水利水电工程毕业设计英文翻译,混凝土重力坝
水利水电专业毕业论文 文献翻译 坝(可编辑)
水利水电专业毕业论文文献翻译坝（可编辑）水利水电专业毕业论文文献翻译坝Dam The first dam for which there are reliable records was build or the Nile River sometime before 4000 B.C. 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 U.S.S.R. on the vaksh River near the border of Afghanistan. This dam will be 1017ft333m 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 PL92-367requires 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 waterbehind 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 includedin 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 adecade or longer after the first stage The height of a dam isdefined 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.2.Forced on dams A 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 component of the hydrostatic force is the force or unit width of dam it is Where 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 the dam .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 ofgravity of this volume of water Water under pressure inevitablyfinds 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 atthe upstream face heelto full tail-water pressure at the downstream face toe.For this assumption the uplift force U is Urh1+h2t/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 byEq.2Various assumption have been made regarding the distribution ofuplift pressures.The ////0>. 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。
毕业设计水利水电工程英文文献翻译
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 thegenerator, 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. prime mover +electric generator) is collectively known as power plant. The building, in which the entire machinery along with other auxiliary units is installed, is known as power house.Keywords hydraulic turbines hydro-electric power classification of hydel plantshead schemeThere has been practically no increase in the efficiency of hydraulic turbines since about 1925, when maximum efficiencies reached 93% or more. As far as maximum efficiency is concerned, the hydraulic turbine has about reached the practicable limit of development. Nevertheless, in recent years, there has been a rapid and marked increase in the physical size and horsepower capacity of individual units.In addition, there has been considerable research into the cause and prevention of cavitation, which allows the advantages of higher specific speeds to be obtainedat higher heads than formerly were considered advisable. The net effect of this progress with larger units, higher specific speed, and simplification and improvements in design has been to retain for the hydraulic turbine the important place which it has long held at one of the most important prime movers.1. types of hydraulic turbinesHydraulic turbines may be grouped in two general classes: the impulse type which utilizes the kinetic energy of a high-velocity jet which acts upon only a small part of the circumference at any instant, and the reaction type which develops power from the combined action of pressure and velocity of the water that completely fills the runner and water passages. The reaction group is divided into two general types: the Francis, sometimes called the reaction type, and the propeller type. The propeller class is also further subdivided into the fixed-blade propeller type, and the adjustable-blade type of which the Kaplan is representative.1.1 impulse wheelsWith the impulse wheel the potential energy of thewater in the penstock is transformed into kinetic energy in a jet issuing from the orifice of a nozzle. This jet discharge freely into the atmosphere inside the wheel housing and strikes against the bowl-shaped buckets of the runner. At each revolution the bucket enters, passes through, and passes out of the jet, during which time it receives the full impact force of the jet. This produces a rapid hammer blow upon the bucket. At the same time the bucket is subjected to the centrifugal force tending to separate the bucket from its disk. On account of the stresses so produced and also the scouring effects of the water flowing over the working surface of the bowl, material of high quality of resistance against hydraulic wear and fatigue is required. Only for very low heads can cast iron be employed. Bronze and annealed cast steel are normally used.1.2 Francis runnersWith the Francis type the water enters from a casing or flume with a relatively low velocity, passes through guide vanes or gates located around the circumstance, and flows through the runner, from which it discharges into a draft tube sealed below the tail-water level. All therunner passages are completely filled with water, which acts upon the whole circumference of the runner. Only a portion of the power is derived from the dynamic action due to the velocity of the water, a large part of the power being obtained from the difference in pressure acting on the front and back of the runner buckets. The draft tube allows maximum utilization of the available head, both because of the suction created below the runner by the vertical column of water and because the outlet of he draft tube is larger than the throat just below the runner, thus utilizing a part of the kinetic energy of the water leaving the runner blades.1.3 propeller runnersnherently suitable for low-head developments, the propeller-type unit has effected marked economics within the range of head to which it is adapted. The higher speed of this type of turbine results in a lower-cost generator and somewhat smaller powerhouse substructure and superstructure. Propeller-type runners for low heads and small outputs are sometimes constructed of cast iron. For heads above 20 ft, they are made of cast steel, a much more reliable material. Large-diameter propellers。
08水利专业混凝土重力坝毕业论文中英文资料外文翻译文献 (1)
