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建筑土木工程外文翻译外文文献英文文献及译文土工织物加筋垫层加固软土地基

Geotextile reinforced by soft soil1. IntroductionGeotextile known, it has high tensile strength, durability, corrosion resistance, texture, flexibility, combined with good sand, to form reinforced composite foundation, effectively increase the shear strength , tensile properties, and enhance the integrity and continuity of soil. Strengthening mechanism for the early 60's in the 20th century, Henri Vidal on the use of triaxial tests found a small amount of fiber in the sand, the soil shear strength can improve the image of more than 4 times in recent years, China's rock Laboratory workers also proved in the reinforced sand can effectively improve the soil's bearing capacity, reduce the vertical ground settlement, effectively overcome the poor soil and continuity of overall poor performance. As with the above properties of reinforced soil and the characteristics of its low price, so the project has broad application prospects.2.1 Project OverviewThe proposed retaining wall using rubble retaining wall of gravity, the wall is 6 meters high, the bearing capacity of foundation soil required to 250kPa, while the basement geology from the top down as follows: ①clay to a thickness of 0.7 to 2 meters saturated, soft plastic; ② muddy soil, about 22 - 24 meters thick, saturated, mainly plastic flow, local soft plastic; ③ sand layer to a thickness of 5 to 10 meters, containing silty soil and organic matter, saturated, slightly wet; ④ gravel layer, the thickness of the uneven distribution points, about 0 to 2.2 meters, slightly dense; ⑤ weathered sandstone. Including clay and silty soil bearing capacity is 70kPa, obviously do foundation reinforcement.2.2 Enhanced Treatment of reinforced foundation cushion Reinforcement replacement method can be used for sand and gravel used forsoil treatment, but due to loose bedding, based on past experience, witha gravel mat to treat a large settlement of the foundation always exist, even the characteristics of poor, often resulting in cracks in the superstructure, differential settlement of the image, this works for6-meter-high rubble retaining walls, height and large, and because the walls are 3 meters high wall, if there is differential settlement of retaining walls, cracks, will result in more serious consequences and thus should be used on the cushion reinforcement through economic and technical analysis, decide on the sand and gravel stratum were reinforced hardening. Reinforcement treatment method: first the design elevation and the basement excavation to 200mm thick layer of gravel bedding, and then capped with a layer of geotextile, and then in the thick sand and gravel on the 200, after leveling with the yellow sand using roller compaction; second with loaded bags of sand and gravel laying of geotextile, the gap filled with slag, geotextile bags capped 100 thick gravel, roller compaction. Its on repeat laying geotextile → → compacted gravel, until the design thickness of the cushion, the bridge is 1 m thick cushion, a total of 4 layers of geotextile, two bags of sand.This method works fast, simple machine, investment, after years of use, that reinforce good effect, building and construction units are satisfied.3 ExperienceTo achieve the reinforced soil reinforcement effect, must be reinforced earth construction technology, construction strict quality control: 1, geotextile should increase the initial pre-stress, and its end should be a reliable anchor to play the tensile strength of geotextile, anchoring more firmly, more capacity to improve, the foundation of the stress distribution more uniform, geotextile side Ministry of fixed length by laying end to ensure the fold, the folded end wrapped sand to increase its bond strength to ensure that the use will not be pulled out duringthe period.Second, the construction process have a significant effect on the reinforcement effect, the construction should be as soon as possible so that geotextile in tension, tensile strength geotextile can be played only when the deformation, so do not allow construction of geotextile crease occurs, the earth Fabric tension leveling as much as possible. Geotextile in order to have enough by the early Dutch strain, according to the following procedure works: ① laying geotextile; ② leveled the tension at both ends; both ends of the folded package gravel and sand filling at both ends; ③ center fill sand; ④ 2 higher end of sand; ⑤ Finally, the center of sand filling. Click here to enable the construction method of forming corrugated geotextile being stretched as soon as possible, to play a role in the early loaded.Third, the construction of geotextile-reinforced cushion should the level of shop using geotextile geotextile and laying of gravel bags cushion the turn to play bag cushion integrated turn out good, flexural rigidity, and dispersion of good and peace bedding layer of the overall continuity of good advantages.4 ConclusionGeotextile reinforced by soft soil is an effective, economical, safe, reliable, simple method, but the literature describes only qualitative, experience more components, yet the lack of rigorous The theoretical formula, reliable test data to be adequate, these are yet to be theoretical workers and the general engineering and technical personnel continue to explore.土工织物加筋垫层加固软土地基1. 引言土工织物又称土工聚合物，它具有高抗拉强度，耐久性、耐腐蚀性，质地柔韧，能与砂土很好地结合，组合成加筋土复合地基，有效地提高土的抗剪强度、抗拉性能，增强土体的整体性和连续性。

软土路基外文翻译--论公路路基施工技术

毕业设计（论文）外文翻译学生姓名：院（系）：专业班级：指导教师：完成日期：要求1.外文翻译是毕业设计（论文）的主要内容之一，学生必须独立完成。

2.外文翻译文内容应与学生的专业或毕业设计（论文）内容相关，不得少于15000印刷字符。

3.外文翻译文用A4纸打印。

文章标题用3号宋体，章节标题用4号宋体，正文用小4号宋体；页边距上下左右均为2.5cm,左侧装订，装订线0.5cm。

按中文翻译在上，外文原文在下的顺序装订。

4.年月日等的填写，用阿拉伯数字书写，要符合《关于出版物上数字用法的试行规定》，如“2009年2月15日”。

5.所有签名必须手写，不得打印。

论公路路基施工技术1引言公路路基施工是整个公路施工工程的关键所在，稍有偏差，将给整个工程埋下质量隐患。

例如，在公路施工中常会遇到诸如软土路基，黄土路基等不良路基，如不加以特别处理，会引起填方路堤施工后沉降或不均匀沉陷，路面纵横坡变碎，平整度下降，导致行车颠簸等，严重影响公路的正常使用，造成大量的人力、物力、财力浪费。

因此，路基施工应根据施工当地地形、地质状况、公路等级、所在地区的气候、结合施工填挖方平衡等来选择施工方法。

2路基填压公路路基的强度和稳定性很大程度取决于路基填料的性质及其压实的程度。

从现有条件出发，改进填土要求和压实条件是保证路基质量经济有效的方法。

2.1路基填料现行《公路路基设计规范》（以下简称规范）规定了对路基填料的要求。

对路基填料的最小强度和最大粒径给了量化的标准，采用承载比实验（CBR）值表征路基土的强度，引入了路床的概念。

对上路床的填料提出了限制条件，高速公路和一级公路路面底以下0cm-30cm的路床填料，其CBR值应大于8，对下路床及下面的填土也给出相应的规定值。

2.2路基压实当前路基施工，普遍采用了大吨位的压路机，碾压效果有了明显的改善。

对于提高路基土的压实度起了很好的作用。

规范规定高速公路和一级公路路面底面以下80cm－150cm部分的上路堤其压实度必须≥95％，对其它等级公路当铺筑高级路面时，其压实度亦应按高速公路和一级公路的标准采用。

土木工程垃圾填埋场毕业论文中英文资料外文翻译文献

中英文资料外文翻译文献Several Motives to Bring the Research on Landfill Cap Covers to the Standard of the Researchers about Bottom LinersABSTRACT: The behavior of the cap barrier (and mainly the sealing layer) in the central area of a landfill where the slope is low, is considered. The main regulations about landfills are concentrated in the present time on the requirements related to the bottom barrier. The cap barrier has also a fundamental function (to limit or to control the humidity of the confined waste). It is shown in this Lecture, which is supported by the presentation of some experimental researches, that meeting this target is really a big challenge and also an important ecological challenge since landfills are an important spring of methane, potent greenhouse gas. First and foremost an in-depth research on the behavior of the confined waste is necessary to demonstrate the technical interest of geo synthetic solutions and also to devise new geo synthetic systems.KEY WORDS: landfill, waste, biodegradation, greenhouse gas, settlementINTRODUCTIONFirstly, it’s worth noting that landfills should be considered as a modern technique of treatment of waste, which was moving and developing significantlyduring the last decade. The main regulations about landfills are concentrated in the present time on the requirements related to the bottom barrier. The cap barrier has also a fundamental function (to limit or to control the humidity of the confined waste). To cover with an efficient cap barrier a waste disposal is a key issue.In a previous Keynote Lecture (Gourc, 2004), the global problem of stability of geosynthetics composite systems used as cap barriers on steep slopes of landfills were considered (Gourc et al, 2008).In the present Lecture, the behavior of the cap (and mainly the sealing liner) in the central area of a landfill is considered. It is demonstrated that an in-depth knowledge of the waste behavior is required before to optimize the concept of the liner. Geo synthetics solutions are very often better than mineral layers; in many cases these geo synthetics solutions have already proved their worth, but new applications are still possible. The application of geo synthetics to cap over of new landfills but also of old uncontrolled dumps is a promising market.CAP COVER REQIREMENTSThe French regulation does not completely specify the structure of the cap cover (Decree Sept. 1997) and recommend only two concepts according to the nature of waste (Fig. 1):-for Municipal Solid Waste (MSW) , with a biodegradable part, the cover must be provided “with a semi-permeable layer in natural fine soil compacted on a thickness of at least 1 meter, or any equivalent device ensuring the same effectiveness.”-for Hazardous waste, it must be provided “with an impermeabl e layer of 1 meter characterized by an hydraulic conductivity lower than 1.10-9m/s associated at a geomembrane or any equivalent device.”Indeed this regulation does not meet the many concerns related to the behavior of a landfill cap cover under complex solicitations.STORAGE OF HAZARDOUS WASTELandfill for this type of waste includes generally, following regulations in many countries, a cap cover with a compacted clay liner (CCL). Imperviousness of clay isessential to safeguard the hazardous wastes against wetting, in order to prevent leaching and washing of the waste and consequently possible pollution of the ground water in case of filing of the bottom barrier. However the CCL meets many problems, in particular those related to its mechanical solicitations after closing the cell, specifically differential settlements.Some experiences carried out in France which demonstrate the sensitivity of CCL to cracking in case of bending solicitation are presented:Behavior of a clay layer subjected to a sinkhole situation.Test procedureThe experiments were performed on the CERED site (Suez) (Fig.2) on clay material with a large proportion of coarse soil (material conventionally used in France for waste landfill sites).The CCL (Aupicon et al, 2002) is compacted on a cavity of (2m×2m) filled with expanded clay beads. In a second stage, the clay beads are removed, simulating a concentrated subsidence of the waste. This condition is specifically severe but may correspond to realistic situation for instance in case of internal collapsing or burning of a piece of waste.Two conditions were considered:-The first one was a layer of unreinforced clay, thickness H reduced to 0.6 m, above a sinkhole with a span of a length L of 2 meters.- The second one was a layer of the same clay, thickness H reduced to 0.6 m, reinforced at the base by a geosynthetic sheet, (Fig.2). The tensile stiffness of the synthetic sheet (overall length of 8 m) is J=1818 kN/m. The anchorage of the sheet (free ends) is obtained by friction (no sliding observed at the edges).The vertical deflection (f) is recorded at every stage of the experience.Layer of reinforced clayDuring the first step (the process of emptying of the cavity), a detaching is observed between the lower and upper sub-layers of clay, revealing cracks inclined towards the edges of the cavity (Fig.2 and 3) corresponding to the compaction in two stages. The poor interlocking between two compacted layers is a classical fault and itwas finally interesting even if it was unintentional. Consequently the lower sub-layer behaved independently like a 0.3 m layer subjected to bending under its own weight. The geotextile followed the deformation of the lower sub-layer but was not very sollicitated: the maximum vertical displacement of the lower sub-layer being still small (f = 10mm). The upper sub-layer did not deform significantly under its own weight and it could be considered that water and gas tightness were kept satisfactory for this layer.In a second step, an overload was put at the surface in order to increase the bending deformation of the structure (Fig. 4). Finally as it was impossible to obtain a short term collapse of the structure, the long term deflection was monitored under a constant overload (q) for several months. An increase in vertical deflection (creep+ anchorage slip) of the clay and geo synthetic liner was observed. The evolution of the vertical deflection during the complete experience versus the total vertical load applied to the geotextile (Q=own weight of the clay layer + overload q) is plotted on the (Fig.5)。

