量化评价模型在万家屯水库除险加固效果评价中的应用

当前关于病险水库加固效果的综合评价理论和模型较少,从而使得无法系统、全面的反映加固工程的效果。据此,文章从效益、工程技术、方案设计和康复程度等因素出发,提出加固效果评价指标量化方法和影响因素的"积木模型",探讨静态、动态、主客观权重以及时效与非时效指标量化方法,从而构建量化的加固效果评价模型。将万家屯水库加固工程选用该模型评价,工程验收结论、加固实际状况与评价结果保持较好的一致性。     

大坝综合评价指标专家主观权重的计算方法

水库大坝除险加固评价时采用专家打分的方法,往往忽略了不同专家间权威性的差异。本文提出了考虑专家权威性的病险水库加固评价专家主观权重的计算方法,从硬指标(包括资历、学术成果等)和软指标(包括评价实践经验、专业熟练程度和职业道德等)来衡量专家的权威性,并通过模糊优选理论确定各专家相对应的主观权重值,以权威优属度作为专家权威性的评价指标,增大权威性高的专家在水库大坝除险加固效果评价中的权重;通过归一化处理,得到参与加固效果评价的各位专家的权重向量;将专家主观权重计算方法与专家的客观权重计算方法配合使用,获得特定指标的专家综合权重,进而可对病险水库加固效果进行科学的评价。     

基于功能康复程度信息模型的病险水库除险加固效果评价

通过分析水利工程除险加固效果的关键性因素,从防洪安全、渗流稳定、结构稳定、工程地质与质量、金属与电气结构安全、抗震安全、运行管理等方面建立水库功能康复评价体系,结合指标的时效非时效、定性定量关系进行信息量化,并依据时变特征计算各指标的组合权重、动态与静态权重。然后在指标康复等级提升模型中引入Logistic方程的安全度曲线,通过信息输出实现综合评价。研究表明:在水利工程除险加固效果评价中功能康复程度信息模型具有较强的有效性与科学性,评价结果能够客观、全面的反映水库大坝加固的实际状况。     

基于风险的病险水库除险加固方案优化技术

目前病险水库的除险加固设计只偏重于工程治理措施,倾向于水库大坝工程的安全,未考虑除险加固设计方案对下游居民安全、社会经济、城镇交通等的风险以及对自然环境的影响。因此,基于风险分析的除险加固优化技术对于今后病险水库除险加固方案是有效和必要的。本文参考国外病险水库大坝安全和除险加固风险分析理论的最新进展,结合我国病险水库大坝和除险加固技术的特点,进行了除险加固方案与大坝风险关联分析与决策、除险加固方案评价指标分析和基于风险分析的除险加固方案优化技术的研究,提出了基于风险的病险水库除险加固方案的评价、分析和优化方法,为今后病险水库除险加固工作提供技术支撑。     

病险水利工程除险加固效果评价研究进展

除险加固效果评价是目前国内病险水利工程除险加固项目后评价中急需解决的关键问题。针对综合评价所需的指标体系和方法体系,从宏观定性评价、单一效能量化评价、综合评价指标体系、指标权重、评价等级划分及确定等方面,综述了病险水利工程除险加固效果评价的研究进展。认为今后应构建能兼顾病险水利工程除险加固治理效果通用性和特殊性的综合评价指标体系,建立除险加固效果评语集、评价指标权重和等级隶属度三方面的云模型,并强化除险加固效果评价中的可持续发展效应。     

基于云模型的病险水闸除险加固效果综合评价

病险水闸除险加固效果评价是一个复杂的系统工程,其评价指标信息、权重和评语集均具有模糊性与不确定性。为了对病险水闸除险加固效果进行综合评价,根据《中央政府投资项目后评价管理办法》,建立了包含5个一级评价指标和21个二级评价指标的综合评价指标体系,拟定了百分制下的评价等级划分标准。在此基础上,引入云模型理论,建立了权重云模型、评语集云模型和评价指标信息云模型,进而利用云模型的数字特征来量化评价过程中不确定性的传播效应和评价结果的可信性及稳定性。太浦闸实例分析验证了此方法的可行性与实用性,结果表明权重的不确定性对评价结果有较大影响,该闸除险加固效果处于“效果极佳”等级,与实际情况相符。提出的评价指标体系和云模型评价方法可用于其他病险水利工程的除险加固效果评价中。     

基于AHM的水库除险加固排序方法研究

在水库大坝风险评价概念的基础上,利用层次分析模型方法对病险水库溃坝后果综合系数进行了定量分析。结果表明:应以生命损失的权重系数来控制溃坝后果综合系数,从而获得病险水库的风险量化指数,为病险水库除险加固排序提供依据,使风险大的水库能优先得到除险加固。     

大坝除险加固效果评价的时效性指标量化模型

大坝除险加固效果评价指标包括时效性指标和非时效性指标两类,时效性指标的量化是进行大坝除险加固效果定量评价的关键。针对现有大坝除险加固评价体系中时效性指标量化理论较为缺失的问题,基于无量纲化的定量时效性指标,研究了大坝性态变化以及指标等级变化对时效性指标评价的影响,推导了安全度和等级提升系数的公式,进而建立了时效性指标量化模型。以江西某水库除险加固为例,分析除险加固前、后各时效性指标的变化情况,并对模型的合理性进行了验证。结果表明,应用本文建立的大坝除险加固时效性指标量化模型可合理评价除险加固过程中的时效性指标。     

