高密度电阻率法在水坝隐患探测中的应用

本文以某水库土质坝体的勘察为例 ,介绍了高密度电阻率法在坝体隐患探测中的实际应用     

堤坝隐患探测中的探地雷达技术

阐述了探地雷达的工作原理和堤坝隐患探测的流程图,介绍了探地雷达在堤坝结构层厚度、裂缝识别、洞穴探测、含水量、孔隙率和坝体浸润线探测中的一般原理和研究现状,为进一步研究提供了技术路线和基本思路。     

地球物理方法在某水库坝体隐患探测中的应用研究

水库坝体隐患有可能演变为险情,危及下游居民生命财产安全,开展水库坝体隐患调查工作具有重要意义.分析某水库坝体正常土体与隐患之间的波速、电阻率、介电常数差异,针对性地采用瑞雷波法、高密度电阻率法、地质雷达法等综合物探技术探测某水库坝体隐患,最终查明约8.5 m以下地层为坝基土;坝身土体具有上密下疏的结构特征,圈出三处异常...     

沥青混凝土心墙堆石坝渗漏探测与套阀管法控制性灌浆渗漏处理措施研究

针对沥青混凝土芯墙堆石坝坝体和坝基多重介质物理力学性状差异大、应力应变状态复杂、坝体渗漏探测和处理难度大的问题,基于工程实例,形成先分析地质、设计和施工过程资料,再利用物探为辅、钻孔探测为主的综合探测手段,进一步确定大坝渗漏范围和性质;同时针对堆石坝堆石结构特点制定了套阀管法和多种浆液体系的控制性灌浆工艺。采用上述方法进行处理后,大坝总渗漏量从最初的700多L/s减少到了6.4 L/s,处理效果明显。     

地质雷达在防渗墙检测中的应用

水库堤坝中的防渗墙属于隐蔽型的重要水利工程,坝体的结构层形态复杂多变,探测难度大,为确保水库堤坝安全可靠地运行,采用高分辨率的物探方法对其探测是必需的.基于地质雷达检测技术,以某水库堤坝检测为实例,通过RADPR0软件对地质雷达资料进行处理,并对该雷达图像做出合理的地质解释,从而查明墙体内可能存在的不连续地段,以便及时...     

土石坝下伏基岩交错断层导水示踪研究

 截至2007年,深圳一水库实际渗漏量是设计渗漏量的10倍,渗流情况非常复杂。为找出渗漏量偏大的原因并确定渗漏通道的位置,运用综合分析法研究坝体的渗流情况。首先采用示踪法得到坝体温度场和流速场,找出渗漏异常区;其次通过温度异常区和测压管资料分析,得出渗漏区主要处于基岩中,并存在集中渗漏通道的可能;最后综合水库水文地质条件以及坝体施工过程,确定土石坝下伏基岩交错断层为渗漏主通道,在此基础上建立水库渗漏概念模型。综合分析方法能克服单一方法的多解性,是水库渗漏探测的有效方法,具有一定的工程意义。     

水利堤坝工程防渗加固施工技术

<正>一、引起堤坝渗漏的原因(一)坝体裂缝坝体裂缝是常见的造成坝体渗漏的原因之一。由于在水坝蓄水的过程中大量势能累计,使坝体难以承受巨大的水压,从而导致坝体出现裂缝。(二)渗漏管破裂渗漏管破裂会致使坝体本身渗漏程度加重,由于坝体内部本身设有具备一定排水功能的渗漏管,一旦渗漏管出现破裂,则无法稳定调节渗漏的速度,使坝体受水流侵蚀加快,从而产生危害。(三)年久失修因为坝体年久失修,导致坝体质量下     

隔河岩水电站厂房后边坡与拱坝的相互作用研究

以边坡稳定性和坝体的应力校核为目的,分别建立边坡和坝体的数值模型;采用试算迭代的方法,对边坡和坝体的相互影响做出评价。分离同步建模和迭代试算联合使用,不仅节约建模时间,还可极大地降低建模的难度。为更好地模拟施工过程,反映坡体和坝体的应力和变形过程,在边坡开挖、卸荷、加固工况计算已完成的基础上进行坝体推力施加的分析;同时还考虑边坡上游面的水库水压力作用。分析结果表明,坝体与边坡的相互作用并不大,坝体推力对边坡位移的影响在坝肩周围30m范围内,该作用并不影响边坡和坝体的整体稳定。上述结论不仅可论证坝体设计的合理性,也为边坡和坝体的安全运营提供一定的参考。     