混凝土工艺中英文对照外文翻译文献

混凝土工艺中英文对照外文翻译文献混凝土工艺中英文对照外文翻译文献(文档含英文原文和中文翻译)Concrete technology and developmentPortland cement concrete has clearly emerged as the material of choice for the construction of a large number and variety of structures in the world today. This is attributed mainly to low cost of materials and construction for concrete structures as well as low cost of maintenance.Therefore, it is not surprising that many advancements in concrete technology have occurred as a result of two driving forces, namely the speed of construction and the durability of concrete.During the period 1940-1970, the availability of high early strength portland cements enabled the use of high water content in concrete mixtures that were easy to handle. This approach, however, led to serious problems with durability of structures, especially those subjected to severe environmental exposures.With us lightweight concrete is a development mainly of the last twenty years.Concrete technology is the making of plentiful good concrete cheaply. It includes the correct choice of the cement and the water, and the right treatment of the aggregates. Those which are dug near by and therefore cheap, must be sized, washed free of clay or silt, and recombined in the correct proportions so as to make a cheap concrete which is workable at a low water/cement ratio, thus easily comoacted to a high density and therefore strong.It hardens with age and the process of hardening continues for a long time after the concrete has attained sufficient strength.Abrams’law, perhaps the oldest law of concrete technology, states that the strength of a concrete varies inversely with its water cement ratio. This means that the sand content (particularly the fine sand which needs much water) must be reduced so far as possible. The fact that the sand “drinks” large quantities of water can easily be established by mixing several batches of x kg of cement with y kg of stone and the same amount of water but increasing amounts of sand. However if there is no sand the concrete will be so stiff that it will be unworkable thereforw porous and weak. The same will be true if the sand is too coarse. Therefore for each set of aggregates, the correct mix must not be changed without good reason. This applied particularly to the water content.Any drinkable and many undrinkable waters can be used for making concrete, including most clear waters from the sea or rivers. It is important that clay should be kept out of the concrete. The cement if fresh can usually be chosen on the basis of the maker’s certificates of tensile or crushing tests, but these are always made with fresh cement. Where strength is important , and the cement at the site is old, it should be tested.This stress , causing breakage,will be a tension since concretes are from 9 to 11times as strong in compression as in tension, This stress, the modulus of rupture, will be roughly double the direct tensile breaking stress obtained in a tensile testing machine,so a very rough guess at the conpressive strength can be made by multiplying the modulus of rupture by 4.5. The method can be used in combination with the strength results of machine-crushed cubes or cylinders or tensile test pieces but cannot otherwise be regarded as reliable. With these comparisons, however, it is suitable for comparing concretes on the same site made from the same aggregates and cement, with beams cast and tested in the same way.Extreme care is necessary for preparation,transport,plating and finish of concrete in construction works.It is important to note that only a bit of care and supervision make a great difference between good and bad concrete.The following factors may be kept in mind in concreting works.MixingThe mixing of ingredients shall be done in a mixer as specified in the contract.Handling and ConveyingThe handling&conveying of concrete from the mixer to the place of final deposit shall be done as rapidly as practicable and without any objectionable separation or loss of ingredients.Whenever the length of haul from the mixing plant to the place of deposit is such that the concrete unduly compacts or segregates,suitable agitators shall be installed in the conveying system.Where concrete is being conveyed on chutes or on belts,the free fall or drop shall be limited to 5ft.(or 150cm.) unless otherwise permitted.The concrete shall be placed in position within 30 minutes of its removal from the mixer.Placing ConcreteNo concrete shall be placed until the place of deposit has been thoroughly inspected and approved,all reinforcement,inserts and embedded metal properly security in position and checked,and forms thoroughly wetted(expect in freezing weather)or oiled.Placing shall be continued without avoidable interruption while the section is completed or satisfactory construction joint made.Within FormsConcrete shall be systematically deposited in shallow layers and at such rate as to maintain,until the completion of the unit,a plastic surface approximately horizontal throughout.Each layer shall be thoroughly compacted before placing the succeeding layer.CompactingMethod. Concrete shall be thoroughly compacted by means of suitable tools during and immediately after depositing.The concrete shall be worked around all reinforcement,embedded fixtures,and into the comers of the forms.Every precaution shall be taken to keep the reinforcement and embedded metal in proper position and to prevent distortion.Vibrating. Wherever practicable,concrete shall be internally vibrated within the forms,or in the mass,in order to increase the plasticity as to compact effectively to improve the surface texture and appearance,and to facilitate placing of the concrete.Vibration shall be continued the entire batch melts to a uniform appearance and the surface just starts to glisten.A minute film of cement paste shall be discernible between the concrete and the form and around the reinforcement.Over vibration causing segregation,unnecessary bleeding or formation of laitance shall be avoided.The effect spent on careful grading, mixing and compaction of concrete will be largely wasted if the concrete is badly cured. Curing means keeping the concretethoroughly damp for some time, usually a week, until it has reached the desired strength. So long as concrete is kept wet it will continue to gain strength, though more slowly as it grows older.Admixtures or additives to concrete are materials are materials which are added to it or to the cement so as to improve one or more of the properties of the concrete. The main types are:1. Accelerators of set or hardening,2. Retarders of set or hardening,3. Air-entraining agents, including frothing or foaming agents,4. Gassing agents,5. Pozzolanas, blast-furnace slag cement, pulverized coal ash,6. Inhibitors of the chemical reaction between cement and aggregate, which might cause the aggregate to expand7. Agents for damp-proofing a concrete or reducing its permeability to water,8. Workability agents, often called plasticizers,9. Grouting agents and expanding cements.Wherever possible, admixtures should be avouded, particularly those that are added on site. Small variations in the quantity added may greatly affect the concrete properties in an undesiraale way. An accelerator can often be avoided by using a rapid-hardening cement or a richer mix with ordinary cement, or for very rapid gain of strength, high-alumina cement, though this is very much more expensive, in Britain about three times as costly as ordinary Portland cement. But in twenty-four hours its strength is equal to that reached with ordinary Portland cement in thirty days.A retarder may have to be used in warm weather when a large quantity of concrete has to be cast in one piece of formwork, and it is important that the concrete cast early in the day does not set before the last concrete. This occurs with bridges when they are cast in place, and the formwork necessarily bends under the heavy load of the wet concrete. Some retarders permanently weaken the concrete and should not be used without good technical advice.A somewhat similar effect,milder than that of retarders, is obtained with low-heat cement. These may be sold by the cement maker or mixed by the civil engineering contractor. They give out less heat on setting and hardening, partly because they harden more slowly, and they are used in large casts such as gravity dams, where the concrete may take years to cool down to the temperature of the surrounding air. In countries like Britain or France, where pulverized coal is burnt in the power stations, the ash, which is very fine, has been mixed with cement to reduce its production of heat and its cost without reducing its long-term strength. Up to about 20 per cent ash by weight of the cement has been successfully used, with considerable savings in cement costs.In countries where air-entraining cement cement can be bought from the cement maker, no air-entraining agent needs to be mixed in .When air-entraining agents draw into the wet cement and concrete some 3-8 percent of air in the form of very small bubbles, they plasticize the concrete, making it more easily workable and therefore enable the water |cement ratio to be reduced. They reduce the strength of the concrete slightly but so little that in the United States their use is now standard practice in road-building where heavy frost occur. They greatly improve the frost resistance of the concrete.Pozzolane is a volcanic ash found near the Italian town of Puzzuoli, which is a natural cement. The name has been given to all natural mineral cements, as well as to the ash from coal or the slag from blast furnaces, both of which may become cements when ground and mixed with water. Pozzolanas of either the industrial or the mineral type are important to civil engineers because they have been added to oridinary Portland cement in proportions up to about 20 percent without loss of strength in the cement and with great savings in cement cost. Their main interest is in large dams, where they may reduce the heat given out by the cement during hardening. Some pozzolanas have been known to prevent the action between cement and certain aggregates which causes the aggregate to expand, and weaken or burst the concrete.The best way of waterproof a concrete is to reduce its permeability by careful mix design and manufacture of the concrete, with correct placing and tighr compaction in strong formwork ar a low water|cement ratio. Even an air-entraining agent can be used because the minute pores are discontinuous. Slow, careful curing of the concrete improves the hydration of the cement, which helps to block the capillary passages through the concrete mass. An asphalt or other waterproofing means the waterproofing of concrete by any method concerned with the quality of the concrete but not by a waterproof skin.Workability agents, water-reducing agents and plasticizers are three names for the same thing, mentioned under air-entraining agents. Their use can sometimes be avoided by adding more cement or fine sand, or even water, but of course only with great care.The rapid growth from 1945 onwards in the prestressing of concrete shows that there was a real need for this high-quality structural material. The quality must be high because the worst conditions of loading normally occur at the beginning of the life of the member, at the transfer of stress from the steel to the concrete. Failure is therefore more likely then than later, when the concrete has become stronger and the stress in the steel has decreased because of creep in the steel and concrete, and shrinkage of the concrete. Faulty members are therefore observed and thrown out early, before they enter the structure, or at least before it The main advantages of prestressed concrete in comparison with reinforced concrete are :①The whole concrete cross-section resists load. In reinforced concrete about half the section, the cracked area below the neutral axis, does no useful work. Working deflections are smaller.②High working stresses are possible. In reinforced concrete they are not usually possible because they result in severe cracking which is always ugly and may be dangerous if it causes rusting of the steel.③Cracking is almost completely avoided in prestressed concrete.The main disadvantage of prestressed concrete is that much more care is needed to make it than reinforced concrete and it is therefore more expensive, but because it is of higher quality less of it needs to be needs to be used. It can therefore happen that a solution of a structural problem may be cheaper in prestressed concrete than in reinforced concrete, and it does often happen that a solution is possible with prestressing but impossible without it.Prestressing of the concrete means that it is placed under compression before it carries any working load. This means that the section can be designed so that it takes no tension or very little under the full design load. It therefore has theoretically no cracks and in practice very few. The prestress is usually applied by tensioning the steel before the concrete in which it is embedded has hardened. After the concrete has hardened enough to take the stress from the steel to the concrete. In a bridge with abutments able to resist thrust, the prestress can be applied without steel in the concrete. It is applied by jacks forcing the bridge inwards from the abutments. This methods has the advantage that the jacking force, or prestress, can be varied during the life of the structure as required.In the ten years from 1950 to 1960 prestressed concrete ceased to be an experinmental material and engineers won confidence in its use. With this confidence came an increase in the use of precast prestressed concrete particularly for long-span floors or the decks of motorways. Whereever the quantity to be made was large enough, for example in a motorway bridge 500 m kong , provided that most of the spans could be made the same and not much longer than 18m, it became economical to usefactory-precast prestressed beams, at least in industrial areas near a precasting factory prestressed beams, at least in industrial areas near a precasting factory. Most of these beams are heat-cured so as to free the forms quickly for re-use.In this period also, in the United States, precast prestressed roof beams and floor beams were used in many school buildings, occasionally 32 m long or more. Such long beams over a single span could not possibly be successful in reinforced concrete unless they were cast on site because they would have to be much deeper and much heavier than prestressed concrete beams. They would certainlly be less pleasing to the eye and often more expensive than the prestressed concrete beams. These school buildings have a strong, simple architectural appeal and will be a pleasure to look at for many years.The most important parts of a precast prestressed concrete beam are the tendons and the concrete. The tendons, as the name implies, are the cables, rods or wires of steel which are under tension in the concrete.Before the concrete has hardened (before transfer of stress), the tendons are either unstressed (post-tensioned prestressing) or are stressed and held by abutments outside the concrete ( pre-tensioned prestressing). While the concrete is hardening it grips each tendon more and more tightly by bond along its full length. End anchorages consisting of plates or blocks are placed on the ends of the tendons of post-tensioned prestressed units, and such tendons are stressed up at the time of transfer, when the concrete has hardened sufficiently. In the other type of pretressing, with pre-tensioned tendons, the tendons are released from external abutments at the moment of transfer, and act on the concrete through bond or archorage or both, shortening it by compression, and themselves also shortening and losing some tension.Further shortening of the concrete (and therefore of the steel) takes place with time. The concrete is said to creep. This means that it shortens permanently under load and spreads the stresses more uniformly and thus more safely across its section. Steel also creeps, but rather less. The result of these two effects ( and of the concrete shrinking when it dries ) is that prestressed concrete beams are never more highly stressed than at the moment of transfer.The factory precasting of long prestressed concrete beams is likely to become more and more popular in the future, but one difficulty will be road transport. As the length of the beam increases, the lorry becomes less and less manoeuvrable until eventually the only suitable time for it to travel is in the middle of the night when traffic in the district and the route, whether the roads are straight or curved. Precasting at the site avoids these difficulties; it may be expensive, but it has often been used for large bridge beams.混凝土工艺及发展波特兰水泥混凝土在当今世界已成为建造数量繁多、种类复杂结构的首选材料。

