黄河下游截渗墙对地下水影响的数学模型与评价

在分析水文地质条件和建立黄河下游(河南段)影响带数学模型的基础上,采用FEFLOW软件建立了三维地下水流模拟模型。详细描述了模型中截渗墙的处理,并用模型模拟了截渗墙建成后黄河侧渗量和地下水流场的变化。结果为截渗墙埋深为20m和45m时,黄河年间侧渗量减少率相应为5.50%和7.48%,影响范围位于大堤两侧10km以内。地下水位的变化表现为大堤内侧水位相应升高,大堤外侧水位相应下降。     

黄河下游截流墙对地下水影响的数学模型与评价

在分析水文地质条件和建立黄河下游（河南段）影响带数学模型的基础上，采用FEFLOW软件建立了三维地下水流模拟模型。详细描述了模型中截渗墙的处理，并用模型模拟了截渗墙建成后黄河侧渗量和地下水流场的变化。结果为截渗墙埋深为20m和45m时，黄河年间侧渗量减少率相应为5．50％和7．48％，影响范围位于大堤两侧10km以内。地下水位的变化表现为大坦内侧水位相应升高，大堤外侧水位相应下降。     

河渠水位对两侧地下水的影响

河渠水位与两侧地下水位关系密切,直接影响当地工农业生产的发展,沿河地区的地下水位变化,受水文、气象、河渠结构、两岸土壤、水文地质条件、地形等因素的制约。本文对河渠水位上升、下降引起两侧地下水位变化的范围、距河不同地点地下水位上升、下降速度和高度,以及河水与两侧地下水的相互补给流量进行了试验研究。并分别对河渠侧渗与降雨入渗,对两侧地下水位变化特征的影响进行了分析比较,试验结果表明,侧渗引起地下水位的变化出现在近河一定范围内,降雨入渗则引起大面积的地下水位上升。根据地下水位变化规律,探讨了修建截渗工程,发展井灌、建立田间排水系统等调节地表水与地下水的措施。     

流水壕泉域修建地下水库可行性分析

在分析流水壕泉域水文地质条件的基础上,提出设立地下截渗墙修建地下水库的办法,以拦蓄地下水资源。经过可行性分析,在流水壕泉域内修建人工地下水库是可行的,在古洼槽分布区补设开采井群抽取地下水,实现地下水库集中供水,并可获得开采量5400 m3/d。修建后可以解决由于附近煤矿不合理开采导致的缺水问题。     

大顶子山水库浸没治理方案设计与模拟探讨

以贯穿式截渗墙、25米悬挂式截渗墙及综合排水3种浸没治理方案为预设情境,分别利用地下水计算机模型计算后,得出模拟结果。结果表明,贯穿式截渗墙截渗效果一般,25 m悬挂式截渗墙截渗效果不明显,强排水方案治理效果较显著。     

多头小直径深层搅拌截渗墙成墙质量的影响因素分析

截渗墙成墙质量的影响因素较多,诸如地下水位的高低、水泥掺入量、水泥品种和标号、地下水和土壤含盐量及施工工艺等,均不同程度的对成墙质量发生影响.结合新疆生产建设兵团农一师胜利水库除险加固工程,探讨了多头小直径深层搅拌截渗墙成墙质量的影响因素,可供相关施工单位参考.     

平原水库“防-截-导”渗流控制对坝后地下水位的影响

针对干旱区平原水库渗漏引起的坝后土壤盐渍化问题,基于非饱和渗流理论,以恰拉水库坝后农田地下水位埋深为研究对象,采用数值模拟的方法研究了平原水库"防-截-导"渗流控制对坝后地下水埋深的影响。从防渗措施,截渗沟深度,截渗沟内积水排导情况等方面对比分析。结果表明:截渗沟深度与截渗沟积水深度的变化都会影响坝后农田地下水埋深,截渗沟越深,沟内积水深度越小对降低下游地下水位越有利。在"截渗-导渗"的联合作用下,确定无防渗措施、水平铺盖、垂直防渗墙3种工况下联合截渗沟最适深度分别为4. 5、4. 5、3. 5 m。其中垂直防渗结合"截渗-导渗"的作用效果最佳,是无防渗措施条件下的1. 16～1. 30倍,是水平铺盖措施条件下的1. 15～1. 21倍。可见"防-截-导"的综合控渗机制可有效控制下游的渗流量从而降低坝后农田地下水位,防止坝后农田土壤盐渍化的发生,治理下游的生态环境。     

