Landslides and Rainfall Characteristics Analysis in Taipei City during the Typhoon Nari Event     

Fan-Chieh Yu  Tien-Chien Chen  Meei-Ling Lin  Chien-Yuan Chen  Wen-Hai Yu 《Natural Hazards》2006,37(1-2):153-167

The severe Typhoon Nari ended on September 15, 2001 with a high-intensity and high-accumulation storm that dumped up to 1249 mm of rain in Taipei City, Taiwan. The high-intensity and high-accumulation event caused flooding and triggered more than 400 soils slips and debris flows and large, complex landslides. Detailed information on 63 events, including rainfall, initiation time, and magnitude of landslides were documented and analyzed to identify the landslides and rainfall characteristic in Taipei City during Typhoon Nari. The result reveals that slump, slide, and debris flow events are associated with the situation of high-intensity or high-accumulation rainfall. The rainfall intensity-duration condition resulted in smaller magnitude and shallow failures. Medium to massive landslide were mainly related to the high-accumulation rainfall. A landslide regionalization process based on rainfall, geomorphologic and geologic characteristics is proposed. Results of the proposed process show good agreement with landslide events observed in the Taipei City during Typhoon Nari.  相似文献   

居住用途宗地集约利用潜力微观评价探讨——以福州市为例     

肖宝玉  张文开  章牧 《福建地理》2006,(4)

对福州市6宗典型居住用途宗地的容积率、建筑密度、人均用地面积、公共服务设施、绿地率等方面进行调查,采用模糊数学法、专家咨询法等对居住用地的集约利用潜力进行定量和定性评价,确定每宗土地的集约利用潜力等级,得出福州市居住用地总体容积率偏高、建筑密度偏大的结论,提出在今后城市居住用地规划中应当适当下调容积率或建筑密度,提高居住用地的居住质量和土地利用的经济效益等建议.  相似文献   

Spectral shape,epsilon and record selection   总被引：4，自引：0，他引：4  

Jack W. Baker  C. Allin Cornell 《地震工程与结构动力学》2006,35(9):1077-1095

Selection of earthquake ground motions is considered with the goal of accurately estimating the response of a structure at a specified ground motion intensity, as measured by spectral acceleration at the first‐mode period of the structure, Sa(T₁). Consideration is given to the magnitude, distance and epsilon (ε) values of ground motions. First, it is seen that selecting records based on their ε values is more effective than selecting records based on magnitude and distance. Second, a method is discussed for finding the conditional response spectrum of a ground motion, given a level of Sa(T₁) and its associated mean (disaggregation‐based) causal magnitude, distance and ε value. Records can then be selected to match the mean of this target spectrum, and the same benefits are achieved as when records are selected based on ε. This mean target spectrum differs from a Uniform Hazard Spectrum, and it is argued that this new spectrum is a more appropriate target for record selection. When properly selecting records based on either spectral shape or ε, the reductions in bias and variance of resulting structural response estimates are comparable to the reductions achieved by using a vector‐valued measure of earthquake intensity. Copyright © 2006 John Wiley & Sons, Ltd.  相似文献   

Evaluation of residual drift demands in regular multi‐storey frames for performance‐based seismic assessment     

Jorge Ruiz‐García  Eduardo Miranda 《地震工程与结构动力学》2006,35(13):1609-1629

This paper summarizes results of a comprehensive analytical study aimed at evaluating the amplitude and heightwise distribution of residual drift demands in multi‐storey moment‐resisting frames after earthquake excitation. For that purpose, a family of 12 one‐bay two‐dimensional generic frame models was subjected to an ensemble of 40 ground motions scaled to different intensities. In this investigation, an inelastic ground motion intensity measure was employed to scale each record, which allowed reducing the record‐to‐record variability in the estimation of residual drift demands. The results were statistically processed in order to evaluate the influence of ground motion intensity, number of stories, period of vibration, frame mechanism, system overstrength, and hysteretic behaviour on central tendency of residual drift demands. In addition, a special emphasis was given to evaluate the uncertainty in the estimation of residual drift demands. Results of incremental dynamic analyses indicate that the amplitude and heightwise distribution of residual drift demands strongly depends on the frame mechanism, the heightwise system structural overstrength and the component hysteretic behaviour. An important conclusion for performance‐based assessment is that the evaluation of residual drift demands involves significantly larger levels of uncertainty (i.e. record‐to‐record variability) than that of maximum drift demands, which suggests that this variability and corresponding uncertainty should be explicitly taken into account when estimating residual drift demands during performance‐based seismic assessment of frame buildings. Copyright © 2006 John Wiley & Sons, Ltd.  相似文献   

A simple approach for determining particle size enlargement mechanisms in nickel reduction     

V.C. Taty Costodes  C.F. MausseK. Molala  A.E. Lewis 《International Journal of Mineral Processing》2006

