Determination of mechanical properties of traditional masonry walls in dwellings of Faial Island,Azores     

Aníbal Costa 《地震工程与结构动力学》2002,31(7):1361-1382

The determination of mechanical properties of masonry walls is a fundamental pre‐requisite for the characterization of the seismic response of traditional buildings, which helps on the definition of adequate rehabilitation and strengthening procedures. This paper presents a testing campaign carried out in the Cedros region of Faial Island, Azores, hit by the July 98 earthquake, aiming at the determination of physical and mechanical properties of stone masonry walls, namely the mass density and Young's modulus. The paper describes the developed testing techniques as a contribution to the study and the preservation of traditional masonry buildings. Copyright © 2002 John Wiley & Sons, Ltd.  相似文献   

河岸带及其生态重建研究   总被引：41，自引：3，他引：41  

张建春  彭补拙 《地理研究》2002,21(3):373-383

河岸带具有重要的生态、社会、经济和旅游价值。河岸带研究以生态学、水文学和地貌学为基础涉及多种学科和技术。我国河岸带及其退化生态系统重建理论与实践研究均较为薄弱。本文基于 6年河岸带退化生态系统重建的科学研究实践 ,阐述了河岸带研究的意义、内容及其生态、经济和社会效能 ;分析了河岸带生态重建的理论与技术方法 ,探讨了河岸带滩地生态重建的措施及河岸带今后管理的目标、原则和方向 ,并以皖天柱山麓潜水河岸带滩地生态重建为例进行了验证  相似文献   

济宁市湿地评价及恢复研究     

宋印刚  宋洪梅  胡猛  蔡宪文 《湿地科学与管理》2007,3(3):34-37

根据济宁市2003年湿地调查,运用矩阵对济宁市湿地进行评价分析,生态类型很好的占25%,较好的占21%,好的占19%,中等的占15%,差的占12%,很差的占8%,并提出了湿地保护恢复措施,为全市湿地资源研究和生态系统管理提供了科学依据。  相似文献   

A one‐dimensional model for simulating armouring and erosion on hillslopes: 2. Long term erosion and armouring predictions for two contrasting mine spoils     

Saniya Sharmeen  Garry R. Willgoose 《地球表面变化过程与地形》2007,32(10):1437-1453

This paper investigates the dynamics of soil armouring as a result of fluvial erosion for a non‐cohesive sandy gravel spoil from the Ranger Mine, Australia, and a cohesive silt loam spoil from the Northparkes Mine, Australia, using a model for hillslope soil armouring. These long term predictions concentrate on the temporal and spatial changes of the spoil grading and erosion over 100–200 years for the flat cap regions (1–2%) and steep batter edges (10–30%) typically encountered on waste rock dumps. The existence of a significant rock fragment fraction in the Ranger spoil means that it armours readily, while Northparkes does not. For Ranger the waste rock showed reductions in (1) cumulative erosion of up to 81% from that obtained by extrapolating the initial erosion rate out 100 years and (2) the erosion/year by more than 10‐fold. For Northparkes reductions were less marked, with the maximum reduction in erosion/year being 37% after 200 years. For Ranger the reductions were greatest and fastest for intermediate gradient hillslopes. For the steepest hillslopes the armouring decreased because the flow shear stresses were large enough to mobilize all material in the armour layer. Model uncertainty was assessed with probabilistic confidence limits demonstrating that these erodibility reductions were statistically significant. A commonly used hillslope erosion model (sediment flux = β₁ discharge m₁ slope n₁) was fitted to these predictions. The erodibility, β₁, and m₁ decreased with time, which was consistent with our physical intuition about armouring. At Ranger the parameter m₁ asymptoted to 1·5–1·6 while at Northparkes it asymptoted to 1·2–1·3. At Ranger transient spatial trends in armouring led to a short term (50–200 years in the future) reduction in n₁, to below zero under certain circumstances, recovering to an asymptote of about 0·5–1. At Northparkes n₁ asymptoted to about 0·6, with no negative transients predicted. The m₁ and n₁ parameters predicted for Ranger were shown to be consistent with field data from a 10‐year‐old armoured hillslope and consistent with published relationships between erodibility and rock content for natural hillslopes. Copyright © 2007 John Wiley & Sons, Ltd.  相似文献   

Spatio-temporal analysis of fish and their habitat: a case study on a highly degraded Swiss river system prior to extensive rehabilitation     

Christine Weber  Armin Peter  Flavio Zanini 《Aquatic Sciences - Research Across Boundaries》2007,69(1):162-172

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重庆三峡水库生态经济区农业生态环境问题与重建研究   总被引：3，自引：0，他引：3  