土木工程专业外语混凝土含翻译

4 Where fresh concrete is placed on hardened concrete, a good bond must be developed.5 The temperature of fresh concrete must be controlled from the time of mixing through final placement, and protected after placement.。

to avoid segregation.Selection of the most appropriate technique for economy depends on jobsite conditions, especially project size, equipment, and the contractor’s experience.In building construction，power-operated buggies; drop bottom buckets with a inclined chutes; flexible and rigid pipe by pumping;which either dry materials and water are sprayed separately or mixed concrete is shot against the forms; and for underwater placing, tremie chutes (closed flexible tubes).side-dump cars on narrow-gageFor pavement, concrete may be placed by bucket from the swinging boom of a paving mixer, directly by dump truck or mixer truck, or7 Even within the specified limits on slump and water-cementitious materials ratio, excess water must be avoided.In this context, excess water is presented for the conditions of placing if evidence of water rise (vertical segregation) or water flow (horizontal segregation) occurs.Excess water also tends to aggravate surface defects by increasedleakage through form openings. The result may be honeycomb, variations in color, or soft spots at the surface.8 In vertical formwork, water rise causes weak planes between each layer deposited. In addition to the deleterious structural effect, such planes, when hardened, contain voids which water may pass through.9 In horizontal elements, such as floor slabs, excess water rises and strength, low high and generallypoor quality.10 The purpose of consolidation is to eliminate voids of air and to ensure intimate complete contact of the concrete with the surfaces of the forms and the reinforcement.Intense vibration, however, may also reduce the volume of desirable entrained air; but this reduction can be compensated by adjustment of the mix proportions11 Powered internal vibrators are usually used to achieve consolidation. For thin slabs, however, high-quality, low-slump concrete can be effectively consolidated, without excess water, by mechanical surface vibrators.For precast elements in rigid external vibration is highly effective. External vibration is also effective with in-place forms, but should not be used unless the formwork is for theimpact of the vibrator.12 Except in certain paving operations, vibration of the reinforcement should be it is effective, thevertical rebars passing into partly set concrete below may be harmful.Note, however, that re-vibration of concrete before the final set, under controlled conditions, can improve concrete strength markedly and reduce surface voids.This technique is too difficult to control for general use on field-cast vertical elements, but it is very effective in finishing slabs with powered vibrating equipment.13 The interior of columns is usually congested; it contains a large volume of reinforcing steel compared with the volume of concrete, and has a large height compared with its cross-sectional dimensions.Therefore, though columns should be continuously cast, the concrete should be placed in 2-to 4-ft-deep increments and consolidated with internal vibrators. These should be lifted after each increment has been vibrated.If delay occurs in concrete supply before a beenWhen the remainder of the column isportion slightly.14 In all columns and reinforced narrow walls, concrete placing should begin with 2 to 4 inches of grout. Otherwise, loose stone will collect at the bottom, resulting in the formation of honeycomb. This grout should be proportioned for about the same slump as the concrete or slightly more, but at the same or lower water-cementitious material ratio.the same proportions of butWhen concrete is placed for walls,the only practicable means to avoid segregation is to place no more than a 24-in layer in one pass. Each layer should be vibrated separately and kept nearly level.15 For walls deeper than 4 ft, concrete should be placed through vertical. The concrete should not fall free more than 4 ft or segregation will occur, with the coarse aggregate ricocheting off thelayers after the initial layer should be penetrated by.can be beneficial (re-vibration), but control under variable jobsite conditions is too uncertain for recommendation of this practice for general use.16 The results of poor placement in walls are frequently observed:slope layer lines; honeycombs, leaking, if water is present; and, if cores are taken at successive heights, up to a 50% reduction in strength from bottom to top. Some precautions necessary to avoid these ill effects are:17 Do not move concrete laterally with vibrators18 For deep, long walls, reduce the slump for upper layers 2 to 3 in below the slump for the starting layer.19 On any placing of layers, vibrate the concrete20 Concrete should be inspected for the owner before, during, and after casting. Before concrete is placed, the formwork must be free of ice and debris and properly coated with bond-breaker oil.The rebars must be in place, properly supported to bear any traffic they will receive during concrete placing.inserts, and other items to be embedded must be inConstruction personnel should be available, usually carpenters, bar placers and other trades, if piping or electrical conduit is to be embedded, to act as form watchers and to reset any rebars, conduit, or piping displaced.21 As concrete is cast, the slump of the concrete must be observed and regulated within prescribed limits, or the specified strengths based on the expected slump may be reduced.An inspector of placing who is also responsible for sampling and making cylinders, should test slump, temperatures, and unit weights, during concreting and should control any field adjustmentThe inspector should also that handling, placing, and finishing procedures that agreed on in advance are properly followed, to avoid segregated concrete.should ensure that any construction joints made necessary by stoppage of concrete supply, rain, or other delays are properly located and made in accordancewith procedures specified or approved by the engineer.22 Inspection is complete only when concrete is cast, finished, protected for curing, and attains full strength.1混凝土适当放置的原则是：2在混合器和放置点之间的所有操作（包括最终固结和精整）期间必须避免分离。

