水利水电英语课文翻译
水利水电工程专业英语教材翻译
P71 2-1混凝土重力坝类型基本上，重力水坝保持其对设计载荷从几何形状和混凝土的质量和强度稳定坚固的混凝土结构。
一般情况下，它们在一条直线轴构成，但也可以稍微弯曲或成角度，以适应特定的现场条件。
重力坝通常由非溢流坝段（S）和溢出部分或溢洪道。
这两个一般混凝土的施工方法，混凝土重力坝是常规放置大体积混凝土和碾压。
Conventional concrete dams.传统的混凝土大坝。
（1）传统上放置大体积混凝土坝的特点是建筑施工中用的材料和配料使用的技术，混匀，放置，固化和大体积混凝土的温度控制（美国混凝土学会（ACI）207.1 R-87）。
典型溢出和非溢出部分示于图2-1和图2-2。
建筑采用已开发和完善了多年设计和建造大体积混凝土大坝的方法。
普通混凝土的水泥水化过程限制大小和混凝土浇筑的速度和建设就必须在巨石满足裂缝控制要求。
通常采用大尺寸的粗集料，混合比例被选择为产生低坍落度混凝土，使经济，在放置期间保持良好的加工性，水化过程中发育的最低温度上升，并产生重要性能如强度，抗渗性和耐久性。
大坝建设与传统的混凝土容易便于安装管道，压力管道，画廊等，在结构内。
（2）施工过程包括配料和混合，运输，安置，振动，冷却，固化，并准备电梯间的水平施工缝。
在重力坝大体积混凝土通常证明一个现场搅拌站，并需要足够的质量和数量，位于或项目的经济范围内的总根源。
一般是在水桶由卡车，铁路，起重机，索道，或这些方法的组合进行4至12立方码大小不等，从批次厂坝运输。
最大桶大小通常是通过有效地扩散和振动混凝土桩后它被从桶倾倒的能力受到限制。
混凝土被放置在5-升降机至10英尺的深度。
每部电梯由连续层不超过18至20英寸。
振动一般由大的人，气动，开钻式振动器进行。
保洁水平施工缝固化过程中去除表面上的薄弱浮浆薄膜的方法包括绿色切削，湿喷砂和高压气水射流。
传统的混凝土安置的其他详情载于EM 1110-2-2000。
（3）由于水泥水化产生的热量，需要在大体积混凝土的放置和放置几天后仔细的温度控制。
水利水电工程专业英语——河流工程篇
水利水电工程专业英语——河流工程篇1。
Some Problems Related to Alluvial Rivers(1)1。
与冲积河流相关的一些问题(1）Many of the earlier civilizations came into being the fertile valleys of large rivers. Civilizations prospered in the Nile valley in Egypt, along the Tigris and Eupharates rivers in Mesopotamia，along the Indus River. As early as 4000 B。
C. people built dams across the rivers to store water，dug canals for navigation purposes and also to carry water to the fields to produce much-needed food. Together with the problems associated with the irrigation works，these earlier civilizations were confronted with the problems of flood control and the Chinese had developed excellent systems of dikes for the protection of inhabited areas against floods。
很多早期的文明都孕育在大江大河的肥沃的河谷。
这些文明繁荣在在埃及尼罗河谷,沿着美索不达米亚的底格里斯河和幼发拉底河，沿着印度河流域。
早在公元前4000年，人们就横跨河流修建水坝来蓄水，以航运及将水带到农田以生产更加非常需要的事物为目的而开挖渠道.与同灌溉工程相关的问题一样，这些早期文明也面临着防洪的问题，而中国人则已经发展了防洪保护居住区的优秀堤防体系.Thus，since the dawn of civilization, mankind has faced problems associated with rivers，and solved them to the best of their ability。
水利水电工程专业英语Chapter 2 (25-38)
倍数的比较
• A is N times as large (long，heavy……）as B • A is N times larger (longer, heavier…) than B • A is larger (longer、heavier···) than B by N times
The oxygen atom is 16 times heavier than the hydrogen atom。 氧原子的重量是氢原子的16倍。 This substance reacts three times as fast as the other one 这一物质的反应速度比另一物质快两倍。
倍数的减少
half as much as twice less than
• “比……少一半”或“比……少二分之一”
The new engine may use half as much oil as the old one。 新引擎的油耗比旧引擎少一半。 The power output of the machine is twice less than its input。 该机器的输出功率比输入功率小二分之一。
倍数的译法
as+形容词+as+数词+…… 动词+as+副词+数词+…… as large as+数词……可译成“大到(至)……" as many as十数词… 可译成“多达……” as high as+数词…… 可译成“高达……” as low as十数词…… 可译成“低到(至)……” The temperature of liquid nitrogen is as low as -196℃
水利专业英语翻译部分
Lesson1 importa nce of water 水的重要性Water is best known and most abundan t of all chemica l compoun ds occurri ng in relativ ely pureformontheearth’ssurface. Oxygen,the most abundan t chemica l element, is present in combina tion with hydroge n to the extentof 89 percent in water. Water coversabout three fourths of the earth's surface and permeat es cracksof much solid land. The polar regions are overl ai d with vast quantiti es of ice, and the atmosphere of the earth carries water vapor in quantiti es from 0.1 percent to 2 percent by weight.It has been estimat ed that the amountof water in the atmosph ere above a squaremile of land on a mild summerday is of the order of 50,000 tons.在地球表面以相对纯的形式存在的一切化合物中，水是人们最熟悉的、最丰富的一种化合物。
在水中，氧这种最丰富的化学元素与氢结合，其含量多达89%。
水利水电工程专业英语——水文与水资源篇
水利水电工程专业英语——水文与水资源篇1. Hydrological Cycle and Budget1.水文循环与预算Hydrology is an earth science. It encompasses the occurrence, distribution, movement, and properties of the waters of the earth and their environmental relations. Closely allied fields include geology, climatology, meteorology and oceanography.水文学是一门地球科学。
它包含地球水资源的发生、分布、运动和特质，以及其环境关系。
与之密切相关领域包括地质学，气候学，气象学和海洋学。
The hydrologic cycle is a continuous process by which water is transported from the oceans to the atmosphere to the land and back to the sea. Many sub-cycles exist. The evaporation of inland water and its subsequent precipitation over land before returning to the ocean is one example. The driving force for the global water transport system is provided by the sun, which furnishes the energy required for evaporation. Note that the water quality also changes during passage through the cycle; for example, sea water is converted to fresh water through evaporation.水文循环是一个连续的过程，在这个过程中水从海洋被运输到大气中，降落到陆地，然后回到海洋。
水利水电工程专业英语的阅读与翻译
-graph
表示写 ，画， 记录结 果
和用具
photograph 照片，monograph 专题，论文
-let
表示小
droplet 水滴，streamlet 小溪
-logy
表示 学科
hydrology 水文学，geology 地质学
-meter
表示计，仪 表
barometer 气压计，voltmeter 电压表
uni
单，
uniflow 单向流，unify 统一
vari
变化
variable 变量，可变的，variation 变化，偏差
vers
转，向
reverse 反向，transverse 横向
vis
看
visual 直观的，prevision 预见
（2）英 语单词 的词尾 是接在 词根后 面的部 分，一 般地， 词尾的 意义比 较狭窄 和明 确，常 可根据 词尾来 判断英 语中大
水 利水 电工程 专业 英语的 阅读与 翻译
水利水电 工程
专业英语的阅读与翻译 刘景植 编
二 OO 四年十二月
水利水电 工程专 业英语 的阅读 与翻译
前言
当前，世 界科学 技术发 展十分 迅速， 为了了 解、学 习和借 鉴国 外先进 的科学 技术， 为我国 的社会 主义建 设服务 ，需要
大量的阅 读和翻 译国外 科技文 献资料 。另外 ，近年 来和在 以后 的若干 年内， 我国在 水利水 电建设 中，从 国外引 进了且
多数词的 词类。
专业英语 词汇中 的一些 常用的 词尾：
词尾
意义
词例
Ⅰ、名词 词尾
-age
表示抽象概 念，量 ，性质 ，状态 ，行为 等
水利水电工程专业英语段翻译
•Owingto the fact that electr icity can be transm itted from whereit is genera ted to whereit is needed by meansof powerlinesand transf ormer s, largepowerstatio ns can be builtin remote places far fromindust rialcenter s or largecities, as is citedthe case with hydroe lectr ic powerstatio ns that are insepa rable from watersource s.•由于电力可以从发电的地方通过电线和变压器输送到需要用电的地方，因此大型电站可以建在远离工业中心或大城市的地方，离不开水源的水力发电站就常常是这样建立的。
Ideall y suited to narrow canyon s compos ed of rock, the archdam provid es an econom icaland effici ent struct ure to contro lthe stream flow. The load-carryi ng capaci ty of an arch damenable s the design er to conser ve materi al and stillmainta in anextrem ely safe struct ure.•拱坝最适合于修建在岩石峡谷中，它是一种控制河道中水流经济而有效的建筑物。
一座拱坝的承载能力足以使设计人员用较少的材料而仍能建成极为安全的结构。
水利水电专业毕业设计外文翻译
毕业设计（论文）外文翻译题目水库及电力系统简介专业水利水电工程班级2007级四班学生陈剑锋指导教师杨忠超重庆交通大学2011 年RESERVOIRSWhen a barrier is constructed across some river in the form of a dam, water gets stored up on the upstream side of the barrier, forming a pool of water, generally called a reservoir.Broadly speaking, any water collected in a pool or a lake may be termed as a reservoir. The water stored in reservoir may be used for various purposes. Depending upon the purposes served, the reservoirs may be classified as follows: Storage or Conservation Reservoirs.Flood Control Reservoirs.Distribution Reservoirs.Multipurpose reservoirs.(1) Storage or Conservation Reservoirs. A city water supply, irrigation water supply or a hydroelectric project drawing water directly from a river or a stream may fail to satisfy the consumers’ demands during extremely low flows, while during high flows; it may become difficult to carry out their operation due to devastating floods. A storage or a conservation reservoir can retain such excess supplies during periods of peak flows and can release them gradually during low flows as and when the need arise.Incidentally, in addition to conserving water for later use, the storage of flood water may also reduce flood damage below the reservoir. Hence, a reservoir can be used for controlling floods either solely or in addition to other purposes. In the former case, it is known as ‘Flood Control Reservoir’or ‘Single Purpose Flood Control Reservoir’, and in the later case, it is called a ‘Multipurpose Reservoir’.(2) Flood Control Reservoirs A flood control reservoir or generally called flood-mitigation reservoir, stores a portion of the flood flows in such a way as to minimize the flood peaks at the areas to be protected downstream. To accomplish this, the entire inflow entering the reservoir is discharge till the outflow reaches the safe capacity of the channel downstream. The inflow in excess of this rate is stored in stored in the reservoir, which is then gradually released so as to recover the storage capacity for next flood.The flood peaks at the points just downstream of the reservoir are thus reduced by an amount AB. A flood control reservoir differs from a conservation reservoir only in its need for a large sluice-way capacity to permit rapid drawdown before or after a flood.Types of flood control reservoirs. There are tow basic types of flood-mitigation reservoir.Storage Reservoir or Detention basins.Retarding basins or retarding reservoirs.A reservoir with gates and valves installation at the spillway and at the sluice outlets is known as a storage-reservoir, while on the other hand, a reservoir with ungated outlet is known as a retarding basin.Functioning and advantages of a retarding basin:A retarding basin is usually provided with an uncontrolled spillway and anuncontrolled orifice type sluiceway. The automatic regulation of outflow depending upon the availability of water takes place from such a reservoir. The maximum discharging capacity of such a reservoir should be equal to the maximum safe carrying capacity of the channel downstream. As flood occurs, the reservoir gets filled and discharges through sluiceways. As the reservoir elevation increases, outflow discharge increases. The water level goes on rising until the flood has subsided and the inflow becomes equal to or less than the outflow. After this, water gets automatically withdrawn from the reservoir until the stored water is completely discharged. The advantages of a retarding basin over a gate controlled detention basin are:①Cost of gate installations is save.②There are no fates and hence, the possibility of human error and negligence in their operation is eliminated.Since such a reservoir is not always filled, much of land below the maximum reservoir level will be submerged only temporarily and occasionally and can be successfully used for agriculture, although no permanent habitation can be allowed on this land.Functioning and advantages of a storage reservoir:A storage reservoir with gated spillway and gated sluiceway, provides more flexibility of operation, and thus gives us better control and increased usefulness of the reservoir. Storage reservoirs are, therefore, preferred on large rivers which require batter controlled and regulated properly so as not to cause their coincidence. This is the biggest advantage of such a reservoir and outweighs its disadvantages of being costly and involving risk of human error in installation and operation of gates.(3) Distribution Reservoirs A distribution reservoir is a small storage reservoir constructed within a city water supply system. Such a reservoir can be filled by pumping water at a certain rate and can be used to supply water even at rates higher than the inflow rate during periods of maximum demands (called critical periods of demand). Such reservoirs are, therefore, helpful in permitting the pumps or water treatment plants to work at a uniform rate, and they store water during the hours of no demand or less demand and supply water from their ‘storage’ during the critical periods of maximum demand.(4) Multipurpose Reservoirs A reservoir planned and constructed to serve not only one purpose but various purposes together is called a multipurpose reservoir. Reservoir, designed for one purpose, incidentally serving other purpose, shall not be called a multipurpose reservoir, but will be called so, only if designed to serve those purposes also in addition to its main purpose. Hence, a reservoir designed to protect the downstream areas from floods and also to conserve water for water supply, irrigation, industrial needs, hydroelectric purposes, etc. shall be called a multipurpose reservoir.水库拦河筑一条像坝的障碍时，水就被拦蓄在障碍物的上游并形成水塘．通常称之为水库。