混凝土重力坝中英文资料外文翻译文献混凝土重力坝基础流体力学行为分析摘要：一个在新的和现有的混凝土重力坝的滑动稳定性评价的关键要求是对孔隙压力和基础关节和剪切强度不连续分布的预测。
本文列出评价建立在岩石节理上的混凝土重力坝流体力学行为的方法。
该方法包括通过水库典型周期建立一个观察大坝行为的数据库，并用离散元法（DEM）数值模式模拟该行为。
一旦模型进行验证，包括岩性主要参数的变化，地应力，和联合几何共同的特点都要纳入分析。
斯威土地，Albigna 大坝坐落在花岗岩上，进行了一个典型的水库周期的特定地点的模拟，来评估岩基上的水流体系的性质和评价滑动面相对于其他大坝岩界面的发展的潜力。
目前大坝基础内的各种不同几何的岩石的滑动因素，是用德国马克也评价模型与常规的分析方法的。
裂纹扩展模式和相应扬压力和抗滑安全系数的估计沿坝岩接口与数字高程模型进行了比较得出，由目前在工程实践中使用的简化程序。
结果发现，在岩石节理，估计裂缝发展后的基础隆起从目前所得到的设计准则过于保守以及导致的安全性过低，不符合观察到的行为因素。
关键词：流体力学，岩石节理，流量，水库设计。
简介：评估抗滑混凝土重力坝的安全要求的理解是，岩基和他们上面的结构是一个互动的系统，其行为是通过具体的材料和岩石基础的力学性能和液压控制。
大约一个世纪前，Boozy大坝的失败提示工程师开始考虑由内部产生渗漏大坝坝基系统的扬压力的影响，并探讨如何尽量减少其影响。
今天，随着现代计算资源和更多的先例，确定沿断面孔隙压力分布，以及评估相关的压力和评估安全系数仍然是最具挑战性的。
我们认为，观察和监测以及映射对大型水坝的行为和充分的仪表可以是我们更好地理解在混凝土重力坝基础上的缝张开度，裂纹扩展，和孔隙压力的发展。
图.1流体力学行为：（一）机械;（二）液压。
本文介绍了在过去20个来自Albigna大坝，瑞士，多年收集的水库运行周期行为的代表的监测数据，描述了一系列的数值分析结果及评估了其基础流体力学行为。
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。
华北水利水电大学水利水电工程毕业设计外文翻译
DESIGN CONSIDERATIONS OF A HIGH ROCKFILL DAMNAM NGUM 2 CFRD, LAO PDRRuedi Straubaar1, Eva van Gunsteren2 and Stephen Moll31Geotechnical and Dam Engineering Expert, Pöyry Energy Ltd. (formerly Electrowatt Engineering Ltd.)Hardturmstrasse 161, CH-8037 Zurich, SwitzerlandE-mail: ruedi.straubhaar@2 Project Engineer and Assistant Project Manager for Nam Ngum 2, Pöyry Energy Ltd. (formerly Electrowatt Engineering Ltd.) Hardturmstrasse 161, CH-8037 Zurich, SwitzerlandE-mail: eva.van-gunsteren@3 Dam Engineer, Pöyry Energy Ltd. (formerly Electrowatt Engineering Ltd.) Hardturmstrasse 161,CH-8037 Zurich, SwitzerlandE-mail: stephen.moll@Abstract: Nam Ngum 2 dam, a large concrete face rock fill dam (CFRD) of 182 m height, is under construction and impounding is scheduled to start at beginning of April 2010. The dam is situated in a narrow valley and founded on sedimentary rock of variable strength.Dam design principles comprising dam zoning, face slab design and instrumentation are outlined. Foundation treatment including groutingand measures below the plinth are presented. The properties of the available rockfill materials and their influence on the dam zoning are discussed.Emphasis is given to the rockfill properties and placement procedures which influence dam behaviour during construction, impounding and operation.Key words: CFRD, Rockfill, Face Slab, Instrumentation1Nam Ngum 2 Hydropower SchemeThe Nam Ngum 2 (NN2) hydropower scheme is located on the Nam Ngum river in Lao PDR, about90 km north of the capital city of Vientiane and some 35 km upstream of the existing Nam Ngum 1dam and powerhouse. With an installed capacity of 615 MW, the project will produce energy for the Thai electricity grid. A significant component of the scheme is the 182 m high concrete face rock fill dam, with a volume of 9.5 M m3 and a crest length of 500 m. The dam will impound a reservoir with a volume of approximately 4.2 M m3.Construction of the NN2 Project commenced in late 2005 and is scheduled for completion in the second half of 2010. Rock fill placement in the dam body commenced in January 2008, and will be finished in early November 2009. Face slab construction, which is divided into an upper and lower stage, commenced in December 2008 and will becompleted by beginning of April 2010, when impounding will begin. The reservoir will fill during one rainy season, enabling commissioning to take place during the second half of 2010.2Considerations with respect to dam deformationsConcrete face rock fill dams are considered inherently safe for a wide range of weak and strong rock fill (Cooke 1991) and deformation of the rock fill is often assumed not being a governing concern provided the dam is well engineered and the dam foundation is of adequate quality. It is often assumed that dam settlements are a simple function of the dam height and that they are not likely to exceed 1 % of the compacted fill height with horizontal deformations less than 50 % of the settlements. Predictions are also often made based on laboratory tests and dam deformation analyses.2.1 Rock fill testing performed for NN2 CFRDFor the construction of the NN2 dam quarried rock of sedimentary formations are available. The source material, consisting basically of sandstone and siltstone, has been investigated by drilling, quarry trials, laboratory testing and trial embankment construction. The essential tests are index property tests, compressive strength and basic friction angle tests. Tests were also performed on saturated specimen, which normally gives more representative lower values.Of particular interest are always large scale triaxial and compressibility tests, which have been carried out for NN2 by the IWHR1 in China.2.2 Dam analyses and zoning of NN2 CFRDTest results from the IWHR as well as results from the AIT2 and site laboratories were used as basis for dam analyses. Stability as well as 2D and 3D deformation analyses were carried out by the IWHR. Based on the results of the analyses and also based on visual observation which indicated a very high desintegration potential of the siltstone, it had to be concluded that only sandstone is suitable as rock fill for the construction of the high embankment. By using only sandstone for rock fill it was concluded that the dam deformation will be within acceptable and normal limits.During construction it was observed that also fine grained sandstone, porous or weathered sandstone of moderate quality is being obtained from quarrying which can not always completely be separated and wasted. Therefore the dam zoning was adjusted to permit also placement of lower quality rock fill in the central part of the dam embankment. The adjusted dam zoning is shown in Figure 2.3 Observed deformations on constructed damsOften it is assumed that for strong rock fills the settlements are small,less than about 1% of the fill height. It is further commonly assumed that the settlements develop essentially during construction.Although