涂膜防水屋面的质量控制与施工

涂膜防水屋面的质量控制在施工过程中有着重要的作用,本文分析了涂膜防水屋面的质量要求并提出了提高涂膜防水屋面质量的措施,为工程施工提供参考。     

用刚柔结合的方式处理高原屋面防水取得好效果

一般常规屋面的防水处理，大都采用柔性防水屋面或刚性防水屋面．所谓柔性防水屋面的一般作法是：在屋面找千层上先做冷底子油结合层，再在上面做两毡三油防水层，上铺绿豆砂保护层．所谓刚性防水屋面的一般作法是：在屋面找平层上，做40～60mm厚的钢筋混凝土防水层（内配公4～6的双向钢筋网），并按开间或一定的结构尺寸分块，分隔缝用沥青油膏填满．由于羊湖电站地处高原，具有空气稀薄、日照时间长，昼夜温差与四季温差较大，气候特别干燥等特点，柔性屋面夏季易流淌、冬季易冻裂，刚性屋面分隔缝处也是夏天流淌厉害，冬天缝隙加大．无论…     

谈建筑屋面的防水设计

首先提出了建筑屋面防水设计的重要性,进而通过建筑屋面防水的设计原理、建筑屋面排水组织的步骤及建筑屋面的构造层次等方面阐述如何进行合理的建筑屋面防水设计,从而为解决屋面的渗漏问题提供必要的前提和基础。     

防水材料的选用及发展方向

防水材料的选用要根据防水等级、防水方案来确定设防道教和厚度.本文以屋面防水为例,阐述了防水材料的选用及发展方向.     

水口水电站厂房屋面防水层施工

文中介绍屋面防水施工，着重介绍了“８５１”涂膜防水胶和ＣＰＥ防水卷材的施工工艺。     

寒冷地区房屋保温和屋面防水新思维

针对寒冷地区屋面新老结构不同做法的实际情况 ,提出了对三毡四油防水、珍珠岩保温旧作法的改造条件 ,并分析了这一旧方法的弊病 ,并建议了采用苯板保温、镀锌铁皮防水的寒区屋面保温防水新作法。     

屋面防水施工质量控制

屋面渗漏、防水效果不佳是建筑工程中存在的质量通病,也是多年来一直未能很好解决的难题。它严重影响建筑物的正常使用,侵蚀建筑物结构主体,同时给人民的生产、生活带来诸多不便和不必要的经济损失。本文将分析当前屋面渗漏、防水存在的问题,针对存在的问题,探讨屋面防水的施工技术及施工质量保障措施。     

屋面倒置式防水新工艺在莲花电站厂房中的应用

建于东北高寒地区的厂房建筑物,如何根治冬季屋面积雪冻融结冰,致使防水材料破坏,导致屋面漏水这一难题,目前国内尚无成熟经验。通过大量的资料分析、调研和现场试验,我们总结出适合寒冷地区建筑物屋面防水新工艺。本文将阐述地处高寒地区的莲花水电站厂房屋面采用倒置式防水新工艺成功应用情况,可供类似工程借鉴。     

屋面防水施工质量控制

屋面渗漏、防水效果不佳是建筑工程中存在的质量通病,也是多年来一直未能很好解决的难题。它严重影响建筑物的正常使用,侵蚀建筑物结构主体,同时给人民的生产、生活带来诸多不便和不必要的经济损失。本文将分析当前屋面渗漏、防水存在的问题,针对存在的问题,探讨屋面防水的施工技术及施工质量保障措施。屋面渗漏、防水层的耐用年限短是目前工程质量中出现的比较严重的问题、防水质量的低劣是造成渗漏的最直接的原因。影响渗漏的因素是多方面的,在施工中人们往往忽略了选材、设计、管理维护,以致给工程质量留下后期隐患。近年来,虽然各种新型防水材料相继问世,但由于价格较高,缺乏施工经验,且耐久性还有待于进一步检验等原因,目前还是以采用较为廉价的材料为主。采用刚性防水和柔性防水相结合的办法,理论上可提高屋面的防水,而在实际施工中,或多或少地存在一些不够重视底层刚性防水层的现象,使得刚性防水层开裂,起鼓或渗漏,这样刚性防水层形同虚设,加上柔性防水层也存在其自身的缺点,因而"双重保险"也不能有效防止屋面渗漏。     

住宅工程屋面渗漏防治

住宅工程屋面渗漏是一个长期困扰人们的质量通病,防治应以防为主治为辅.但是要真正攻克这一通病,还应从多角度研究对策措施.这里从屋面防水等级、防水节点详图、保温设置提出一些想法.     

Call for Papers

正As the eldest and most distributed professional journal of water industry,Water Wastewater Engineering(W WE)gained very wide acceptance from the colleagues working in this field in this country since start publication in 1964.Now it is administrated by the Ministry of Construction of the People’s Republic of China and sponsored by the China Civil Engineering Society etc.     