This paper examines the active mechanisms responsible for the size enlargement of nickel metal particles during reduction by hydrogen gas. The population balance, related to particle size distribution, is discretized and solved with the method of moments to model the experimental data. This data was generated in a solution of intermittently constant supersaturation during the batch reduction in an 11,000 l of autoclave. PSD and mass distributions were determined by periodically removing suspension samples. In the proposed model, only the growth mechanism is taken into account and aggregation is ignored. Comparison of simulated and experimental PSD and mass distributions show that growth was not the only active mechanisms. Results from the plant indicate that there is an increase in particle size as the cycle progresses. The model generally underpredicts the growth shift in the PSDs' for the early and the larger densifications although it correctly predicts the growth shift in the middle densifications. Constant growth is therefore not the exclusive controlling mechanism. The findings have been confirmed by the trend of the zeroth moment as a function of time.  相似文献   

Regional disparity in the changes of agricultural land use intensity in China during 1980–2002     

LIU Chengwu  LI Xiubin 《地理学报》2006,16(3):286-292

Based on the cost-benefit data (1980–2002) of farm products and China Agriculture Yearbooks, this paper studies the regional disparity in the changes of the agricultural land use in China during the period 1980–2002 from three aspects such as the degree of intensity, the sown area and the abandoned farmland. The results show that: (1) The degree of intensity of land use in the western region during 1980–2000 has a strong uptrend, but in the eastern and central regions the degree of intensity descends obviously and has shown a continuous downtrend since 1997. (2) The total sown area shrinks notably in the eastern region, while it enlarges constantly in the western region. (3) The sown area in the eastern, central and western regions has gone through a similar cyclic process: down (1980–1985)–up (1985–1991)–down (1991–1994)–up (1994–1999)–down (1999–2002). However, there are obvious differences in amplitude variation and tendency among them. The sown area has shrunk in the eastern region and expanded in the central and western regions especially before 1999. (4) The most cases of abandoned farmland are reported in the central region, the second in the eastern region and the least in the western region. The abandonment phenomena chiefly occurred during 1992–1995 in the eastern region, and during 1998–2002 in the central region.  相似文献   

空间集聚与外商直接投资的区位选择——基于珠江三角洲地区的实证分析   总被引：7，自引：0，他引：7  

李郇  DING Xin-Zheng  丁行政 《地理科学》2007,27(5):636-641

在揭示改革开放以来外商直接投资在珠江三角洲空间分布呈现向珠江三角洲集聚的基础上,采用动态局部调整模型对1992～2003年外商直接投资在珠江三角洲9个地级城市中的区位选择影响因素进行了实证分析,结果表明外商直接投资在广东省的区位选择,除受到城市区位特性因素的影响外,更为主要的影响因素是外商直接投资的集聚效应,即与城市已有的外商直接投资数量呈正相关,存在外商直接投资的空间集聚效应,进一步的提出了通过产业集群培育和升级促进珠江三角洲城市外商直接投资持续集聚的策略.  相似文献   

含淹没植物河流水流紊动强度最大值及其影响因素          下载免费PDF全文

李艳红  李栋  范静磊 《水科学进展》2007,18(5):706-710

根据含淹没植物河流水流紊动强度与流速和流速分布的关系,建立紊动强度经验公式,并数学推导证明了紊动强度垂向分布最大值的存在。根据实验数据,该紊动强度最大值的大小及出现位置受植物和水流条件的影响:植物的存在增加水流阻力,植物排列密度改变紊动强度最大值的大小;植物叶片的摆动形成水流紊动的主要干扰源,植物/水深相对高度控制紊动强度最大值的出现位置;断面平均流速的变化改变水流的稳定性和植物冠层的高度,对紊动强度最大值的大小和出现位置均有一定影响。  相似文献   

珠穆朗玛峰绒布河谷近地层大气湍流及能量输送特征分析   总被引：14，自引：1，他引：14       下载免费PDF全文

仲雷  马耀明  李茂善 《大气科学》2007,31(1):48-56

利用中国科学院2005年珠穆朗玛峰地区科学考察期间 (4月2日至6月7日) 收集的大气观测资料，分析了珠峰绒布河谷近地层水平风速、温度、湍流强度、湍流通量日变化及地表能量平衡特征。通过分析得出近地层三维风速方差与稳定度的关系基本满足1/3次方规律；珠峰绒布河谷近地层大气水平风速、温度、动量通量、感热通量和潜热通量均存在明显的日变化；地表获得的能量很大一部分以感热形式散失掉了，潜热所占比重很小。另外，还发现绒布河谷地区地表能量通量各分量并不满足能量平衡方程Rn=Hs+Le+G。通过对地面加热场的分析发现珠峰地表白天是强热源，晚上转变为弱冷源。  相似文献   

A point hailfall classification based on hailpad measurements: The ANELFA scale     

J. Dessens  C. Berthet  J.L. Sanchez 《Atmospheric Research》2007,83(2-4):132-139

The ANELFA scale for hailfall intensity is proposed on the model of the 6-class Fujita scale for tornadoes. It is based on more than three thousand point hailfalls measured by hailpads over a 16-year period in France. The class number of a hailfall is determined by the integer value of the largest measured hailstone diameter in cm, or by equivalence with current objects: A0 to A5 for pea, grape, pigeon's egg, walnut, hen's egg, orange. The class number is followed by a plus or minus sign if the ground is significantly more or less than half-covered by hailstones respectively. When the scale is applied to the ANELFA data, a log-normal distribution is found for the class distribution, allowing the frequency determination of the upper class ever observed until now at the hailpad stations.  相似文献