these assumptions were correct for many dams, a few dams did show much more settlements (Kjaernsli et al. 1992). More recent data of observed crest settlements are presented in Figure 3.For the 165 m high Atatürk dam in Turkey high post construction settlements developed. The post construction settlement rate of 0.02 % per year, which can be considered as maximum acceptable creeping pace after impounding, is even 10 years after completion of construction still exceeded.It has to be taken as a fact that deformations often exceed common values and are not always predictable. Laboratory tests are restricted to small maximum particle sizes and do not always reflect the behaviour of large size rock fill.4 Factors influencing the deformations of rock fill damsFactors influencing the magnitude of settlements are discussed in the following. Some information are taken from an unpublished research by Victor Milligan and Lisa Coyne “Review of factors influencing the settlement of rock fill dams”.4.1 Particle size and shapeThere is evidence that the modulus of deformation increases withincreasing particle size. Tests by Marachi et al. (1969) indicated that compressibility is highest for 150 mm particle size and least for 12 mm particle size. It has to be assumed that for particle sizes exceeding 150 mm the compressibility will further increase. A similar effect has to be assumed for the shear strength of rock fill. Increasing particle size somewhat reduces the shear strength depending on the basic characteristics of the source rock.The effect of particle shape on compressibility is well known. McDowell et al. (2004) stated that the “particle shape seems to have a greater effect (on compressibility) than mineralogy”. There is a pronounced reduction in modulus as the particle shape changes from rounded to angular.4.2 Gradation and state of packingIt is well known that uniformly graded rock fill is much more compressible than broadly graded rock fill. In general a uniformity coefficient of 30 is desired to obtain a reasonable gradation.Gradation and density have an essential effect on the state of packing.4.3 Wetting and compactionThe method of rock fill placement has a considerable influence on the compressibility of the rock fill.Water added to the rock fill weakens the rock and induces breakage and crushing of the rock particles, inparticular if the rock fill particles have a relatively high porosity. This will in general cause increased settlement and result in an increase of the long term stiffness of the fill. It is also well known that with smaller lift thicknesses and increased compaction energy the dam deformations are reduced.4.4 Effects of degradationDegradation depends on the stress level and the strength of the rock particles. Under a given stress level, the breakage of rounded particles is much less than that of angular particles. Well graded rounded particles have more contact points and thus experience less stress at contact points. In contrast uniform and sharply shaped particles experience much higher stresses at contact points with an increasing potential for particle breakage and creep.4.5 Predicted versus observed settlementsAlthough the various factors affecting the compressibility of rockfill are well known, it is not always possible to predict the dam deformation with the desired reliability. Laboratory testing and analytical modeling may not be sufficient to conclude on the dam behaviour, in particular the long term creeping of the structure. It is a fact that the observed deformation can exceed the predicted ones.Some of the factors influencing the compressibility can be controlledby the construction methodology. Other factors as the particle shape and strength can not be influenced, they are rather given by the rock type.Important is an adequate instrumentation of the dam and to compare the observed behaviour of the dam with the predictions and observations.4.6 Rock fill used at NN2For NN2, the conditions of the rock fill are as follows:- The particle size of the rock fill is relatively large and the particle shape is quite angular.- The gradation of the rock fill is often uniform and gap-graded, with a lack of rock fragments of gravel size.- The densities obtained after placement are adequate, although segregated areas observed may lead to increased post construction settlements.- Due to the gap grading and the high sand content, wetting of the fill leads to the development of a mud layer on the rock fill surface, which needs to be removed.- The amount of water effectively added to the fill is around 100-150 l/m3 which is considerably lower than the initially foreseen amount of 250 l/m3.The currently available information from settlement monitoring data indicate that there is a significant increase of settlements at higher stresslevels and also a tendency of quite pronounced creep settlements. The modulus of deformation during construction has decreased from initial values as high as 150 to 200 MPa to currently quite low to moderate values of around 30 to 70 MPa.5 Foundation TreatmentThe geological formations at the dam site consist of medium bedded to massive cliff-forming sandstone and interbedded thin to thick bedded siltstone. Three easterly trending folds whose axes are nearly perpendicular to the Nam Ngum river are present at the dam site. The cliff-forming sandstone is generally slightly jointed to massive, whereas the interbedded siltstone is moderately to closely jointed. The quality of the foundation rock varies within the following limits:- Sandstone: fresh, hard and slightly fractured to weathered and heavily fractured.- Siltstone: fresh and hard to weathered, soft and slaking.The foundation treatment at Nam Ngum 2 mainly aims on:- Positive control of seepage below the plinth.- Providing a stable and non-erodible foundation beneath and around the plinth.