土木外文翻译原文和译文

A convection-conduction model for analysis of thefreeze-thawconditions in the surrounding rock wall of atunnel in permafrost regionsAbstractBased on the analyses of fundamental meteorological and hydrogeological conditions at the site of a tunnel in the cold regions, a combined convection-conduction model for air flow in the tunnel and temperature field in the surrounding has been constructed. Using the model, the air temperature distribution in the Xiluoqi No. 2 Tunnel has been simulated numerically. The simulated results are in agreement with the data observed. Then, based on the in situ conditions of sir temperature, atmospheric pressure, wind force, hydrogeology and engineering geology, the air-temperature relationship between the temperature on the surface of the tunnel wall and the air temperature at the entry and exit of the tunnel has been obtained, and the freeze-thaw conditions at the Dabanshan Tunnel which is now under construction is predicted.Keywords: tunnel in cold regions, convective heat exchange and conduction, freeze-thaw.A number of highway and railway tunnels have been constructed in the permafrost regions and their neighboring areas in China. Since the hydrological and thermal conditions changed after a tunnel was excavated，the surrounding wall rock materials often froze, the frost heaving caused damage to the liner layers and seeping water froze into ice diamonds，which seriously interfered with the communication and transportation. Similar problems of the freezing damage in the tunnelsalso appeared in other countries like Russia, Norway and Japan .Hence it is urgent to predict the freeze-thaw conditions in the surrounding rock materials and provide a basis for the design，construction and maintenance of new tunnels in cold regions.Many tunnels，constructed in cold regions or their neighbouring areas，pass through the part beneath the permafrost base .After a tunnel is excavated，the original thermodynamical conditions in the surroundings are and thaw destroyed and replaced mainly by the air connections without the heat radiation, the conditions determined principally by the temperature and velocity of air flow in the tunnel，the coefficients of convective heat transfer on the tunnel wall，and the geothermal heat. In order to analyze and predict the freeze and thaw conditions of the surrounding wall rock of a tunnel，presuming the axial variations of air flow temperature and the coefficients of convective heat transfer, Lunardini discussed the freeze and thaw conditions by the approximate formulae obtained by Sham-sundar in study of freezing outside a circular tube with axial variations of coolant temperature .We simulated the temperature conditions on the surface of a tunnel wall varying similarly to the periodic changes of the outside air temperature .In fact，the temperatures of the air and the surrounding wall rock material affect each other so we cannot find the temperature variations of the air flow in advance; furthermore，it is difficult to quantify the coefficient of convective heat exchange at the surface of the tunnel wall .Therefore it is not practicable to define the temperature on the surface of the tunnel wall according to the outside air temperature .In this paper, we combine the air flow convective heat ex-change and heat conduction in the surrounding rock material into one model，and simulate the freeze-thaw conditions of the surrounding rock material based on the in situ conditions of air temperature，atmospheric pressure，wind force at the entry and exit of the tunnel，and the conditions of hydrogeology and engineering geology.重庆交通大学土木工程专业（隧道与城市轨道交通工程方向）毕业设计外文翻译Mathematical modelIn order to construct an appropriate model, we need the in situ fundamental conditions as a ba-sis .Here we use the conditions at the scene of the Dabanshan Tunnel. The Dabanshan Tunnel is lo-toted on the highway from Xining to Zhangye, south of the Datong River, at an elevation of 3754.78-3 801.23 m, with a length of 1 530 m and an alignment from southwest to northeast. The tunnel runs from the southwest to the northeast.Since the monthly-average air temperature is beneath 0`}C for eight months at the tunnel site each year and the construction would last for several years，the surrounding rock materials would become cooler during the construction .We conclude that, after excavation, the pattern of air flow would depend mainly on the dominant wind speed at the entry and exit，and the effects of the temperature difference between the inside and outside of the tunnel would be very small .Since the dominant wind direction is northeast at the tunnel site in winter, the air flow in the tunnel would go from the exit to the entry. Even though the dominant wind trend is southeastly in summer, considering the pressure difference, the temperature difference and the topography of the entry and exit，the air flow in the tunnel would also be from the exit to entry .Additionally，since the wind speed at the tunnel site is low，we could consider that the air flow would be principally laminar.Based on the reasons mentioned，we simplify the tunnel to a round tube，and consider that theair flow and temperature are symmetrical about the axis of the tunnel，Ignoring the influence of the air temperature on the speed of air flow, we obtain the following equation:where t ，x ，r are the time ，axial and radial coordinates; U ，V are axial and radial wind speeds; T is temperature; p is the effective pressure(that is ，air pressure divided by air density); v is the kinematic viscosity of air; a is the thermal conductivity of air; L is the length of the tunnel; R is the equivalent radius of the tunnel section; D is the length of time after the tunnel construction;，f S (t), u S (t) are frozen and thawed parts in the surrounding rock materials respectively; f λ,u λand f C ,u C are thermal conductivities and volumetric thermal capacities in frozen and thawed parts respectively; X= (x , r)，ξ(t) is phase change front; Lh is heat latent of freezing water; and To is critical freezing temperature of rock ( here we assume To= -0.1℃).2 used for solving the modelEquation(1)shows flow. We first solve those concerning temperature at that the temperature of the surrounding rock does not affect the speed of air equations concerning the speed of air flow, and then solve those equations every time elapse.2. 