地铁火灾场景设计探讨

近年来，地铁火灾是火灾科学界研究的热点。火灾场景设计是开展地铁火灾研究的基础环节，它对地铁内的烟气运动和人员疏散有重要的影响。通过对国内外文献的调研发现，地铁火灾场景的设计并无统一明确的表述。在综合前人研究的基础上，对地铁火灾场景中需要确定的火灾荷载和起火点位置进行了初步探讨，并给出了分析结果。     

基于虚拟现实的建筑火灾模拟系统

提出了将虚拟现实技术应用于建筑火灾模拟的方法,在交互式虚拟环境中实现了基于火灾数值模拟的火灾场景模拟。根据火灾场模拟软件FDS的计算结果,控制虚拟火灾场景中火焰和烟雾的蔓延,使得虚拟场景中火灾的发展接近实际火灾的情况。模拟系统中通过纹理贴图和粒子系统等技术实现了逼真的火灾场景可视化。还介绍了实现灭火作战模拟和训员疏散模拟的技术细节。在以上方法的基础上研制了建筑火灾模拟原型系统,该系统可应用于电子消防预案制作、灭火作战演练、人员疏散演练、建筑性能化防火设计与评估,以及灾害条件下人的疏散行为研究等各个方面。     

Patterns of preference and practice: bridging actors in wildfire response networks in the American Northwest

The roles of bridging actors in emergency response networks can be important to disaster response outcomes. This paper is based on an evaluation of wildfire preparedness and response networks in 21 large‐scale wildfire events in the wildland—urban interface near national forests in the American Northwest. The study investigated how key individuals in responder networks anticipated seeking out specific people in perceived bridging roles prior to the occurrence of wildfires, and then captured who in fact assumed these roles during actual large‐scale events. It examines two plausible, but contradictory, bodies of theory—similarity and dissimilarity—that suggest who people might seek out as bridgers and who they would really go to during a disaster. Roughly one‐half of all pre‐fire nominations were consistent with similarity. Yet, while similarity is a reliable indicator of how people expect to organise, it does not hold up for how they organise during the real incident.     

能源供应系统地震次生火爆灾害危险性评估

能源供应系统的地震安全是防震减灾中的一个重要课题.提出了能源供应系统地震次生火爆灾害危险性的分析方法和评估过程,给出了具体评估内容和可操作的量化评估方法,还对危险性较高的设施设备提出了明确的结构评估流程,这些方法为评估能源供应系统地震次生火爆灾害提供了有效途径,具有很好的应用前景.     

某综合楼钢结构抗火安全设计与评估(Ⅰ) --人员疏散及建筑火灾温度场分析

随着建筑设计理念及建筑技术的发展,很多新型建筑超出了当前防火规范所涉及的范围,这类建筑就要根据性能化思想来进行防火设计。某综合楼为一高层钢结构建筑,采用先进的建筑理念,在建筑内部设置了很多的大空间。基于这一新颖的结构,采用性能化方法对其进行了人员疏散时间、空气升温及结构构件升温等方面的研究。其中人员疏散通过计算机疏散模型进行了研究,大空间火灾升温采用FDS软件进行了模拟,构件升温采用AN SY S软件进行了分析。结合《规范》要求,确定了火灾时合理的人员疏散时间、空气升温及构件升温。     

地表火蔓延的真实感仿真

地表火蔓延的计算机仿真在火灾的扑救、预防及评估等方面具有重要的应用价值。现有的研究大多偏重于火焰蔓延的数值模拟和简单可视化,影响了人们对火灾蔓延的直观认识和临场感。提出了一种基于图形绘制技术的地表火蔓延的真实感仿真技术。首先,根据地表火蔓延的物理规律,并考虑到地形、气候和可燃物等因素的影响,提出了一种基于Rothermel模型的地表火随时间变化蔓延的建模方法。然后,采用基于GIS地形数据和高程图绘制相结合的方法绘制场景地形。再改进传统的粒子系统绘制技术对火焰进行真实感绘制。该方法可以通过变化不同的参数而富有真实感地再现不同环境条件下地表火蔓延场景,能够为灭火决策提供依据。最后,文中给出了不同条件下地表火场景的绘制结果。     

基于微粒群算法的供水管网抗震优化设计

以管网年费用折算值为优化目标、管网拓扑结构与管径为优化参数、管网节点最低可靠度为约束条件,建立了供水管网抗震优化设计模型。利用微粒群算法对这一模型进行了求解,该算法以管网作为微粒个体,通过不断地更新微粒的位置来搜索最优的管网结构,直到最后给出优化的管网结构。利用上述方法对一典型供水管网进行了抗震优化设计分析,给出了3种不同节点最低可靠度约束条件下的优化改造方案。     

