路面設(shè)計(jì)外文翻譯---柔性路面設(shè)計(jì)

1、<p><b>　　英文翻譯</b></p><p>　　Flexible pavement design</p><p>　　Generally speaking,pavements(and bases) may be divided into two broad classifications or tipes:rigid and flexible. A

2、s commonly used in the United States,the term “rigid pavement”is applied to wearing surfaces constructed of Portland-cement concrete. A pavement constructed of concrete is assumed to possess considerable flexural strengt

3、h that will permit it to act as a beam and allow it to bridge over minor irregularities which may occor in the base or subgrade on which it rests;hence the term “ri</p><p>　　All other types of pavement have

4、traditionally been classed as “flexible”.A commonly used definition is that “a flexible pavement is a structure that maintains contact with and distributes loads to the subgrade and depends on aggregate interlock,particl

5、e friction,and cohesion for stability”.Thus,the classical flexible pavement include primarily those pavement that are composed of a series of granular layers topped by a relatively thin high-quality bituminous wearing su

6、rface .Typically,the highes</p><p>　　The structure of flexible pavement is composed of a “wearing surface”, base, subbase(not always used), and subgrade . The wearing surface and the base often comprise two

7、or more layers that are somewhat different in composition and that are put down in separate construction operations.On many heavy-duty pavements,a subbase of select material is often placed between the base and subgrade.

8、the wearing surface may range in thickness from less than 1 in. in the case of a bituminous surface used for l</p><p>　　The base is a layer (or layers) of very high stability and density. Its principle purpo

9、se is to distribute or “spread” the stresses created by wheel loads acting on the wearing surface so that the stresses transmitted to the subgrade will not be sufficiently great to result in excessive deformation or disp

10、lacement of that foundation layer. The base must also be of such character that it is not damaged by capillary water and/or frost action. Locally available materials are extensively used for ba</p><p>　　A su

11、bbase of granular material or stabilized material may be used in areas where frost action is severe, in locations where the subgrade soil is extremely weak. It may also be used , in the interests of economy ,in locations

12、 where suitable subbase material are cheap than base materials of higher quality.</p><p>　　The subgrade is the foundation layer, the structure that must eventually support all the loads which come onto the p

13、avement. In some cases this layer will simply be the natural earth surface. In other or more usual instances it will be compacted soil existing in a cut section or the upper layer of an embankment section. In the fundame

14、ntal concept of the action of flexible pavement,the combined thickness of subbase (if used), base, and wearing surface must be great enough to reduce the stresses o</p><p>　　The principle factors entering in

15、to the problem of the thickness design of flexible pavement are:</p><p>　　Traffic loading.</p><p>　　Climate or environment.</p><p>　　Material characteristics.</p><p>　　

16、A number of other elements must also be considered in order to arrive at a final thickness design. This include cost, construction, maintenance,an design period. Thus, the students should realize that the design process

17、is complex, and it is highly unlikely that any extremely simple method of approach will prove entirely successful under all conditions.</p><p>　　Protection of the subgrade from the loading imposed by traffic

18、 is one of the primariy functions of a pavement structure. The designer must privide a pavement that can withstand a large number of repeated applications of variable-magnitude loading.</p><p>　　The magnitud

19、e of maximum loading is commonly controlled by legal load limits. Traffic surveys and loadometer studies are often used to establish the relative magnitude and occurrence of the various loading to which a pavement is sub

20、jected. Prediction or estimation of the total traffic that will use a pavement during its design ife is a very difficult but obviously important task.</p><p>　　The climate or environment in which a flexible

21、pavement is to be established has an important influence on the behavior and performance of the various in the pavement and subgrade. Probablly the two climate factors of major significance are temperature and moisture.&

22、lt;/p><p>　　The magnitude of temperature and its fluctuations affect the properties of certain materials. For example, high temperatures cause asphaltic concrete to lose stability whereas at low temperatures as