- Protection of foundation rock susceptible to erosion.- Levelling of abrupt irregularities in the dam foundation and very steep abutment slopes to reduce differential settlements.With respect to foundation treatment requirements the embankment foundation is divided into three areas. The foundation for the plinth is considered separately since it has more stringent requirements for rock quality and preparation.The upstream third of the embankment is founded on fresh to slightly weathered rock. The central part of the embankment is founded on slightly to moderately weathered rock. The requirements for the downstream third are less rigorous, and the foundation on moderately weathered rock is acceptable. At the riverbed the present dense alluvium of maximum 15 m thickness was left in place only in the central part of the dam body.Particular attention is paid to areas where the foundation of the dam consists of siltstone or highly weathered or intensively fractured sandstone. Such foundation rock is susceptible to erosion requires special protection. For this purpose a 100 mm wire mesh reinforced shotcrete blanket, covered by filters, is provided to cover the erodible rock within the foundation downstream of the plinth up to a distance of 0.3 H (H = reservoir head) from the plinth. In addition, and within the entire dam foundation area up to the downstream slope erodible foundation rock is。
毕业设计重力坝外文
The Kurpsai hydroelectric station is being constructed on the Naryn River 40 km downstream from the Toktogul hydrostation. The structure was designed by the Central Asian Branch of the All-Union Planning, Surveying, and Scientific-Research Institute (Gidroproekt). The concrete gravity dam of the hydrostation is located in a trapezoidal canyon with a slope steepness of about 450. With consideration of the cut made for dam the bottom width of the canyon is 80 m and at the crest level -- 365 m. The dam height is 113 m, the upstream face is vertical, the slope of the downstream face of four channel sections is 0.7, of the leftbank sections 0.75, and of the right-bank 0.8 (Fig. I). The floor and walls of the canyon are composed of sandstones and argillites forming thin alternating layers steeply dipping toward the upper pool. Three zones are distinguished with respect to the degree of preservation of the rocks: zone Ii of severely weathered rock with fractures filled with weathering products; zone Is, within which the fractures are relatively clean; deep zone II of relatively preserved rocks. Fracturing of the rock is represented by four joint systems, of which only the bedding joints aresufficiently clearly expressed with respect to length. According to the results of field experiments the calculated characteristics of the shear strength of the rock are taken equal to C = 0.3 MPa, tan =0.9. Deformation of the rock is characterized by a modulus of deformation El = 2 5 0 0 MPa for the near-surface zone Is and E2 = 7000 MPa for zone II of preserved rocks at a depth of 10-35 m from the surface of the cut. Since the region of the structure belongs to a zone of possible intensity 9 earthquakes, a special combination of loads, including seismic, is the main design case for the dam. Maximum simplification of construction works, which makes it possible not only to reduce the cost but also to shorten the construction, was adopted as the principal factor of increasing the technical and economic indices of the structure in the design. The bulk of the technical--economic effect was achieved due to the following technical decisions. Preparation of the supporting surface of the dam consisted in removing the most weathered rock of zone I~ with fractures filled with weathering products without organizing horizontal support areas under the bank sections of the dam. Under conditions of the mountain canyon such a decision was exceptionally effective, making it possible not only to reduce the amount of rock excavation to a minimum but also to simplify construction works. The dam is being constructed in layers 0.75-1 m thick uniformly over the entire dam without the use of pipe cooling. The temperature regime of the concrete masonry during the construction period is being regulated by surface watering of the blocks with river water starting a day after concreting the layer and before covering it with the next layer. The dimensions of the concreting blocks coincide in plan with the dimensions of the sections (Fig. i). The vertical joints between sections are formed during "face-to-face" concreting of adjacent sections with the use of permanent reinforced-concrete formwork. The joints, having vertical offsets with a depth of 0.8 m, are separated by waterbars into grouting segments and are equipped with reusable grouting outlets for conducting periodic grouting as the dam cools and the joints open. The concrete mix is delivered from the Toktogul concrete plant located in the city of Karakul. To reduce the volume of concrete, the design profile was selected with consideration of the effect of an increase of stability of a gravity dam under conditions of a narrow mountain canyon.* *See Yu. P. Kornev, "The Kurpsai hydroelectric station on the Naryn River," Gidrotekh. Stroit., No. ii (1981). Translated from Gidrotekhnicheskoe Stroitel'stvo, No. i, pp. 7-11, January, 1982. 0018-8220/82/1601-0001507.50 9 1982 Plenum Publishing Corporation
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。
水利水电工程毕业设计英语翻译
