论三门峡水库在黄河防洪工程体系中的作用

通过对三门峡水库运用40余年来社会效益、经济效益以及负面影响的论述，分析了三门峡水库在未来黄河防洪减淤工程体系中的作用和地位，讨论了潼关高程淤积抬升的主要原因及降低潼关高程的综合治理措施，指出了小浪底水库建成后，决定三门峡水库运用方式的主要因素仍是黄河下游和渭河下游的防洪减淤问题。同时，给出了三门峡水库不同运用阶段的水位控制运用指标的建议：①继续做好三门峡水库335m防洪水位和326m防凌水位运用的准备；②汛期平水期保持库水位不超过305m，当入库流量大于1500m^3／s，实施敞泄排沙，并控制北村断面1000m^3／s流量相应水位不超过310m；③非汛期运用水位原则上最高不超过318m，遇调水调沙等特殊情况，需要短时间调蓄时，最高水位不得超过320m，非汛期平均运用水位按照不超过316m控制；④实施渭河下游综合治理，降低潼关高程。     

非汛期潼关高程与三门峡水库运用关系分析

三门峡水库建库前，潼关高程即呈微升趋势，并具有“汛期下降、非汛期上升”之规律。根据潼关高程上升的物理成因分析，结合建库后实测资料及逐步线性回归模型计算，分析认为：非汛期高水位期间的来沙量Ws对潼关高程上升量△H有一定影响，不同信度水平（α=0.01-0.10）下对潼关高程有影响的临界库水位不同（H＝322．24－320．56m），非汛期运用水位326－322．24m所造成的淤积影响，一般可在汛期大洪水过程得以消除；运用水位低于临界水位，基本不对潼关高程产生影响。     

黄河潼关河段清淤研究

影响潼关高程的主要因素有来水来沙条件、上下游河段冲淤状况和坝前运用水位，其中来水来沙条件起着主导作用，潼关高程的变化受下邻河段（黄淤３６～４１断面）冲淤的影响要大于上邻河段（黄淤４１～４５断面），减少三门峡水库非汛期高水位的运用对减缓非汛期潼关高程的抬升起着重要作用，清淤河段选在黄淤３０断面以上，重点在黄淤３６～４１断面。清淤时间分为桃汛期和汛期两个时段，清淤对潼关高程的上升趋势起到了一定的抑制作     

潼关高程的稳定降低与渭河下游河道综合治理

本文采用实测资料分析和泥沙数学模型计算等方法对潼关高程的稳定降低和渭河下游河道的综合治理等重要问题进行了研究,得到了如下认识:(1)潼关是三门峡库区的天然卡口和渭河下游河道的侵蚀基准面,从减少渭河下游淤积、减轻渭河下游洪涝灾害及改善渭河流域生态环境等方面考虑,降低潼关高程是十分必要的;(2)通过调整三门峡水库运用水位,潼关高程是可以降低的,但不同的来水来沙条件下降低的程度是不同的,近期目标可确定为下降1m,采用多种措施的组合后的中长期目标可确定为下降2m;(3)潼关高程降低到相对稳定的状态一般需要4～8年,这与来水来沙条件和三门峡水库运用方式有关;(4)建议三门峡水库运用水位近期采用汛期敞泄、非汛期控制在312～318m范围内的方案,综合考虑后认为非汛期水位目前控制在315m较好;(5)渭河下游河道的治理应采取包括降低潼关高程、河道整治与疏浚、加高加固堤防和跨流域调水等综合措施。     

桃汛期潼关高程冲刷条件研究

通过1974年以来的实测资料,分析了三门峡水库运用水位、桃汛洪水情况、前期河床条件等与桃汛期潼关高程变化的关系,指出在目前的河床边界条件下,桃汛期潼关高程冲刷下降0．2m左右的条件为：潼关站洪峰流量为2500m^3／s,10d洪量为13亿m^3,三门峡水库起调水位为313m。     