水利电力英文翻译英文+中文
OVERFLOW SPILLWAYAn overflow spillway is a section of dam designed to permit water to pass over its crest. Overflow spillways are widely used on gravity, arch, and buttress dams. Some earth dams have a concrete gravity section designed to serve as a spillway. The design of the spillway for tow dams is not usually critical, and a variety of simple crest patterns are used. In the case of large dams it is important that the overflowing water be guided smoothly over the crest with a minimum of turbulence. If the overflowing water breaks contact with the spillway surface, a vacuum will form at the point of separation and cavitations may occur. Cavitations plus the vibration from the alternates making and breaking of contact between the water and the face of the dam may result in serious structural damage.Cavities filled with vapor, air, and other gases will form in a liquid whenever the absolute pressure of the liquid is close to the vapor pressure. This phenomenon, cavitations, is likely to occur where high velocities cause reduced pressure. Such conditions may arise if the walls of a passage are so sharply curved as to cause separation of flow from the boundary. The cavity, on moving downstream, may enter a region where the absolute is much higher. This causes the vapor in the cavity to condense and return to liquid with a resulting implosion, or collapse, extremely high pressure result. Some of the implosive activity will occur at the surfaces of the passage and in the crevices and pores of the boundary material. Under a continual bombardment of these implosions, the surface undergoes fatigue failure and small particles are broken away, giving the surface a spongy appearance. Thisdamaging action of cavitations is called pitting.The ideal spillway would take the form of the underside of the napped of a sharp-crested weir when the flow rate corresponds to the maximum design capacity of the spillway. More exact profiles may be found in more extensive treatments of the subject. The reverse curve on the downstream face of the spillway should be smooth and gradual; A radius of about one-fourth of the spillway height has proved satisfactory. Structural design of an ogee spillway is essentially the same as the design of a concrete gravity section. The pressure exerted on the crest of the spillway by the flowing water and the drag forces caused by fluid friction are usually small in parison with the other forces acting on the section. The change in momentum of the flow in the vicinity of the reverse curve may, however, create a force which must be considered. The requirements of the ogee shape usually necessitate a thicker section than the adjacent no overflow sections.A saving of concrete can be effected by providing a projecting corbel on the upstream face to control the flow in outlet conduits through the dam, a corbel will interfere with gate operation. The discharge of an overflow spillway is given by the weir equation23C Q Lh ω=Where Q=discharge, or sec /3m t coefficien C =ωL=coefficienth=head on the spillway (vertical distance from the crest of the spillway tothe reservoir level), mThe coefficient ωC varies with the design and head. Experimental models are often used to determine spillway coefficient. End contractions on a spillway reduce the effective length below the actual length L. Square-cornered piers disturb the flow considerably and reduce the effective length by the width of the piers plus about 0.2h for each pier.Streamlining the piers or flaring the spillway entrance minimizes the flow disturbance. If the cross-sectional area of the reservoir just upstream from the spillway is less than five times the area of flow over the spillway, the approach velocity with increase the discharge a noticeable amount. The effect of approach velocity can be accounted for by the equation2320g 2V h Q ⎪⎪⎭⎫ ⎝⎛+=L C ω where 0V is the approach velocity.PROPERTIES OF CONCRETEThe characteristics of concrete should be considered in relation to the quality for any given construction purpose. The closest practicable approach to perfection in every property of the concrete would result in poor economy under many conditions, and the most desirable structure is that in which the concrete has been designed with the correct emphasis on each of the various properties of the concrete, and not solely with a view to obtaining, say, the maximum possible strength.Although the attainment of the maximum strength should not be the sole criterionin design, the measurement of the crushing strength of concrete cubes or cylinders provides a means of maintaining a uniform standard of quality, and, in fact, is the usual way of doing so. Since the other properties of any particular mix of concrete are related to the crushing strength in some manner, it is possible that as a single control test it is still the most convenient and informative.The testing of the hardened concrete in prefabricated units presents no difficulty, since plete units can be selected and broken if necessary in the process of testing. Samples can be taken from some parts of a finished structure by cutting cores, but at consider one cost and with a possible weakening of the structure. It is customs, therefore, to estimate the properties of the concrete in the structure on the oasis of the tests made on specimensmounded from the fresh concrete as it is placed. These specimens are pacted and cured in a standard manner given in BS 1881 in 1970 as in these two respects it is impossible to simulate exactly the conditions in the structure. Since the crushing structure is also affected by the size and shape of a specimen or part of a structure, it follows that the crushing strength of a cube is not necessary the same as that of the mass of exactly the same concrete.Crushing strengthmm,or Concrete can be made having a strength in pression of up to about 80N/2 even more depending mainly on the relative proportions of water and cement, that is, the water/cement ratio, and the degree of paction. Crushing strengths ofmm at 28 days are normally obtained on the site with between 20 and 50 N/2reasonably good supervision, for mixes roughly equivalent to 1:2:4 of cement: sand: coarse aggregate. In some types of precast concrete such as railway sleepers,mm at 28 days are obtained with rich mixes strengths ranging from 40 to 65 N/2having a low water/cement ratio.The crushing strength of concrete is influenced by a number of factors in addition to the water/cement ratio and the degree of paction. The more important factors areType of cement and its quality. Both the rate of strength gain and the ultimate strength may be affected.Type and surface texture of aggregate. There is considerable evidence to suggest that some aggregates produce concrete of greater pressive and tensile strengths than obtained with smooth river gravels.Efficiency of curing. A loss in strength of up to about 40 per cent may result from premature drying out. Curing is therefore of considerable, importance both in the field and in the making of tests. The method of curing concrete test cubes given in BS 1881 should, for this reason, be strictly adhered to.Temperature In general, the rate of hardening of concrete is increased by an increase temperature. At freezing temperatures the crushing strength may remain low for some time.Age Under normal conditions increase in strength with age, the rate of increase depending on the type of cement with age. For instance, high alumina cement produces concrete with a crushing strength at 21 hours equal to that of normalPortland cement concrete at 28 days. Hardening continues but at a much slower rate for a number of years.The above refers to the static ultimate load. When subjected to repeated loads concrete fails at a load smaller than the ultimate static load, a fatigue effect.A number of investigators have established that after several million cycles of loading, the fatigue strength in pression is 50-60 per cent of the ultimate static strength.Tensile and flexural strengthThe tensile strength of concrete varies from one-eighth of the pressive strength at early ages to about one- twentieth later, and is not usually taken into account in the design of reinforced concrete structures. The tensile strength is, however, of considerable importance in resisting cracking due to changes in moisture content or temperature. Tensile strength tests are used for concrete roads and airfields.The measurement of the strength of concrete in direct tension is difficult and is rarely attempted. Two more practical methods of assessing tensile strength are available. One gives a measure of the tensile strength in bending, usually termed the flexural strength. BS 1881:1970 gives details concerning the making and curing of flexure test specimens, and of the method test. The standard size of specimen is 150mm×150mm×750mm long for aggregate of maximum size 40mm. If the largest nominal size of the aggregate is 20mm, specimens 100mm×100mm×750mm long may be used.A load is applied through two rollers at the third points of the span untilthe specimen breaks. The extreme fiber stresses, that is, pressive at the top and tensile at the bottom, can then be puted by the usual beam formulae. The beam will obviously fail in tension since the tensile strength is much lower than the pressive strength. Formulae for the calculation of the modulus of rupture are given in BS 1881:1970.Test specimens is the form of beams are sometimes used to measure the modulus of rupture or flexural strength quickly on the site. The two halves of the specimen may then be crushed so that besides the flexuralstrength the pressive strength can be approximately determined on the same sample. The test is described in BS 1881:1970.Values of the modulus of