1 Procedure used for solving the continuity and momentum equations重庆交通大学土木工程专业（隧道与城市轨道交通工程方向）毕业设计外文翻译Since the first three equations in(1) are not independent we derive the second equation by xand the third equation by r. After preliminary calculation we obtain the following elliptic equation concerning the effective pressure p:Then we solve equations in(1) using the following procedures:(i ) Assume the values for U0，V0;( ii ) substituting U0，V0 into eq. (2)，and solving (2)，we obtain p0;(iii) solving the first and second equations of(1)，we obtain U0，V1;(iv) solving the first and third equations of(1)，we obtain U2，V2; (v) calculating the momentum-average of U1，v1 and U2，v2，we obtain the new U0，V0;then return to (ii);(vi) iterating as above until the disparity of those solutions in two consecutive iterations is sufficiently small or is satisfied，we then take those values of p0，U0 and V0 as the initial values for the next elapse and solve those equations concerning the temperature..2 .2 Entire method used for solving the energy equationsAs mentioned previously，the temperature field of the surrounding rock and the air flow affect each other. Thus the surface of the tunnel wall is both the boundary of the temperature field in the surrounding rock and the boundary of the temperature field in air flow .Therefore， it is difficult to separately identify the temperature on the tunnel wall surface，and we cannot independently solve those equations concerning the temperature of air flow and those equations concerning the temperature of the surrounding rock .In order to cope with this problem，we simultaneously solve the two groups of equations based on the fact that at the tunnel wall surface both temperatures are equal .We should bearin mind the phase change while solving those equations concerning the temperature of the surrounding rock ，and the convection while solving those equations concerning the temperature of the air flow, and we only need to smooth those relative parameters at the tunnel wall surface .The solving methods for the equations with the phase change are the same as in reference [3].2.3 Determination of thermal parameters and initial and boundaryconditions2.3.1 Determination of the thermal parameters. Using p= 1013.25-0.1088 H ，we calculateair pressure p at elevation H and calculate the air density ρ using formula GTP =ρ, where T is the yearly-average absolute air temperature ，and G is the humidity constant of air. Letting P C be the thermal capacity with fixed pressure, λ the thermal conductivity ，and μ the dynamic viscosity of air flow, we calculate the thermal conductivity and kinematic viscosity using the formulas ρλP C =ａ and ρμν=. The thermal parameters of the surrounding rock are determined from the tunnel site.2 .3.2 Determination of the initial and boundary conditions .Choose the observed monthly average wind speed at the entry and exit as boundary conditions of wind speed ，and choose the relative effective pressure p=0 at the exit ( that is ，the entry of the dominant wind trend) and ]5[22/)/1(v d kL p ⨯+= on the section of entry ( that is ，the exit of the dominant wind trend )，where k is the coefficient of resistance along the tunnel wall, d = 2R ，and v is the axial average speed. We approximate T varying by the sine law according to the data observed at the scene and provide a suitable boundary value based on the position of the permafrost base and the geothermal gradient of the thaw rock materials beneath the重庆交通大学土木工程专业（隧道与城市轨道交通工程方向）毕业设计外文翻译permafrost base.3 A simulated exampleUsing the model and the solving method mentioned above，we simulate the varying law of the air temperature in the tunnel along with the temperature at the entry and exit of the Xiluoqi No.2 Tunnel .We observe that the simulated results are close to the data observed[6].The Xiluoqi No .2 Tunnel is located on the Nongling railway in northeastern China and passes through the part beneath the permafrost base .It has a length of 1 160 m running from the northwest to the southeast, with the entry of the tunnel in the northwest，and the elevation is about 700 m. The dominant wind direction in the tunnel is from northwest to southeast, with a maximum monthly-average speed of 3 m/s and a minimum monthly-average speed of 1 .7 m/s . Based on the data observed，we approximate the varying sine law of air temperature at the entry and exit with yearly averages of -5℃，-6.4℃ and amplitudes of 18.9℃ and 17.6℃respectively. The equivalent diameter is 5 .8m，and the resistant coefficient along the tunnel wall is 0.025.Since the effect of the thermal parameter of the surrounding rock on the air flow is much smaller than that of wind speed，pressure and temperature at the entry and exit，we refer to the data observed in the Dabanshan Tunnel for the thermal parameters.Figure 1 shows the simulated yearly-average air temperature inside and at the entry and exit of the tunnel compared with the data observed .We observe that the difference is less than 0 .2 `C from the entry to exit.Figure 2 shows a comparison of the simulated and observed monthly-average air temperature in-side (distance greater than 100 m from the entry and exit) the tunnel. We observe that the principal law is almost the same，and the main reason for the difference is the errors that came from approximating the varying sine law at the entry and exit; especially , the maximum monthly-average air temperature of 1979 was not for July but for August.Fig.1. Comparison of simulated and observed air temperature in Xiluoqi No.2 Tunnel in 1979.1,simulated values;2,observed valuesFig.2.The comparison of simulated and observed air temperature inside The Xiluoqi No.2 Tunnel in 1979.1,simulated values;2,observed values4 Prediction of the freeze-thaw conditions for the Dabanshan Tunnel 4 .1 Thermal parameter and initial and boundary conditionsUsing the elevation of 3 800 m and the yearly-average air temperature of -3℃, we calculate the air density p=0 .774 kg/m 3.Since steam exists In the air, we choose the thermal capacity with a fixed pressure of air ),./(8744.10C kg kJ C p = heat conductivity )./(100.202C m W -⨯=λ andand the dynamic viscosity )../(10218.96s m kg -⨯=μ After calculation we obtain the thermal diffusivity a= 1 .3788s m /1025-⨯ and the kinematic viscosity ，s m /1019.125-⨯=ν .Considering that the section of automobiles is much smaller than that of the tunnel and the auto-mobiles pass through the tunnel at a low speed ，we ignore the piston effects ，coming from the movement of automobiles ，in the diffusion of the air.We consider the rock as a whole component and choose the dry volumetric cavity 3/2400m kg d =λ,content of water and unfrozen water W=3% and W=1%, and the thermal conductivity c m W o u ./9.1=λ,c m W o f ./0.2=λ,heat重庆交通大学土木工程专业（隧道与城市轨道交通工程方向）毕业设计外文翻译capacityc kg kJ C o V ./8.0= and d u f W w C γ⨯++=1)128.48.0(,d u u Ww C γ⨯++=1)128.48.0( According to the data observed at the tunnel site ，the maximum monthly-average wind speed is about 3 .5 m/s ，and the minimum monthly-average wind speed is about 2 .5 m/s .We approximate the wind speed at the entry and exit as )/](5.2)7(028.0[)(2s m t t v +-⨯=, where t is in month. The initial wind speed in the tunnel is set to be.0),,0(),)(1(),,0(2=-=r x V R r U r x U a The initial and boundary values of temperature T are set to bewhere f(x) is the distance from the vault to the permafrost base ，and R0=25 m is the radius of do-main of solution T. We assume that the geothermal gradient is 3%，the yearly-average air temperature outside tunnel the is A=-3C 0，and the amplitude is B=12C 0.As for the boundary of R=Ro ，we first solve the equations considering R=Ro as the first type of boundary; that is we assume that T=f(x)⨯3%C 0on R=Ro. We find that, after one year, the heat flow trend will have changed in the range of radius between 5 and 25m in the surrounding rock.. Considering that the rock will be cooler hereafter and it will be affected yet by geothermal heat, we appoximately assume