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81.
按新旧规范设计的多层住宅砖房地震易损性的对比 总被引:1,自引:0,他引:1
本文采用概率方法借助于拉丁超立方采样技术和非线性地震反应时程分析对按现行规范设计的多层住宅砖房的地震易损性进行分析,并与按上一代规范设计的多层住宅砖房的地震易损性分析结果[1]进行了比较,为进一步研究这类结构的地震安全性、未来地震的损失预测以及防震减灾对策奠定基础。 相似文献
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83.
干旱区地下水脆弱性特征及评价方法探讨 总被引:29,自引:18,他引:29
干旱区地下水脆弱性是地下水系统本身固有的不稳定属性,是系统结构、功能状态在人类活动干扰及气候变化等自然因素作用下具有的敏感性、易变性和弹性的综合反映。可以以河川径流中冰雪融水比重、地表径流入渗占地下水补给比例、地下水补给强度、地表水的引用率等十项指标(IRRUDQELTS)进行定量评价。通过对塔里木盆地南缘地下水脆弱性评价,表明该区属地下水严重脆弱区,其中又以民丰县、皮山县为极端脆弱,结果与实际情况相符合,说明该评价指标体系具有一定的科学性。 相似文献
84.
选用大雾观测资料测算城市地区的雾灾危险性指数,以规则网格作为评估单元,逐网格计算网格区域内的路网密度,以此作为雾灾的空间脆弱性指标,并针对重点设施的分布情况对脆弱性指数进行空间叠加订正;选用网格内的人口密度作为雾灾的易损性指标;危险性、脆弱性及易损性3项指标按5:2:1的分配比例综合测算雾灾的风险指数。实例研究选用北京地区1996年1月—2006年12月的大雾资料,按空间网格化方法对大雾灾害风险进行评估,结果表明:北京地区雾灾脆弱性指数的高值区域与高速路及环城路延伸方向一致,城市中心为人口集中分布地区,其综合风险指数高,与高速路段、环城路及机场等地段均为雾灾的高风险区域,北京东南部地区年平均雾日数相对较多,危险性指数值也较高,是雾灾较高风险区域。 相似文献
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86.
岩溶地区地下水污染风险评价方法探究——以地苏地下河系流域为例 总被引:1,自引:0,他引:1
岩溶地下水污染风险评价对岩溶地下水的保护、管理和合理利用具有重要意义。文章总结了近年来国内外地下水污染风险评价方面的研究进展,针对目前评价体系存在的不足,构建了适合岩溶区地下水污染风险评价体系。该方法基于欧洲模式,实现地下水防污性能评价;污染负荷评价则考虑污染物在覆盖层中的衰减过程,利用折减系数实现污染负荷量化;最后,基于GIS空间叠加分析耦合防污性能与污染负荷评价,实现区域地下水污染风险评价。文章以地苏地下河系流域为例,开展岩溶区域地下水污染风险评价,结果表明:区域整体地下水污染风险偏低,地下水中等及以上污染风险区域面积424.41 km2,占研究区总面积的39.03%,主要分布在研究区中东部地苏乡、东庙乡、六也乡局部等人类活动频繁与地苏地下河干流中下游段。地下水污染风险空间分布特征不仅显示了岩性、坡度、岩溶网络发育等自然条件对评价结果的影响,同时也反映了人类活动的影响。地势平缓,岩溶发育程度强烈,加之人类活动频繁是导致区域地下水污染风险较高的原因所在。 相似文献
87.
本文采用类比法和定量化方法对上海宝山区村镇民房震害损失进行了预测。在此基础上,对上海已有的和新建的民房提出抗震对策和措施。 相似文献
88.
This paper quantitatively explores farmers' vulnerability to flood in the Poyang Lake Region (PLR) with the supports of GIS spatial functions. The analysis consists of three major steps,which is based on the spatial unit of township. Firstly,the spatial extent and charac-teristics of flood risk areas were determined using a digital elevation model (DEM) derived from the 1:50,000 topographic map. Secondly,for each of the township,six indices indicating the economic activities of local farmers were calculated. These indices are: rural population proportion,cultivated land proportion,GDP per unit area,employment proportion of primary industry,net rural income per capita and agricultural income proportion. These six indices were then normalized and used for later vulnerability assessment. Thirdly,the normalized indices (as GIS data layers) were overlaid with the flood risk areas to produce the risk coeffi-cient for each township and to calculate the overall vulnerability for each township. The analysis results show that in the PLR there are high flood risk areas where the farmers' livings are seriously influenced or threatened. About 55.56% of the total 180 townships in the flood risk areas have a high degree of flood vulnerability. The townships under flood risk are mainly distributed in the areas around the Poyang Lake and the areas along the "five rivers". 相似文献
89.
Atoll island vulnerability to flooding and inundation revealed by historical reconstruction: Fongafale Islet, Funafuti Atoll, Tuvalu 总被引:1,自引:1,他引:0
Hiroya Yamano Hajime Kayanne Toru Yamaguchi Yuji Kuwahara Hiromune Yokoki Hiroto Shimazaki Masashi Chikamori 《Global and Planetary Change》2007,57(3-4):407-416
The reef islands formed on coral atolls are generally small, low, and flat, with elevations of only a few meters. These islands are thus highly vulnerable to elevated sea levels caused by extreme events and global warming. Such vulnerability was recently evidenced at Fongafale Islet, the capital of Tuvalu, when it flooded during accelerated spring high tides possibly related to sea level rise caused by global warming. Many factors, not only environmental but also economic and social, determine the vulnerability of an island to sea level rise. In this study, we used data spanning 108 yrs to reconstruct changes in topography, land use/cover, population, and the distribution of buildings at Fongafale Islet. The results indicate that the vulnerability of Fongafale Islet relates to its original landform characteristics: the central part of the island was formerly dominated by swampland that flooded at high tides. Fongafale Islet experienced greater population in-migration and centralization beginning in the 1970s following the independence of Tuvalu and Kiribati. Migrants were also responding to declines in overseas mining operations and limited options for paid employment. As the population increased, construction took place in vulnerable swampland areas. Our results clearly demonstrate that examinations of global environmental issues should focus on characteristics specific to the region of interest. These characteristics should be specified using historical reconstruction to understand and address the vulnerability of an area to global environmental changes. 相似文献
90.
Kunming Basin locates middle of Yunnan altiplano and has a particularity in geography, topographic and geological environment. With the urban dilation quickly, add the reason of the unreasonable city layout, conflicts between environment and urban resources consumption become shrill increasingly. It is human being activities that lead to vulnerability and depravation of geological environment in local. Take a few examples on geological environment to expatiate relationship between urban construction and geological environment carrying capacity, and find a way how to make a better plan for urban sustainable development to achieve new balance between man and nature in local. 相似文献