地铁隧道地震动力响应模拟试验研究

为研究地震荷载作用下隧道结构的动力响应,以指导隧道修建施工和衬砌支护,提高地铁隧道的整体抗震能力,采用理论分析、数值模拟和室内试验相结合的方法,对地铁隧道地震动力响应进行研究。选取沈阳地铁2号线某段隧道为工程背景,在理论分析地铁隧道地震动力响应的前提下,运用FLAC~(3D)数值软件模拟地铁隧道地震动力响应情况,地铁隧道两帮壁正负45°区域剪应力、主应力和位移最显著,监测点加速度变化趋势与输入地震波加速度时程曲线较为一致。在室内振动台试验中,地基土体表面峰值加速度明显比地基土体深部大,隧道两帮壁正负45°位置附近应变最大,振动停止后应变并未归零。数值模拟与室内试验研究结果较为吻合表明,由于人工波的地震烈度较现场波大,地铁隧道的地震扰动强烈;地铁隧道两帮壁正负45°区域地震动力响应剧烈,极易发生破坏。可根据这一现象有针对性地采取抗震措施,保证地铁隧道的安全、稳定。     

Assessing the impact of the Indian Ocean tsunami on households: a modified domestic assets index approach

This paper offers a potential measurement solution for assessing disaster impacts and subsequent recovery at the household level by using a modified domestic assets index (MDAI) approach. Assessment of the utility of the domestic assets index first proposed by Bates, Killian and Peacock (1984) has been confined to earthquake areas in the Americas and southern Europe. This paper modifies and extends the approach to the Indian sub‐continent and to coastal surge hazards utilizing data collected from 1,000 households impacted by the Indian Ocean tsunami (2004) in the Nagapattinam district of south‐eastern India. The analyses suggest that the MDAI scale is a reliable and valid measure of household living conditions and is useful in assessing disaster impacts and tracking recovery efforts over time. It can facilitate longitudinal studies, encourage cross‐cultural, cross‐national comparisons of disaster impacts and inform national and international donors of the itemized monetary losses from disasters at the household level.     

Housing anxiety and multiple geographies in post-tsunami Sri Lanka

Tsunami intervention has been an extraordinary and unprecedented relief and recovery operation. This article underlines the complexities posed by shelter and housing intervention in post-tsunami Sri Lanka, revealing a pragmatic, reductionist approach to shelter and housing reconstruction in a contested and fragmented environment. Competition, housing anxiety and buffer zone implementation have resulted in compulsory villagisation inland, stirring feelings of discrimination and tension, and becoming major obstacles to equitable rebuilding of houses and livelihoods. A new tsunami geography has been imposed on an already vulnerable conflict-based geography, in which shelter has been conceived as a mono-dimensional artefact. An analysis of the process and outcomes of temporary and permanent post-tsunami housing programmes yields information about the extent to which shelter policies and programmes serve not only physical needs but 'higher order' objectives for a comprehensive and sustainable recovery plan.     

流作用下泥沙悬浮释放污染物的数值分析

基于一维垂向模型(1DV模型),建立了波流共同作用下泥沙悬浮释放污染物的数学模型,模型通过验证可较好的描述床面附近紊动特性、水流结构、泥沙垂向分布及污染物解吸释放规律. 利用数学模型,通过设置不同的模拟情景,分析计算了波流共同作用下泥沙悬浮特征、污染物释放动态过程及时空分布特征. 研究表明: 波流共同作用下,吸附态污染物及总污染物垂向分布与悬浮泥沙分布一致,波浪底部边界层的周期性振荡限制了从底部悬扬的泥沙向上部水体的扩散,在近床面存在梯度较大的高浓度层,在悬浮释放的初期,溶解态污染物的垂向分布规律与吸附态污染物一致,达到平衡后,沿垂向均匀分布.水流流速和波浪强度对泥沙悬浮释放污染物有着不同程度的影响,水流对泥沙及污染物的垂向分布影响明显,波浪的影响主要体现在床面附近形成高浓度含沙层和污染物层.     