that the boundary R=Ro is the second type of boundary; that is ，we assume that the gradient value ，obtained from the calculation up to the end of the first year after excavation under the first type of boundary value, is the gradient on R=Ro of T.Considering the surrounding rock to be cooler during the period of construction ，we calculatefrom January and iterate some elapses of time under the same boundary. Then we let the boundaryvalues vary and solve the equations step by step(it can be proved that the solution will not depend on the choice of initial values after many time elapses ).1)The yearly-average temperature on the surface wall of the tunnel is approximately equal to the ai4 .2 Calculated resultsFigures 3 and 4 show the variations of the monthly-average temperatures on the surface of the tunnel wall along with the variations at the entry and exit .Figs .5 and 6 show the year when permafrost begins to form and the maximum thawed depth after permafrost formed in different surrounding sections.Fig.3.The monthly-average temperature parison of the monthly- On the surface of Dabanshan Tunnel.I, average temperature on the surface The month,I=1,2,3,,,12 tunnel with that outside the tunnel. 1,inner temperature on the surface ;2,outside air temperatureFig.5.The year when permafrost Fig.6.The maximum thawed depth after Begins to from in different permafrost formed in different years Sections of the surroundingrock重庆交通大学土木工程专业（隧道与城市轨道交通工程方向）毕业设计外文翻译4 .3 Preliminary conclusionBased on the initial-boundary conditions and thermal parameters mentioned above, we obtain the following preliminary conclusions: r temperature at the entry and exit. It is warmer during the cold season and cooler during the warm season in the internal part (more than 100 m from the entry and exit) of the tunnel than at the entry and exit . Fig .1 shows that the internal monthly-average temperature on the surface of the tunnel wall is 1.2℃ higher in January, February and December, 1℃higher in March and October, and 1 .6℃ lower in June and August, and 2qC lower in July than the air temperature at the entry and exit. In other months the infernal temperature on the surface of the tunnel wall approximately equals the air temperature at the entry and exit.2) Since it is affected by the geothermal heat in the internal surrounding section，especially in the central part, the internal amplitude of the yearly-average temperature on the surface of the tunnel wall decreases and is 1 .6℃ lower than that at the entry and exit.3 ) Under the conditions that the surrounding rock is compact , without a great amount of under-ground water, and using a thermal insulating layer(as designed PU with depth of 0.05 m and heat conductivity λ=0.0216 W/m℃，FBT with depth of 0.085 m and heat conductivity λ=0.0517W/m℃)，in the third year after tunnel construction，the surrounding rock will begin to form permafrost in the range of 200 m from the entry and exit .In the first and the second year after construction, the surrounding rock will begin to form permafrost in the range of 40 and 100m from the entry and exit respectively .In the central part，more than 200m from the entry and exit, permafrost will begin to form in the eighth year. Near the center of the tunnel，permafrost will appear in the 14-15th years. During the first and second years after permafrost formed，the maximum of annual thawed depth is large (especially in the central part of the surrounding rock section) and thereafter it decreases every year. The maximum of annual thawed depth will be stable until the 19-20th yearsand will remain in s range of 2-3 m.4) If permafrost forms entirely in the surrounding rock，the permafrost will provide a water-isolating layer and be favourable for communication and transportation .However, in the process of construction，we found a lot of underground water in some sections of the surrounding rock .It will permanently exist in those sections，seeping out water and resulting in freezing damage to the liner layer. Further work will be reported elsewhere.重庆交通大学土木工程专业（隧道与城市轨道交通工程方向）毕业设计外文翻译严寒地区隧道围岩冻融状况分析的导热与对流换热模型摘要通过对严寒地区隧道现场基本气象条件的分析，建立了隧道内空气与围岩对流换热及固体导热的综合模型;用此模型对大兴安岭西罗奇2号隧道的洞内气温分布进行了模拟计算，结果与实测值基本一致;分析预报了正在开凿的祁连山区大坂山隧道开通运营后洞内温度及围岩冻结、融化状况.关键词严寒地区隧道导热与对流换热冻结与融化在我国多年冻土分布及邻近地区，修筑了公路和铁路隧道几十座.由于隧道开通后洞内水热条件的变化;，普遍引起洞内围岩冻结，造成对衬砌层的冻胀破坏以及洞内渗水冻结成冰凌等，严重影响了正常交通.类似隧道冻害问题同样出现在其他国家（苏联、挪威、日本等)的寒冷地区.如何预测分析隧道开挖后围岩的冻结状况，为严寒地区隧道建设的设计、施工及维护提供依据，这是一个亟待解决的重要课题.在多年冻土及其临近地区修筑的隧道，多数除进出口部分外从多年冻土下限以下岩层穿过.隧道贯通后，围岩内原有的稳定热力学条件遭到破坏，代之以阻断热辐射、开放通风对流为特征的新的热力系统.隧道开通运营后，围岩的冻融特性将主要由流经洞内的气流的温度、速度、气—固交界面的换热以及地热梯度所确定.为分析预测隧道开通后围岩的冻融特性，Lu-nardini借用Shamsundar研究圆形制冷管周围土体冻融特性时所得的近似公式，讨论过围岩的冻融特性.我们也曾就壁面温度随气温周期性变化的情况，分析计算了隧道围岩的温度场[3].但实际情况下，围岩与气体的温度场相互作用，隧道内气体温度的变化规律无法预先知道，加之洞壁表面的换热系数在技术上很难测定，从而由气温的变化确定壁面温度的变化难以实现.本文通过气一固祸合的办法，把气体、固体的换热和导热作为整体来处理，从洞口气温、风速和空气湿度、压力及围岩的水热物理参数等基本数据出发，计算出围岩的温度场.1数学模型为确定合适的数学模型，须以现场的基本情况为依据.这里我们以青海祁连山区大坂山公路隧道的基本情况为背景来加以说明.大坂山隧道位于西宁一张业公路大河以南，海拔3754.78~3801.23 m ，全长1530 m ,隧道近西南—东北走向. 由于大坂山地区隧道施工现场平均气温为负温的时间每年约长8个月，加之施工时间持续数年，围岩在施土过程中己经预冷，所以隧道开通运营后，洞内气体流动的形态主要由进出口的主导风速所确定，而受洞内围岩地温与洞外气温的温度压差的影响较小；冬季祁连山区盛行西北风，气流将从隧道出曰流向进口端，夏季虽然祁连山区盛行东偏南风，但考虑到洞口两端气压差、温度压差以及进出口地形等因素，洞内气流仍将由出口北端流向进口端.另外，由于现场年平均风速不大，可以认为洞内气体将以层流为主基于以上基本情况，我们将隧道简化成圆筒，并认为气流、温度等关十隧道中心线轴对称，忽略气体温度的变化对其流速的影响，可有如下的方程:其中t 为时间，x 为轴向坐标，r 为径向坐标;U, V 分别为轴向和径向速度，T 为温度，P 为有效压力(即空气压力与空气密度之比少，V 为空气运动粘性系数，a 为空气的导温系数，L 为隧道长度，R 为隧道的当量半径，D 为时间长度)(t S f , )(t S u 分别为围岩的冻、融区域. f λ,u λ分别为冻、融状态下的热传导系数，f C ,u C 分别为冻、融状态下的体积热容量，X=(x,r) , )(t ξ为冻、融相变界面,To 为岩石冻结临界温度(这里具体计算时取To=-0.10C 0)，h L 为水的相变潜热.重庆交通大学土木工程专业（隧道与城市轨道交通工程方向）毕业设计外文翻译2 求解过程由方程(1)知，围岩的温度的高低不影响气体的流动速度，所以我们可先解出速度，再解温度.2.1 连续性方程和动量方程的求解由于方程((1)的前3个方程不是相互独立的，通过将动量方程分别对x 和r 求导，经整理化简，我们得到关于压力P 的如下椭圆型方程:于是，对方程(1)中的连续性方程和动量方程的求解，我们按如下步骤进行:(1)设定速度0U ,0V ;( 2)将0U ,0V 代入方程并求解，得0P(3)联立方程(1)的第一个和第二个方程，解得一组解1U ,1V ;(4)联立方程((1)的第一个和第三个方程，解得一组解2U ,2V ;(5)对((3) ,(4)得到的速度进行动量平均,得新的0U ,0V 返回(2) ;(6)按上述方法进行迭代，直到前后两次的速度值之差足够小.以0P ,0U ,0V 作为本时段的解,下一时段求解时以此作为迭代初值.2. 2 能量方程的整体解法如前所述，围岩与空气的温度场相互作用，壁面既是气体温度场的边界，又是固体温度场的边界，壁面的温度值难以确定，我们无法分别独立地求解隧道内的气体温度场和围岩温度场.为克服这一困难，我们利用在洞壁表面上，固体温度等于气体温度这一事实，把隧道内气体的温度和围岩内固体的温度放在一起求解，这样壁面温度将作为末知量被解出来.只是需要注意两点:解流体温度场时不考虑相变和解固体温度时没有对流项;在洞壁表面上方程系数的光滑化.另外，带相变的温度场的算法与文献[3]相同.2. 3热参数及初边值的确定热参数的确定方法: 用p=1013.25-0.1088H 计算出海拔高度为H 的隧道现场的大气压强，再由GT P =ρ计算出现场空气密度ρ，其中T 为现场大气的年平均绝对温度，G 为空气的气体常数.记定压比热为P C ,导热系数为λ，空气的动力粘性系数为μ.按ρλP C =ａ和ρμν= 计算空气的导温系数和运动粘性系数.围岩的热物理参数则由现场采样测定.初边值的确定方法:洞曰风速取为现场观测的各月平均风速.取卞导风进曰的相对有效气压为0，主导风出口的气压则取为]5[22/)/1(v d kL p ⨯+=，这里k 为隧道内的沿程阻力系数，L 为隧道长度，d 为隧道端面的当量直径，ν为进口端面轴向平均速度.进出口气温年变化规律由现场观测资料，用正弦曲线拟合，围岩内计算区域的边界按现场多年冻土下限和地热梯度确定出适当的温度值或温度梯度. 3 计算实例按以上所述的模型及计算方法，我们对大兴安岭西罗奇2号隧道内气温随洞曰外气温变化的规律进行了模拟计算验证，所得结果与实测值[6]相比较,基本规律一致.西罗奇2号隧道是位十东北嫩林线的一座非多年冻土单线铁路隧道，全长1160 m ,隧道近西北一东南向，高洞口位于西北向，冬季隧道主导风向为西北风.洞口海拔高度约为700 m ,月平均最高风速约为3m/s,最低风速约为1.7m/s.根据现场观测资料，我们将进出口气温拟合为年平均分别为-5C 0和-6.4C 0，年变化振幅分别为18.9C 0和17.6C 0的正弦曲线.隧道的当量直径为5.8 m,沿程阻力系数取为0.025.由于围岩的热物理参数对计算洞内气温的影响远比洞口的风速、压力及气温的影响小得多，我们这里参考使用了大坂山隧道的资料.图1给出了洞口及洞内年平均气温的计算值与观测值比较的情况，从进口到出口，两值之差都小于0.2C 0.图2给出了洞内 (距进出口l00m 以上)月平均气温的计算值与观测值比较的情况，可以看出温度变化的基本规律完全一致，造成两值之差的主要原因是洞口气温年变化规律之正弦曲线的拟合误差，特别是1979年隧道现场月平均最高气温不是在7月份，而是在8月份.重庆交通大学土木工程专业（隧道与城市轨道交通工程方向）毕业设计外文翻译图1. 比较1979年在西罗奇周家山2号隧道仿真试验与观察的空气温度.1、模拟值;2、观测值图2。

