AutoCAD Civil 3D在双曲拱坝建模中的应用

以水利水电工程中大坝体型较为复杂的双曲拱坝为例,从原始地形曲面创建、拱坝体型装配设置、大坝圆弧曲线放样、边坡开挖、挖填方工程量计算等方面介绍了Civil 3D在水利工程中坝体建模方面的应用。总结了Auto CAD Civil 3D在在水利工程中的应用前景,可为水利水电工程设计者提供参考。     

AutoCAD Civil 3D在新疆某水利工程设计中的应用

以新疆某土石坝建模为例,从地形曲面生成、大坝主体放坡、边坡开挖、土方量计算等方面介绍了Civil 3D在水利工程中坝体建模方面的应用,借助Civil 3D三维建模方面的功能,直观展示坝体三维模型效果。总结了AutoCAD Civil 3D在坝体建模中的主要优点和在水利工程中的应用前景。     

Civil 3D软件在桑干河河道综合治理工程的应用

Civil 3D软件已在水利工程中有大量应用,Civil 3D不仅包含了AutoCAD的全部功能,并且还可以动态更新三维模型设计,极大地方便了设计工作,同样在施工阶段也可发挥其工程量计算的优势。以桑干河应县段河道综合治理工程为例,通过建立地形曲面、创建路线、生成纵断面、创建开挖和回填模型、生成横断面和工程量计算等主要步骤阐述Civil 3D软件的优点。     

土石坝设计中AutoCAD Civil 3D技术的应用

文章旨在借助AutoCAD Civil 3D软件,通过对土石坝工程的实例设计,对如何运用Civil 3D软件,建立地形曲面、创建路线及纵断面、创建断面装配、确定库容曲面等进行详细叙述,希冀能对水利工程设计者提供参考。     

Civil 3D输水管线设计在水利工程中的应用

Civil 3D软件是面向对象模型设计的建筑信息解决方案,其部件编辑器对管道结构进行模型编辑,在地形曲面中对模型进行装配,生成三维管道模型,并根据设计要求生成不同桩号管道横断面,按照管道横断面材料的划分分别计算横断面面积及累计体积。通过调整管道模型参数,三维模型、横断面及工程计算相应联动调整。Civil 3D在水利工程中的应用将大幅提高水利工程长距离管道设计的效率及减轻设计人员的工作强度。     

Civil 3D参数化重力坝建模在水利工程中的应用

Civil 3D软件是面向对象模型设计的建筑信息解决方案,其部件编辑器对重力坝结构进行参数化模型编辑,在地形曲面中对模型进行装配,生成三维重力坝模型,并根据要求生成不同部位坝体横断面,计算不同材料分区的横断面面积及累计体积。通过调整模型参数,重力坝三维模型、横断面及工程计算相应联动调整。Civil 3D在水利工程中的应用将大幅提高水利工程重力坝设计的效率及减轻设计人员的工作强度。     

Civil 3D参数化渠道建模在水利工程中的应用

Civil 3D软件是面向对象模型设计的建筑信息解决方案,其部件编辑器对渠道结构进行参数化模型编辑,在地形曲面中对模型进行装配,生成三维渠道模型,并根据设计要求生成不同桩号渠道横断面,按照渠道横断面材料的划分分别计算横断面面积及累计体积。通过调整渠道模型参数,三维模型、横断面及工程计算相应联动调整。Civil 3D在水利工程中的应用将大幅提高水利工程长距离渠道设计的效率及减轻设计人员的工作强度。     

Civil 3D在水库前期规划中的应用

文章以青海某水库前期规划为例,介绍了Civil 3D在地形生成、坝体建模、库容分析、工程量提取等方面的应用。与传统方式相比,利用Civil 3D软件进行前期规划设计,具有直观、准确、快速的特点。     

Civil3D在退圩还湖设计项目中的应用

Civil 3D可为土木工程提供很好的土方算量解决方案,以兴化市洋汊荡退圩还湖工程为例,介绍Civil 3D在工程项目中的应用技巧。主要过程为,整理现有地形图后创建原始地形曲面,根据规划设计完成后的AUTOCAD文件导入分块,通过在设计时设置相关设计高程参数,分块创建设计高程地形表面(以T2分块为例),对比原始地形曲面和设计高程地形表面,创建三角网体积曲面(T2tiji),查询挖填方量后,快速进行土方挖填计算,为平原地区水利工程开展规划设计提供了借鉴。     

基于AutoCAD Civil 3D的水利工程地质三维模型

Civil 3D软件包含了传统CAD的全部功能,同时实现了三维动态模型的设计。文中以某水库工程地质勘察的三维地质建模过程为例,通过创建地形曲面、地层实体、坝基开挖曲面、生成施工结果等步骤来介绍Civil 3D的建模过程,为水利工程地质勘察三维建模提供参考。     

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。