某水电站大坝二枯碾压混凝土坝体局部补强灌浆处理

某水电站大坝工程二枯施工的碾压混凝土局部坝体取芯效果差,进行了坝体局部补强灌浆,并进行了坝体局部补强灌浆处理效果分析评价,大坝蓄水后坝体运用情况良好。     

土坝渗透稳定可靠性分析方法及应用

采用确定性分析方法分析土坝渗透稳定的理论和方法已经较为完善,但它由于没有考虑坝体材料参数的变异性,因此得出的安全分析成果并不能完全可靠地表征其安全性。利用概率与统计的方法对土坝渗透稳定进行可靠性分析则可考虑坝体材料等一些不确定因素对土坝的渗透稳定影响。首先利用统计方法对坝体材料物理参数进行分析,得出了参数的概率分布类型,然后运用可靠性分析原理,构造土坝渗透破坏功能函数,分析土体有效重度、内摩擦角,坝体、坝基材料渗透系数对功能函数的影响,并采用几何法对坝体渗透破坏可靠指标进行计算,得出坝体发生渗透破坏的概率。利用上述方法对一土坝渗透稳定进行了分析。结果分析表明,坝体渗透破坏的概率随着土体有效重度和内摩擦角变异性的增加而增加,并且土体内摩擦角的变异性对坝体渗透破坏的影响较大,坝体渗透变异性对坝体渗透破坏的影响较大;另外,随着库水位的升高,坝体发生渗透破坏的概率也显著增加。     

Zustandsuntersuchung und Instandsetzung am Hauptdach des Hauses der Kulturen der Welt in Berlin

The main roof of the ”Haus der Kulturen der Welt“ in Berlin Which is very well‐known on account of its history and striking structural design – was to be inspected by the author to determine its condition and analysed with regard to the durability of the existing liquid synthetic sealant. The roof structure consists of a biaxial, curved area‐covering structural element with circumferential edge beams of pre‐stressed lightweight concrete. This is the result of the reconstruction between 1984 and 1987 following a partial collapse of the then Berlin Congress Hall in 1980. The very thin roof shell is also made of lightweight concrete and, like the edge beams, has a polyurethane‐based spray‐on seal that was specially developed for this purpose as protection against the ingress of moisture. The reason why this, at the time, novel type of seal was chosen was that it should take into account the fact that the roof design urgently needed some kind of protection against moisture that had to compensate the expected changes shape and crack movements of the roof with no damage. The following article reports on the nature, scope and main results of the analysis of the condition of the roof seal, edge beams and abutments. It will also describe the repair recommendations resulting from the investigations, which form the basis of the execution of work at the present point in time. Apart from presenting the technical principles and special features of the building that have to be taken into account during any repairs, the special features of the execution will also be addressed.     

Magnetoelastische Spannkraftmessung in Bauwerken

Magnetoelastic Measurement of Prestressing Force in Civil Structures The knowledge of the tensile force of prestressing steel elements and its reliable and non‐destructive determination are of essential importance for the assessment of the structural health condition of prestressed concrete structures and tie‐back systems in terms of structural safety, serviceability and durability. For the evaluation of the prestressing force in steel tension members, the measurement technique presented in this contribution is using the magneto‐elastic effect (ME‐effect) of ferromagnetic materials. This effect describes the reverse‐proportional correlation between the mechanical stress and the magnetic properties of ferromagnetic materials. The cylindrical coiled sensors pushed over the tendon and the measuring device developed and practically optimized at the iBMB/MPA of the TU Braunschweig enable a fast and reliable measurement of the prestressing steel force after an initial calibration. In this contribution first the state of the art of prestress measurement techniques for steel tension members is presented. Afterwards, the ME‐measuring method with the basics and merits of magneto‐elastic prestressing force identification is shown. Further recent research results as well as several building applications will be discussed.     