土木工程外文翻译(中英互译版)

使用加固纤维聚合物增强混凝土梁的延性Nabil F. Grace, George Abel-Sayed, Wael F. Ragheb摘要：一种为加强结构延性的新型单轴柔软加强质地的聚合物(FRP)已在被研究，开发和生产(在结构测试的中心在劳伦斯技术大学)。

这种织物是两种碳纤维和一种玻璃纤维的混合物，而且经过设计它们在受拉屈服时应变值较低，从而表达出伪延性的性能。

通过对八根混凝土梁在弯曲荷载作用下的加固和检测对研制中的织物的效果和延性进行了研究。

用现在常用的单向碳纤维薄片、织物和板进行加固的相似梁也进行了检测，以便同用研制中的织物加固梁进行性能上的比拟。

这种织物经过设计具有和加固梁中的钢筋同时屈服的潜力，从而和未加固梁一样，它也能得到屈服台阶。

相对于那些用现在常用的碳纤维加固体系进行加固的梁，这种研制中的织物加固的梁承受更高的屈服荷载，并且有更高的延性指标。

这种研制中的织物对加固机制表达出更大的奉献。

关键词：混凝土，延性，纤维加固，变形介绍外贴粘合纤维增强聚合物〔FRP〕片和条带近来已经被确定是一种对钢筋混凝土结构进行修复和加固的有效手段。

关于应用外贴粘合FRP板、薄片和织物对混凝土梁进行变形加固的钢筋混凝土梁的性能，一些试验研究调查已经进行过报告。

Saadatmanesh和Ehsani〔1991〕检测了应用玻璃纤维增强聚合物(GFRP)板进行变形加固的钢筋混凝土梁的性能。

Ritchie等人〔1991〕检测了应用GFRP，碳纤维增强聚合物〔CFRP〕和G/CFRP板进行变形加固的钢筋混凝土梁的性能。

Grace等人〔1999〕和Triantafillou〔1992〕研究了应用CFRP薄片进行变形加固的钢筋混凝土梁的性能。

Norris，Saadatmanesh和Ehsani〔1997〕研究了应用单向CFRP薄片和CFRP织物进行加固的混凝土梁的性能。

在所有的这些研究中，加固的梁比未加固的梁承受更高的极限荷载。

土木工程外文翻译资料

Reinforced ConcretePlain concrete is formed from a hardened mixture ofcement ,water ,fine aggregate, coarse aggregate (crushed stone or gravel),air, and often other admixtures. The plastic mix is placed and consolidated in the formwork, then cured to facilitate the acceleration of the chemical hydration reaction lf the cement/water mix, resulting in hardened concrete. The finished product has high compressive strength, and low resistance to tension, such that its tensile strength is approximately one tenth lf its compressive strength. Consequently, tensile and shear reinforcement in the tensile regions of sections has to be provided to compensate for the weak tension regions in the reinforced concrete element.It is this deviation in the composition of a reinforces concrete section from the homogeneity of standard wood or steel sections that requires a modified approach to the basic principles of structural design. The two components of the heterogeneous reinforced concrete section are to be so arranged and proportioned that optimal use is made of the materials involved. This is possible because concrete can easily be given any desired shape by placing and compacting the wet mixture of the constituent ingredients are properly proportioned, the finished product becomes strong, durable, and, in combination with the reinforcing bars, adaptable for use as main members of any structural system.The techniques necessary for placing concrete depend on the type of member to be cast: that is, whether it is a column, a bean, a wall, a slab, a foundation. a mass columns, or an extension of previously placed and hardened concrete. For beams, columns, and walls, the forms should be well oiled after cleaning them, and the reinforcement should be cleared of rust and other harmful materials. In foundations, the earth should be compacted and thoroughly moistened to about 6 in. in depth to avoid absorption ofthe moisture present in the wet concrete. Concrete should always be placed in horizontal layers which are compacted by means of high frequency power-driven vibrators of either the immersion or external type, as the case requires, unless it is placed by pumping. It must be kept in mind, however, that over vibration can be harmful since it could cause segregation of the aggregate and bleeding of the concrete.Hydration of the cement takes place in the presence of moisture at temperatures above 50°F. It is necessary to maintain such a condition in order that the chemical hydration reaction can take place. If drying is too rapid, surface cracking takes place. This would result in reduction of concrete strength due to cracking as well as the failure to attain full chemical hydration.It is clear that a large number of parameters have to be dealt with in proportioning a reinforced concrete element, such as geometrical width, depth, area of reinforcement, steel strain, concrete strain, steel stress, and so on. Consequently, trial and adjustment is necessary in the choice of concrete sections, with assumptions based on conditions at site, availability of the constituent materials, particular demands of the owners, architectural and headroom requirements, the applicable codes, and environmental reinforced concrete is often a site-constructed composite, in contrast to the standard mill-fabricated beam and column sections in steel structures.A trial section has to be chosen for each critical location in a structural system. The trial section has to be analyzed to determine if its nominal resisting strength is adequate to carry the applied factored load. Since more than one trial is often necessary to arrive at the required section, the first design input step generates into a series of trial-and-adjustment analyses.The trial-and –adjustment procedures for the choice of a concretesection lead to the convergence of analysis and design. Hence every design is an analysis once a trial section is chosen. The availability of handbooks, charts, and personal computers and programs supports this approach as a more efficient, compact, and speedy instructional method compared with the traditional approach of treating the analysis of reinforced concrete separately from pure design.EarthworkBecause earthmoving methods and costs change more quickly than those in any other branch of civil engineering, this is a field where there are real opportunities for the enthusiast. In 1935 most of the methods now in use for carrying and excavating earth with rubber-tyred equipment did not exist. Most earth was moved by narrow rail track, now relatively rare, and the main methods of excavation, with face shovel, backacter, or dragline or grab, though they are still widely used are only a few of the many current methods. To keep his knowledge of earthmoving equipment up to date an engineer must therefore spend tine studying modern machines. Generally the only reliable up-to-date information on excavators, loaders and transport is obtainable from the makers.Earthworks or earthmoving means cutting into ground where its surface is too high ( cuts ), and dumping the earth in other places where the surface is too low ( fills). Toreduce earthwork costs, the volume of the fills should be equal to the volume of the cuts and wherever possible the cuts should be placednear to fills of equal volume so as to reduce transport and double handlingof the fill. This work of earthwork design falls on the engineer who lays out the road since it is the layout of the earthwork more than anything else which decides its cheapness. From the available maps ahd levels, the engineering must try to reach as many decisions as possible in the drawing office by drawing cross sections of the earthwork. On the site when further information becomes available hecan make changes in jis sections and layout,but the drawing lffice work will not have been lost. It will have helped him to reach the best solution in the shortest time.The cheapest way of moving earth is to take it directly out of the cut and drop it as fill with the same machine. This is not always possible, but when it canbe done it is ideal, being both quick and cheap. Draglines, bulldozers and face shovels an do this. The largest radius is obtained with the dragline,and the largest tonnage of earth is moved by the bulldozer, though only over short distances.The disadvantages of the dragline are that it must dig below itself, it cannot dig with force into compacted material, it cannot dig on steep slopws, and its dumping and digging are not accurate.Face shovels are between bulldozers and draglines, having a larger radius of action than bulldozers but less than draglines. They are anle to dig into a vertical cliff face in a way which would be dangerous tor a bulldozer operator and impossible for a dragline. Each piece of equipment should be level of their tracks and for deep digs in compact material a backacter is most useful, but its dumping radius is considerably less than that of the same escavator fitted with a face shovel.Rubber-tyred bowl scrapers are indispensable for fairly level digging where the distance of transport is too much tor a dragline or face shovel. They can dig the material deeply ( but only below themselves ) to a fairly flat surface, carry it hundreds of meters if need be, then drop it and level it roughly during the dumping. For hard digging it is often found economical to keep a pusher tractor ( wheeled or tracked ) on the digging site, to push each scraper as it returns to dig. As soon as the scraper is full,the pusher tractor returns to the beginning of the dig to heop to help the nest scraper.Bowl scrapers are often extremely powerful machines;many makers build scrapers of 8 cubic meters struck capacity, which carry 10 m ³ heaped. The largest self-propelled scrapers are of 19 m ³ struck capacity ( 25 m ³ heaped )and they are driven by a tractor engine of 430 horse-powers.Dumpers are probably the commonest rubber-tyred transport since they can also conveniently be used for carrying concrete or other building materials. Dumpers have the earth container over the front axle on large rubber-tyred wheels, and the container tips forwards on most types, though in articulated dumpers the direction of tip can be widely varied. The smallest dumpers have a capacity of about 0.5 m ³, and the largest standard types are of about 4.5 m ³. Special types include the self-loading dumper of up to 4 m ³ and the articulated type of about 0.5 m ³. The distinction between dumpers and dump trucks must be remembered .dumpers tip forwards and the driver sits behind the load. Dump trucks are heavy, strengthened tipping lorries, the driver travels in front lf the load and the load is dumped behind him, so they are sometimes called rear-dump trucks.Safety of StructuresThe principal scope of specifications is to provide general principles and computational methods in order to verify safety of structures. The “ safety factor ”, which according to modern trends is independent of the nature and combination of the materials used, can usually be defined as the ratio between the conditions. This ratio is also proportional to the inverse of the probability ( risk ) of failure of the structure.Failure has to be considered not only as overall collapse of the structure but also as unserviceability or, according to a more precise. Common definition. As the reaching of a “ limit state ” which causes the construction not to accomplish the task it was designed for. There are two categories of limit state :(1)Ultimate limit sate, which corresponds to the highest value of the load-bearing capacity. Examples include local buckling or global instability of the structure; failure of some sections and subsequent transformation of the structure into a mechanism; failure by fatigue; elastic or plastic deformation or creep that cause a substantial change of the geometry of the structure; and sensitivity of the structure to alternating loads, to fire and to explosions.(2)Service limit states, which are functions of the use and durability of the structure. Examples include excessive deformations and displacements without instability; early or excessive cracks; large vibrations; and corrosion.Computational methods used to verify structures with respect to the different safety conditions can be separated into:(1)Deterministic methods, in which the main parameters are considered as nonrandom parameters.(2)Probabilistic methods, in which the main parameters are considered as random parameters.Alternatively, with respect to the different use of factors of safety, computational methods can be separated into:(1)Allowable stress method, in which the stresses computed under maximum loads are compared with the strength of the material reduced by given safety factors.(2)Limit states method, in which the structure may be proportioned on the basis of its maximum strength. This strength, as determined by rational analysis, shall not be less than that required to support a factored load equal to the sum of the factored live load and dead load ( ultimate state ).The stresses corresponding to working ( service ) conditions with unfactored live and dead loads are compared with prescribed values( service limit state ) . From the four possible combinations of the first two and second two methods, we can obtain some useful computational methods. Generally, two combinations prevail:(1)deterministic methods, which make use of allowable stresses.(2)Probabilistic methods, which make use of limit states.The main advantage of probabilistic approaches is that, at least in theory, it is possible to scientifically take into account all random factors of safety, which are then combined to define the safety factor. probabilistic approaches depend upon :(1)Random distribution of strength of materials with respect to the conditions of fabrication and erection ( scatter of the values of mechanical properties through out the structure );(2)Uncertainty of the geometry of the cross-section sand of the structure ( faults and imperfections due to fabrication and erection of the structure );(3)Uncertainty of the predicted live loads and dead loads acting on the structure;(4)Uncertainty related to the approximation of the computational method used ( deviation of the actual stresses from computed stresses ).Furthermore, probabilistic theories mean that the allowable risk can be based on several factors, such as :(1)Importance of the construction and gravity of the damage by its failure;(2)Number of human lives which can be threatened by this failure;(3)Possibility and/or likelihood of repairing the structure;(4)Predicted life of the structure.All these factors are related to economic and social considerations such as：(1)Initial cost of the construction;(2)Amortization funds for the duration of the construction;(3)Cost of physical and material damage due to the failure of the construction;(4)Adverse impact on society;(5)Moral and psychological views.The definition of all these parameters, for a given safety factor, allows construction at the optimum cost. However, the difficulty of carrying out a complete probabilistic analysis has to be taken into account. For such an analysis the laws of the distribution of the live load and its induced stresses, of the scatter of mechanical properties of materials, and of the geometry of the cross-sections and the structure have to be known. Furthermore, it is difficult to interpret the interaction between the law of distribution of strength and that of stresses because both depend upon the nature of the material, on the cross-sections and upon the load acting on the structure. These practical difficulties can be overcome in two ways. The first is to apply different safety factors to the material and to the loads, without necessarily adopting the probabilistic criterion. The second is an approximate probabilistic method which introduces some simplifying assumptions ( semi-probabilistic methods ) .。

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欣达维出版公司世界科学日报2014卷，文章编号968738，共8页 /10.1155/2014/968738研究论文对南沙软土蠕变特性的试验研究罗清子陈小平中国教育部工程灾害预测与控制重点实验室，科学与工程学院，济南大学，广州510632。