Household self‐blame for disasters: responsibilisation and (un)accountability in decentralised participatory risk governance

The most important theoretical argument concerning decentralised participatory governance is that it can make a government more accountable for the needs of the governed. Key to this process are participatory spaces that act as mechanisms for dialogue between citizens and local government. However, within Cochabamba, a city in the centre of Bolivia, South America, ‘at‐risk’ citizens engage minimally with disaster risk issues in participatory spaces, despite high levels of civic participation. This is because ‘at‐risk’ populations view disasters as a private/household problem that is symptomatic of household error, rather than seeing them as a broader public problem due to wider structural inequalities. Consequently, they redistribute responsibility for disaster risk reduction towards households, which (re)produces the absolution of government authorities as guarantors of disaster risk reduction. This paper challenges the normative assumption that participatory spaces facilitate democratic deliberation of disaster risk reduction and the downward accountability of local government for disaster risk reduction.     

城市火灾模拟分析与消防应急指挥系统的设计与实现

城市火灾对人类的危害极大,建立城市消防地理信息系统是减轻城市火灾的有效途径。剖析了传统火灾报警与消防调度模式存在的弊端,尝试提出城市火灾模拟分析与消防应急指挥的融合模式,并运用GIS技术设计和实现了城市火灾模拟分析与消防应急指挥系统。解决了系统实现过程中的一系列关键技术:基于两种方式的接警空间定位、复杂条件下大区域火灾蔓延动态模拟分析、火灾损失预测与评估及消防应急指挥决策模型等。     

售票机的不同位置对地铁车站火灾烟气特性影响的CFD模拟

合理的空间布局对地铁车站消防安全具有十分重要的作用,而售票机的布置方位是影响地铁车站火灾烟气特性的一个主要因素。以某城市在建的地铁站站厅层为物理模型,采用FDS软件对售票机在不同位置情况下火灾的烟气流动情况进行模拟分析,通过比较邻近售票机处的疏散出口的温度、烟气浓度以及能见度,提出了售票机和疏散出口之间较为合理的距离,为实际工程提供可参考的依据。     

苏通大桥结构健康状态评估技术研究与应用(1):拉索损伤识别

采用改进的RBF神经网络建立了苏通大桥拉索损伤识别方法。2个不同阶固有频率之比是仅与损伤位置有关的结构振动参数,据此定义了用于损伤定位的损伤特征指标,并用其来训练神经网络;提出了基于R2+准则与Jackknife校验的改进RBF算法,以有效地控制RBF网络的过拟合现象。算例结果表明,所提出的方法可以较好地对苏通大桥斜拉索进行损伤识别。     

排烟方式对大空间建筑火灾空气升温的影响

为了考察烟气排放对大空间建筑火灾温度场的影响,利用FDS程序仿真模拟了火灾场景,系统分析了不同排烟系统对温度场的影响。结果表明:烟气排放对温度的影响较大,最大降温幅度可达原最高温度的50%左右;降温幅度与建筑高度有密切联系;当建筑高度小于12m时,按规范设计的自然排烟系统下的火场温度低于机械排烟的火场温度;当建筑高度达到或超过12m时,自然排烟系统下的火场温度将接近或高于机械排烟的火场温度。     

计算机模拟在火灾科学与工程研究中的应用

计算机模拟技术尤其是场模拟技术是近年来发展完善的高新技术,在许多工程领域和基础研究方面得到广泛应用。但其在大灾科学和工程领域的应用研究刚刚起步。本文在介绍场模拟基本方法的基础上,重点介绍了场模拟方法中大涡模拟技术的基本理论和方法,并将其引入火灾动力学的研究中。列出了火灾动力学大涡模拟的基本方程、湍流模型、燃烧模型和幅射模型。并用此方法模拟了油罐区火灾动力学演化实例,据此可提出更有效的控制和补救措施。 通过利用场模拟方法中的大涡模拟技术研究典型工业重点火灾危险源——油罐区火灾动力学演化实例,可以看出场模拟技术在安全工程领域方面的发展前景。预计它将成为安全工程领域中的安全管理、危险性评估以及安全事故处理决策支持等的有效手段。     

生命线网络系统抗震拓扑优化的Benchmark模型

生命线系统拓扑优化问题的Benchmark模型是评测新型算法正确性和适用性的重要手段。基于此,首先以生命线网络系统抗震拓扑优化分析模型为背景,建立了该优化问题的三个Benchmark模型,并在Visual Compaq Fortran开发环境下,通过穷举法统计出解空间的所有网络,进而甄选出不同节点可靠度约束下的最优网络和若干次优网络,最后利用上述Benchmark模型对生命线网络系统抗震拓扑优化中的蚁群算法进行测试。结果表明,当网络规模较小时,蚁群算法能精确地搜索到最优解;当网络规模增大后,蚁群算法也能以较大概率搜索到最优解或次优解。     