谈贯标中企业如何做好检验和试验工作

根据在贯彻GB／T 19001－ISO9000族标准过程中的实际工作经验,从贯彻中为什么要抓好检验和试验工作入手,对检验和试验依据的管理,检验和试验设计的控制,检验和试验人员的培训,检验和试验记录的填写,保存和分析四个方面进行了论述,阐述了检验和试验工作在贯标中的重要性。     

Colour and turbidity removal with reusable magnetite particles—VII: A colloid chemistry study of the effect of inorganic ions on the efficiency of clarification

The removal of colour and turbidity from natural waters by the addition of magnetite is an interfacial process. Furthermore the components of this system are either of colloidal dimensions or of a surface active nature and thus this method of water clarification is very much in the realm of surface and colloid chemistry. Electrokinetic techniques have been used to examine the influence of a number of inorganic species, commonly encountered in the practical situation, on the surface properties of magnetite and consequently on the efficiency of the process.     

Alternative Methods of Procurement for Works of Water and Environmental Management

The paper considers methods of procurement for the construction of water- and sewage-treatment works other than the traditional use of the ICE 5th Edition Conditions of Contract and Bills of Quantities. This is as a consequence of the speed at which schemes are currently required within the water industry.
The paper particularly focuses on the use of target contracts, using the Institution of Chemical Engineers'Green Book form, and considers various types of target. It also discusses the form which tender documents may take, and how targets may be calculated.
Tendering procedures, including the use of two-stage tenders and negotiated targets, are considered, as are the procedures for cost monitoring and the financial management of the contract. Finally, the role of the engineer and quantity surveyor is considered.     

斜坡失稳的突变模型与混沌机制

针对斜坡平在滑动失稳问题,运用突变理论方法,给出了快速滑坡和慢还滑坡发生的判据,提出了刚度效应失稳新理论,指出刚体极限平衡稳定性评价方法有较大缺陷;根据建立的斜坡演非线性动力学模型,发现外部环境因素的作用一斜坡系统的响应有复杂的非线性关系,当斜坡本身的非线性作用与外部环境因素的作用能力相当时,斜坡化过程会出现混沌现象,其通向混沌之路是通过倍周期分叉实现的。     

Erfahrungen bei der Beurteilung der Dauerhaftigkeit vorgespannter Bewehrung von älteren Spannbetonbrücken

Experiences due to the evaluation of the durability of prestressed reinforcements in old prestressed concrete bridges. Old prestressed concrete bridge superstructures exhibiting cracks across the prestressed reinforcement need detailed inspections for estimating maintenance requirements. Only this type of evaluation makes it possible to determine the required extent and nature of maintenance. In this paper essential steps of the “Directive of the durability of prestressed reinforcements in old prestressed concrete bridge superstructures” of the Federal Highway Research Institute are explained, also against the effects of growing heavy traffic with expected higher gross weights and axle loads.     

景框的中介——电影与建筑中的动态布局

本文探讨了作为电影和建筑中的一个主要空间构成主题——景框理念。对空间的电影几何关系和建构几何关系的设置.体块、空间、视角、景观、相机和演员的相对位置和组织等.会产生特殊的张力、关系和动态——所有这一切都指向景框所带来的触媒作用和示能作用。电影与建筑中的空间是许多潜在的力量和相互作用的动力场,它涉及对空间景框、机制和策略的部署与调控,由此实现构成的、语义的和叙事的目的。景框建立了边界,但也促进并提醒可能会遇到的那些模棱两可、针锋相对与制约的突破.以及一种呈现怪诞特征的潜力。     

A Survey of Ferruginous Minewater Impacts in the Welsh Coalfields

The aim of this study was to locate all ferruginous discharges within the Welsh coalfield areas and to assess their impact upon receiving watercourses. The project was undertaken in two stages. In the first stage, visual assessments were carried out on an area of river bed affected by iron hydroxide deposition. Chemical samples of the discharges and the receiving watercourse were analysed for a suite of physico-chemical determinands. Ninety discharges were located impacting upon 59.4 km of river, and an area of 22 ha was affected by iron hydroxide deposits.
A ranking method, incorporating the physical/chemical determinands, was developed to assess the comparative impact which discharges were having on receiving watercourses. A total of 33 of the top ranked discharges- (20 to classified watercourses and 13 to unclassified watercourses) having the highest environmental impact were selected; chemical, biological and fisheries impact assessments were then carried out on these discharges in the second stage of the project. The sites were then ranked on the basis of biological and fisheries impact. A list of the highest impacted sites was produced, and some of these were further investigated for remediation options and associated costs.