作者陈小平，通讯地址; chenxp@收到时间：2013年10月21日；接受时间：2013年12月19日；发表时间：2014年1月9日。

这是一个在知识共享归属许可下发布的开放的文章,允许在任何媒介不受限制地使用、分配和复制,提供最初的工作是正确地引用。

通过调查，在珠江三角洲海陆交互相沉积土的蠕变特性进行了一系列试验。

次固结试验结果表明，固结压力对次固结系数的影响是有条件的，这是由固结状态决定。

次固结系数的压缩系数的比值（c a C C ）几乎是恒定的，和值为0.03。

在剪切盒测试，直接的纯粹的蠕变破坏土壤主要受剪切应力而不是积累的剪切应变。

三轴蠕变特征与排水条件密切相关，并整理可以削弱蠕变效应。

当软土的三轴蠕变损伤，应变率将大幅增加。

1 前言随着中国经济的快速发展，基础设施建设日益繁荣，而带来的长期沉降，长期强度，和其他问题进入人们的视线。

软土广泛分布于中国，其变形和强度随时间变化，因此蠕变作用不能忽视。

一些实验理论研究和已经完成调查的定量和定性分析了蠕变特性。

泰勒和麦茜特]1[研究了软土的次固结现象，他们认为通过土壤颗粒的摩擦阻力引起的土的次固结沉降。

梅西里和歌德维斯基]2[总结前人对正常固结土的次固结试验结果，发现固结系数和压缩指数二者间具有良好的线性关系。

纽兰和阿里利讨论固结压力对次固结系数的影响，他们认为在先期固结压力阶段固结系数与固结压力无关。

然而，纳什等人不同意这一观点和报道，认为固结系数随着固结压力的增加先增加，然后下降。

莱罗艾尔等人讨论争论主要集中在固结压力和固结系数之间的关系。

次固结有体积蠕变；然而，三轴蠕变的耦合之间的剪切蠕变和土壤体积蠕变。

主教和拉文博雷]5[做实验来探讨原状土的蠕变特性，这是由其他研究]96[ 进一步研究。

海陆交互相沉积软土具有一般软土的共同特征，如水分含量较高，更大的孔隙比，压缩性较高，较低的剪切强度，和更高的灵敏度]10[。

然而，由于其特殊的沉积环境和沉积泥沙含量高，有一些基本的物理力学性质不同于海相软土。

在本文中，进行研究的海陆交互相沉积从南沙广州软土的蠕变特性进行了一系列的试验。

水含量分别为48%和73%，孔隙比0e 为1.71–2.16，这两者都是很大的变异性和低于海洋软土。

土壤样品的平均液限l w 大约是47.8%，平均塑限p w 约为24%。

2 实验2.1 次固结试验当主固结完成后，软土的蠕变变形会随着时间的延长，与次固结效应不可忽略。

软土不同深度，有近似的水含量（约56%）和密度（1.723cm g ），进行了研究，并对软土的次固结特性的样品进行固结试验研究。

一个直径61.8mm 高度为20mm 的标本进行了研究，并测试方案如下。

（1）1号软土采样深度为6m 。

加载顺序12.5→ 25→ 50→100→200→400 kPa ，并为每级荷载加载时间为三天。

（2）2号软土采样深度是16m 。

加载顺序为50→100→200→400 kPa ，并为每级荷载加载时间为三天。

2.2 剪切盒试验在剪切盒测试，原状土试样有相同的大小在固结试验的试样，和水含量为48%；密度为1.743cm g 。

剪切盒试验是由直剪仪的剪切力控制进行了改装，通过控制直剪仪常规应变，探讨海陆交互相沉积软土的剪切蠕变特性，并示意图如图1。

每个级别的剪切应力的实验应用是通过以下方式确定：进行固结排水试验确定土壤样品不同固结压力下的峰值强度f τ直接剪切，然后根据公式n fi ττ=定义每个水平剪切应力的剪切蠕变试验，当装载时间和为4∼6。

峰值强度的固结排水直剪试验不同固结压力下列在表1，和每个阶段的持续时间的剪切应力，剪切变形小于0.01d mm 的标准确定。

图1：剪切箱示意图（1）垂直位移计 ;（2）上盒;（3）透水石;（4）下面的对话框;（5）盖板装;（6）试件;（7）压缩框架;（8）水平位移计;（9）滑轮;（10）重量。

2.3 三轴蠕变试验三轴蠕变机制是从次固结和剪切蠕变，这是剪切蠕变和土壤的体积蠕变之间的耦合的机制不同。

为了使在交互式海洋和陆地沉积软土蠕变性能的进一步研究中，排水蠕变试验及不排水蠕变试验的应力控制式三轴仪进行执行，且室内温度保持在24℃消除影响温度对测试。

在三轴蠕变试验中，试样的直径为39.1mm ，8mm ，其水含量为54％，密度是1.683cm g 。

在这些测试中，土壤样品进行了固结围压200 kPa 首先在两天，然后每个水平偏应力是由不同排水条件下的步骤进行，历时三天。

一个全面的压力下的三轴试验的峰值强度f τ（kPa 200=p ）是由常规三轴仪得到的这是210kPa ，排水三轴试验和100kPa 的不排水三轴试验，用于确定加载时间。

3 结论3.1 次固结图2和图3给出从不同深度的原状土测试t e lg -曲线，和次固结系数与固结压力之间的关系如图4所示。

图2 测试1号软土样t e lg -曲线图3 测试2号软土样t e lg -曲线图4 次固结系数与固结系数a C 负荷p 曲线从图2可以看出，（1）的主、次固结的分区不明显；（2）kPa 50≥p 时，每级荷载下的t e lg -曲线互相平行，也就是说，次固结系数不依赖于固结荷载和保持恒定的。

但当固结量小，对次固结系数有一定的变化。

这些结论也可以从图3，我们可以发现，当kPa 50≥p ，对软土样品号1次固结系数是一个随固结压力的增加的顺利停止。

从图3可以得到（1）当固结是小的，初级的次固结划分可以很容易地得到了；然而，随着固结压力增加的主、次固结划分不够清楚；（2）当负荷率是相同的，这t e lg -曲线都没有再相互平行的kPa 200<p 的情况下，这意味着，次固结系数不是一个常数，涉及固结荷载。

它也可以从图4，次固结系数先增加然后开始随固结压力的增大而减小。

然而，当kPa 200>p ，次固结系数接近一个恒定，不会再改变。

总之，对土体固结状态的次固结，固结压力取决于之间的相关性系数。

当固结压力小于先期固结压力，软土在固结状态和随固结压力的增加，此时的次固结系数。

当软土层进入正常固结状态作为固结荷载值不断增加，对次固结系数将减少与随固结压力和接近一个常数，和最大达到固结压力的方法，先期固结压力。

软土的由纳什等人给出的一维固结试验结果。

]11[坟等等人]12[也显示出了相似的现象，和尹等]13[认为，当固结压力小于先期固结压力时，次固结系数与固结压力。

然而，贝耶伦]14[和Shietal 等人的试验结果。

]15[还暗示，次固结系数不随固结压力的变化。

这是由于软土取样深度较浅，由试验固结压力大于先期固结压力；在这种情况下，软土在正常固结状态和次固结系数不依赖于固结压力。

因此，公式（1）就可以使用计算正常固结土的次固结系数基于上述分析，公式（2）中所述固结压力对次固结系数的影响是根据Mesri 和卡斯特罗]16[建立研究的成果在土的固结试验中压缩系数c C 是可以得到，根据试验结果，次固结和本文所研究的土壤的可压缩性系数之间的关系可以被写为c a C C 03.0=。

)l g (c a t t e C ∆= (1) c a C C α= (2)3.2 剪切蠕变试验结果表明，不同固结压力下的剪切蠕变曲线大致相同；然而，当固结压力小时，对t lg -γ曲线非线性关系更为明显。

不同的压力下的剪切应变γ相对于时间的变化是绘制在图5（a ）–5（d ）。

图5 （a ）直剪蠕变试验p=50kPa （b ）直剪蠕变试验p=100kPa（c ）直剪蠕变试验p=200kPa （d ）直剪蠕变试验p=300kPa从图5可以看到5（a ）–5（d ）的瞬时变形和剪切与相同荷载作用下的剪应力随应变速率增加。

当剪切应力小时，如f f τττ4.0~2.0=，对于变形大的一部分，瞬时变形的帐户，随着时间的增加剪应变值几乎没有变化。

换句话说，变形小的剪切应力几乎没有剪切蠕变。

当剪切应力越来越大，剪切蠕变变形越来越明显，包括大位移，这将导致更明显的剪切应变和时间之间的非线性关系。

只要剪应力增加到峰值强度f τ，在没有明显的加速蠕变破坏之前土样将在很短的时间内损坏（0.1∼10min ），并随固结压力的提高减少故障时间。

这表明间接纯粹的蠕变破坏土主要受剪切应力而不是积累的剪切应变。

此外，基于结果的剪切蠕变试验了不同固结压力下，我们可以发现，7.0~6.0=p c τ；也就是说，固结作用可以使直接剪切蠕变达到峰值强度的。

在固结排水直剪试验中当剪应力达到峰值强度f τ，土样不会有直接剪切蠕变损伤，然而，当剪切应力达到的强度f τ后，土样将被破坏。

我们可以发现，在相同固结压力下c τ比f τ更大，和f c ττ随固结压力的增加而增大。

图6 （a ）t lg '-γ曲线p=50kPa （b ）t lg '-γ曲线p=100kPa（c ）t lg '-γ曲线p=200kPa （d ）t lg '-γ曲线p=300kPa 从图5可以看到5（a ）–5（d ）的t lg '-γ曲线发现某一固结压力下的剪切应力的增加，剪应变率的增大，在剪应力达到峰值强度直剪蠕变，剪应变率随时间的增加而减少，在每一层的剪切应力。

研究发现，随着剪应力一定的固结压力下，越来越多的剪应变率变大，在剪应力达到峰值强度直剪蠕变，剪应变率随时间的增加而减少，在每一层的剪切应力。

加载初期，随着时间的发展，剪应变率迅速减小，然后迅速趋近于零；然而，在这种情况下，土样不会因为大量的初始剪切应变率的损坏。

当剪应力达到c τ，剪应变率加载后会在最后导致土样破坏一个很短的时间内急剧增加。

随着固结压力的增加，失效时间减小，应变率降低期越来越短。

它得出的结论是，最初的高剪切应变率不造成土壤的剪切蠕变损伤，而剪切应变率上升的发展将使土壤的最终破坏。

3.3 三轴蠕变三轴蠕变试验结果示于图7和图8，其中1ε是轴向应变和1'ε为轴向应变速率。

为了得到荷载的轴向应变- 时间曲线，分别是“Chenmethod”用于]17[，并根据不同的偏应力轴向应变与时间的关系曲线，分别绘制在图7（a）和图7（b）所示。

该结果表明，该轴向应变和蠕变的土样特征是由于不同的排水条件不同，并且不排水蠕变试验轴向应变比在相同的偏应力排水蠕变试验的小。

在排水蠕变试验的情况下，土壤样品具有较大的变形，但没有发生故障;然而，土样的排量增大急剧一次偏应力达到115kpa的不排水蠕变.在不排水蠕变的条件下，形变是刚刚由蠕变引起的；然而，在排水蠕变试验中，变形是由合并的影响和蠕变在一起。