23、phaltic concrete becomes very hard and stiff. Low temperature and temperature fluctuations are also associated with frost heave and freeze-thaw damage.</p><p>　　Granular materials, if not properly graded, ca

24、n experience frost heave. Likewise, the subgrade can exhibit extensive loss in strength if it becomes frozen. Certain stabilized materials (lime, cement, and lime-fly ash treated) can suffer substantial damage if a large

25、 number of freeze-thaw cycles occur in the material.</p><p>　　Moisture also has an important influence on the behavior and performance of many materials. Moisture is an important ingredient in frost-related

26、damage. Subgrade soils and other paving materials weaken appreciably when saturated, and certain clayey soil exhibit substantial moisture-included volume change. </p><p>　　Subgrade moisture conditions chan

27、ge is affecting road structural strength, stiffness and stability of the important factors. Subgrade moisture influence has the following main factors: atmospheric precipitation and evaporation, infiltration of surface w

28、ater, groundwater impact, temperature changes caused by humidity.</p><p>　　Cyclical atmospheric temperature changes throughout the year, day and night temperatures for each day a certain extent cyclical chan

29、ges. Surface directly exposed to the air, and experiencing the impact of these changes, in particular surface material most affected. Road surface temperature change with the weather temperature is roughly synchronized.

30、Surface layer temperature at different depths within the same generation as the cyclical changes in atmospheric temperature, but the magnitude of ch</p><p>　　One of frost damage is frozen, it not only affect

31、s the normal running of vehicles, and sometimes the destruction of the pavement structure. Produce frost heave for two reasons: First, as water is frozen, the volume will increase by 9%; second is due to the weak foundat

32、ion soil to freeze the area with water movement results. Subgrade frost heaving caused by three factors: the sensitivity of frozen soil subgrade; temperature decreased slowly; groundwater supply of water to keep the froz

33、en zone.</p><p>　　The advent of spring, began to melt the frozen roadbed, will lose their bearing capacity of soil, leading to road damage, a phenomenon known as the spring melt boil, boil and mainly due to

34、the melting process is top down, when the embankment top soil begins to melt, the water can not be excluded, so the soil has been saturated melting. If by this time a large number of heavy vehicles, road structure would

35、be seriously damaged.</p><p>　　Of the road is a sticky, elastic-plastic materials and the combination of mineral aggregate particles consisting of roads, including the addition of cement concrete as a surfac

36、e layer and the surface structure of a variety of other grass-roots level. Flexible pavement design including pavement layer combination of design, structural calculation and the road pavement material mix design. This c

37、hapter elaborates the following aspects: elastic layered system theory, the pavement layer combination o</p><p>　　In reality, the road base material and the soil is not in any case have elastic properties. N

38、on-linear elastic - viscous - plastic theory, under certain conditions more accurately describe the stress state of the road, but taking into account the role of the transient driving wheels in the pavement structure, th

39、e stress was small, so you can road as each layer is an ideal elastic body, multi-layer linear elastic theory to application to design calculations. Multi-layer linear elastic theory must</p><p>　　1.Layers o

40、f material are continuous, homogeneous, isotropic and to obey Hooke's law, and the displacement and deformation is small; </p><p>　　2. The next level (soil basis) in the horizontal direction and vertical

41、 direction down to infinity, The elastic layer is above all have a certain thickness, but the horizontal direction is infinite; </p><p>　　3. layers of infinite distance in the horizontal direction and the ne

42、xt layer down to infinite depths, the stress, strain and displacement is zero; </p><p>　　4. layers the contact conditions between fully continuous; </p><p>　　5. do not count weight.</p>&

43、lt;p>　　Flexible Pavement Structure Design's mission is to design principles in general under the guidance of the road, according to the road level, requirements and design life of the cumulative equivalent standar

44、d axle load axle, considering the supply of road materials, the degree of influence of natural factors and the specific construction conditions, determine a reasonable level of the pavement structure and select the appro