rupture are utilized in some methods of design of unreinforced concrete roads and runways, in which reliance is placed on the flexuralstrength of the concrete to distribute concentrated loads over a wide area.More recently introduced is a test made by splitting cylinders by pression across the diameter, to give what is termed the splitting tensile strength; Details of the method are given in BS 1881:1970.Values of the modulus of rupture are utilized in some methods of design of unreinforced concrete roads and runways, in which reliance is place on the flexural strength of the concrete to distribute concentrated loads over a wide area.More recently introduced is a test made by splitting cylinders by pression across the diameter, to give what is termed the splitting tensile strength; Details of the method are given in BS 1881:1970. the testing machine is fitted with anextra bearing bar to distribute the load along the full length of the cylinder Plywood strips, 12mm wide and 3mm thick are inserted between the cylinder and the testing machine bearing surfaces top and bottom.From the maximum applied load at failure the tensile splitting strength is calculated as follows:ld p2f t π=Where =t f splitting tensile strength, N/2mmP=maximum applied load in Nl=length of cylinder in mmd=diameter in mmAs in the case of the pressive strength, repeated loading reduces the ultimate strength so that the fatigue strength in flexure is 50-60 per cent of the static strength.Shear strengthIn practice, shearing of concrete is always acpany pression and tension caused by bending, and even in testing is impossible to staminate an element of bending. RESERVOIRSWhen a barrier is constructed across some river in the form of a dam, water gets stored up on the upstream side of the barrier, forming a pool of water, generally called a reservoir.Broadly speaking, any water collected in a pool or a lake may be termed as a reservoir. The water stored in reservoir may be used for various purposes.Depending upon the purposes served, the reservoirs may be classified as follows: Storage or Conservation Reservoirs.Flood Control Reservoirs.DistributionReservoirs.Multipurpose reservoirs.(1) Storage or Conservation Reservoirs. A city water supply, irrigation water supply or a hydroelectric project drawing water directly from a river or a stream may fail to satisfy the consumers’ demands during extremely low flows, while during high flows; it may bee difficult to carry out their operation due to devastating floods. A storage or a conservation reservoir can retain such excess supplies during periods of peak flows and can release them gradually during low flows as and when the need arise.Incidentally, in addition to conserving water for later use, the storage of flood water may also reduce flood damage below the reservoir. Hence, a reservoir can be used for controlling floods either solely or in addition to other purposes. In the former case, it is known as ‘Flood Control Reservoir’or ‘Single Purpose Flood Control Reservoir’, and in the later case, it is called a ‘Multipurpose Reservoir’.(2) Flood Control Reservoirs A flood control reservoir or generally called flood-mitigation reservoir, stores a portion of the flood flows in such a way as to minimize the flood peaks at the areas to be protected downstream. To acplish this, the entire inflow entering the reservoir is discharge till the outflowreaches the safe capacity of the channel downstream. The inflow in excess of this rate is stored in stored in the reservoir, which is then gradually released so as to recover the storage capacity for next flood.The flood peaks at the points just downstream of the reservoir are thus reduced by an amount AB. A flood control reservoir differs from a conservation reservoir only in its need for a large sluice-way capacity to permit rapid drawdown before or after a flood.Types of flood control reservoirs. There are tow basic types of flood-mitigation reservoir.Storage Reservoir or Detention basins.Retarding basins or retarding reservoirs.A reservoir with gates and valves installation at the spillway and at the sluice outlets is known as a storage-reservoir, while on the other hand, a reservoir with ungated outlet is known as a retarding basin.Functioning and advantages of a retarding basin:A retarding basin is usually provided with an uncontrolled spillway and an uncontrolled orifice type sluiceway. The automatic regulation of outflow depending upon the availability of water takes place from such a reservoir. The maximum discharging capacity of such a reservoir should be equal to the maximum safe carrying capacity of the channel downstream. As flood occurs, the reservoir gets filled and discharges through sluiceways. As the reservoir elevation increases, outflow discharge increases. The water level goes on rising until the flood hassubsided and the inflow bees equal to or less than the outflow. After this, water gets automatically withdrawn from the reservoir until the stored water is pletely discharged. The advantages of a retarding basin over a gate controlled detention basin are:① Cost of gate installations is save.② There are no fates and hence, the possibility of human error and negligence in their operation is eliminated.Since such a reservoir is not always filled, much of land below the maximum reservoir level will be submerged only temporarily and occasionally and can be successfully used for agriculture, although no permanent habitation can be allowed on this land.Functioning and advantages of a storage reservoir:A storage reservoir with gated spillway and gated sluiceway, provides more flexibility of operation, and thus gives us better control and increased usefulness of the reservoir. Storage reservoirs are, therefore, preferred on large rivers which require batter controlled and regulated properly so as not to cause their coincidence. This is the biggest advantage of such a reservoir and outweighs its disadvantages of being costly and involving risk of human error in installation and operation of gates.(3) Distribution Reservoirs A distribution reservoir is a small storage reservoir constructed within a city water supply system. Such a reservoir can be filled by pumping water at a certain rate and can be used to supply water evenat rates higher than the inflow rate during periods of maximum demands (called critical periods of demand). Such reservoirs are, therefore, helpful in permitting the pumps or water treatment plants to work at a uniform rate, and they store water during the hours of no demand or less demand and supply water from their ‘storage’during the critical periods of maximum demand.(4) Multipurpose Reservoirs A reservoir planned and constructed to serve not only one purpose but various purposes together is called a multipurpose reservoir. Reservoir, designed for one purpose, incidentally serving other purpose, shall not be called a multipurpose reservoir, but will be called so, only if designed to serve those purposes also in addition to its main purpose. Hence, a reservoir designed to protect the downstream areas from floods and also to conserve water for water supply, irrigation, industrial needs, hydroelectric purposes, etc. shall be called a multipurpose reservoir.THE ELECTRIC POWER SYSTEMA great amount of effort is necessary to maintain an electric power supply within the requirement of the various types of customers served. Large investments are necessary, and continuing advancements in methods must be made as loads steadily increase from year to year. Some of the requirements for electric power supply are recognized by most consumers, such as proper voltage, availability of power on demand, reliability, and reasonable cost. Other characteristics, such as frequency, wave shape, and phase balance, are seldom recognized by the customer but are given constant attention by the utility power engineers.The voltage of the power supply at the customer’s service entrance must be held substantially constant. Variations in supply voltage are, from the customer’s view, detrimental in various respects. For example, below-normal voltage substantially reduces the light output from incandescent lamps. Above-normal voltage increase the light output but substantially reduces the life of the lamp. Motor operate at below-normal voltage draw abnormally high current and may overheat, even when carrying no more than the rated horsepower load. Over voltage on a motor may cause excessive heat loss in the iron of the motor, wasting energy and perhaps damaging the machine. Service voltages are usually specified by a nominal value and the voltage than maintained close to this value, deviating perhaps less than 5 percent above or below the nominal value. For example, in a 120-volt residential supply circuit, the voltage might normally vary between the limits of 115 and 125 volts as customer load and system conditions change throughout the day.Power must be available to the consumer in any amount that be may require from minute to minute. For example, motors may be turned on or off, without advance warning to the electric power pany. As electrical energy cannot be stored (except to a limited extent in storage batteries), the changing loads impose severe demands on the control equipment of any electrical power system. The operating staff must continually study load patterns to predict in advance those major load changes that follow known schedules, such as the starting and shutting down of factories at prescribed hours each day.The demands for reliability of service increase daily as our industrial and social environment bees more plex. Modern industry is almost locally dependent on electric power for its operation. Homes and office buildings are lighted, heated, and ventilated by electric power. In some instances loss of electric power may even pose a threat a life itself. Electric power, like everything else that is man-made can never be absolutely reliable. Occasional interruptions to service in limited areas will continue. Interruptions to large areas remain a possibility, although such occurrences may be very infrequent. Further interconnection of electric supply systems over wide areas, continuing development of reliable automated control systems and apparatus; provision of additional reserve facilities; and further effort in developing personnel to engineer, design, construct, maintain, and operate these facilities will continue to improve the reliability of the electric power supply.The cost of electric power is a prince consideration in the design and operation of electric power is a prime consideration in the design and operation of electric power system. Although the cost of almost all