李孝坤 《中国地质灾害与防治学报》2005,16(2):97-101

农业生态环境是农业可持续发展的基础。重庆三峡水库生态经济区是重庆市确立的以生态建设为重点的经济区。鉴于该区农村面积广、农业人口多、贫困面大、农村移民任务重的基本情况，决定了农业及农村在社会经济可持续发展中的重要战略地位。深入分析了重庆三峡水库生态经济区农业生态环境存在的水土流失、水环境污染、土地污染、生物多样性破坏、自然灾害频繁等主要问题及其对农业生产的影响，从因地制宜合理利用农业资源、调整农业产业结构、优化农业空间布局，大力发展生态农业，控制并治理各种工业及生活污染、推行清洁生产，控制人口增长、实施生态移民、协调人地关系，加强生态环境法制化管理、依法保护农业生态环境等方面提出了保护及建设的对策。  相似文献   

基于GIS的工程移民DSS研究   总被引：4，自引：0，他引：4  

王家耀  姚松龄 《测绘学院学报》2000,17(1):38-41,45

工程移民指工程建设引起的非自愿的搬迁安置活动,工程移民决策包括规划决策和管理决策,这在国内外都是一个新课题,基于ＧＩＳ的工程移民ＤＳＳ是实施科学决策的有效手段,本文对工程移民决策支持的理论、方法进行了探讨,并结合万家寨工程移民决策支持进行了试验。  相似文献   

Social Cohesion; Is it sufficient? Migrant communities in two disadvantaged neighborhoods in Istanbul     

Hürriyet G. Ögdül 《GeoJournal》2000,51(4):321-328

Planners assume that old neighbourhoods have an atmosphere in which social relations can easily flourish. They also regard the strong social ties within a neighborhood as the guarantee for the success of housing rehabilitation. This article argues that existence of social cohesion in a neighbourhood is not necessarily an advantage in a process of modernisation and rehabilitation. In some cases the community may constitute a closed `island' especially in places where communities have historically inherited an hierarchical character. The article is based on a recent research project dealing with urban communities in inner city areas of Istanbul, especially those containing migrant populations which seemingly have strong community ties. The historical background of the community from the Ottoman period is examined in the first part of the article. The roots of the community as a territorial administrative unit (mahalle) and its modification in contemporary migrant communities are analysed. The second part of the article presents the results of two case studies. One of the case studies is a social housing district where the migrant community is mixed and social relations with the rest of the city are relatively well developed. The other case study area is an historical district where strong social ties create an introverted character of the community in spite of its central location. The result of the study reveals that urban `communities' in a city like Istanbul have both negative and positive aspects. Primarily it is important to assess and understand the degree of `opennes' of the community to the outer world. In any action to be taken planners should look not only inside the community, but also at its 'outer' relations.  相似文献   

贵州典型喀斯特环境退化与自然恢复速率   总被引：41，自引：3，他引：38  

杨胜天  朱启疆 《地理学报》2000,55(4):459-466

喀斯特环境退化与自然恢复速率是具有重要意义的问题。在分析贵族典型喀斯特环境主要因子关系的基础上,确定用土地覆盖、植被状况和土壤属性反映喀斯特环境退化与自然恢复过程,应用和地面观测方法对研究区土地覆盖、植被覆盖、生物生产量、生物多样性和土壤理化性质等指标进行研究,从而得出研究区喀斯特环境退化与自然恢复规律及其相应的速率。  相似文献   

西南喀斯特地区地表水热过程研究进展与展望   总被引：1，自引：0，他引：1  

Gao Jiangbo  Wu Shaohong  Dai Erfu  Hou Wenjuan 《地球科学进展》2015,30(6):647-653

西南喀斯特地区水文二元结构以及生境条件的异质性导致地表水热过程异常复杂。水热过程机理研究薄弱,已经成为生态系统退化关键过程识别、生态恢复重建推进的关键限制因素。首先从野外科学实验、陆面过程参数化、遥感反演技术3个方面简要论述了地表水热过程的研究方法,指出在喀斯特地区,目前亟需开展的工作是在样地和坡面尺度上对地表水热过程进行系统的观测和实验,以深化水热过程机理研究,并发展适用于喀斯特地区的陆面过程模式和遥感反演模型。进而评述西南喀斯特地区地表水热过程已有研究进展与存在问题:水分循环研究的重视,但在特殊的地质背景与复杂的生境条件下,土壤水分时空异质性及降雨入渗产流和土壤侵蚀过程的机理仍不明晰,而且水热耦合研究非常缺失。最后从地表水热过程机理、水热过程变化影响机制、生态系统恢复重建水热调控等方面展望了其未来发展趋势。  相似文献