45、priate economic composition materials, combined into both withstand traffi</p><p>　　Combination of flexible pavement structural design should follow the following basic principles: </p><p>　　1,

46、route, embankment, road do take into consideration the overall design; </p><p>　　2, according to the structure, function and transport layer characteristics of selected structural levels; </p><p&g

47、t;　　3, the strength to adapt to traffic load and stiffness combination; </p><p>　　4, pay attention to its own characteristics each layer, make layer combination; </p><p>　　5, the appropriate num

48、ber of layers and thickness;</p><p>　　6, to consider the impact of water temperature conditions to ensure stability.</p><p><b>　　柔性路面設(shè)計(jì)</b></p><p>　　一般來講，路面（和路基）可以分為兩種類型

49、：剛性路面和柔性路面?！皠傂月访妗币辉~在美國(guó)通常指由普通水泥混凝土修筑的道路面層。人們認(rèn)為，混凝土路面可以像梁一樣具有較高的彎曲強(qiáng)度并能夠跨越基層或路基上的一些微笑的不平整的地帶，因此稱為“剛性”。同樣，支撐磚層或砌體層的混凝土基座也可以說成是剛性的。</p><p>　　所有其他形式的路面在傳統(tǒng)上都被歸類于柔性路面。柔性路面的一個(gè)常用的定義是：柔性路面是與基層緊密接觸，并將荷載傳遞給路基的一種結(jié)構(gòu)，他依靠集料之

50、間的嵌擠力、顆粒的摩擦力和粘結(jié)力來保持其穩(wěn)定性。因此，傳統(tǒng)的柔性路面主要是指那些在許多粒料層的上面鋪上比較薄的高質(zhì)量的瀝青面層所構(gòu)成的路面。通常將優(yōu)質(zhì)材料用于面層或面層附近。應(yīng)該指出，某些瀝青路面與傳統(tǒng)的剛性路面由很大的相似性，例如，鋪有較厚瀝青面層的路面或由瀝青、水泥、石灰/粉煤灰所構(gòu)成的集料組成的基層的路面。然而，為便于說明，這些路面被認(rèn)為是柔性的。</p><p>　　柔性路面的結(jié)構(gòu)由面層、基層、底基層（有

51、時(shí)不采用）和路基組成。其中面層和基層通常由兩層或更多層組成，每一層的材料成分不完全相同并采用分層鋪設(shè)的施工方法。對(duì)于許多承受重載的道路的路面，要選擇合適的底基層材料，鋪設(shè)與基層與路基之間。對(duì)于低成本、交通量不大的道路的瀝青路面，面層的厚度不應(yīng)低于1in；對(duì)于交通量繁忙的道路，采用瀝青混凝土面層，其厚度要達(dá)到6in或更厚一些。</p><p>　　面層必須能夠承受車輛行駛時(shí)所產(chǎn)生的磨蝕作用，并具有足夠的穩(wěn)定性來抵抗

52、車輛荷載作用下的推擠和碾壓。除此之外，面層還應(yīng)該能有效阻止過量的表面積水滲入到其下的面層和路基中去。</p><p>　　路基由一層(或多層)穩(wěn)定性和密實(shí)度很高的材料組成。它的主要作用是將車輛荷載作用于路面時(shí)所產(chǎn)生的應(yīng)力分布或“分散”傳遞，使得傳到路基中的應(yīng)力不會(huì)使其產(chǎn)生過大的變形和位移?；鶎舆€必須具有能夠抵抗由毛細(xì)水或冰凍作用產(chǎn)生的損害的功能?；鶎拥氖┕げ牧现饕∮糜诋?dāng)?shù)兀谝粋€(gè)國(guó)家的不同地區(qū)所使用的材料的種類