The role of religion in local perceptions of disasters: the case of post-tsunami religious and social change in Samoa

ABSTRACT

This paper explores religious perceptions of disasters and their implications for post-disaster processes of religious and cultural change. Based on ethnographic fieldwork in post-tsunami Samoa, this study investigates how people in two tsunami-affected villages make sense of the tsunami, its causes and impact based on different Christian understandings: the tsunami as divine punishment or as a sign of the Second Coming. I argue that these different perceptions of the tsunami are used in bringing about or opposing religious and cultural change based on different ideals of continuity and change.     

Calamity,kastom, and modernity: local interpretations of vulnerability in the western Pacific

On 2 April 2007 a large tsunami struck the small island of Simbo in the western Solomon Islands. It obliterated two villages, killed 10 people, and provoked communities on the northern half of the island to permanently relocate their settlements. In this article I examine how the Simbo people experienced and perceived this catastrophic event. Local discourses about the tsunami, its aftermath, and its selective lethality reveal how Simboans do not employ spiritual or naturalistic rationales to conceptualize vulnerability. Rather it is described in terms of the anxieties and novel opportunities associated with encroaching modernity and other exogenous large-scale social and economic processes. The case exemplifies the tensions and contradictions that arise when communities actively negotiate and trade-off one set of vulnerabilities for others as social and ecological contexts transform. I argue that an improved understanding of local interpretations of vulnerability is critical if our interest is to better cope with inevitable future ecological disturbances.     

爆炸的破坏作用与伤害分区

讨论冲击波的各种破坏准则，即超压准则、冲量准则和超压～冲量准则；提出故爆炸伤害／破坏分区的概念，叙述了伤害／破坏区域划分的具体方法并进行了数值模拟计算。最后，还对中文有些问题作了简要说明。     

中国东部海域发生海啸的可能性分析

由强地震引发的印度洋大海啸在短短几个小时内就演变成了一场巨大的人间惨剧。这样的2004年12月26日自然灾害,人类能不能预防?它的形成机制是什么?我国历史上发生过海啸吗?在未来我国哪些地区会发生海啸?就上述问题,作了可能性分析。印度洋海啸的发生可以说既是天灾,也是人祸。人类虽说还不能控制地震、海啸等天灾的发生,但可以通过预报等措施来减轻它们造成的损失。我国历史时期曾发生过多次海啸,台湾周围海域是海啸的高发区域,其次是大陆架区域,渤海是低发区域。在未来,东海、南海,特别是台湾岛附近海域具备产生海啸的条件,即海南、台湾存在成灾条件;其次是上海,广州,也存在潜在的海啸危险;沿海其它城市亦应居安思危。     

超声波技术在污泥处理利用中的应用现状及前景预测

本文介绍低频超声波技术在城市污水厂污泥处理中应用的原理以及可以带来的经济和环境效益。指出，对一定量的剩余污泥进行超声处理后进行发酵，或者将其回流到生化池进水，可以增加沼气产量，并使最终的泥饼数量减少。通过分析德国的应用实例，说明了超声波设备可以带来的运行成本方面的好处。     

Computer-aided modeling of the protective effect of explosion relief vents in tunnel structures

This paper aims at contributing to the efficient design of explosion protection systems against confined explosions. The issue addressed concerns the quantitative estimation of the protective effect of explosion relief vents in the case of confined explosions inside tunnels. A series of virtual experiments performed by computer simulation, revealed how the number of vents, their diameter, as well as the angle between the vents and the tunnel, influences the blast wave attenuation. The computational study was performed considering a complicated large-scale tunnel configuration with branches on its half portion. The purpose was the calculation of the attenuation effect due to the presence of vents by comparing the total explosion-specific impulse developing at antidiametric positions inside the tunnel. Simulations were carried out via a three-dimensional numerical model built in the computational fluid dynamics code CFX 5.7.1, which has been validated in previous papers against experimental overpressure histories data demonstrating reasonable performance. Computer results showed that the use of branch vents provides an effective method for shock wave attenuation following an explosion, whereas their statistical elaboration revealed that the attenuation is mainly affected by the number of vents and their diameter. In contrast, the angle between the side vents and the main tunnel appeared to slightly affect the pressure wave weakening. Eventually, the quantitative influence of the above parameters was effectively illustrated in functional diagrams, so that the total attenuation effect may be promptly estimated, if the design variables are known. In addition, two statistical models with reasonable fitting to the calculated data are proposed, which express the attenuation effect as a dependent variable of the design variables including their interactions.