外文资料翻译学院(直属系):能源与环境学院年级、专业: 2009级水利水电工程学生姓名:李巧龙学号: 3120指导教师:杨耀完成时间: 2013年 5 月 27 日hydraulic turbines1 introductionPower 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.There has been practically no increase in the efficiency of hydraulic turbines since about 1925, when maximum efficiencies reached 93% or more. As far as maximum efficiency is concerned, the hydraulic turbine has about reached the practicable limit of development. Nevertheless, in recent years, there has been a rapid and marked increase in the physical size and horsepower capacity of individual units.In addition, there has been considerable research into the cause and prevention of cavitation, which allows the advantages of higher specific speeds to be obtained at higher heads than formerly were considered advisable. The net effect of this progress with larger units, higher specific speed, and simplification and improvements in design has been to retain for the hydraulic turbine the important place which it has long held at one of the most important prime movers.2 types of hydraulic turbinesHydraulic turbines may be grouped in two general classes: the impulse type which utilizes the kinetic energy of a high-velocity jet which acts upon only a small part of the circumference at any instant, and the reaction type which develops power from the combined action of pressure and velocity of the water that completely fills the runner and water passages. The reaction group is divided into two general types: the Francis, sometimes called the reaction type, and the propeller type. The propeller class is also further subdivided into the fixed-blade propeller type, and the adjustable-blade type of which the Kaplan is representative.2.1 impulse wheelsWith the impulse wheel the potential energy of the water in the penstock is transformed into kinetic energy in a jet issuing from the orifice of a nozzle. This jet discharge freely into the atmosphere inside the wheel housing and strikes against the bowl-shaped buckets of the runner. At each revolution the bucket enters, passes through, and passes out of the jet, during which time it receives the full impact force of the jet. This produces a rapid hammer blow upon the bucket. At the same time the bucket is subjected to the centrifugal force tending to separate the bucket from its disk. On account of the stresses so produced and also the scouring effects of the waterflowing over the working surface of the bowl, material of high quality of resistance against hydraulic wear and fatigue is required. Only for very low heads can cast iron be employed. Bronze and annealed cast steel are normally used.2.2 Francis runnersWith the Francis type the water enters from a casing or flume with a relatively low velocity, passes through guide vanes or gates located around the circumstance, and flows through the runner, from which it discharges into a draft tube sealed below the tail-water level. All the runner passages are completely filled with water, which acts upon the whole circumference of the runner. Only a portion of the power is derived from the dynamic action due to the velocity of the water, a large part of the power being obtained from the difference in pressure acting on the front and back of the runner buckets. The draft tube allows maximum utilization of the available head, both because of the suction created below the runner by the vertical column of water and because the outlet of he draft tube is larger than the throat just below the runner, thus utilizing a part of the kinetic energy of the water leaving the runner blades.2.3 propeller runnersnherently suitable for low-head developments, the propeller-type unit has effected marked economics within the range of head to which it is adapted. The higher speed of this type of turbine results in a lower-cost generator and somewhat smaller powerhouse substructure and superstructure. Propeller-type runners for low heads and small outputs are sometimes constructed of cast iron. For heads above 20 ft, they are made of cast steel, a much more reliable material. Large-diameter propellers may have individual blades fastened to the hub.2.4 adjustable-blade runnersThe adjustable-blade propeller type is a development from the fixed-blade propeller wheel. One of the best-known units of this type is the Kaplan unit, in which the blades may be rotated to the most efficient angle by a hydraulic servomotor. A cam on the governor is used to cause the blade angle to change with the gate position so that high efficiency is always obtained at almost any percentage of full load.By reason of its high efficiency at all gate openings, the adjustable-blade propeller-type unit is particularly applicable to low-head developments where conditions are such that the units must be operated at varying load and varying head. Capital cost and maintenance for such units are necessarily higher than for fixed-blade propeller-type units operated at the point of maximum efficiency.hydro-electric powerFaraday 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 prod uce 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. prime mover +electric generator) is collectively known as power plant. The building, in which the entire machinery along with other auxiliary units is installed, is known as power house.1 thermal and hydropowerAs stated earlier, the turbine blades can be made to run by the energy of fuels or flowing water. When fuel is used to produce steam for running the steam turbine, then the power generated is known as thermal power. The fuel which is to be used for generating steam may either be an ordinary fuel such as coal, fuel oil, etc., or atomic fuel or nuclear fuel. Coal is simply burnt to produce steam from water and is the simplest and oldest type of fuel. Diesel oil, etc. may also be used as fuels for producing steam. Atomic fuels such as uranium or thorium may also be used to produce steam. When conventional type of fuels such s coal, oil, etc. (called fossils ) is used to produce steam for running the turbines, the power house is generally called an Ordinary thermal power station or Thermal power station. But when atomic fuel is used to produce steam, the power station, which is essentially