modities has risen steadily over the past many years, the cost per kilowatt-hour of electrical energy has actually declined. This decrease in cost has been possible because of improved efficiencies of the generating stations and distribution systems. Although franchises often grant the electric power pany exclusive rights for the supply of electric power to an area. There is keen petition between electric power and other forms of energy, particularly for heating and for certain heavy load industrial processes.The power supply requirements just discussed are all well known to most electric power users. There are, however, other specifications to the electric power supply which are so effectively handled by the power panies that consumers are seldom aware that such requirements are of importance.The frequency of electric power supply in the United States is almost entirely 60 hertz (formerly cycles per second). The frequency of a system is dependent entirely upon the speed at which the supply generator is rotated by its prime mover. Hence frequency control is basically a matter of speed control of the machines in the generating stations. Modern speed-control systems are very effective and hold frequency almost constant. Deviations are seldom greater than 0.02 hertz.In an ac system the voltage continually varies with time, at one instant being positive and a short time later being negative, going through 60 plete cycles of change in each second. Ideally a plot of the time change should be a sine wave.In poorly designed generating equipment, harmonics may be present and the wave shape may be somewhat. The presence of harmonics produces unnecessary losses in the customer’s equipment and sometime produces hum in nearby telephone lines. The voltage wave shape is basically determined by the construction of the generation equipment. The power panies put specification limitations on the harmonic content of generator voltages and so require equipment manufactures to design and build their machines to minimize from this effect. ENVIRONMENT POLLUTIONThe existence of pollution in the environment, as a national and a world problem,was not generally recognized until the 1960s.Today many people regard pollution as a problem that will not go away, but one that could get worse in the future. It is increasingly being appreciated that the general effects of pollution produce a deterioration of the quality of the environment. This usually means that pollution is responsible for dirty streams, rivers and sea shorts, atmospheric contamination, the dissociation of the countryside, urban dereliction, affecting the environment in which people reside, work, and spend their leisure time.The present increasing emphasis upon pollution may create the impression that there has been a relatively sudden deterioration of the environment, that was not apparent twenty or thirty years ago. This is not the case. Pollution must have started at the time when man began to use the natural resources of the environment for his own benefit. At he began to develop a settled life in small munities, the activities of clearing trees, building shelter, cultivating crops, and preparing and cooking food must have altered the natural environment. Later, as the human population increased and became concentrated into large munities which developed craft skills. There were increasing quantities of human and animal waste and rubbish to be disposed of in the early days of man’s existence the amount of waste was small. It was disposed of locally and had virtually no effect upon the environment. Later, when large human settlements and towns were established, waste disposal began to cause obvious pollution of streets and water courses. In the thirteenth century the prevalence of cholera, typhus, typhoid and bubonic plague was associated with the lack of proper waste disposal methods. By themed-nineteenthcentury the population of the UK had increased to 22 million, and many canals and rivers were grossly polluted with sewage and industrial waste. Some sewerage systems existed in towns, but the collected sewage was discharged into the nearest river without ant treatment. Salmon had pletely disappeared from the River Thames and outbreaks of cholera still occurred in London. A Royal mission on the Prevention of River Pollution was established in 1857, and eventually the first preventive river pollution legislation was passed in 1876 and 1890. However, there was little significant improvement in pollution until after the First World War, and the condition of rivers had deteriorated again by the end of the Second World War. Even today, a number of British and continental coastal towns discharge almost untreated sewage into near-shore waters.The increasing pollution of land water was acpanied by air pollution. This must have begun as soon as man started to use wood fires to provide ‘space hosting’and a means of cooking food. Later surface, soft coal was discovered and used as a fuel, and records shown that coal smokes was a nuisance in London in the thirteenth century. In 1273,Edward I made the first ever anti-pollution law to prevent the use of coal for domestic heating, so smoke pollution has been recognized for at least 700 years. However, smoke pollution in London continued and is recorded in both the sixteenth and seventeenth centuries. In the late eighteenth and throughout the nineteenth centuries there was a marked increase in air pollution, because of the greater use of coal by developing industry. From 1750, the chemical industry began to develop, and this caused the discharge of acid fumes into the smoky airof some manufacturing towns. A Royal mission was set up in 1862 to consider air pollution and this resulted in the first Alkali Act in 1863, which set limits to the concentration of acid in discharged waste gases. However, the increasing domestic and industrial bustion of coal, and the production of piped coal gas from 1815, caused air pollution to steadily get worse. Large cities were particularly affected, and the well known 5 day smog incident in London in 1952 directly contributed to the deaths of 4000 people. As a result, the Beaver mittee on Air Pollution was established in 1953, and the Clean Air Act was passed in 1956. This was the first effective statute to provide the means of controlling atmospheric pollution.Noise pollution probably started when man first developed machines. The increase in industrial plants in the nineteenth century produce indoor noise pollution of the working environment for many factory and mill workers over a 6 day week. Outdoors, the development of private and public transport bright environmental noise, as the railway services came into use during the 1830s, motor transport from 1900, and regular aero plane services from 1922. during the first half of the twentieth century environmental noise considerably increased, but it was not recognized as pollution. Industrial and outdoor noise was designated as ‘nuisance’when the Noise Abatement Act was passed in 1960. Whereas the earlier increase in noise occurred in work places and in connection with transport, during the past thirty years noise has spread into the home and places of leisure and entertainment. Certainly the most rapid increase in environmental pollution has。
水利水电翻译
Design of SpillwaysSpillways are ordinarily classified according to their most prominentfeature .Commonly referred to types can be listed as follows.1. Free Overall (Straight Drop) SpillwaysA free overfall or straight drop spillways is one in which the flow drops freely from the crest. This type is suited to a thin arch or deck overflow dam or to a crest is which has a nearly vertical downstream face. Occasionally the crest is extended in the form of an overhanging lip to direct small discharges away from the face of the overfall section.Where no artificial protection is provided at the base of the overfall, scour will occur in most streambeds and will form a deep plunge poll. The volume and depth of the hole are related to the range of discharges, the height of the drop, and the depth of tailwater.A free overfall spillways is not adaptable for high drops on yielding foundations, because of the large impact forces which must be absorbed by the apron at the pointof impingement of the jet. Vibrations incident to the impact might crack or displace the structure, with danger from failure by piping or undermining. Ordinarily, the useof this structure for hydraulic drops from head pool to tailwater in excess of 20 feet should not be considered.2. Ogee (Overflow) SpillwaysThe ogee spillways has a control weir which is ogee or S-shaped in profile. The upper curve of the ogee ordinarily is made to conform closely to the profile of lower nappe of a ventilated sheet falling from a sharp-crested weir. Flow over the crest is made to adhere to the face of the profile by prevening access of air to the under sideof the sheet. For discharges at designed head, the flow glides over the crest with no interference from the boundary surface and attains near maximum discharge efficiency. The profile below the upper curve of the ogee is continued tangent along a slope to support the sheet on the face of the overflow. A reverse curve at the bottom of the slope turns the flow onto the apron of a stilling basin or into the spillway discharge channel.An ogee crest and apron may comprise all entire spillway, such as the overflow portion of a concrete gravity dam, or the ogee crest may only be the control structure for some other type of spillway. Because of its high discharge efficiency, thenappe-shaped profile is used for most spillway control crests.3. Side Channel SpillwaysThe side channel spillway is one in which the control weir is placed along the side of and approximately parallel to the upper portion of the spillway discharge channel. Flow over the crest falls into a narrow trough opposite the weir, turns an approximate right angle, and then continues into the main discharge channel.Discharge characteristics of a side channel spillway are similar to those of an ordinary overflow and are dependent on the selected profile of the weir crest. The discharge constriction may be a point of critical flow in the channel, an orifice control, or a conduit or tunnel flowing full. Although the side channel is neither hydraulically efficient nor inexpensive, it has advantages which make it adaptable to certainspillway layouts.4. Chute (Open Channel or Trough) SpillwaysA spillways, whose discharge is conveyed from the reservoir to the downstream river level through an open channel, placed either along a dam abutment or through a saddle, might be called a chute, open channel, or trough