AutoCAD Civil 3D在亭子水利枢纽测量工作中的应用

本文结合亭子口水利枢纽施工中的测量工作,介绍了Civil 3D在亭子口水利枢纽工程中的应用,借助Civil 3D三维方面的功能,复核土、石方工程量。     

亭子口水利枢纽水土保持方案编制思路

通过研究亭子口水利枢纽工程特点及其自然环境特点,分析了工程的水土流失特点及存在的水土保持问题,在明确工程区水土流失防治目标及水土流失防治重点的基础上,拟定出了适合于亭子口水利枢纽工程的水土保持方案编制思路.     

亭子口水利枢纽工程水轮发电机组接力器安装

亭子口水利枢纽工程水轮发电机组接力器没有按传统的测量吊线方案进行安装调整,而是通过联板实际连接的方式进行安装、调整与测量,消除了中间环节的测量误差。介绍亭子口水利枢纽工程首台水轮发电机组接力器安装及调整方法,为后续机组接力器安装、调整工作提供了可操作的实际工程依据。     

亭子口水利枢纽110kV变电站的运行维护管理

本文根据亭子口水利枢纽工程的特点,着重从亭子口110kV变电站的日常运行管理、电力设备负荷维护管理、巡视检查等方面,介绍了亭子口变电站设备的运行维护管理工作。     

亭子口水利枢纽防洪作用分析

亭子口水利枢纽是嘉陵江干流梯级开发的控制性工程,是国务院<关于加强长江近期防洪建设若干意见>确定的完善长江防洪体系近期建设的防洪工程之一.根据流域防洪规划的要求,结合防洪控制站洪水组合特性及防护对象分布特点,介绍了亭子口水库"固定下泄量法"和"补偿调度"相结合的防洪凋度方式,并分析了亭子口水利枢纽的防洪作用.     

2010年嘉陵江亭子口水利枢纽洪水预报

2010年7月23，25日，受上游流域强降雨影响，嘉陵江亭子口水利枢纽出现了两次较大洪水。亭子口水利枢纽水情中心在分析亭子口水利枢纽以上流域特性的基础上，根据实测水文资料，对流域暴雨、洪水实况、洪水预报方案进行了分析，制定了亭子口水利枢纽洪水预报方案，并根据预报方案及时、准确地进行了洪水预报。亭子口上游围堰2次洪水的水位预报误差仅为0.2, 0.21 m，为亭子口水利枢纽工程建设的安全度汛提供了有力的保障，也为下游地区的地方防汛工作起到了耳目和参谋作用。     

亭子口水利枢纽工程建设管理综述

水利工程建设管理需根据各自工程的特点,实施全方位、动态管理.结合嘉陵江亭子口水利枢纽的工程特点及其工程建设管理的难点,从工程安全控制、质量控制、创优工作、进度控制、造价控制、优化工作等方面,重点论述了工程建设过程中所采取的工程管理措施.严格有效地实施这些措施,确保亭子口水利枢纽工程建设进展顺利,同时涌现出了许多亮点.     

亭子口水利枢纽施工期水情自动测报系统

针对亭子口水利枢纽所在流域暴雨、洪水特性和河网特征,科学布设水情站网,在满足施工期洪水预报精度和预见期的前提下,尽可能缩小系统规模,降低投资.亭子口水利枢纽水情自动测报系统采用卫星为主、GSM为辅的组网方式,自报式工作体制,结构合理,经济实用,在施工期防洪度汛工作中发挥了重要作用.     

亭子口水利枢纽工程550 kV GIS安装技术

结合亭子口水利枢纽550 kV GIS布置设计,提出了采用封闭静置防尘的安装措施;采用DILO真空泵组,优化安装工艺程序,缩短了安装时间;结合GIS的结构特点,进行了分步耐压试验,内装电压互感器、避雷器后电压试验带局部放电检测.目前亭子口水利枢纽550 kV GIS安装调试和现场耐压试验皆一次顺利通过,说明GIS安装技术满足工程要求.     