a thermal power station, is called an atomic power station or nuclear power station. In an ordinary thermal power station, steam is produced in a water boiler, while in the atomic power station; the boiler is replaced y a nuclear reactor and steam generator for raising steam. The electric power generated in both these cases is known as thermal power and the scheme is called thermal power scheme.But, when the energy of the flowing water is used to run the turbines, then the electricity generated is called hydroelectric power. This scheme is known as hydro scheme, and the power house is known as hydel power station or hydroelectric power station. In a hydro scheme, a certain quantity of water at a certain potential head is essentially made to flow through the turbines. The head causing flow runs the turbine blades, and thus producing electricity from the generator coupled to turbine. In this chapter, we are concerned with hydel scheme only.2 classification of hydel plantsHydro-plants may be classified on the basis of hydraulic characteristics as follow: ①run-off river plants ; ②storage plants ; ③pumped storage plants ; ④tidal plants. they are described below:(1)Run-off river plants.These plants are those which utilize the minimum flow in a river having no appreciable pondage on its upstream side. A weir or a barrage is sometimes constructed across a river simply to raise and maintain the water level at apre-determined level within narrow limits of fluctuations, either solely for the power plants or for some other purpose where the power plant may be incidental. Such a scheme is essentially a low head scheme and may be suitable only on a perennial river having sufficient dry weather flow of such a magnitude as to make the development worthwhile.Run-off river plants generally have a very limited storage capacity, and can use water only when it comes. This small storage capacity is provided for meeting the hourly fluctuations of load. When the available discharge at site is more than the demand (during off-peak hours ) the excess water is temporarily stored in the pond on the upstream side of the barrage, which is then utilized during the peak hours.he various examples of run-off the river pant are: Ganguwal and Kolta power houses located on Nangal Hydel Channel, Mohammad Pur and Pathri power houses on Ganga Canal and Sarda power house on Sarda Canal.The various stations constructed on irrigation channels at the sites of falls, also fall under this category of plants.(2) Storage plantsA storage plant is essentially having an upstream storage reservoir of sufficient size so as to permit, sufficient carryover storage from the monsoon season to the dry summer season, and thus to develop a firm flow substantially more than minimum natural flow. In this scheme, a dam is constructed across the river and the power house may be located at the foot of the dam such as in Bhakra, Hirakud, Rihand projects etc. the power house may sometimes be located much away from the dam (on the downstream side). In such a case, the power house is located at the end of tunnels which carry water from the reservoir. The tunnels are connected to the power house machines by means of pressure pen-stocks which may either be underground (as in Mainthon and Koyna projects) or may be kept exposed (as in Kundah project).When the power house is located near the dam, as is generally done in the low head installations ; it is known as concentrated fall hydroelectric development. But when the water is carried to the power house at a considerable distance from the dam through a canal, tunnel, or pen-stock; it is known as a divided fall development.(3) Pumped storage plants.A pumped storage plant generates power during peak hours, but during theoff-peak hours, water is pumped back from the tail water pool to the headwater pool for future use. The pumps are run by some secondary power from some other plant in the system. The plant is thus primarily meant for assisting an existing thermal plant or some other hydel plant.During peak hours, the water flows from the reservoir to the turbine and electricity is generated. During off-peak hours, the excess power is available from some other plant, and is utilized for pumping water from the tail pool to the head pool, this minor plant thus supplements the power of another major plant. In such a scheme, the same water is utilized again and again and no water is wasted.For heads varying between 15m to 90m, reservoir pump turbines have been devised, which can function both as a turbine as well as a pump. Such reversible turbines can work at relatively high efficiencies and can help in reducing the cost of such a plant. Similarly, the same electrical machine can be used both as a generator as well as a motor by reversing the poles. The provision of such a scheme helps considerably in improving the load factor of the power system.(4) Tidal plantsTidal plants for generation of electric power are the recent and modern advancements, and essentially work on the principle that there is a rise in seawater during high tide period and a fall during the low ebb period. The water rises and falls twice a day; each fall cycle occupying about 12 hours and 25 minutes. The advantage of this rise and fall of water is taken in a tidal plant. In other words, the tidal range, i.e. the difference between high and low tide levels is utilized to generate power. This is accomplished by constructing a basin separated from the ocean by a partition wall and installing turbines in opening through this wall.Water passes from the ocean to the basin during high tides, and thus running the turbines and generating electric power. During low tide, the water from the basin runs back to ocean, which can also be utilized to generate electric power, provided special turbines which can generate power