type spillway. These designations can apply regardless of the control device used to regulate the flow. Thus, a spillway having a chute-type discharge channel,though controlled by an overflow crest, a gated orifice, a side channel crest, or some other control device, might still be called a chute spillway. However, the name is most often applied when the spillway control is placed normal or nearly normal to the axis of an open channel, and where the streamlines of flow both above and below the control crest follow in the direction of the axis.The chute spillway has been used with earth fill dams more often than any other type. Factors influencing the selection of chute spillways are the simplicity of their design and construction, their adaptability to almost any foundation condition, and the overall economy often obtained by the use of large amounts of spillways excavationin the dam embankment.Chute spillways ordinarily consist of an entrance channel, a control structure, a discharge channel, a terminal structure, and an outlet channel. The simplest form of chute spillway has a straight centerline and is of uniform width. Often, either the axis of the entrance channel or that of the discharge channel must be curved to fit the alignment to the topography. In such cases,the curvature is confined to the entrance channel if possible, because of the low approach velocities. Where the discharge channel must be curved, its floor is sometimes superelevated to guide thehigh-velocity flow around the bend, thus avoiding a piling up of flow toward the outside of the chute.5. Conduit and Tunnel SpillwaysWhere a closed channel is used to convey the discharge around or under a dam, the spillway is often called a tunnel or conduit spillway, as appropriate. The closed channel may take the from of a vertical or inclined shaft, a horizontal tunnel through earth or roke, or a conduit constructed in open cut and backfilled with earth materials. Most forms of control structures,including overflow crest,vertical of inclined orifice entrances, drop inlet entrances, and side channel crests, can be used with conduit and tunnel spillways.With the drop inlet or orifice control, the tunnel or conduit size is selected so that it flows full for only a short section at the control and thence partly full for its remaining length. To guarantee free flow in the tunnel, the ratio of the flow area to the total tunnel area is often limited to about 75 percent. Air vents may be provided at critical points along the tunnel or conduit to insure an adequate air supply which will avoid unsteady flow through the spillway.Tunnel spillways may present advantages for dam sites in narrow canyons with steep abutments or at sites where there is danger to open channels from snow or rock slides. Conduit spillways may be appropriate at dam sites in wide valleys, where the abutments rise gradually and are at a considerable distance from the stream channel.Use of a conduit will permit the spillway to be located under the dam near the streambed.6. Drop Inlet (Shaft or Morning Glory) SpillwaysA drop inlet or shaft spillway, as the name implies, is one in which the water enters over a horizontally positioned lip, drops through a vertical or sloping shaft, and then flow to the downstream river channel through a horizontal or near horizontal conduit or tunnel. The structure may be considered as being made up of three elements; namely,an overflow control weir, a vertical transition,and a closed discharge channel. Where the inlet is funnel-shaped, this type of structure is often called a "morning glory" or "glory hole" spillway.Discharge characteristics of the drop inlet spillway may vary with a range of head. For example, as the heads increase on a glory hole spillway, the control will shift from weir flow over the crest to tube flow in the transition and then to full pipe flow in the downstream portion. A drop inlet spillway can be used advantageously at dam sites in narrow canyons where the abutments rise steeply or where a diversion tunnel or conduit is available for use as the downstream leg. Another advantage of this type of spillway is that near maximum capacity is attained at relatively low heads.7. Siphon SpillwaysA siphon spillway is a closed conduit system formed in the shape of an inverted U, positioned so that inside of the bend of the upper passageway is at normal reservoir storage level. The initial discharges of the spillway, as the reservoir level rises above normal, are similar to flow over a weir. Siphonic action takes place after the air in the bend over the crest has been exhausted. Continuous flow is maintained by the suction effect due to the gravity pull of the water in the lower leg of the siphon.The principal advantage of a siphon spillway is its ability to pass full capacity discharges with narrow limits of headwater rise. A further advantage is its positive and automatic operation without mechanical devices or moving parts.设计溢洪道溢洪道设计溢洪道通常分类根据其最突出的特征。
水利水电工程专业英语段翻译
•Owing to the fact that electricity can be transmitted from where it is generated to where it is needed by means of power lines and transformers, large power stations can be built in remote places far from industrial centers or large cities, as is cited the case with hydroelectric power stations that are inseparable from water sources.•由于电力可以从发电的地方通过电线和变压器输送到需要用电的地方，因此大型电站可以建在远离工业中心或大城市的地方，离不开水源的水力发电站就常常是这样建立的。
Ideally suited to narrow canyon s composed of rock, the arch dam provides an economical and efficient structure to control the stream flow. The load-carrying capacity of an arch damenables the designer to conserve material and still maintain an extremely safe structure.•拱坝最适合于修建在岩石峡谷中，它是一种控制河道中水流经济而有效的建筑物。
一座拱坝的承载能力足以使设计人员用较少的材料而仍能建成极为安全的结构。
•The general theory of arch dam design is comparatively new and changing rapidly as more information is obtained. Engineers have cautiously applied mathematical theory, the law of mechanics, and theories of elasticity to reduce the thickness of arch dams and gain substantial economies.•拱坝的一般设计理论比较新颖，同时在获得更多的资料之后，理论的变化也很迅速。
毕业设计水利水电工程英文文献翻译
外文文献：hydraulicturbines and hydro—electric powerAbstractPower may be developed from water by three fundamental processes ：by action of its weight, of its pressure，or of its velocity，or by a combination of any or all three。
In modern practice the Pelton or impulse wheel is the only type which obtains power by a single process the action of one or more high-velocity jets. This type of wheel is usually found in high—head developments. Faraday had shown that when a coil is rotated in a magnetic field electricity is generated. Thus, in order to produce electrical energy, it is necessary that we should produce mechanical energy，which can be used to rotate the ‘coil’。
The mechanical energy is produced by running a prime mover （known as turbine ）by the energy of fuels or flowing water. This mechanical power is converted into electrical power by electric generator which is directly coupled to the shaft of turbine and is thus run by turbine. The electrical power, which is consequently obtained at the terminals of the generator，is then transited to the area where it is to be used for doing work.he plant or machinery which is required to produce electricity (i.e。
水利水电工程中英文对照外文翻译文献
中英文对照外文翻译文献(文档含英文原文和中文翻译)译文：研究钢弧形闸门的动态稳定性摘要由于钢弧形闸门的结构特征和弹力，调查对参数共振的弧形闸门的臂一直是研究领域的热点话题弧形弧形闸门的动力稳定性。
在这个论文中，简化空间框架作为分析模型，根据弹性体薄壁结构的扰动方程和梁单元模型和薄壁结构的梁单元模型，动态不稳定区域的弧形闸门可以通过有限元的方法，应用有限元的方法计算动态不稳定性的主要区域的弧形弧形闸门工作。
此外，结合物理和数值模型，对识别新方法的参数共振钢弧形闸门提出了调查，本文不仅是重要的改进弧形闸门的参数振动的计算方法，但也为进一步研究弧形弧形闸门结构的动态稳定性打下了坚实的基础。
简介低举升力，没有门槽，好流型，和操作方便等优点，使钢弧形闸门已经广泛应用于水工建筑物。
弧形闸门的结构特点是液压完全作用于弧形闸门，通过门叶和主大梁，所以弧形闸门臂是主要的组件确保弧形闸门安全操作。
如果周期性轴向载荷作用于手臂，手臂的不稳定是在一定条件下可能发生。
调查指出:在弧形闸门的20次事故中，除了极特殊的破坏情况下，弧形闸门的破坏的原因是弧形闸门臂的不稳定;此外，明显的动态作用下发生破坏。
例如:张山闸，位于中国的江苏省，包括36个弧形闸门。
当一个弧形闸门打开放水时，门被破坏了，而其他弧形闸门则关闭，受到静态静水压力仍然是一样的，很明显，一个动态的加载是造成的弧形闸门破坏一个主要因素。
因此弧形闸门臂的动态不稳定是造成弧形闸门(特别是低水头的弧形闸门)破坏的主要原是毫无疑问。
基于弧形闸门结构和作用力的特点，研究钢弧形闸门专注于研究弧形闸门臂的动态不稳定。
在1980年的，教授闫世武，教授张继光公认的参数振动引起的弧形闸门臂动态不稳定的是原因之一。
他们提出了一个简单的分析方法，近年来，在一些文献中广泛地被引用进来调查。
然而，这些调查的得到都基于模型，弧形闸门臂被视为平面简单的梁，由于弧形弧形闸门是一个复杂的空间结构，三维效果非常明显，平面简单的梁的模型无法揭示这个空间效果，并不能精确的体现弧形闸门臂的动态不稳定性，本文提出一种计算方法用于分析弧形闸门的动态不稳定。
水电工程英语学习和翻译
但一定要想办法验证。对于猜测出来的术语，都应到专业网站上去查实后才会采用。
如电气词汇，可上国际电工协会的文章里核对；水电的词汇，可上美国陆军工程师团 的文章里核对。术语选择时，最忌望文生义。如在翻译一篇风电文章时，有译者将 “风机”不假思索地翻译成“fan”,实际上应翻译成”wind turbine”，它们可是完全
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水利水电外文翻译2
The roller-compacted concrete gravity dam(1)The synopsis of the roller—compacted concrete gravity damThe concrete gravity dam shares with the embankment the central attributes of simplicity of concept and adaptability, but conventional mass concrete construction rates, unlike those for embankment construction ,remain essentially as they were m the 1950s. the volume instability of mass concrete due to thermal effects imposes severe limitations on the size and rate of concret pour, causing delay and disruption through the need to provide contraction joints and similar design features. Progressive reductions in cement content and partial replacement of cement with PFA have served only to contain the problem. Mass concrete construction remains a semi-continuous and labour- intensive operation of low overall productivity and efficiency.In some circumstances the technical merits of the gravity dam and the embankment may be evenly balanced. selection resting on estimated construction cost. Economic advantage will almost invariably favour the embankment. particularly if constructed in compacted rockfill. In some instances ,however, factors such as locating a spillway of sufficient capacity etc. may indicate the concrete gravity dam as being a preferable design solution. provided that the cost differential lies within acceptable limits.Despite advances in embankment dam engineering, therefore, there remains a strong incentive to develop a cheaper concrete gravity dam.The problem of optimizing concrete dam construction and reducing costs can be approached in several ways. In the absence of progress towards an ideal cement and a dimensionally stable concrete the most promising lines of approach may be classified as follows:1. A reappraisal of design criteria, particularly with regard to accepting modest tensile stresses;2.The development of improved mass concretes through the use ofadmixtures to enhance tensile strength and to modify stress-strain response. and/or the use of modified cements with reduced thermal activity;3. The development of rapid continuous construction techniques based on the use of special concrete.Neither of the first two approaches is capable of offering other than a token reduction in cost. the third option offers the greatest potential through financial benefits associated with a shortening of construction period by up to 35% combined with a lower-cost variant of concrete.The concept of dam construction using roller-compacted concrete (RCC), first developed in the 1970s, is based primarily on approach 3.Several variants of RCC have now been developed and offer the prospect of significantly faster and cheaper construction. particularly for large.gravity dams.