基于BP神经网络的MIKE SHE模型参数率定

为了更精细地对水文全过程进行描述和解析,更准确地构建分布式水文模型,以丹麦Karup流域为例,对MIKE SHE模型的饱和导水率、饱和带水平水力传导系数、河床透水系数进行了参数率定,模拟流域的日径流过程。结果表明:基于BP神经网络反分析的参数率定方法比MIKE SHE模型参数自动率定计算得到的均方根误差RMSE小,模型效率系数Ens更接近1;采用BP神经网络反演率定参数后,3组测试样本的日径流模拟过程的RMSE分别为0.04,0.03,0.08 m³/s,Ens均为0.99,且模拟结果能较好地反映径流的实际变化趋势。因此,这种基于BP神经网络反分析的参数率定方法对构建分布式水文模型具有一定的价值。     

MIKE SHE模型在灞河径流模拟中的应用研究

以灞河流域作为研究区域,依据该流域水文气象1990-2010年实测资料,采用MIKE SHE模型对流域径流进行模拟研究,利用Arc Gis等技术建立了模型数据库,对模型参数进行了率定和验证,使用多目标(均方根平方误差、模型效率系数和决定系数)对模型适用性进行了评价。结果表明:年径流模拟效果比较好,MIKE SHE模型在灞河流域的适用性较好,研究所率定的参数可为进一步研究灞河流域水资源利用与管理提供依据。     

国内MIKE SHE水文模型研究与应用综述

为跟踪MIKE SHE水文模型在我国的研究与应用情况,把握MIKE SHE水文模型研究动向,对MIKE SHE水文模型的发展历程进行介绍,分析了该模型的基本原理与结构。同时对该模型在各领域的研究情况进行了综述,其中包括区域水文模拟、地下水水文分析、降雨-径流模拟以及洪水预报等内容。并针对目前国内模型应用中存在的数据支撑、处理及模型算法选用问题,提供了新的思路。     

基于MIKE SHE的洪水模拟与尺度效应分析

以淮河黄泥庄流域为研究对象,构建用于洪水模拟预报的分布式流域水文模型MIKE SHE,根据参数物理意义以及率定的方式确定MIKE SHE的模型参数。选用流域出口控制站黄泥庄水文站1983年～2009年间的21场洪水资料,对建立的模型进行了模拟与验证。在此基础上,研究设定了5种网格大小及5种时间步长,探究时空尺度变化对模型模拟效果的影响。结果表明,MIKE SHE模型对时间与网格尺度大小均较为敏感,且在一定尺度范围内,洪峰与洪量随网格增大而增大,随时间步长增加而减小。     

基于BTOPMC的无资料区水文模拟及相似性分析

针对稀缺资料地区分布式水文模型无法直接应用的问题,以无径流观测资料的西充河流域(西充境内)为研究区、以相近的李子溪流域为参证流域,建立了BTOPMC模型进行流域水文相似性分析,并采用参数移植法模拟研究区径流过程。结果表明：参证流域径流模拟结果良好,经参数转移之后的BTOPMC模型具有一定的适用性。该方法解决了水文模型在参数移植构成中的不确定性问题,可为其他无观测资料流域的模拟提供借鉴。     

汉江流域分布式水循环模拟研究

详细描述了汉江流域分布式水文模型构建和求解的过程,验证了WEP模型模拟研究区水循环的可行性。提出了"参数分区"的新理念,为研究参数不确定性空间变异提供了高效的模型空间结构。分别采用分割样本检验法和代表样本检验法对模型模拟结果进行检验。模拟结果的评价采用年径流总量模拟的误差RE、Nash指数及模拟的降雨径流相关系数个指标。     

基于MIKE SHE模型率定在地下水分析研究中的应用

分布式水文模型是通过水循环的动力学机制来描述和模拟流域水文过程的数学模型。MIKE SHE作为一种分布式水文模型被越来越多地运用到流域规划、水资源管理、水资源评价等方面。要成功地建立起一个MIKE SHE模型除需要有充分的基础资料收集和前期准备工作外,后期的模型率定也是至关重要的一环。本文就渗透系数和给水度在MIKE SHE模型率定阶段的作用进行了分析。     

基于CMADS驱动下SWAT模型的敖江流域径流模拟

目前针对气象、水文资料不足的小尺度流域进行径流模拟的研究相对较少。选取敖江流域为研究区,利用中国大气同化驱动数据集(CMADS)驱动SWAT模型对该流域2008—2016年进行逐月径流模拟,并使用水文比拟法结合邻近的2个传统气象站计算出模拟时段的观测数据以完成模型参数的率定与验证。结果表明:模拟结果与观测值较吻合,率定期(2010—2013年)评价指标决定系数R²和Nash-Suttcliffe系数NS分别为0.84和0.76,验证期(2014—2016年)两者分别为0.85和0.74,均达到了模型的评价要求。研究成果表明CMADS驱动下的SWAT模型适用敖江流域的径流模拟,采用水文比拟法适合在水文资料不足的地区进行径流计算,可为缺少气象与水文资料的小尺度流域进行径流模拟提供参考。     

新安江模型参数变化对流域降雨径流过程的影响分析

水文模型可以模拟自然流域的降雨径流过程,在降雨径流过程模拟中,水文模型参数的选择往往会影响模型对流域径流过程的模拟效果.针对新安江模型,以陕西黑河金盆水库流域为研究流域,分析新安江模型参数变化对模拟流域降雨径流过程的影响,以确定新安江模型参数的敏感程度,从而服务于研究流域的汛期水文预报参数修正.模拟结果表明:在研究流域新安江模型参数中KKSS、KKG、WLM、WDM、kg、k为敏感参数,对模拟流域降雨径流过程的影响较大;参数WUM、IMP、B、c、SM、EX为不敏感参数,对模拟流域降雨径流过程影响较小.     

基于MIKE SHE模型的地下水评价

依据收集的水文、气象、开发利用、水文地质等资料,借助MIKE SHE模型建立地表-地下水耦合的分布式水文模型,模拟地下水补给、径流、排泄动态过程,进行均衡分析,分区评估地下水资源量。结果显示:水源开采区地下水资源量0.48亿m3,农业开采区地下水资源量1.30亿m3,工农开采区地下水资源量2.12亿m3,可为地下水资源及生态持续发展提供理论依据。     

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…