A fuzzy multicriteria evaluation system for the assessment of tunnels vis-à-vis surface roads: the WPMA case—part II

The Fuzzy Multicriteria Evaluation System (FUMES) is applied on a real evaluation problem such as the Western Peripheral Motorway of Athens (WPMA). The lack of a formal development model of the study area suggested an evaluation strategy, which is characterized by the high uncertainty of the evaluation environment. This has resulted in using judgments when quantitative information on the performance of the tunnel or the surface road was not available. It also resulted in employing a relatively large number of alternative scenarios to deal with the different policy goals. The attempted impact analysis generated crisp and fuzzy scores for each competing alternative. The different scenarios under which the various alternatives were evaluated are of two types: socio-economic and policy scenarios. Subsequently, the criteria weights were computed using the Fuzzy Hierarchical Analysis and the different CBA and MCA methods were applied. Finally, the output of the evaluation determined that the surface road is the most ‘stable’ solution for all the ‘extrovert’ development scenarios, while the tunnel is more preferable for all the ‘introvert’ development scenarios.     

瀑布沟工程的水文分析计算

本文简要的介绍了瀑布沟工程水文分析计算主要依据站的选定和基本资料的插补延长,以及径流、洪水的分析计算方法.在可行性研究阶段水文成果(通过审查)和新设立的毛头码水文站所取得的数年水文资料的基础上,将初设阶段对可行性研究阶段的水文分析计算方法和成果进行验证和补充的情况重点予以介绍.     

Flood frequency and routing processes at a confluence of the middle Yellow River in China

Floods cause environmental hazards and influence on socio‐economic activities. In this study, we evaluated the historic flood frequency at a confluence in the middle Yellow River, China. A non‐parametric, multivariate, empirical, orthogonal function matrix model, which consists of time correlation coefficients of flood discharge at different gauge stations and flood events was used for the analysis of flood frequency. The model addresses the characteristics of confluent floods such as frequency and the probability in multiple tributary rivers. Flood frequency analysis is often coupled with studies of hydrological routing processes that reduce the flood capacity of the rivers. Flood routing to the confluence were simulated using kinematic wave theory. Results of this flood frequency analysis showed that flooding frequency has intensified in the past 500 years, especially during the 19th century. Flooding in streams above the confluence was more frequent than in streams below the confluence. Over the last 2000 years, concurrent flooding in multiple tributary rivers accounted for 67.5% of the total flooding in the middle Yellow River. Simulation of flood routing processes shows that the decreased flooding capacity and elevated river bed of the shrunken main channel leads to an increased flood wave propagation time (24–52.3 h) in the study area after 1995. The model indicates that human activities, such as constructions of the Sanmenxia Dam, have changed flood routing boundary conditions and have contributed to the increased flood frequency at the confluence. Copyright © 2007 John Wiley & Sons, Ltd.     

浍河水库泄洪洞结构优化研究

根据有限元计算原理，结合山西临汾地区浍河水库泄洪洞，对土坝下的大型软基涵洞分层填土施工过程和蓄水对结构的影响进行了模拟计算，得到了更贴近实际的涵洞结构内力和涵洞土压力分布规律，并根据实际地基条件及现有涵洞的两种常见的结构形态对涵洞结构形式进行了优化，其成果已用于设计和施工，证明了该研究方法的科学性和结论的正确性。     

Evaluation of a system of wind tunnels for field studies of ammonia loss from grassland through volatilisation

Rates of ammonia (NH₃) loss from a ryegrass sward measured using a system of small wind tunnels were compared with concurrent measurements made using a micrometeorological mass balance method. Measurements were made during two experiments within a circular plot (radius 10m) treated with urea at a rate of 200kgNha^?1. In the first experiment, air speed through the tunnels was adjusted as necessary to maintain a value of approximately 1ms^?1. This value differed on most occasions from the mean ambient wind speed which was measured at a height of 250mm and which ranged from 0.61 to 2.95ms^?1. Rates of loss measured using the wind tunnels differed by a factor of between two and five from those measured using the mass balance method; there was no consistent pattern in the differences between the rates of loss. The total losses of NH₃ measured during 15 days were equivalent to 49.1 and 30.2kg Nha^?1 for the mass balance and wind tunnel methods, respectively. In the second experiment, air speed through the tunnels was adjusted as necessary to maintain a value as close as possible to the mean ambient wind speed measured at a height of 250mm. Rates of NH₃ loss measured using the two methods did not differ significantly; total losses of NH₃ during 17 days were equivalent to 96.9 and 101kg Nha^?1 for the mass balance and wind tunnel methods, respectively. The difference between the findings of the two experiments could be attributed to the direct effect of air speed through the tunnels rather than to differences between ambient temperatures and those inside the tunnels. During and following periods of rain the rates of loss measured using the tunnels were up to six times greater than those observed with the mass balance method. Rates of loss measured by the two methods became similar again when the tunnels were moved following rain. The study demonstrates that enclosures can be designed and operated to provide reliable measurements of the rate of NH₃ loss from grassland. Potential applications of the two methods are discussed.     

安徽省旱涝急转规律的认识与研究

旱涝急转是指某一地区或某一流域发生较长时间干旱时，突遇集中强降雨，引发山洪暴发、河水陡涨．客水入侵、内水难以及时外排的一种自然现象。旱涝急转极易造成人员伤亡、水库垮坝等重大经济损失。在防汛抗旱中，安徽省要充分认识旱涝急转的危害性，加强应急管理，具体包括思想上保持高度的警觉，加快防汛抗旱工程体系和预测预警体系建设，有效应对旱涝急转。     

小型水库溃坝洪水演算探讨

本文简要介绍了现有溃坝洪水的计算方法,根据新疆奎屯河"87"溃坝性洪水演算实例.推荐了一种简单可靠的适合小型水库溃坝洪水计算的方法.     

宜昌站泄流能力变化对葛洲坝设计洪水影响

宜昌水文站是葛洲坝、三峡水利枢纽的设计依据站。葛洲坝水利枢纽动工修建和运行 ,对该站水位流量关系中低水部分产生了影响。探讨了该河段泄流能力的变化对葛洲坝水利枢纽设计洪水有无影响的问题。用1 967～ 1 999年实测资料对宜昌站以汛期平均水位为参数的水位流量关系曲线簇进行了检验 ,大部分年份最大日平均流量、3、7、1 5、30d洪量的偏差在± 4 %之间 ,说明曲线簇推流具有相当的精度。证明了宜昌河段中低水泄流能力的变化对葛洲坝水利枢纽设计流量和校核流量基本没有影响     

平衡纵剖面数值试验及其对防洪的影响研究

本文采用一维非恒定流非均匀沙的水沙数学模型，以长江中游螺山汉口河段为背景，进行了根化数值模拟试验，分析了该概化河段平衡纵剖面的变化规律及其与上游来水来沙条件的关系，并和相应的理论公式进行了比较。在此基础上，对水沙条件发生较在变化时的平衡纵比降以及带来的对长江中下游防洪的影响进行了分析。     

《关于加强嫩江松花江近期防洪建设的若干意见》论证概要

水利部《关于加强嫩江松花江近期防洪建设的若干意见》近期已由国务院办公厅批转有关省、自治区和国务院有关部门执行。本文简单介绍了《关于加强嫩江松花江近期防洪建设的若干意见》编制过程中对设计洪水、防洪标准、工程布局和非工程措施的论证情况和主要结论。