地下厂房施工过程的三维非线性数值模拟分析

根据冗各电站地下厂房开挖支护的施工顺序,以隐式杆单元模拟锚杆,以壳单元模拟混凝土喷层,采用三维非线性有限元技术,对洞室群的开挖支护动态过程进行了模拟计算。通过三维非线性有限元计算分析得到:洞室群动态开挖过程中围岩应力变形的分布规律,围岩塑性区的发展规律,锚杆受力变化情况。计算结果表明:整个开挖过程中,洞周围岩位移变化规律正常,量值较小,塑性区主要分布在洞室周边,围岩稳定性较好;但在洞室交叉口处围岩的变形较大,出现较大范围的塑性区,在此基础上提出了支护措施优化方案,并对优化方案的效果进行了评价。     

Evaluation of freshwater mussel relocation as a conservation and management strategy

The relocation of unionacean mussels is commonly used as a conservation and management tool in large rivers and streams. Relocation has been used to recolonize areas where mussel populations have been eliminated by prior pollution events, to remove mussels from construction zones and to re-establish populations of endangered species. More recently, relocation has been used to protect native freshwater mussels from colonization by the exotic zebra mussel Dreissena polymorpha. We conducted a literature review of mussel relocations and evaluated their relative success as a conservation and management strategy. We found that 43% of all relocations were conducted because of construction projects that were forced to comply with the Endangered Species Act 1973 and that only 16% were monitored for five or more consecutive years. Most (43%) relocation projects were conducted from July to September, presumably a period when reproductive stress is relatively low for most species and the metabolic rate is sufficient for reburrowing in the substrate. The mortality of relocated mussels was unreported in 27% of projects; reported mortality varied widely among projects and species and was difficult to assess. The mean mortality of relocated mussels was 49% based on an average recovery rate of 43%. There is little guidance on the methods for relocation or for monitoring the subsequent long-term status of relocated mussels. Based on this evaluation, research is needed to develop criteria for selecting a suitable relocation site and to establish appropriate methods and guidelines for conducting relocation projects.     

基于模型试验的河床砂砾石层基本特性研究

为了经济可靠地确定深厚覆盖层的基本特性参数,以大渡河双江口水电站坝基河床砂砾石层基本特性研究为工程背景,进行大尺寸模型试验,研究河床砂砾石层的旁压模量和动探击数随密度、级配以及上覆压力的变化规律。根据室内模型试验结果,结合现场旁压试验及钻孔试验成果,推断出坝址区河床砂砾石相关层位的密度,并依此进行砂砾石室内力学试验,获得设计所需力学参数。研究成果可为深厚覆盖层基本特性测试提供新的方法。     

SPATIAL AND TEMPORAL WATER QUALITY VARIABILITY IN AQUATIC HABITATS OF A CULTIVATED FLOODPLAIN

The floodplains of lowland rivers contain diverse aquatic habitats that provide valuable ecosystem services but are perturbed when intensively cultivated. Hydrologic, water chemistry and biological (fish) conditions in five aquatic habitats along the Coldwater River, Mississippi, were measured for more than 4 years: the river, two severed meanders that functioned as backwaters, a managed wetland and an ephemeral channel draining cultivated fields. Off‐channel habitats were connected to downstream regions 0.10% to 32% of the dry season and 24% to 67% of the wet season. The median temperatures for the five monitored sites ranged from 18°C to 23°C, the median total solids concentration for all sites was 135 mg L^?1, the median total phosphorus was 0.29 mg L^?1 and the median total nitrogen was 1.56 mg L^?1. Chemical and physical water quality displayed strong seasonal differences between the wet winter/spring and the dry summer/fall periods so that temporal variation consisted of gradual seasonal trends superimposed on strong diurnal variations. All off‐channel habitats exhibited periods of hypoxia and temperatures >30°C during the dry season. Between‐site gradients of water and habitat quality were strongly coupled to water depth and runoff loading. The rehabilitation of one backwater by increasing water depth and diverting agricultural runoff was associated with improved water quality and fish species richness relative to an adjacent untreated backwater. The diversion of polluted runoff and the use of water control structures to maintain greater water depth were observed to be effective management tools, but the former reduces the water supply to habitats that tend to dry up and the latter reduces connectivity. Published in 2011 by John Wiley & Sons, Ltd.     

