白沙水库设计洪水复核探析

设计洪水复核是水库管理工作中的重要课题,也是病险水库除险加固的的基本环节之一,对设计洪水复核成果进行分析,探索科学合理的设计洪水计算方法,最大限度的发挥水库的综合效益意义重大。通过对白沙水库建库以来历次洪水复核的成果进行比较分析,寻求适宜的设计洪水计算方法,提出水库设计洪水复核中应注意的一些问题。     

黄泥田水库洪水复核方法分析

根据贵州省病险水库大坝安全复核的要求,洪水复核作为水库安全复核的重要一环,显得尤为重要。洪水复核就是对原设计洪水成果的复核,由于余庆县绝大多数小型水库始建于20世纪60—70年代,由群众投工投劳修建,没有设计,也无施工记录等档案资料,加上这些水库运行年限较长,导致水库不能正常运行,工程效益不仅不能发挥,而且威胁到人们的生命和财产安全。结合贵州省余庆县黄泥田水库大坝安全复核,分析了山区小型水库的洪水复核,指出了今后洪水复核应注意的问题,并提出一些建议,以供参考。     

双库调洪演算在大坑水库的应用研究

设计洪水复核对水库的安全至关重要,在设计洪水复核过程中,遵循"多种方法、综合分析、合理选用"的原则,为水库工程提供切合实际和可靠的洪水复核成果.该文以大坑水库为例,针对大坑水库由2个小(一)型水库连通组成的特点,探讨双库调洪演算算法,对大坑水库设计洪水复核进行研究,为水库工程的抗洪能力评价和日常运行调度提供基础依据.     

新疆中葛根水库设计洪水复核及合理性分析

水库工程运行期间,受各类因素影响易产生安全隐患。为提升水库工程的安全性,对其进行洪水复核。结合新疆中葛根水库实况,对基本资料进行搜集、整理和复核,选择具体计算方法,总结复核过程中需要注意的问题,并对复核的合理性进行分析。从相应的设计洪峰流量和各个时段具体洪量成果以及相关参数、地区性综合检查和水库工程各个阶段相应的设计成果三个方面进行合理性分析,为水库设计洪水复核提供借鉴。     

水库工程除险加固设计中的水文形势及洪水复核问题

针对目前水库工程除险加固设计水文计算工作所面临的形势和特点，展开分析，论述洪水复核应注意的问题。     

水利水电工程除险加固中的设计洪水复核

随着经济社会的高速发展、大江大河大湖的初步治理、水库工程的建设等,我国已初步形成了一个较为完整的防洪减灾体系.目前,我国已建成各类水库9万余座,仅长江流域截止1990年即建成大中小型水库4万余座,总库容1 415.6亿m3.在水利水电工程除险加固设计中,设计洪水复核对工程的安全及除险加固的规模至关重要.阐述洪水复核的基本任务和一般思路,强调基本资料在复核中的重要作用,并应注重分析人类活动影响、建库后产流汇流特性的变化及其对洪水的影响,在设计洪水复核过程中,遵循"多种方法、综合分析、合理选用"的原则,为工程除险加固提供切合实际和可靠的洪水复核成果.     

小型水库防洪监测预警预报方法探讨

近年来,小流域暴雨洪水频发,对众多小型水库度汛安全造成严重威胁。本人就最大限度地发挥非工程措施在小型水库防御暴雨洪水工作中的重要作用,重点阐述了小型水库的复核计算、防洪预案的反演算、暴雨洪水监测、预警、预报方法及应注意的事项,可供小型水库相关技术人员参考。     

江西省水库安全鉴定中防洪复核若干问题探讨

水库防洪能力复核是水库安全鉴定中的重要工作.本文对水库防洪复核遇到和忽略的问题进行了总结,从资料收集与现场检查、基础资料复核、洪水标准、设计洪水、调洪演算和抗洪能力复核等方面展开讨论,旨在为今后水库大坝的防洪安全复核提供参考.     

地区综合法在无资料地区防洪工程洪水复核中的应用

对无实测水文资料的中小型水利工程的洪水复核工作,选择地区暴雨推求设计雨量的计算方法,是推求设计洪水工作中必须论证的问题,不同的推求方法会影响到洪水复核工作的最终成果。通过大量的水库洪水复核工作,得出了地区综合法在无资料地区水利工程洪水复核中的广泛应用,其资料准确、方法简单。     

岩垱水库除险加固设计洪水分析

采用暴雨资料及暴雨图表等方法对设计洪水进行复核,为岩垱水库除险方案和加固措施提供依据.在复核过程中,通过对暴雨特性、暴雨频率分析,利用设计点暴雨、设计雨型和设计面暴雨计算成果,采用扣损法进行产流复核分析,瞬时单位线法进行汇流复核分析,从而确定岩垱水库除险加固工程的设计洪水.通过与原设计洪水成果和地理位置邻近的其他水库洪水成果的对比分析,以及岩垱水库除险加固竣工投入运行3年来,经受住了洪水考验的事实说明本次洪水复核计算成果较为合理.     

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.     

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.     

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。     

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.     

Automated system for removal and pneumatic transport of fly ash from electric precipitator hoppers

A system for removal and pneumatic transport of fly ash is examined, in which air pulses act on batches (pistons) of ash formed in a duct. Studies are made of the effect of several physical parameters on the force required to displace a piston of ash and these serve as a basis for choosing a system for removal and pneumatic transport of ash simultaneously from several hoppers of an electric precipitator. This makes it possible to separate the ash particles according to size without introducing additional components. Formulas are given for calculating the structural and dynamic parameters of this system and measurements of indirect dynamic parameters are used to calculate the input-output characteristics of the system. In order to optimize the system, configurations for summing several ducts into a single transport duct for pneumatic ash transport are proposed. Some variants of dry ash utilization and the advantages of producing of size-separated particles are considered. __________ Translated from élektricheskie Stantsii, No. 2, pp. 26–30 (2008).     

The flood pulse advantage and the restoration of river-floodplain systems

The ‘flood pulse advantage’ is the amount by which fish yield per unit mean water area is increased by a natural, predictable flood pulse. Evidence for this increase is presented from tropical and temperate fisheries. It is argued that increasing multispecies fish yield by restoring the natural hydrological regime is consistent with increasing production of other trophic levels and with restoration from ecological and aesthetic viewpoints. When applied to a river-floodplain system, this restoration would provide a large, self-sustaining potential for recreation, commercial exploitation, and flood control. An interim ‘natural flood pulse’ restoration approach is proposed for systems modified for navigation. This approach approximates the natural hydrological regime in a river reach and is intended as a first step in the long process of restoring the watershed.     

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.