基于AutoBank的液压坝稳定性分析

液压坝设计中,准确进行液压坝的渗流和结构稳定计算分析至关重要。本文以库峪河液压坝为例,通过采用AutoBank有限元分析软件,构建液压坝有限元模型,模拟分析不同工况下液压坝的渗流和结构稳定性。结果表明,液压坝的渗流稳定与抗滑稳定均满足要求,液压坝结构稳定。分析成果可为库峪河液压坝的设计提供依据,对类似工程的渗流和结构稳定计算分析提供参考。     

液压升降坝工程对河道防洪的影响

在近年拦河建筑物中,液压升降坝属于一种新型的应用方式,但是目前液压升降坝工程对河道防洪所产生的各种影响还没有相关研究文献支持。鉴于此,文章主要研究对液压升降坝工程对河道防洪产生的影响,通过对比坝型比选计算,结果发现,相比于传统拦河建筑物来说,液压升降坝的影响比较小,同时文章还详细分析了液压升降坝工程对河道防洪产生影响的表现,旨在液压升降坝工程建设过程中全面考虑各种影响因素,充分发挥液压升降坝工程的作用。     

液压升降坝工程计算方法的探究

液压升降坝是近年来出现的一种新型翻板坝,力学结构科学,属于低水头建筑物。以洛南县老君山文化旅游景区液压坝工程为例,主要探究液压升降坝在水力计算和稳定计算分析的方法,以确保液压坝在运用期及设计洪水期间的安全可靠,该液压坝工程建成后经过两年的蓄水运行及洪水的冲刷,液压坝段工程完好,未出现冲毁现象。以期为类似项目提供参考。     

齐齐哈尔市劳动湖液压坝设计及其稳定性计算分析

文章对劳动湖液压坝设计及其稳定性计算进行分析。液压坝位于劳动湖6+450处,坝轴线垂直于河道布置,液压坝长60.5m。液压坝采用钢筋混凝土结构,顺水流方向分别布置了上游防渗膜、钢筋混凝土铺盖、坝底板、混凝土防渗墙、消力池、海漫及下游防冲槽。     

汾河中游核心区液压坝坝基地质问题及处理措施

汾河中游核心区干流1~5号液压坝坝基地层结构相似,其中汾河流域生态修复中游核心区干流上拟建15座液压坝中坝基地质条件最差,存在工程地质问题最多,地基处理最具代表性的有5座液压坝。对1~5号液压坝坝基工程地质条件进行了描述,查明了1~5号液压坝坝基存在的主要工程地质问题,最后采用网格状水泥搅拌连续防渗墙对地基进行了处理,从而保证了1~5号液压坝按期开工和安全运营。     

液压升降坝在城市河道中的选型设计

城市河道设计中常有兼顾景观要求。通过分析液压升降坝的工作原理,论述液压升降坝的结构组成和工作特点。通过闸型比选论述液压升降坝的优缺点,结合工程实例详细介绍了液压升降坝在工程设计中的布置特点,为城市河道设计景观闸型的选型设计提供参考。     

液压坝在河道整治中的应用

汾河流域生态修复中游核心区干流蓄水工程采用液压坝进行全断面蓄水。液压坝是一种由我国自主研发的新型活动坝技术,它兼顾了橡胶坝和翻板坝等传统活动坝的优点,又克服了这些坝型的缺点。文章就液压坝在河道整治中的应用进行总结,为类似工程提供参考。     

液压升降坝在汾河干流蓄水工程中的应用

为蓄滞洪水,充分利用雨洪资源,达到重建河流水系、抬升地下水位、净化水质等目的,拟在汾河干流大堤内建设15座壅水闸坝。对橡胶坝、液压升降坝、钢坝闸三种坝型进行比选后,建议蓄水闸坝均采用液压升降坝,并详细地介绍了液压升降坝的坝型设计。     

高寒地区大型液压升降坝设计问题探讨

辽宁省海城市大型液压升降坝是目前国内已建的挡水面积最大的液压升降坝,也是在高寒地区建设的第一座液压升降坝。该坝挡水面积达960 m~2,拦蓄水量达336.79万m~3。解决该工程防冰害设计及汛期消能防冲问题,是工程成功与否的基础。通过参考先行建设的一座小型液压坝积累的经验,提出了该坝在防冰害设计和消能防冲方面的设计思路,并在实际运行中取得了很好的效果。相关设计方案可供其他液压升降坝设计参考。     

汾河流域生态修复工程7#液压坝坝基土性质对施工影响简析

7#液压坝是在汾河中游核心区干流15座液压坝施工过程中存在工程地质问题最多的液压坝。文中结合前期勘察资料,对7#液压坝坝基土的工程地质条件进行了较详细的描述,并对其成因及物理力学性质进行总结,根据其工程地质性质对当前施工过程中遇到的工程地质问题进行了分析,并提出最终处理建议。     

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…