for either direction of flow are installed. Such plants are useful at places where tidal range is high. Rance power station in France is an example of this type of power station. The tidal range at this place is of the order of 11 meters. This power house contains 9 units of 38,000 kW.Hydro-plants or hydroelectric schemes may be classified on the basis of operating head on turbines as follows: ①low head scheme (head<15m); ②medium head scheme (head varies between 15m to 60 m) ③high head scheme (head>60m). They are described below:(1) Low head scheme.A low head scheme is one which uses water head of less than 15 meters or so. A run off river plant is essentially a low head scheme, a weir or a barrage is constructedto raise the water level, and the power house is constructed either in continuation with the barrage or at some distance downstream of the barrage, where water is taken to the power house through an intake canal.(2) Medium head schemeA medium head scheme is one which used water head varying between 15 to 60 meters or so. This scheme is thus essentially a dam reservoir scheme, although the dam height is mediocre. This scheme is having features somewhere between low had scheme and high head scheme.(3) High head scheme.A high head scheme is one which uses water head of more than 60m or so. A dam of sufficient height is, therefore, required to be constructed, so as to store water on the upstream side and to utilize this water throughout the year. High head schemes up to heights of 1,800 meters have been developed. The common examples of such a scheme are: Bhakra dam in (Punjab), Rihand dam in (U.P.), and Hoover dam in (U.S.A), etc.The naturally available high falls can also be developed for generating electric power. The common examples of such power developments are: Jog Falls in India, and Niagara Falls in U.S.A.水轮机1.概述水的能量可以通过三种基本方法来获得：利用水的重力作用、水的压力作用或水的流速作用，或者其中任意两种或全部三种作用的组合。
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Concrete Gravity DamThe type of dam selected for a site depends principally on topographic, geologic,hydrologic, and climatic conditions. Where more than one type can be built, alternative economic estimates are prepared and selection is based on economica considerations.Safety and performance are primary requirements, but construction time and materials often affect economic comparisons.Dam ClassificationDams are classified according to construction materials such as concrete or earth. Concrete dams are further classified as gravity, arch, buttress, or a combination of these. Earthfill dams are gravity dams built of either earth or rock materials, with particular provisions for spillways and seepage control.A concrete gravity dam depends on its own weight for structural stability. The dam may be straight or slightly curved, with the water load transmitted through the dam to the foundation material. Ordinarily, gravity dams have a base width of 0.7 to 0.9 the height of the dam. Solid rock provides the best foundation condition. However, many small concrete dams are built on previous or soft foundations and perform satisfactorily. A concrete gravity dam is well suited for use with an overflow spillway crest. Because of this advantage, it is often combined with an earthfill dam in wide flood plain sites.Arch dams are well suited to narrow V- or U-shaped canyons. Canyon walls must be of rock suitable for carrying the transmitted water load to the sides of the canyon by arch action. Arch sections carry the greatest part of the load; vertical elements carry sufficient load through cantilever action to produce cantilever deflections equal to arch deflections. Ordinarily, the crest length-to-height ratio should be less than 5, although greater ratios have been used. Generally, the base width of modern arch dams is 0.1 to 0.3 the height of the impounded water. A spillway may be designed into the crest of an arch dam.Multiple arches similarly transmit loads to the abutment or ends of the arch. This type of dam is suited to wider valleys. The main thrust and radial shears are transmitted to massive buttresses and then into the foundation material.Buttress dams include flat-slab, multiple-arch, roundhead-buttress, and multiple-dome types. The buttress dam adapts to all site locations. Downstream face slabs and aprons are used for overflow spillways similar to gravity dam spillways. Inclined sliding gates or light-weight low-head gates control the flow.The water loads are transmitted to the foundation by two systems of load-carrying members. The flat slabs, arches, or domes support the direct water load. The face slabs are supported by vertical buttresses. In most flat-slab buttress dams, steel reinforcement is used to carry thetension forces developed in the face slabs and buttress supports. Massive-head buttresses eliminate most tension forces and steel is not necessary.Combiantion designs may utilize one or more of the previously mentioned types of dams. For example, studies may indicate that an earthfill dam with a center concrete gravity overflow spillway section is the most economial in a wide, flat valley. Other design conditions may dictate a multiple-arch and buttress dam section or a buttress and gravity dam combination.Site ExplorationThe dam location is determined by the project’s functions. The exact site within the general location must be determined by careful project consideration and systematic studies.In preliminary studies, two primary factors must be determined-the topography at the site and characteristics of the foundation materials. The first choice of the type of dam is based primarily on these two factors. However, the final choice will usually be controlled by construction cost if other site factors are also considered.Asite exploration requires the preparation of an accurate topographic map for each possible