库水波动下库岸边坡地下水浸润线解析解及误差分析

解析法是库岸边坡地下水浸润线计算中便于实际应用的方法,但该方法须基于若干假定并对潜水运动基本方程线性化后才能求解。针对各假定和线性化过程建立不同的地下水渗流数学模型,用解析法和有限元法解答上述数学模型,分析各误差大小及其规律。结果表明：库岸垂直处理带来的误差要小于方程线性化处理和不考虑非饱和渗流带来的误差,而且它们都随渗透系数变大而减小;在三峡库区库水调度情况下,假定库水位等速变化带来的误差对大多岸坡而言可以忽略;计算库岸边坡地下水浸润线时,解析法只适用于水位变化幅度相比含水层厚度较小,且几何边界规则、岩土结构简单、岩土体渗透性较好时的情况。     

Changes in Summer Irrigated Crop Area and Water Use in Southeastern Turkey from 1993 to 2002: Implications for Current and Future Water Resources

Changes in summer irrigated cropland acreage and related water use are estimated from satellite remote sensing and ancillary data in semi-arid Southeastern Turkey where traditionally dry agricultural lands are being rapidly transformed into irrigated fields with the help of water from the Euphrates-Tigris Rivers. An image classification methodology based on thresholding of Landsat NDVI images from the peak summer period reveals that the total area of summer irrigated crops has increased three-fold (from 35,000 ha to over 100,000) in the Harran Plain between 1993 and 2002. Coupled analysis of annual irrigated crop area from remote sensing and potential evapotranspiration based estimates of irrigation water requirements for cotton indicate a corresponding increase in agricultural water use from about 370 million cubic meters to over one billion cubic meters, a volume in accordance with the state estimates. These estimates have important implications for understanding the rapid changes in current agricultural withdrawals in Southeastern Turkey and form a quantitative basis for exploring the changes in future water demands in the region. For example, expansion of irrigated lands have led to a steady decrease in potential evaporation due to increased roughness and decreased humidity deficit in the Harran Plain. Assuming that the changes in future evaporation conditions will be of similar nature, water use for irrigation is expected to decrease over 40 percent in future irrigation sites. Incorporating this decrease in overall planning of the irrigation projects currently under construction should lead to improved management, and by extension, sustainability of water resources in the region.     

基于BP神经网络-马尔科夫链模型的隧道围岩位移预测

在隧道工程施工中,围岩位移预测起着很重要的作用。将BP神经网络-马尔科夫链模型引入到隧道围岩位移预测中来,通过对训练样本的学习,利用BP神经网络实现了对位移时间序列的滚动预测,同时得到了实测值与预测值的相对误差;在此基础上利用马尔科夫链对相对误差进行修正,有效地提高了预测结果的精度。并将该模型应用于某公路隧道拱顶下沉位移时序预测中,结果表明该模型具有精度高、科学可靠的特点,为隧道围岩变形的预测提供了新的途径。     

Short communication. Pipelines as a refuge for freshwater snails

In the lower River Murray, Australia, populations of gastropods have declined markedly over the past 40 years. Of the native fauna of about 18 species, only the ancylid Ferrissia petterdi remains common (but in patches), and another five species feature in sporadic local resurgences. Until recently the viviparid Notopala was thought to be extinct. The introduced physid Physa acuta is widespread, but in low numbers. The decline probably is associated with flow regulation, high turbidity and the introduction of common carp. Snail populations have persisted, however, in irrigation pipelines fed from the river, where they periodically cause blockages. This paper reports the discovery of the only known populaion of Notopala hanleyi in a pipeline where the inner wall accumulates microbial and other organic matter, providing high quality food for snails. In the Murray before regulation most of the periphytic biomass was probably microbial, as fluctuating water levels would have maintained littoral communities in a highly productive, early state of succession his postulated that, by stabilizing seasonal water levels, regulation has promoted the production of filamentous green algae, an inferior food source, and so displaced snail populations from the open aquatic environment.     

Spatio‐temporal variation of gross CO2 and CH4 diffusive emissions from Australian reservoirs and natural aquatic ecosystems,and estimation of net reservoir emissions

Carbon dioxide (CO₂) and methane (CH₄) diffusive emissions were measured during two field surveys in Queensland and Tasmania, Australia, using the floating chamber method. Bubbling and degassing emissions in 2010 were estimated in Koombooloomba Dam reservoir using only inverted funnels and gas concentrations, respectively. A total of 14 reservoirs and 16 rivers and lakes were sampled from 2006 to 2010. Spatial variation was substantial within each water body, as well as between them. The main drivers of diffusive emission variation were physiographic region and climate, with a clear demarcation being observed between diffusive emissions from tropical Queensland and temperate Tasmania, and between the humid West Coast Range (Tasmania) and dry Central Plateau (Tasmania). Higher CO₂ and CH₄ diffusive emissions were observed during the dry season, when long water residence times would promote organic matter degradation. Estimated total gross emissions, including diffusive, bubbling and degassing emissions, for Koombooloomba Dam reservoir were about 1.5 × 10⁶ t CO₂eq km² per year, or 24 × 10⁶ t CO₂eq per year. This corresponds to a plant emission factor of 3.18 kg CO₂eq MWh^?1. Using an estimate of terrestrial emissions derived from literature data for the Tully River catchment area, rough estimated net emissions from the catchment area are about 44 kt CO₂eq per year, or 5.83 kg CO₂eq MWh^?1, which is in the lower range of the studied reservoirs.