(2) developments in roller-compacted concrete dam constructionThe RCC dam has developed rapidly since construction of the earliest examples in the early 1980s. and in excess of 200 large dams had been completed in RCC by 2000.the majority of RCC dams have Been gravity structures, but the RCC technique has been extended to a number of archgravity and thick arch dams As confidence has grown RCC has been used for progressively larger dams, and RCC is being employed for the major part of the 7. 6 x 106m3 volume and 217m high longtan gravity dam, under construction in China. In a number of recent instances the RCC gravity dam option has been selected in preference to initial proposals for the construction of a rockfill embankment.The early RCC dam were noted for problems associated with relatively high seepage and leakage through the more permeable RCC. and for a degree of uncontrolled cracking (Hollingworth and Geringer. 1992). A rela -tively low interlayer bond strength also prompted some concern. particularly in the context of seismic loading .the philosophy of RCC dam design has inconsequence evolved. with emphasis being placed on optimizing design anddetailing to construction in RCC rather than using RCC to construct a con- ventional gravity dam .This trend has led to the common provision ofan”impermeable” upstream element or barrier, e. g. by a slip-formed facing (Fig 3.22 and also New Victoria dam.Australia (Ward and Mann ,1992)).An alternative is the use of a PVC or similar synthetic membrane placed against or Just downstream of a high-quality concrete upstream face In the case of the 68m high Concepcion gravity dam, Honduras. a 3 .2mm PVC geomembrane backed by a supporting geotextile drainage layer was applied to the upstream face of the RCC (Giovagnoli, schrader and Ercoli ,1992). Recent practice has also moved towards control of cracking by sawn transverse Joints, or by the cutting of a regular series of slots to act as crack Inducers.The very considerable cost savings attaching to RCC construction are dependent upon plant and RCC mix optimization ,and hence continuity of the RCC placing operation. This in turn requires that design features which interfere continuous unobstructed end-to-end placing of the RCC, egg. galleries. internal pipework, etc.. Must be kept to the minimum and simplified. Experiments with retrospectively excavating gallerries by trenching and by driving a heading in the placed RCC fill at Riou, France. have proved successful (goubet and guerinet, 1992).Vertical rates of raising of 2.0-2.5 m week-1 are attainable for RDLC and high-paste RCCs compared with 1. 0-1.5m week-1 for RCD con- struction As one example, the Conception dam, Honduras, referred to earlier was raised in seven months. A lean RCC mix (cement content 80-95kgm-3) was employedfor the 290 x 103m3 of RCC fill, and a continuous mixing plant was used In conjunction with a high-speed belt conveyor system. Placing rates of up to 4000m3 days-1 were ultimately attained (Gio vagnoli, Schraderand Ercoli, 1992).The employment of RCC fill has also been extended to the upgrading of existing dams, e.g. by placing a downstream shoulder where stability is deficient (Section 3. 2. 9) .RCC has also Been applied to general remedialworks and to raising or rebuilding older dams. the benefits of RCC con- struction have also been appropriate. in special circumstances. to the con- struction of smaller dams, e.g. Holbeam wood and New Mills in the UK (Iffla, Millmore and Dunstan. 1992).ICOLD Bulletin 75 (ICOLD,1989) provides a comprehensive over- view of the use of RCC for dam construction. Recent US developments are discussed in Hansen (1994). Design options with respect to upstream face construction have Been reviewed in some detail by Schrader (1993).Construction in RCC is recognized as providing the way forward in concrete dam engineering .An extensive review of current issues in RCC dam design and construction is presented within Li (1998) .Major issues discussed include the need. or otherwise, for a conventional concrete upstream face, and the question of resistance to high seismic Ioading.where dynamic tensile strength of the interlayer bond between successive layers of RCC will be critical.The recently completed 95m high RCC gravity dam. at P1atanovryssi, Greece, located in a seismic zone is described in Stefanakos and Dunston (1999). the design peak ground acceleration corresponding to the MCE at Platanovryssi was determined as 0.385g, equating to a maximum dynamic crack inducers vibrated into the RCC. the “joints” were subsequently sealed by a 600mm wide external waterstop bonded to the face. Seepage through the dam body diminished to a satisfactory 10-12l/s over the first 12 months' operational service.The first use of RCC in Turkey, for the 124m high by 290m long Cine gravity dam (originally planned as a rockfill embankment with a clay core) is presented in Ozdogan (1999). the low-paste RCC used for cine has a cement content of 70kg/m3. with 90kg/m3 of PFA and 88 l/m3 of water. Target 180 day compressive strength was specified as 24MN/m2.碾压混凝土重力坝(1)碾压混凝土坝的简介混凝土重力坝和土石坝样具有概念简单和适用性强的特性，但常规大体积混凝土施工速度不象土石坝施工提高那样快，还维持在1950年代的水平。
水利水电专业毕业论文文献翻译中英文对照[管理资料]
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DamThe first dam for which there are reliable records was build or the Nile River sometime before 4000 . It was used to divert the Nile and provide a site for the ancient city of Memphis .The oldest dam still in use is the Almanza Dam in Spain, which was constructed in the sixteenth century. With the passage of time,materials and methods of construction have improved. Making possible the erection of such large dams as the Nurek Dam, which is being constructed in the . on the vaksh River near the border of Afghanistan. This dam will be 1017ft(333m) high, of earth and rock fill. The failure of a dam may cause serious loss of life and property; consequently, the design and maintenance of dams are commonly under government surveillance. In the United States over 30,000 dams are under the control of state authorities. The 1972 Federal Dams Safety Act (PL92-367)requires periodic inspections of dams by qualified experts. The failure of the Teton Dam in Idaho in June 1976 added to the concern for dam safety in the United States.1 Type of DamsDams are classified on the type and materials of construction, as gravity, arch, buttress ,and earth .The first three types are usually constructed of concrete. A gravity dam depends on its own weight for stability and it usually straight in plan although sometimes slightly curved.Arch dams transmit most of the horizontal thrust of the water behind them to the abutments by arch action and have thinner cross sections than comparable gravity dams. Arch dams can be used only in narrow canyons where the walls are capable of withstanding the thrust produced by the arch action. The simplest of the many types of buttress dams is the slab type, which consists of sloping flat slabs supported at intervals by buttresses. Earth dams are embankments of rock or earth with provision for controlling seepage by means of dam may be included in a single structure. Curved dams may combine both gravity and arch action to achieve stability. Long dams often have a concrete river section containing spillway and sluice gates and earth or rock-fill wing dams for the remainder of their length.The selection of the best type of dam for a given site is a problem in both engineering feasibility and cost. Feasibility is governed by topography, geology and climate. For example, because concrete spalls when subjected to alternate freezing and thawing, arch and buttress dams with thin concrete section are sometimes avoided in areas subject to extreme cold. The relative cost of the various types of dams depends mainly on the availability of construction materials near the site and the accessibility of transportation facilities. Dams are sometimes built in stages with the second or late stages constructed a decade or longer after the first stage.The height of a dam is defined as the difference in elevation between the roadway, or spillway crest, and the lowest part of the excavated foundation. However, figures quoted for heights of dams are often determined in other ways. Frequently the height is taken as the net height is taken as the net height above the old riverbed.on damsA dam must be relatively impervious to water and capable of resisting the forces acting on it. The most important of these forces are gravity (weight of dam) , hydrostatic pressure, uplift, ice pressure, and earthquake forces are transmitted to the foundation and abutments of the dam, which react against the dam with an equal and opposite force, the foundation reaction. The effect of hydrostatic forces caused by water flowing over the dam may require consideration in special cases.The weight of a dam is the product of its volume and the specific weight of the material. The line of action of dynamic force passes through the center of mass of the cross section. Hydrostatic force may act on both the upstream and downstream faces of the dam. The horizontal componentH of the hydrostatic force is the force or unit width of damhit is2/2HrhhWhere r is the specific weight of water and h is the depth of water .The line of action of this force is h/3 above the base of thedam .The vertical component of the hydrostatic force is equal to the weigh of water vertically above the face of the dam and passes through the center of gravity of this volume of water.Water under pressure inevitably finds its way between the dam And its foundation and creates uplift pressures. The magnitude of the uplift force depends on the character of the foundation and the construction methods. It is often assumed that the uplift pressure varies linearly from full hydrostatic pressure at the upstream face (heel)to full tail-water pressure at the downstream face (toe).For this assumption the uplift force U isU=r(h1+h2)t/2Where t is the base thickness of the dam and h1and h2 are the water depths at the heel and toe of the dam,respectively. The uplift force will act through the center of area of the pressure trapezoid.Actual measurements on dams indicate that the uplift force is much less than that given by Eq.(2)Various assumption have been made regarding the distribution of uplift of Reclamation sometimes assumes that the uplift pressure on gravity dams varies linearly from two-thirds of full uplift at the heel to zero at the toe. Drains are usually provided near the heel of the dam to permit the escape of seepage water and relieve uplift.译文：坝据可靠记载，世界上第一座坝是公元前4000年以前在尼罗河上修建的。
