Groundwater and highways interaction: past and present experiences of highway construction in Slovenia     

Mihael Brencic 《Environmental Geology》2006,49(6):804-813

During the planning, designing, construction, operation and maintenance of highways, groundwater can be of important environmental and constructional constraint that can significantly influence the safety operation of traffic and of big influence on the operational costs of highways. To classify and conceptualize the relation between groundwater and highways, three important groups of problems can be determined: groundwater protection from highway influences, protection of highway from groundwater and economic use of groundwater for highway operation. In the present study, groundwater management strategies are represented during all life cycles of highways. Greater emphasis is given to groundwater protection and field hydrogeological investigations for proper groundwater management related to the highway. The approach adopted in Slovenia and the role of hydrogeology is given as an illustration.  相似文献   

矿业开发与环境保护关系综述   总被引：4，自引：0，他引：4  

郭路  李云峰  姬亚东 《西北地质》2005,38(2):94-98

笔者介绍了我国矿业发展经历的3个阶段，归纳出我国矿业开发带来的矿山环境问题主要有：地面塌陷、占压破坏土地、改变地质构造、破坏水资源、污染水、污染土壤、污染大气、瓦斯爆炸及河床抬高等。分析了环境恶化的原因主要与区域地质环境条件、历史、经济技术、矿山企业和地方保护主义等因素有关。最后提出了防治矿山环境恶化的对策，对难以治理的地区以预防、避让为主，历史问题由政府和企业共同解决，落实“谁开发、谁保护；谁受益、谁治理；谁破坏、谁恢复”的生态环境保护新机制，加强监管，加强防治对策研究，走综合勘探、综合评价、综合开发、综合利用的发展道路。  相似文献   

北京及其周边地区夏季地闪活动时空特征分析   总被引：13，自引：9，他引：13       下载免费PDF全文

郑栋 孟青吕伟涛  张义军柴秀梅 马明 《应用气象学报》2005,16(5):638-644

利用M-LDARS闪电定位系统对北京及其周边地区1995～1997年6～9月的闪电观测数据, 分析闪电活动的时空分布特征。结果表明:闪电活动在时间分布上存在两个峰值时段, 13 :00～21:00和23:00～次日05 :00。通过对总地闪、分时段及峰值时段的地闪密度分析, 发现北京及周边地区闪电活动有几个明显的集中区域, 地闪高密度区主要出现在下垫面为山脉和水体的地方, 闪电活动与下垫面的水汽条件关系密切, 且正、负地闪的空间分布也呈现较大差异, 表明雷暴云的电荷结构存在一定差异。  相似文献   

成都粘土路堑边坡防护研究     

徐汉斌 《地质灾害与环境保护》2002,13(1):26-28

成都外环路高速公路东半环超过有20km的路段处在成都粘土分布区，针对成都粘土的易滑性，本文提出了全封闭的浆砌片石护坡，土钉墙，非全封闭的锚杆框架护坡，钢纤维混凝土喷锚全封闭护坡，重力式挡土墙等五种方法处理成都粘土路堑边坡工程，施工实践表明，这些方法行之有效，在该类土的边坡防护中值得推广。  相似文献   

Comparative response analysis of conventional and innovative seismic protection strategies     

S. Bruno  C. Valente 《地震工程与结构动力学》2002,31(5):1067-1092

The paper presents a numerical investigation aimed at evaluating the improvements achievable through devices for passive seismic protection of buildings based on the use of shape memory alloys (SMA) in place of conventional steel or rubber devices. To get some generality in the results, different resisting reinforced concrete plane frames were analysed, either protected or not. ‘New’ and ‘existing’ buildings were considered depending on whether seismic provisions are adopted in the building design or not. Base isolation and energy dissipation were equally addressed for both conventional and innovative SMA‐based devices. Fragility analyses were performed using specific damage measures to account for comparisons among different damage types; the results were then used to estimate quantitatively the effectiveness of the various protection systems. More specifically, the assessment involved a direct comparison of the damage reduction provided by each protection system with respect to the severe degradation experienced by the corresponding non‐protected frame. Structural damage, non‐structural damage and damage to contents were used on purpose and included in a subsequent phase of cost analysis to evaluate the expected gains also in terms of economic benefits and life loss prevention. The results indicate that base isolation, when applicable, provides higher degrees of safety than energy dissipation does; moreover, the use of SMA‐based devices generally brings about better performances, also in consideration of the reduced functional and maintenance requirements. Copyright © 2002 John Wiley & Sons, Ltd.  相似文献   