site in the general location. The scale of the maps should be large enough for layout. Exploration primarily determines the conditions that make sites usable or unusable.From the site explorations, tentative sketches can be made of the dam location and project features such as power plants. Physical features at the site must be ascertained in order to make a sketch of the dam and determine the position of materials and work plant during construction. Other factors that may affect dam selection are roadways,fishways, locks, and log passages.TopographyTopography often determines the type of dam. For example, a narrow V-shaped channel may dictate an arch dam. The topography indicates surface characteristics of the valley and the relation of the contours to the various requirements of the structure. Soundness of the rock surface must be included in the topographic study.In a location study, one should select the best position for the dam. An accurate sketch of the dam and how it fits into the topographic features of the valley are often sufficient to permit initial cost estimates. The tentative location of the other dam features should be included in this sketch since items such as spillways can influence the type and location of the dam.Topographic maps can be made from aerial surveys and subsequent contour plotting or they can be obtained from governmental agencies. The topographic survey should be correlated with the site exploration to ensure accuracy. Topographic maps give only the surface profile at thesite. Further geological and foundation analyses are necessary for a final determination of dam feasibility.Foundation and Geological InvestigationFoundation and geological conditions determine the factors that support the weight of the dam. The foundation materials limit the type of dam to a great extent, although such limitations can be compensated for in design.Initial exploration may consist of a few core holes drilled along the tentatively selected site location. Their analysis in relation to the general geology of the area often rules out certain sites as unfeasible, particularly as dam height increases. Once the number of possible site locations has been narrowed down, more detailed geological investiagtions should be considered.The location of all faults, contacts, zones of permeability, fissures, and other underground conditions must be accurately defined. The probable required excavation depth at all points should be derived from the core drill analysis. Extensive drilling into rock formations isn’t necessary for small dams. However, as dam height and safety requirements increase, investigations should be increased in depth and number. If foundation materials are soft, extensive investigations should determine their depth,permeability, and bearing capacity. It is not always necessary orpossible to put a concrete dam on solid rock.The different foundations commonly encountered for dam construction are: (1)solid rock foundations, (2) gravel foundations, (3) silt or fine sand foundations, (4) clay foundations, and (5) nonuniform foundation materials. Small dams on soft foundation ( item 2 through item 5 ) present some additonal design problems such as settlement, prevention of piping, excessive percolation, and protection of foundation from downstream toe erosion. These conditions are above the normal design forces of a concrete dam on a rock foundation. The same problems also exist for earth dams.Geological formations can often be pictured in cross-section by a qualified geologist if he has certain core drill holes upon which to base his overall concept of the geology. However, the plans and specifications should not contain this overall geological concept. Only the logs of the core drill holes should be included for the contractor’s estimates. However, the geological picture of the underlying formations is a great aid in evaluating the dam safety. The appendix consists of excerpts from a geologic report for the site used in the design examples.HydrologyHydrology studies are necessary to estimate diversion requirements during construction, to establish frequency of use of emergency spillways in conjunction with outlets or spillways, to determine peak dischargeestimates for diversion dams, and to provide the basis for power generation. Hydrologic studies are complex; however, simplified procedures may be used for small dams if certain conservative estimates are made to ensure structural safety.Formulas are only a guide to preliminary plans and design computations. The empirical equations provide only peak discharge estimates. However, the designer is more interested in the runoff volume associated with discharge and the time distribution of the flow. With these data, the designer knows both the peak discharge and the total inflow into the reservoir area. This provides a basis for making reliable diversion estimates for irrigation projects, water supply, or power generation.A reliable study of hydrology enables the designer to select the proper spillway capacity to ensure safety. The importance of a safe spillway cannot be overemphasized. Insufficient spillways have caused failures of dams. Adequate spillway capacity is of paramount importance for earthfill and rockfill dams. Concrete dams may be able to withstand moderate overtopping.Spillways release excess water that cannot be retained in the storage space of the reservoir. In the preliminary site exploration, the designer must consider spillway size and location. Site conditions greatly influence the selection of location, type, and components of a spillway. The design flows that the spillway must carry without endangering the dam areequally important. Therefore, study of streamflow is just as critical as the foundation and geological studies of the site.附录2外文翻译混凝土重力坝一个坝址的坝型选择，主要取决于地形、地质、水文和气候条件。