水利水电外文翻译
Hydromechanical analysis of Placing and protecting fillflow behavior in damAbstract:Primary surface according to the design requirements of excavation and stone processing, to ensure that the dense, with certain strength and stability meet the requirements. Quarry mining, transport in the repair of the road at the same time, excavator, bulldozer, with clear reclaimer field covering layer, to ensure that no weed roots and soil tillage. Abandon the material piling up in the yard right as obstinate cultivated material, also prepare slope to prevent soil erosiondam filling should be done: regardless of which part of the fill and the final foundation surface exposure time does not exceed 72 hours. Fill method should also prevent the separation of the filling material. If the contract requirements in different lots of different filling packing and contracting business in construction should prevent of confusion between the different types of fillers.Key words: Hydromechanical fill permeabilityAny undesirable material accumulated on the fill surface shall be removed before placeing the next layer of fill material shall be placed on a previous layer of that has dried out,become saturated or in any way deteriorated by exposure or by spilling of other material or disterbance by mechanical transport or by deposition of wind blown particles or by any other means. Before fresh fill material is placed aoo such deteriorated fill or foreign material shall be removed to a depth at which material of an acceptable standard is exposed. The surface of each layer is to be approved by the Engineer before the next layer is placed.Any fill shall be placed in uniform layers not greater than the approved thickness as specified hereafter and in an orderly sequence approximately horizontal along the centreline of the where specified of directed otherwise, no portion of any embankment shall be stepped more than 3 feet higher than any immediately adjacent portion except where permitted by the Engineer and the slope formed by such steps shall not exceed 1V:3H and not less than 1V:4H from one level to as shown on the Drawings or as otherwise directed, all fill placement surfaces shall be sloped at right angles to the centerline of the embankment in both the upstream and downstream direction from the downstream edge of the core so as to allow run-off and prevent the accumulation of water. The drainage slope on the temporary surface of anny zone shall not exceed 1 on 30 and the highest point shall be de downstream edge of the core.Where,due to the specified geometry of the excavation into the top of the existing embankments, the surface slope is towards the downstream edge of the core, theContractor shall take such measures an necessary to prevent erosion of fine material being washed into the filter zones downstream of the core. Any surface layer of filter material contaminated by such drainage or other cause shall be removed and replaced with fresh filter material before placing the next layer above.Construction of any one embankment shall be carried out over the maximum possible length,mo less than 1500 feet,of that embankment in such a manner that mo temporary construction slope crosses the axis of the embankment except as approved by the Engineer. Where a temporary constrction slope crossing the axis of the embankment is permitted by the Engineer it shall be formed at a gradient of 1V：5H. When subsequently placeing material against this slope it shall be cut back in steps equal to the layer thickness to avoid feather edges. The Contractor shall complete each layer of fill fully up to the abutment contacts and structures and against sloping foundations and ensure that the fill is compacted an specified throughout. The Contractor shall not allow the fill in those areas to lag behind or to get ahead of the normal fill placing operations and form feather edges, except where fill has been placed in advance to cover grouted surface.Should not contain humus soil was used to fill the soil, roots, or other harmful substances, to fill jobs should spread in layers shop, motor grader leveling, each layer of loose paving thickness should be not more than 30cm. Each filler layer thickness is not less than 50 cm, top earthwork embankment to the pavement surface layer at the end of the compaction thickness should not less than 10cm.Where the Contractor is allowed to use either grvel fill and /or sandstone no intermixing of the two materials in a layer shall be allowed. The Constractor may place either of the materials in adjacent layers or sections of the embankment.The Constractor shall be responsible for protecting temporary fill surfaces against damage of erosion. At the end of each working day,or if it start to rain ,the surface of the fill shall be made smooth and compacted with a smooth drum roller with a drainage slope to induce runoff from the filled areas and leave no areas that can retain water. Where necessary, grips,drainage ditches and the like shall be formed to assist drainage and to prevent runoff from damaging placed from heavy rain shall be controlled to prevent gully erosion of the placed fill. Any gully erosion shall be repaired with material compacted in accordance with the Specification, and eroded surfaces shall be restored and graded to ensure a proper bond with new fill placed on eroded material other than gravel and any contaminated material shall be removed from the embankment and placed in designated spoil tips. In particular the Contractor shall ensure that no material is washed into filter or drain material.Where placing of the filter material of drain material is not continuous ,the Constractor shall protect such filter or drain materials by a 2 foot thick layer of coursefilter material or in such other manner approved by the Engineer,and the Contractor shall maintain the protective layer.The Contractor shall keep the work free from standing water to prevent damage to the fill material. When working below the surrounding level, the Contractor shall ensure that material from adjacent areas does not contaminate the fill material,and that runoff does not flow onto the fill.The Contractor shall arrange the timing and rate of placing fill material in sucn way that no part of the workes is over stressed,weakened or endangered. Any part of the fill that be comes saturated or attains excessive moisture content or that is rendered unsuitable due to poor surface drainage, uncontrolled traffic,or for any other reason, shall be excavated and removed to a spoil tip and replaced by fresh fill .If permitted by the Engineer, such fill may be scarified and re-compacted.Unless otherwise approved by the Engineer unrestrained edges of fill, whether for temporary or permanent slops, shall be overbuilt as necessary to allow full compaction to be achieved within defined limits of the fill. The excess material shall be trimmed and removed to leave a regular compacted surface.Slope exposed to view,including riprap and downstream protection slopes, shall be dressed to neatly appearing final surfaces matching the existing slopes.Temporary access ramps shall be removed when work in that area is completed. Any ramps or other areas within the limits of an embankment which, in the opinion of the Engineer have been over-compacted or damaged by the concentrated use by construction equipment,shall be reworked and re-compacted or,if the Engineer requires,shall be excavated, removed to spoil tip and replaced by the fresh fill.When necessary the surface of the layer of fine grained fill material(rolled clay,rolled silt Type A and B ,Rolled Sandstone Type A and B) shall be sprayed with water to prevent drying out and to maintain the correct uniform moisture content prior to placing the next Contractor shall ensure that a good bond is achieved between layers of filland unless otherwise directed, previously compacted layers of fine grain materials shall be harrowed, scarified or otherwise roughened to depth of at least 3 inches and made suitable for covering with future layer of fill.For Hydromechanical analysis of flow behavior in dam,Evaluating the safety of concrete gravity dams against sliding requires an understanding that rock foundations and the structure above them are an interactive system whose behavior is controlled by the mechanical and hydraulic properties of concrete materials and rock foundations. About a century ago, the failure of Boozy Dam prompted dam engineers to start considering the effect of uplift pressures generated by seepage within the dam–foundation system and to explore ways to minimize its effect.. Today, with modern computational resources and much more precedent, it is still most challenging todetermine the pore-pressure distribution along foundation discontinuities to assess pertinent stresses and evaluate factors of safety. It is our opinion that observing and monitoring the behavior of large dams on well mapped and adequately instrumented foundations can bring important insights for a better understanding of factors controlling joint opening, crack propagation, and pore-pressure development in foundations of concrete gravity dams.Fig. behavior of natural joints :(a) mechanical;(b)hydraulic.This paper presents behavior representative of cycles of reservoir operation in the last 20 years collected from monitored data of Albigna Dam, Switzerland, and also describes the results of a series of numerical analyses carried out to assess the hydromechanical behavior of its foundations. Comparisons are made between results of numerical modeling and the actual behavior monitored in the field. Based on these comparisons, a series of conclusions are drawn regarding basic pore-pressure buildup mechanisms in jointed rock masses with implications that may be considered in other engineering projects, where the hydromechanical behavior of jointed rock should be considered. Such projects include pressure tunnels, hazardous waste disposal, and other situations dependent on geologic containment controlled by flow behavior along rock discontinuities.A brief summary of the state-of-the-art of mechanical and hydraulic behavior of individual rock joints is presented here. A more detailed description of rock joint Hydromechanical behavior can be found in Alvarez(1997)and Alvarez et al.