2003～2004年度三门峡水库冲淤特性分析

2003年11月～2004年10月，在三门峡水库进行非汛期控制水位318m原型试验条件下，分析了来水来沙，水库冲淤情况及潼关高程的变化，指出：①运用年入库水量为208．5亿m^3，沙量为3．168亿t，是典型的枯水枯沙年份；②2004年桃汛来水条件优于2003年，桃汛前后潼关高程下降值分别为0．15m和0．21m，主要是因为2003年桃汛期在潼关河段上段进行清淤疏浚，增大了桃汛洪水的冲刷作用；③2003年、2004年三门峡水库进行非汛期控制水位318m原型试验，回水影响范围控制在黄淤33断而以下，该断而以上河道完全处于自然状态，其冲淤变化由该河段比降、断面形态随来水来沙条件进行自动调整，水库运用已不对潼关河段的冲淤产生不利影响；④在有利的水沙条件冲刷和清淤的共同作用下，2003年汛期潼关高程下降0．83m，经过非汛期的冲淤变化，2004年汛前潼奖高程较2003年汛后上升0．30m，汛末潼关高程较汛初下降0．27m，由于汛期水沙条件不利，加上没有进行清淤疏浚，因此汛期潼关高程冲刷下降的幅度小于非汛期淤积上升的幅度。     

三门峡水库"蓄清排浑"运用与潼关高程关系研究

多泥沙河流峡谷型水库“蓄清排浑”运用的前提是：水库非汛期回水淤积要控制在一定范围内，淤积河段汛期存在一定的富裕冲刷能力；低水位运用条件下水库具备较大的泄流排沙规模；汛期洪水的量级较大。三门峡水库在“蓄清排浑”运用情况下，能否使潼关河段维持冲淤平衡，关键在于水库非汛期潼关高程自然上升量加水库高水位运用造成的上升量与汛期潼关高程下降量之间的对比关系。近期黄河洪水量大幅度减少，汛期潼关高程下降量小于非汛期自然上升量，在这种情况下，即使高水位影响因素消除，潼关河床冲淤平衡问题也难以解决，因此，必须采取综合措施控制潼关高程。     

利用并优化桃汛洪水冲刷潼关高程原型试验研究

在分析研究桃汛期潼关高程变化规律及相关影响因子的基础上,提出了潼关高程明显冲刷的洪水条件和三门峡水库控制水位等指标,在2006年桃汛期进行了利用并优化桃汛洪水冲刷降低潼关高程试验.通过调整万家寨水库运用方式,塑造了满足潼关高程冲刷的洪水过程,效果分析表明,试验前后潼关高程降低了0.2m,万家寨和三门峡库区淤积形态得以改善,基本达到了预期目标.     

三门峡水库"318"控制运用对潼关高程变化的影响

基于实测资料分析了三门峡水库自2003年采用"318"控制运用以来,入库水沙条件、运用水位及潼关高程的变化特点,发现"318"控制运用以来的年入库水量有所回升,但入库沙量和含沙量大幅减少;水库运用水位除2003年外,平均运用水位存在逐渐抬升的现象;潼关高程从2002年汛末的328. 78 m降低到2012年的最低值327. 38 m,之后又逐渐回升至2016年汛后的327. 94 m,具有先降低、后升高的特点。建立了潼关高程与前期5年入库水沙条件和运用水位的滞后响应计算公式,可以用来定量估算不同汛期水沙条件及运用水位变化对潼关高程的影响。资料分析与计算结果表明,2003年"318"控制运用以来潼关高程的降低,主要与汛期水量增加及含沙量减小有关。     

桃汛期影响潼关高程升降的敏感性因子分析

从水沙条件和边界条件两个方面,逐项分析了桃汛期洪峰、沙量、水沙搭配以及桃汛期三门峡水库起调水位、前期潼关高程、河床泥沙颗粒组成、纵比降等对潼关高程升降产生的影响。结果表明:在目前边界条件下,要降低潼关高程,三门峡水库桃汛期起调水位应控制在313 m以下,桃汛洪峰流量在不超过小北干流平滩流量的情况情况下越大越好,沙量越小越有利于潼关高程的冲刷下降,含沙量不能太大且要与洪峰对应,在出库含沙量不能与洪峰同步的情况下,要控制好落水期排沙。     

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.