53、會(huì)有很大的變化。例如，基層可有礫石和碎石構(gòu)成或者由經(jīng)過瀝青、水泥和石灰/粉煤灰等穩(wěn)定劑處理過的粒料所構(gòu)成。</p><p>　　由粒料或穩(wěn)定材料組成的底基層可以應(yīng)用于冰凍作用比較嚴(yán)重的和路基土承載力非常差的地區(qū)。從經(jīng)濟(jì)利益角度出發(fā)，它還應(yīng)用于那些底基層材料比優(yōu)質(zhì)的基層材料便宜的地區(qū)。</p><p>　　路基是基礎(chǔ)層，它必須承受作用在路面上的所有荷載。在某些情況下，路基就是簡(jiǎn)單的天然土層。

54、在其他或更多情況下，路基則是構(gòu)成路塹截面或路堤截面上層的壓實(shí)土層。在柔性路面的基本概念中，底基層（如果有的話）、基層、面層必須具有足夠的厚度來減小作用與路基上的應(yīng)力，避免使路基的土層產(chǎn)生過大的位移和變形。</p><p>　　影響柔性路面設(shè)計(jì)厚度的主要因素為：</p><p><b>　　交通荷載。</b></p><p><b>　

55、　氣候或環(huán)境。</b></p><p><b>　　材料特性。</b></p><p>　　為了獲得最終的厚度設(shè)計(jì)結(jié)果，還必須考慮一些其他因素，包括造價(jià)、施工、維修保養(yǎng)和設(shè)計(jì)期限。因此，學(xué)生們應(yīng)該認(rèn)識(shí)到設(shè)計(jì)過成是很復(fù)雜的，不可能由任何一種非常簡(jiǎn)單的方法來成功解決處于不同條件下的所有問題。</p><p>　　保護(hù)路基使其免受由交通運(yùn)

56、輸量所產(chǎn)生的荷載的損傷是路面結(jié)構(gòu)層的一項(xiàng)主要功能。設(shè)計(jì)者還必須使所設(shè)計(jì)的路面能夠承受大量的變化荷載的重復(fù)作用。</p><p>　　最大荷載的數(shù)值通常由法定的荷載限度來控制。通常通過交通量調(diào)查和輪載測(cè)定器來確定所承受的各種荷載的大小和出現(xiàn)頻率。對(duì)在路面的設(shè)計(jì)使用年限中交通量的預(yù)測(cè)和估算將是一項(xiàng)很艱難但顯然是恨重要的工作。</p><p>　　氣候和環(huán)境因素對(duì)于柔性路面的路基、路面材料的使用

57、性能會(huì)產(chǎn)生重要的影響。溫度和濕度可能是其中兩個(gè)最重要的氣候因素。</p><p>　　溫度的高低和變化影響著某些材料的性能。例如，瀝青混凝土在高溫時(shí)會(huì)喪失穩(wěn)定性，而在低溫時(shí)，瀝青混凝土則會(huì)變得非常堅(jiān)硬。低溫和溫度變化還會(huì)導(dǎo)致凍脹和凍融破壞。對(duì)于粒料，如果不采用合適的級(jí)配就會(huì)產(chǎn)生凍脹。同樣，處于凍結(jié)狀態(tài)中路基的強(qiáng)度也將大大降低。一些穩(wěn)定材料（經(jīng)過石灰、水泥和石灰/粉煤灰處理的）如果經(jīng)過很多次的凍融循環(huán)作用就會(huì)遭受相

58、當(dāng)大的損傷。</p><p>　　濕度對(duì)很多種材料的性質(zhì)和性能也有著重要的影響。在與冰凍有關(guān)的破壞中，濕度是一個(gè)重要的因素。飽和的地基土壤和其他筑路材料的強(qiáng)度會(huì)大大降低，某些黏土?xí)憩F(xiàn)出明顯的由水分所引起的體積變化。</p><p>　　路基濕度狀況的變化是影響路面結(jié)構(gòu)強(qiáng)度、剛度與穩(wěn)定性的重要因素之一。影響路基濕度的有以下幾個(gè)主要因素:大氣降水和蒸發(fā)、地面水的滲透、地下水的影響、溫差引起的