ELF propagation parameters for uniform models of the Earth–ionosphere waveguide     

Vadim C. Mushtak  Earle R. Williams 《Journal of Atmospheric and Solar》2002,64(18)

Uniform models for the Earth–ionosphere cavity are considered with particular attention to the physical properties of the ionosphere for the extremely low frequency (ELF) range. Two consistent features have long been recognized for the range: the presence of two distinct altitude layers of maximum energy dissipation within the lower ionosphere, and a “knee”-like change in the vertical conductivity profile representing a transition in dominance from ion-dominated to electron-dominated conductivity. A simplified two-exponential version of the Greifinger and Greifinger (1978) technique widely used in ELF work identifies two slopes in the conductivity profile and, providing accurate results in the ELF communication band (45–75 Hz), simulates too flat a frequency dependence of the quality factor within the Schumann resonance frequency range (5–40 Hz). The problem is traced to the upward migration, with frequency increasing, of the lower dissipation layer through the “knee” region resulting in a pronounced decrease of the effective scale height for conductivity. To overcome this shortcoming of the two-exponential approximation and still retain valuable model analyticity, a more general approach (but still based on the Greifinger and Greifinger formalism) is presented in the form of a “knee” model whose predictions for the modal frequencies, the wave phase velocities and the quality factors reasonably represent observations in the Schumann resonance frequency range.  相似文献   

东北地区生态环境保育与绿色社区建设   总被引：12，自引：6，他引：12  

宋玉祥 《地理科学》2002,22(6):655-659

20世纪以来，东北地区资源环境发生了巨大的变化，为全球范围内具有有短时限人地关系高强度作用特征的典型地区之一。区域资源过量消耗、生态环境趋于恶化，可持续发展面临威胁，保育生态环境成为一项十分迫切的任务。建设“绿色社区”，是生态保育的有效措施和重要内容，也是生态建设的一项基础工程，建立绿色社区的目标的营造绿色文化、保育绿色生态和发展绿色经济，建立绿色社区的基本任务是发展生态经济，保育生态环境，解决农村生态环境退化，促进城市可持续发展。提出了绿色社区建设的实施方案。  相似文献   

湿地旅游可持续发展研究   总被引：28，自引：0，他引：28  

鲁铭  龚胜生 《世界地理研究》2002,11(2):72-79

湿地以其独具特色的自然和文化景观为湿地旅游提供了有利条件。本文在可持续发展思想的基础上提出了湿地旅游这一概念，分析了湿地旅游发展与湿地环境保护之间的关系；针对湿地生物多样性、景观多样性、文化多样性等特点对湿地的旅游价值作了进一步的探讨，提出了湿地旅游可持续发展的几点对策。  相似文献   

高山增水效应及其水资源意义   总被引：9，自引：1，他引：9  

丁贤荣 《山地学报》2003,21(6):681-685

根据高山上云、雾、雨、雪、径流等水资源丰富现象，分析了高山冰川、植被、地形等与汽-水作用关系，提出高山增水效应概念和高山区水资源开发与保护的新思路。高大山体及其造成的垂向对流、高山冰川和高山植被共同作用形成了高山增水效应，并形成良性增水系统。山体愈高大，增水效应愈明显。对内陆干旱地区开发利用更多的高山水资源具有意义。  相似文献   

西藏地质环境问题及保护对策     

张建平  范相德  张建国 《山地学报》2003,21(Z1):17-20

作为青藏高原主体的西藏自治区,地质环境极为复杂,地质灾害相当严重,在一些地段地质灾害严重影响了人们正常的生产生活。因此,加强地质环境保护,为人们创造尽可能好的生产和生活空间,是各级政府义不容辞的责任。本文首先对西藏自治区的地质环境特征作了系统地分析,并对西藏地质环境保护及管理现状作了客观评述,在此基础上指出了西藏地质环境保护中存在的主要问题。最后提出了西藏地质环境保护的对策及建议。  相似文献