嘉陵江亭子口水利枢纽下游河道生态需水量分析

为开展嘉陵江亭子口水利枢纽生态环境影响分析与环境保护可行性论证工作,根据嘉陵江河道形态、径流和环境特征,采用水文学的Tennant法、生态水力学等生态用水量分析方法,分别计算了亭子口水利枢纽下泄生态基流量,并对不同计算方法取得的结果进行了比较与分析。推荐嘉陵江亭子口水利枢纽最小下泄生态流量为120 m3/s。该研究成果为亭子口水利枢纽环境可行性论证提供了决策依据与理论基础。     

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。     

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.     

浙江省水域调查录入系统的设计和应用

浙江省水域调查录入系统将调查数据与电子地图相整合,对分类水域数据进行统计计算,并对输入数据进行合理性和完整性检查,得到调查范围内现有水域的详细数据,实现了水域调查数据输入、计算、统计和查询的数字化管理,提高了工作效率和工作质量,为各地下阶段水域保护规划编制和水域管理工作提供了数据支持。对该系统的设计原则、功能和技术设计等作了介绍。     

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CT-连续加荷水泥乳化沥青混凝土细观损伤规律研究

利用CT技术对水泥乳化沥青混凝土的细观损伤过程进行实时扫描观测,获得了混凝土试件在连续加荷下的CT图像。通过采用直观分析法、CT数分析法、CT数与损伤变量关系3种方法分析表明,水泥乳化沥青混凝土的破坏过程可分为压密、扩容、裂纹扩展、破坏4个阶段,同时混凝土在受压过程中具有韧性,在极限荷载之前各断面处于压密和微扩容的强化阶段,极限荷载之后混凝土从损伤到破坏发展比较平稳。     

Desiccation and recolonization of phytobenthos in a regulated desert river: Colorado River at Lees Ferry,Arizona, USA

We tested the recolonization of the phytobenthic community in the tailwaters of Glen Canyon Dam following long- and short-term experimentally induced desiccation. The response of Cladophora glomerata, Oscillatoria spp., miscellaneous phytobenthos species and periphyton was studied over 18 weeks using three treatments: (1) undisturbed control cobbles from the submerged zone; (2) cobbles desiccated and replaced into the submerged zone; and (3) cobbles desiccated and replaced into the varial zone. Periphyton density and compositional response resulting from these treatments were also examined. Desiccation treatments were significantly different in biomass from controls throughout the study. The biomass of desiccated and replaced river cobbles averaged <30% of the controls for C. glomerata and periphyton during the 18-week recolonization period. In contrast, the biomass of the control Oscillatoria and miscellaneous phytobenthos species averaged only 3 and 50% of that in the desiccation treatments, respectively. Cladophora, the dominant alga, comprised 77% of the phytobenthic biomass. A significant positive relationship between discharge, Cladophora and periphyton biomass was present in all treatments, while there was a negative relationship with discharge for Oscillatoria and miscellaneous phytobenthos species. There was a significant inverse correlation, as well as a pattern of separate biomass dominance, between C. glomerata and Oscillatoria. Cladophora was the dominant phytobenthos species on cobbles below the baseflow and Oscillatoria was dominant on cobbles in the varial zone. In general, the Cladophora biomass decreased under intermittent drying conditions, while Oscillatoria declined under permanently wet conditions. Diatom composition was not significantly different between treatments; however, their density was lower on desiccated cobbles. Diatom density on desiccated cobbles in the submerged and varial zones averaged 69 and 42% of that of the controls, respectively. Recovery and maintenance of benthic resources are hindered by fluctuating flow regimes driven by electricity and irrigation requirements. Repeated desiccation of the phytobenthos has major effects on the bottom-up interactions in the Colorado River ecosystem. © 1998 John Wiley & Sons, Ltd.