59、濕度變化。</p><p>　　大氣溫度在一年四季出現(xiàn)周期性的變化，每一天的晝夜氣溫也出現(xiàn)一定幅度的周期性變化。路面直接暴露在大氣之中，經(jīng)受著這些變化的影響，特別是面層材料所受的影響最大。路面表面的溫度變化與天氣溫度的變化大致是同步的。面層結(jié)構(gòu)內(nèi)不同深度處的溫度也同樣隨著大氣溫度產(chǎn)生周期性的變化，但是變化的幅度隨著深度的增加而逐漸減少。</p><p>　　凍脹是冰凍的危害之一，它不僅影響

60、車輛的正常行駛，有時(shí)還會(huì)使路面結(jié)構(gòu)遭到破壞。產(chǎn)生凍脹的原因有兩個(gè)：一是由于水分凍結(jié)時(shí)，體積將增加9%；二是由于路基土中的弱結(jié)合水向凍結(jié)區(qū)移動(dòng)的結(jié)果。引起路基凍脹有三個(gè)因素：路基土對(duì)冰凍的敏感性；氣溫下降緩慢；地下水不斷向冰凍區(qū)供給水源。</p><p>　　春季來臨，冰凍的路基開始融化，會(huì)使土失去承載力，導(dǎo)致路面損壞，這種現(xiàn)象稱為春融翻漿，翻漿的主要原因是由于融化的過程是自上而下進(jìn)行的，當(dāng)路基頂面土開始融化時(shí)，水

61、分無(wú)法排除，使得已經(jīng)融化的土達(dá)到飽和狀態(tài)。如果此時(shí)有大量重型車輛通過，路面結(jié)構(gòu)便會(huì)遭到嚴(yán)重破壞。</p><p>　　柔性路面是由具有粘性、彈塑性的結(jié)合料和顆粒礦料組成的路面，包括除用水泥混凝土作面層和基層以外的各種路面結(jié)構(gòu)。柔性路面設(shè)計(jì)內(nèi)容包括路面結(jié)構(gòu)層組合設(shè)計(jì)、路面結(jié)構(gòu)計(jì)算以及路面材料配合比設(shè)計(jì)。本章主要從以下幾個(gè)方面進(jìn)行闡述：彈性層狀體系理論、路面結(jié)構(gòu)層組合設(shè)計(jì)原則、路面設(shè)計(jì)標(biāo)準(zhǔn)及相關(guān)參數(shù)、路面厚度計(jì)算及彎

62、拉應(yīng)力驗(yàn)算。</p><p>　　在現(xiàn)實(shí)中路面材料和土基并不是在任何情況下都具有線彈性性能。采用非線性彈-粘-塑性理論，在一定條件下能更準(zhǔn)確地描述路面的受力狀況，但是考慮到車輪行駛作用的瞬時(shí)性，在路面結(jié)構(gòu)中產(chǎn)生的應(yīng)力數(shù)量很小，因此可以將路面各結(jié)構(gòu)層看成是理想線彈性體，從而應(yīng)用多層線彈性理論來進(jìn)行設(shè)計(jì)計(jì)算。多層線彈性理論必須采用如下基本假定：</p><p>　　1.各層材料均為連續(xù)、均勻、

63、各向同性并服從虎克定律，而且位移和形變是微小的；</p><p>　　2.最下一層（土基）在水平方向和垂直向下方向?yàn)闊o(wú)限大，上面各彈性層則均具有一定厚度，但水平方向?yàn)闊o(wú)限大；</p><p>　　3.各層在水平方向無(wú)限遠(yuǎn)處及最下一層向下無(wú)限深處，其應(yīng)力、形變和位移等于零；</p><p>　　4.各層間的接觸條件是完全連續(xù)的；</p><p>