郎川公路附近湿地地下水文数值模拟

郎木寺至川主寺公路改建工程通过我国最大的高原湿地-若尔盖湿地.公路建设会对湿地地下水流动产生阻隔作用,为保护湿地生态环境需要掌握公路附近湿地的地下水文特征.为此,在郎川公路和若尔盖湿地资料收集和实地调查的基础上,通过在典型地区进行抽水试验获得实测数据,并采用数值模拟法进行研究,应用有限差分法,求得地下水含水层参数,这在国内尚属首次.     

高寒湿地公路路基地下水交换模拟研究

因高寒湿地区域的地下水埋深较浅,致使过域公路的路基排水困难.通过选择穿过若尔盖湿地国道213郎川公路典型路段进行地下水位观测,采用GMS软件,模拟研究了6种公路路基处理形式下(粘土换填、塑料排水板、碎石桩、盲沟、片石换填、块石换填)的地下水交换规律.观测及模拟结果表明:在地下水埋藏浅的湿地区域,路基采用盲沟型式时,两侧平均水力梯度为13.2％,梯度差为0.36％,能很好地保证公路两侧的地下水循环:除粘土路基对地下水流有显著的阻滞作用外,其他类型的路基虽然对水流有不同程度的影响,但阻滞作用不甚明显.     

河北省石家庄市某地水文地质勘查

通过对石家庄市某地进行水文地质勘查,查明区域及项目区地质、水文地质条件,包括含水层结构及其分布、地下水流动系统特征、地下水动态特征等,通过开展单孔抽水试验和包气带渗水试验,查明含水层、包气带渗透系数.同时指出区域地下水位呈下降趋势,今后地下水开发利用应做到优化管理,合理利用资源,避免地下水的持续超采,才能实现可持续发展...     

坪上岩溶泉域地下水系统成因分析

西龙池抽水蓄能电站（１２０万Ｋｗ）工程地质勘察中，从边界条件（介质场）入手划分了岩溶地下水系统，论述了各地下水系统的特征及其相互之间的联系。深入地分析地下水系统成因。对拟建的抽水蓄能电站水库水源提供了可靠的资料。     

用抽水试验推求水文地质参数方法初探

在水资源评价工作中,常用到水文地质参数。水文地质参数的推求方法,也是多种多样的。抽水试验是推求地下水参数的常用方法。通过用抽水试验有关资料对两个地下水文地质参数K值和u值的推求方法进行探讨。     

抽水蓄能电站枢纽区地下水动态统计模型及其应用

针对抽水蓄能电站特殊的运行工况,改进了传统的渗流观测资料统计分析模型.以h作为模型的时间单位,建立了以d为周期的多元统计回归模型,并对各影响分量进行分离,结合地质条件分析地下水动态的主要影响因子.通过一抽水蓄能电站工程实例,验证了模型的有效性.     

大黑河旗下营段河谷地下水资源初探

文章通过水文地质调查及水文地质钻探、抽水试验等手段掌握的勘查资料,对大黑河旗下营段河谷地下水资源进行了初步探索,旨在对当地地下水资源的保护利用起到参考。     

湘中地区地下水变化对岩溶塌陷影响分析

通过对湘中地区地岩溶塌陷的调查研究和抽水实验,分析区内地下水的特征及影响因素,岩溶塌陷与地下水关系,结果表明地下水活动是影响岩溶塌陷诸多因素中最活跃因素。     

荷兰人工补给地下水经验及在北京城市供水安全保障中的应用探讨

介绍了荷兰阿姆斯特丹市引莱茵河地表水．利用天然风积沙丘人工补给地下水的成功经验。并结合我国南水北调水源特征和北京地下水回灌条件．探讨了借鉴荷兰经验在北京开展人工补给地下水的可行性。荷兰地下水人工补给既成功阻止了海水入侵,在增加地下水储存量的同时．又提高了供水品质。由于地下水多年超采的累积,北京已形成了巨大的地下水库库容,利用南水北调水源．通过人工湿地、沟渠等组成的人工补给系统和利用现有的地下水源地水井组成的抽水系统．既可降低南水北调水源由于长距离、长时间引水可能出现的水质风险,又能让“客水”与“本地水”充分融合,保障饮用水口感和降低因水源变化可能出现的水质风险,同时增加地下水战略储备。提高供水安全保障。     

河北省某扩建煤矿地下水流场变化数值模拟

为了分析河北某扩建煤矿地下水流场的变化特征,在调查分析研究区水文地质条件的基础上,采用数值模拟技术,利用Visual Modflow软件建立地下水数值模拟模型,基于实测数据对模型进行识别和验证。利用识别后的模型预报未来矿山开采过程中不同含水层水位的变化特征,分析矿山排水对各个含水层的影响。结果表明:矿山扩建后,矿山附近各含水层地下水水位均出现下降,但不同含水层下降幅度不同,其中第3和第4含水层受疏干排水影响较明显,水位下降幅度大;随着矿山长期抽水,第3和第4含水层中地下水降落漏斗范围逐步扩大。     

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。     

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.     

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。