As a consequence, the dynamic interaction between process equipment is neglected. In response to this gap, researchers started a progressive integration of the Pacific Earthquake Engineering Research Center (PEER) Performance-Based Earthquake Engineering (PBEE) risk assessment framework. However, a few limitations still prevent a systematic implementation of this framework to chemical process plants. The most significant are: (i) the computational cost of system-level simulations accounting for coupling between process equipment; (ii) the experimental cost for component-level model validation; (iii) a reduced number of hazard-consistent site-specific ground motion records for time history analyses.In response to these challenges, this paper proposes a recently developed uncertainty quantification-based framework to perform seismic fragility assessments of chemical process plants. The framework employs three key elements: (i) a stochastic ground-motion model to supplement scarcity of real records; (ii) surrogate modeling to reduce the computational cost of system-level simulations; (iii) a component-level model validation based on cost-effective hybrid simulation tests. In order to demonstrate the potential of the framework, two fragility functions are computed for a pipe elbow of a coupled tank-piping system.     

Effects of soil-structure interaction on fragility and seismic risk; a case study of power plant containment

Safety-related structures are designed to provide a safe environment for the occupants and equipment during and after earthquakes. This is due to the fact that any damage imposed to the systems might lead to catastrophic consequences. Seismic probabilistic risk assessment (SPRA) is a systematic approach for the quantification of the seismic risk. One of the crucial steps in this assessment is to determine the seismic capacity of the structures by fragility method. After a review of available methodologies, this article analyzes the seismic fragility for a typical power plant containment considering the effects of soil-structure interaction (SSI). The structure and underneath soil profile are analyzed as a unified model by the subtraction method. Two steps are considered for the assessment of seismic response: In the first step, a fixed-base hypothesis framework is implemented to the computational problem. The second step covers computations taking into account the SSI effects. Using the results of seismic response analysis and safety factor method, seismic fragility of the structure is computed and related fragility curves are developed. Finally, by comparing the fragility curves, the effects of SSI are quantified on the overall seismic risk.     

贵州喀斯特山区生态环境脆弱性及其生态整治

贵州是我国喀斯特地貌最发育的省份之一,属典型的生态环境脆弱区通过对人口容量、生物生产力与生物量、敏感性和承灾能力等4个方面的分析阐述了贵州喀斯特山区生态环境脆弱性的基本特征,探讨了喀斯特脆弱环境形成的自然因子和人类活动因子的影响机理,根据我国西部大开发中生态建设的要求,提出了贵州喀斯特山区脆弱生态环境的整治对策．