冲淤型河道精简流量测次的初步研究

水文勘测站队结合是水文基层管理体制和测验方式的重大改革,要开展站队结合就必须要求流量测验变驻测为巡测,并且测次应尽可能地减少。本文以湖南株洲水文水资源勘测队所属的龙家山站为研究实例,在测站特性分析的基础上,提出了该站精简流量测次的分析途径以及相应的流量巡测方案。该方案不要求实测洪水过程,允许漏测洪峰,流量测次减少75%左右。经过长系列的推流检验,流量误差满足要求。该方案可供类似地区制定巡测方案     

大兴安岭地区水文站巡测可能性初步分析与评价

为适应水利和经济社会的发展,实现＂站队结合,开展巡测＂这一水文现代化的目标,对测站进行流量测次精简分析是十分必要的。文章就黑龙江流域及嫩江流域的一些测站进行了流量测次精简及巡测误差的分析,其结果将作为制定水文巡测方案的重要依据。     

团山子水文站流量测验优化分析

流量监测作为水文监测中的一项重要任务。做好流量测验方法分析工作,是水文监测改革工作的基础。文章通过对团山子水文站的测站特性分析、水位流量单值化分析,探索水位流量变化规律及处理方法,优化流量测次,从而提高测验准确性与时效性。     

流量测次精简和巡测误差分析

流量测次精简分析是一项十分重要和复杂的技术工作，是水文巡测方案制定的依据。文章在总结国内特别是湖南省近年来实践的基础上，提出了各类水位流量关系测站流量测次精简分析的基本途径和主要方法，并给出发巡测误差的主要衡量指标和相应计算公式。     

黄河小川水文站流量测验方案精简分析

根据小川站现有设备和传统测验方法,以缩短流量测验历时、保证测验精度、提高水文测报效率为指导思想,依据GB 50179-93《河流流量测验规范》并结合测站特性,通过流量精简分析方式,合理优化相关测验方案,达到减轻劳动强度和提高测验效率的目的,为其他水文站进行测速垂线和测深垂线的精简提供借鉴。     

水文缆道流量测验误差分析与控制

由于受测验人员、测验仪器灵敏度、外界自然条件和测量对象清晰状况等因素的综合影响,水文缆道流量测验不可避免的带有或大或小的误差。根据临沧市各测站水文缆道设施和测站测验断面情况,从测验设备、测验方法、测验操作上对缆道测流误差来源进行详细分析,并重点阐述了测验误差控制方法。结果可供各水文测站开展水文缆道流量测验工作参考。     

Argonaut-SL流量计在瑞坡水文站的应用研究

水文测验手段自动化和推进水文测站的巡测管理是水文发展的方向,通过在瑞坡水文站安装ArgonautSL流量计,并对Argonaut-SL流量计所测得的指标流速与断面平均流速建立相关回归方程,分析回归方程关系系数的精度,得到Argonaut-SL流量计可以应用于瑞坡水文站的日常流量测验工作中的结论,从而让瑞坡水文站流量测验工作提升到自动化测流水平,解放了生产力,使测站的管理工作由驻测方式转变为巡测方式。     

吕梁市水文监测服务现状分析与对策

以吕梁市各水文测站为研究对象,通过对现阶段吕梁市水文测站存在的水文特性、复杂性和特殊性,流量、泥沙的不同测验要求,驻测、巡测、应急监测的矛盾,使用与维护存在的脱节现象,以及水文站网的布局不够合理等问题的剖析,提出了解决当前水文测站问题的建议。     

牛场水文站畅流期流量测次精简可行性分析

牛场水文站自2001年5月建站以来已收集近15年的水文资料,现阶段该站流量测验存在测次过多、测点过密的现象。在保证资料整编成果可靠性的基础上,适当精简流量测验次数,既能提高功效,又能减轻工作量,对改善基层水文职工的工作条件,促进水文勘测向广度和深度发展具有重要意义。     

息县水文站大洪水测洪方案探讨

测洪方案是水文测站测报洪水的重要技术依据,反映了水文测验断面水沙特性、测验河段水力特性、水文特征及测站测洪能力、测报设施设备、测洪方案等综合信息。采用不同的测验方式和方法所得的测验精度,都应该符合水文测验规范的要求。文章以息县水文站为例,探讨大洪水测洪方案的编制方法,以此借鉴,进而指导和规范洪水期水文测站的水文测验工作。     

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。     

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.     

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。     

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。     

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.