基于大坳灌区扩建地下水环境影响评价

依据大坳灌区水文地质、气象、灌溉、开采、地下水动态监测等方面的资料,在掌握灌区地下水水位动态变化机理及动态特征的基础上,建立了区域的水文地质概念模型。运用地下水数值模拟软件Groundwater Model System建立灌区地下水水流模型,对灌区地下水水位进行模拟。模拟结果表明:地下水位的计算值和实测值吻合较好,该模型可以用来对该灌区新渠系建设后的地下水位进行预测。模型预测结果为:灌区新渠投入运行多年后地下水水位大部分上升值小于0.2 m,最大上升值0.49 m,对区域地下水位总体影响不大,不会引起相应的生态环境问题。     

临淮岗淹没影响处理工程堤防截渗墙施工实践

1工程概况河南省临淮岗淹没影响处理工程是水利部临淮岗洪水控制工程的重要组成部分,位于河南省信阳市固始县沿淮地区,淹没影响区总面积306km~2,居住人口20．9万人。主要建设内容为堤防工程、闸、泵站工程、险工工程、撤退道路工程等。其中为了增加堤防的抗渗性,对部分砂基堤防设截渗墙进行防渗处理,截渗墙工程全长16902m,平均截渗深度4～6m,工程共计11处,其中史灌河堤防2处、泉河堤防7处、潘家沟堤防2处。2施工技术截渗墙工程施工工艺流程如图所示。     

地下水应急开采对兰州三滩傍河水源地的影响

通过建立兰州"三滩"傍河水源地松散岩类孔隙水地下水流数值模拟模型,并根据研究区水文地质条件合理设计地下水应急开采方案,分析了应急开采对黄河水侧渗补给的影响以及水源地地下水位未来5a的演化趋势。结果显示,应急开采条件下,激发了黄河的侧渗补给量,随着时间的推移地下水补采平衡,5a预测期内傍河水源地地下水位未出现持续下降,预测期末水位趋于稳定。     

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。     

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。     

浅谈天湖水电站水轮机运行故障及处理措施

简述天湖水电站投运以来各种故障的表现形式，分析其原因，提出了相应的处理方法及措施，并对合理利用国内外设备提出建议。     

Fish assemblage response to recent mitigation of a channelized warmwater stream

Various designs of low‐head dams are used to rehabilitate streams or forestall upstream channel incision after channelization. We report on the efficacy of using notched sills and grade control structures (GCS) to restore the fish assemblage in Luxapallila Creek, Mississippi. We tested the null hypotheses that habitat variables and species richness, evenness, and assemblage structure would not differ among: (1) a channelized segment with no modifications; (2) a channelized segment mitigated by the installation of sills and GCS; (3) a segment upstream of the installations and undergoing channel incision; and (4) an unaltered segment. Although habitat variables changed, neither species richness, evenness, nor fish assemblage structure differed between mitigated and channelized segments with both exhibiting less richness and different assemblage structures than the unaltered segment. Lack of differences in species richness between the incised and unaltered segments suggest that the GCS may have halted the negative effects of upstream channel incision before species were extirpated. Conspicuous habitat differences between the altered (channelized and mitigated) and unaltered segments were lack of backwaters and canopy coverage and finer substrates in the altered segments. Our results suggest a more comprehensive rehabilitation strategy is required in Luxapallila Creek. Published in 2003 by John Wiley & Sons, Ltd.     

NUMERICAL STUDY OF WAVE EFFECTS ON SURFACE WIND STRESS AND SURFACE MIXING LENGTH BY THREE-DIMENSIONAL CIRCULATION MODELING

1. INTRODUCTION Coastal and continental shelf regions are characterized by intensive interaction between wave and current. These regions are of great economic significance to mankind. Therefore, the modeling of wave and current as well as their mutual int…