浅析方格网法在杨房沟水电站工程计量中的应用

工程计量需要有较强的说服力和较为严谨的计算过程,一般使用横断面进行工程量计量。为了确定方格网土方计算方法在雅砻江杨房沟水电站前期工程计量中的适用性,通过对方格网土方计算原理的探究,分析了其使用范围、适用条件、方格宽度对计算成果的影响及其取值原则。以杨房沟导流洞进口底板地质超挖工程量计量为例,分析了使用方格网土方计算方法的具体应用步骤和其计算快速高效的特点,以及与断面计算方法相比较具有的优势。结果表明,该方法在某些小范围的土石方工程计量中应用,可以提高工程量计量的效率和可靠性。     

数解法在江堤土方量计算中的应用

在江河堤防设计和施工中，都要进行土方工程量的计算。在土方工程量计算工作中，首先要根据设计横断面图计算断面面积。一般计算断面面积多习惯采用传统的网格法。网格法计算断面面积有以下两点弊端。     

Excel软件自动计算土方量的应用方法

在水利工程建设中,尤其是河道清淤、路基填筑、堤防加高培厚等工程建设中,总会遇到计算土方工程量的问题.一般均采用平均断面法计算,即沿工程线路每隔一定间距测一断面,计算出每一断面的方量,然后相邻断面取平均值,再乘以断面间距,计算出两断面之间的工程量,最后将所有工程量相加,即可求得总土方量.笔者结合历次计算的经验教训,总结出采用Excel表格自动计算的方法,可快速准确的求得工程量.     

水利工程土方断面计量方法的优缺点和改进

水利工程领域土方计量一般采用断面法。以南方GPS测量仪器和CASS软件为例,分析水利工程土方断面计量方法包括手动记录和绘图法、利用已知坐标点插值生成断面法、DTM生成断面法和自动生成断面法等的优缺点。其中,DTM生成断面法比较准确但是不能自动计算土方、自动生成断面;自动生成断面法虽然自动功能强但是生成的断面准确性差。为了融合这2种方法的优点,提出DTM自动生成断面法,以解决现有方法精度不高、作业效率低、修改难度大的问题,使水利工程土方断面计量标准化、简单化、快捷化。     

基于BIM的傍山渠道快速计量方法研究

渠道横断面尺寸的确定是水利渠道设计中的重要技术问题之一,且工程计量在施工管理中的重要性与日俱增。通过采用BIM技术,以傍山渠道为研究对象,运用Grasshopper内置的Galapagos运算器和Octopus插件对渠道断面尺寸设计方法进行优化,确定出最佳横断面设计参数,通过渠道计量参数化模型及程序,实现了渠道土方工程量的自动计算。工程算例验证表明,此计量方法实现了工程量的快速计算,可提升傍山渠道设计与计量的工作效率,有效释放了工程人力资源。     

采用三维实体在黄登大坝混凝土计量中的应用

随着科技发展,计量方法也在不断更新,传统的断面法计量与三维实体计量存在的最大差异,就是三维实体比传统断面计量更加严密、精确、直观。以基于VB[1,2]对Auto CAD[3,4]进行的二次开发所实现的仿真实体地形在黄登水电站大坝建基面混凝土浇筑工程量计算中的应用,达到利用三维实体可以充分直观展现地形、地貌特征并改变以往传统混凝土工程量计算方法,使大坝设计体型外建基面部位工程量的计算更严密、快捷、准确。     

坡改梯工程中田块设计参数影响土方工程量的探讨

土地开发整理是维护耕地总量动态平衡并提升土地经济效益的有效措施,也是实现土地集约化利用的必经之路,土方工程量的大小影响着土地整理的投资额度,准确计算土方工程量对于土地整理规划设计、投资的控制和资金的分配使用意义重大。文章采用断面法对坡改梯工程中田块设计参数对土方工程量的影响进行计算与探讨和优化设计,结果表明,田块坡度增加时,田坎高度也增大,且最佳取值为4.5 m以下;而且田面宽度、田面坡度、田坎倾角、田坎高度等是影响坡改梯工程土方工程量的关键性因素,其中田面宽度最适宜范围为10～40 m;考虑到经济效益的提升和机械化操作的适宜性,田面宽度不宜过小,田面坡度增加将引起最小土方量的增大。     

剖面法系列程序

一、编制依据灌区规划是农田水利设计的主体。而土方工程量的计算又是规划设计的主要项目之一。计算土方工程量的传统方法是剖面法。就是用手工或求积仪求出各剖面的地面剖面线和设计剖面线之间的挖填方面积,然后求出挖填方量,再根据挖填方量进行方案比较,以求得最优的断面设计施工方案。     

断面法数据记录、绘图与工程量计算自动化

以徕卡TC1100全站仪为例，讲述了在断面法土方测量中，实现野外数据自动记录、如何在Auto CAD环境下利用Auto LISP编程实现自动绘图、工程量自动计算。提高了工作效率，成果精度高、准确可靠。     

基于Monte Carlo模拟方法的土方开挖回填计算研究

为更精确地进行施工场地土方开挖（回填）的计算与管理,基于Monte Carlo模拟方法模拟土方开挖（回填）断面面积的随机分布状况,计算出不同变异系数情况下的土方开挖（回填）量,并对照实际土方开挖（回填）量,分别与均值法和分段计算法进行比较分析。结果表明：土方计算采用均值计算误差最大,而分段计算法与Monte Carlo计算法的误差最小,最接近实际用量,并且随着变异系数的增大,土方计算量的计量相对误差受影响程度均增大。提出更为合理有效的土方计算方法,解决了分段法土方计量过程中收集、计算大量数据困难的难题。     

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。     

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.     

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。