(1995)and in investigations in laboratory and numerical model simulations carried out by Raven and Gale (1985), Gentier (1987),Esaki et al.(1992),and others.The mechanical behavior of the joint can be represented by a nonlinear nhyperbolic relationship between the applied effective normal stress,，and joint closure,mcni nmc mc n ni V K V V n or V Vn V K n -∆=∆-∆=''')(1σσσ （1） During loading, significant joint closure takes place at low effective normal stresses. The magnitude of the closure per unit of stress decreases rapidly, however, as the stress level increases. The hyperbola is defined by the initial tangent stiffness,Kni, and the asymptote maximum joint closure, Vmc. This relationship is also nonlinearand hysteretic for the unloading condition until effective normal stresses become zero .The values of Kni and Vmc are estimated by regression analysis on experimental data. For natural and induced fractures in granite, these parameters are33.133.1205mc ni mc V K V 〈〈 （2）interrelated and range between the following limits Alvarez et al. (1995):WhereKni is in Mpa/m and Vmc is in m/s.Rough joints exhibit the largest joint maximum closure and the lowest initial joint stiffness, whereas smooth joints have the lowest Vmcand the largest KniThe hydraulic behavior of the rock joint is characterized by the linear relationship between hydraulic aperture,ah, which controls the magnitude of flow, and mechanical joint closure, Vn , which depends on stress levels. Hydraulic apertures are plotted versus their corresponding joint closure to obtain the line ,intercept, aho,initial hydraulic aperture, and the coupled slope coefficient, f,which characterizes the hydromechanical behavior of the joint ,i. e., the relationship between)(hr h n ho h a a V f a a ≥∆-= （3）changes in hydraulic aperture due to changes in mechanical aperture, given byWhere ahris the residual hydraulic aperture.For a given rock joint, there is a relationship between roughness and the coupled coefficient, because f depends on the distribution and tortuosity of flow channels along the joint surface. For ideal parallel plates, with a single flow channel along the entire joint surface, f= concentrated flow channels meandering across the joint surface, f<.h Ga Q h w ∆=3)12μγ（ （4）Hence, the classic cubic law expresses flow rate through a rock joint:Where Q is the flow rate; W is the unit weight of the water; his the head drop along the rock joint; μ is the dynamic viscosity of the water ×10Pa ·s ); ah is the joint hydraulic aperture; and G is the shape factor, which depends on the geometry of flow. For straight flow, G=W/L (where W and L are the width and length, respectively, of the joint); and for divergent radial flow, G=2π/ln (re/ri), where ri and re are the borehole and external cylindrical surface radiuses, respectively.Jointed rock mass permeability change with depth,Alternatively, the rock mass equivalent permeability can be expressed in the same form as the modified cubic law.)1()12(3s a K h w m μγ= （5）Or in terms of hydraulic aperture, to account for spacing of the joints,S:Changes in jointed rock mass permeability due to overburden and confining stresses were calculated using eqs. [1]–[3].The results of a theoretical relationship of rock mass permeability, k, for depths up to 1000 m, using eq. [5] are presented in reduction of hydraulic apertures with increasing overburden stresses results in a rock mass permeability that decreases with an increase in depth from 10 cm/s8near the surface to 10 cm/s at depths of 600–1000 m.The rock mass permeability estimates were obtained assuming f=,Vmc= kni =10vmc, which are representative of the values obtained in laboratory tests carried out in granitic formations(Alvarez et similar to those of the Brazilian test location described in this section. Overburden stresses were estimated using a unit weight of kN/ this case it was assumed that horizontal and vertical stresses are about the same (coefficient of earth pressure at rest Ko=, which are also considered to be representative of the igneous formations at the Brazil test location, but other values of in situ stresses could be estimated, ., for Ko<, vertical joints would have larger permeabilities.Field permeability measurements obtained in Packer tests at a deep open-pit mining project in granitic rock in Brazil are also plotted in for comparison with the theoretical relationship. Values of joint spacing observed from borehole cores are in the range of a few meters, and thus a constant spacing of 5m was assumed in the computations. Values of aho in the range of 300–1000μm were used to determine the theoretical relationships of km=f (z), where z is the depth, and compare with field measurements.Measured permeability values in the two boreholes are relatively high at depths between 100 and 200m, probably denoting the presence of a sheared zone or a zone of more jointed rock. The measured rock permeabilities decrease steadily with an increase in depth, however, and their values correspond well with the theoretical trend of rock mass permeability estimated with the model. Typical hydraulic apertures of 400–500μm and joint stiffness following a hyperbolic relationship with KNI=10V mc and Vmc= ahoseem to agree well with observed field behavior for these crystalline rock masses.Fig. jointed rock mass permeability relationship with depth.Although real Hydromechanical behavior of jointed rock masses is site specific and depends on geologic factors, which need to be taken into account, the proposed approach provides a framework to estimate rock mass permeability during design stages where information is not yet available.References:[1]Canadian Water Resources Journal, 2000, (3),[2]Department of Geography, University of Wisconsin-Milwaukee, . Box 413, Milwaukee, WI 53201-0413, United States[3]Department of Geography, Binghamton University, The State University of New York, . Box 6000, Binghamton, NY 13902, United States[4]School of Chemical & Materials Engineering, National University of Sciences & Technology, Islamabad 44000, Pakistan[5]Building Physics and Services, Department of the Built Environment, Eindhoven University of Technology, . Box 513, 5600 MB Eindhoven, The Netherlands坝体填料的填筑保护及基础流体力学行为分析一填料的填筑保护摘要：基层表面按设计要求开挖和块石处理，确保密实，具有一定强度和稳定性满足要求。
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水利水电英语课文翻译水利水电英语课文翻译课文翻译需要掌握一定的词汇和技巧，当然英语课文翻译可以帮助提高学生的英语水平。
以下是店铺整理的水利水电英语课文翻译，欢迎阅读。
水利水电英语课文翻译1：Lesson 1 importance of water 水的重要性Water is best known and most abundant of all chemical compounds occurring in relatively pure form on the earth‘s surface. Oxygen, the most abundant chemical element, is present in combination with hydrogen to the extent of 89 percent in water. Water covers about three fourths of the earth's surface and permeates cracks of much solid land. The Polar Regions are overlaid with vast quantities of ice, and the atmosphere of the earth carries water vapor in quantities from 0.1 percent to 2 percent by weight. It has been estimated that the amount of water in the atmosphere above a square mile of land on a mild summer day is of the order of 50,000 tons.在地球表面以相对纯的形式存在的一切化合物中，水是人们最熟悉的、最丰富的一种化合物。
在水中，氧这种最丰富的化学元素与氢结合，其含量多达89%。
水覆盖了地球表面的大约3/4的面积，并充满了陆地上的许多裂缝。
地球的两极被大量的冰所覆盖，同时大气也挟带有占其重量0.1%～2%的水蒸气。
据估计，在温暖的夏日，每平方英里陆地上空大气中的水量约为5万吨。
All life on earth depends upon water, the principal ingredient of living cells. The use of water by man, plants, and animals is universal. Without it there can be no life. Every living thing requires water. Man can go nearly two months without food, but can live only three or four days without water.地球上所有的生命都有赖于水而存在，水是活细胞的基本组分（要素）。
人类、和动物都得用水。
没有水就没有生命。
每一种生物都需要水。
人可以接近两个月不吃食物而仍能活着，但不喝水则只能活三四天。
In our homes, whether in the city or in the country, water is essential for cleanliness and health. The average American family uses from 65,000 to 75,000 gallons of water per year for various household purposes.在我们的家庭中，无论是在城市还是农村，水对于卫生和健康来说都是必不可少的。
美国家庭的年平均用水量达6.5～7.5万加仑。
Water can be considered as the principal raw material and the lowest cost raw material from which most of our farm produces is made. It is essential for the growth of crops and animals and is a very important factor in the production of milk and eggs. Animals and poultry, if constantly supplied with running water, will produce more meat, more milk, and more eggs per pound of food and per hour of labor.水可以被认为是最基本的和最廉价的原料。
我们的农产品，大部分都是由它构成的。
水是农作物和动物生长的要素，也是奶类和蛋类生产的一个很重要的因素。
动物和家禽，如果用流动的水来喂养，那么每磅饲料和每个劳动小时会生产出更多的肉、奶和蛋。
:For example, apples are 87% water. The trees on which they grow must have watered many times the weight of the fruit. Potatoes are 75% water. To grow an acre of potatoes tons of water is required. Fish are 80% water. They not only consume water but also must have large volumes of water in which to live. Milk is 88% water. To produce one quart of milk a cow requires from 3.5 to 5.5 quarts of water. Beef is 77% water. To produce a pound of beef an animal must drink many times that much water. If thereis a shortage of water, there will be a decline in farm production, just as a shortage of steel will cause a decrease in the production of automobiles.例如，苹果含87%的水分，苹果树就必须吸收比苹果多许多倍的水分；土豆含75%的水分，那么种植每英亩土豆就需要若干吨水；牛奶含水量为88%，为了生产每夸脱牛奶，母牛需要3.5～5.5 夸脱的水；牛肉含77%的水，为生产1磅牛肉牛必须饮用许多磅水。
如果缺水，就会使农产品减产，就像缺乏钢会引起汽车产量下降一样。
In addition to the direct use of water in our homes and on the farm, there are many indirect ways in which water affects our lives. In manufacturing, generation of electric power, transportation, recreation, and in many other ways, water plays a very important role.水除了直接为我们的家庭和农场利用外，它还以许多间接的方式对我们的产生影响。
在制造、发电、运输、娱乐以及许多行业，水都起着很重要的作用。
Our use of water is increasing rapidly with our growing population. Already there are acute shortages of both surface and underground waters in many locations. Careless pollution and contamination of our streams, lakes, and underground sources has greatly impaired the quality of the water which we do have available. It is therefore of utmost importance for our future that good conservation and sanitary measures be practiced by everyone.我们对水的利用随人口的增长而迅速增加。
在许多地方，无论地面水或地下水都已经严重短缺了。
由于任意污染河流、湖泊和地下水源，已经大大地损害了人们能够利用的水的水质。
因此，人人有责对水采取保护措施和卫生措施，这对于我们人类的未来是极端重要的。
水利水电英语课文翻译2：Lesson 2 the Hydrologic Cycle 水循环In nature, water is constantly changing from one state toanother. The heat of the sun evaporates water from land and water surfaces, this water vapor (a gas), being lighter than air, rises until it reaches the cold upper air where it condenses into clouds. Clouds drift around according to the direction of the wind until they strike a colder atmosphere. At this point the water further condenses and falls to the earth as rain, sleet, or snow, thus completing the hydrologic cycle.在自然界中，水总是不断地从一种状态改变成另一种状态。
太阳热使陆地和水面上的水蒸气。