Contesting the crisis narrative: epidemic accounts in Sierra Leone,Tanzania, and Democratic Republic of the Congo

Scientists and global commentators watched African countries closely in the early months of the COVID-19 pandemic, predicting an impending disaster: the virus was projected to overwhelm already weak health systems. These expectations were informed by imaginaries of Africa as an inevitable site of epidemic disaster. This paper draws on accounts from Sierra Leone, Tanzania, and Democratic Republic of the Congo to contrast global catastrophe framings with everyday imaginations and experiences of crisis and crisis management. Utilising ethnographic research, the paper initially explores how COVID-19 was understood in relation to previous epidemics, from HIV (human immunodeficiency virus) to Ebola, as well as political conflict. It then considers how global crisis narratives both inform and are in tension with everyday collective and personal experiences. The paper brings these empirical reflections into a conversation with theoretical debates on the discursive construction of crisis and its effects, and argues that these tensions matter because crisis framings have consequences.     

Modelling the potential damage-reducing benefits of flood warnings using European cases

In most OECD countries, emergency response to accidents and natural disasters is very dependent on a trained workforce of emergency services volunteers: fire, rescue, medical, care and relief. With its large area, sparsely settled population, and frequent periods of low rainfall, Australia is particularly vulnerable to the threat posed by wildfires. There are an estimated 220,000 rural fire volunteers (in a population of 20 million) in eight state and territory volunteer rural fire services. These fire services have experienced significant decreases in volunteer numbers over the past decade, a trend which is true also of North American volunteer fire services. An investigation suggests that the decrease is driven by two related sets of factors: economic and demographic. Globalisation and deregulation of the economy, and technological innovation, have resulted in structural changes in the nature of work: privatisation, casualisation, self-employment, and demands for increased productivity. These factors make it more difficult for members of communities to volunteer, regardless of their motivation to do so. Further, like many other OECD countries, Australia's birth rate has fallen over the last three decades, resulting in a decline in the proportion of the population aged between 25 and 45 years—a trend that is unlikely to be reversed in the foreseeable future. These economic and demographic changes make it difficult for Australian volunteer rural fire agencies to meet their community protection responsibilities. Responding to these challenges may require radical changes in the way that these fire services are organised and supported.     

不同应力-温度路径下平面钢框架火灾反应的非线性分析

采用考虑温度—应力路径影响的高温下钢材的应力—应变关系,对火灾中钢框架结构的反应进行了非线性分析,旨在尝试提出一种更加符合实际情况的钢结构抗火反应分析新方法。根据已有的试验结果,对高温材性试验数据进行了回归分析,得到了Q235钢在升温恒载、升温加载、升温降载3种基本应力—温度路径下单向拉压时的本构关系式,进而得到不同应力—温度路径下热非弹性应力—应变增量关系式。利用虚功原理,推导出不同应力—温度路径下平面钢框架有限元分析的单元热非弹性刚度方程的显式。同时,对增量迭代法进行了修正,提出升温恒载路径、升温加载路径及升温降载路径3种路径之间切换的判断准则,为结构抗火全过程分析提供了理论基础。     

三跨连续板抗火性能的有限元分析

采用有限元方法对三跨连续钢筋混凝土板局部受火和整体受火下的结构响应进行了数值模拟。结果表明,结构受火位置和受火范围不同时,产生的塑性区位置和范围不同,出现破坏铰的位置不同,但是经过模拟发现塑性区域都是在中间支座附近,破坏铰都是在负筋截断形成,因此结构的负筋长度对结构的耐火性能影响很大;结构在整体受火情况下由于整个结构绕塑性区的抬升作用,造成塑性区附近中跨的抬升,加温结束后整个中跨呈隆起形式,但是中跨局部受火时其中点始终产生向下的挠度,因此在局部受火与整体受火时结构的整体变形不同;在局部受火的时候,由于结构的整体作用使受火跨和未受火跨之间有很大程度的内力调整,这种内力重分布可以很好地提高结构的抗火性能,结构在局部受火的时候耐火性能比整体受火时好出很多。     

道路转角对人员疏散的影响与分析

在封闭建筑和开敞空间的道路设计中,常常忽略道路转角对人员疏散的影响。目前有关道路转角对人员疏散影响的研究多是定性分析,然而对于人员高度聚集的场所,任何细小的疏忽都会导致在火灾和人为灾害疏散过程中的拥堵,甚至造成严重的事故。因此,道路转角对人员疏散的影响不容忽视。本文借助人员疏散仿真软件S IMULEX,定量分析了道路转角对人员疏散的作用,获得了一些规律性的认识,并针对步行道路转角的设计给出了一些建议。