基于模糊灰色聚类-组合赋权的病险水库康复度综合评价方法

针对目前除险加固后病险水库康复度难以准确评价的问题,构建了两层评价指标体系,结合模糊灰色聚类和组合赋权法对病险水库康复度进行量化评价。基于熵权法和层次分析法分别计算各康复类型评价指标的主、客观权重,采用组合赋权法将主、客观权重进行组合,得到能反映主客观影响的组合权重;采用灰色聚类法评价水库各康复类型的康复度,依据病险水库各康复类型聚类系数及组合权重创建综合评价的模糊判断矩阵,依据模糊判断矩阵由熵权法和层次分析法求出各康复类型的权重后采用组合赋权法进行组合,最终采用模糊综合评价法评估病险水库除险加固后的康复度。将该方法用于3座病险水库康复度评价,评价结果与水库除险加固实际情况及验收结论吻合,表明该方法具有一定的工程应用价值。     

基于改进灰靶模型的兰窝水库大坝安全性态评价研究

大坝的定期安全评价,对确保水库大坝安全运行具有重要意义。文章以辽宁省兰窝水库大坝为例,通过对传统灰靶模型的缺陷分析,引入指标权重实现对模型的改进,构建起基于指标权重的改进灰靶评价模型。利用改进后的灰靶模型对兰窝水库大坝安全性态进行评价,结果显示加固前的兰窝水库大坝为三级,属于病险状态,需要进行加固处理;加固后的兰窝水库大坝属于一级,属于健康状态,大坝的除险加固措施是必要的和有效的。     

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.     

Serial discontinuities in a Rocky mountain river. I. Distribution and abundance of plecoptera

Samples were taken year-round at eleven sites along the altitudinal profile (2900-1400 m a.s.l.) of the Gunnison River, a 329 km tributary of the Colorado River, to document the distribution of the Plecoptera and to evaluate responses to hypolimnial-release dams in the headwaters and middle reaches. Twenty-two species were present, with the greatest species richness occurring in an unregulated segment upstream of the middle reach dams; average nymphal biomass over the study period (175 organisms, 395 mg dry mass m^?2) was also greatest in this segment. Only four species (58 organisms, 48 mg m^?2) were present in the tailwaters of the headwater dam and values were greatly reduced (nine species; 35 organisms, 180 mg m^?2) below the middle reach dams. The stonefly community recovered ca. 80 km downstream from the last dam (15 species; 244 organisms, 250 mg m^?2), apparently in response to natural resetting of environmental conditions corresponding to those above the middle reach dams. At the most downstream site (11) only four species (four organisms, 16 mg m^?2) were present. The observed distributional pattern is a classic serial discontinuity in response to hypolimnial stream regulation in a temperate latitude river.     

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。     

Impacts of Microcystis on algal biodiversity and use of new technology to remove Microcystis and dissolved nutrients

Cyanobacteria often dominate eutrophic lakes, outcompeting green algae that are required by fish and zooplankton. This study was undertaken to ascertain the impact of the cyanobacterium, Microcystis, on algal biodiversity. Under laboratory conditions, we found that the presence of Microcystis decreased phyla richness by 58%, phyla evenness by 47%, genera richness by 66% and genera evenness by 51%. Analysis by mixed anova s demonstrated a significant interaction between treatment and time and confirmed a significant reduction in richness and evenness of phyla and genera. We also conducted a phosphate restriction assay on the algae in Mason Lake (Irvine, CA, USA) and found that the threshold needed for algal growth there was 0.02 mg L^?1 PO₄. A pilot study was then conducted to test the effectiveness of the Blue Pro? water treatment facility in removal of this colonial organism from Mason Lake, in addition to removal of dissolved nutrients required for its growth. We measured a 97% reduction in Microcystis cells, a 72% reduction in chlorophyll‐a, and a 96% reduction in phosphate after just one 10 min cycle through the unit. Our study demonstrated that removal of Microcystis colonies may allow green algae to increase in numbers. This may improve algal biodiversity, which will benefit zooplankton and fishes.     

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.     

簸箕李引黄灌区水沙分布及优化调度的经验

灌区利用水沙观测所取得的资料和试验数据，运用水沙运动力学理论，总结分析和揭示了灌区水沙分布的规律和特点。在此基础上，结合灌区的实际运行情况，围绕减少骨干渠道的淤积进行探讨、研究，进而，优化水沙调度方案。该方案实施后，骨干渠道减旅伴效果明显，取得了成功的经验。     

小湾水库大坝防渗面板及其裂缝的加固处理

小湾水库大坝防渗面板整体抗渗性能差,且存在多条裂缝,通过对面板钢丝网喷涂丙乳砂浆加固处理及其裂缝修补,大坝渗漏量明显减少,且左岸上灌浆廊道内及大坝下游坝面92～93 m高程下廊道入口处原有小股射流全部消失.     

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.