外文翻譯-- 公路和機(jī)場路面設(shè)計

1、<p><b>　　中文2942字</b></p><p>　　本科生畢業(yè)設(shè)計（論文）外文資料翻譯</p><p>　　翻譯資料名稱（外文）：</p><p>　　Highway and Airport Pavement Design </p><p>　　翻譯資料名稱（中文）：</p>

2、;<p>　　公路和機(jī)場路面設(shè)計 </p><p>　　學(xué) 院： 建筑工程學(xué)院 系 土木工程 </p><p>　　專 業(yè)： 土 木 工 程 （道橋） </p><p>　　班 級：

3、 </p><p>　　學(xué) 號： </p><p>　　姓 名： </p><p>　　指導(dǎo)教師：

4、 </p><p>　　完成日期： 2012 年 02 月 20 日</p><p>　　Highway and Airport Pavement Design（Excerpt）</p><p>　　T. F. Fwa </p><p>　　Na

5、tional University of Singapore</p><p>　　Introduction </p><p>　　Pavements are designed and constructed to provide durable all-weather traveling surfaces for safe and speedy movement of people and

6、 goods with an acceptable level of comfort to users. These functional requirements of pavements are achieved through careful considerations in the following aspects during the design and construction phases: (a) selectio

7、n of pavement type, (b) selection of materials to be used for various pavement layers and treatment of subgrade soils, (c) structural thickness desig</p><p>　　The two major considerations in the structural d

8、esign of highway and airport pavements are material design and thickness design. Material design deals with the selection of suitable materials for various pavement layers and mix design of bituminous materials (for flex

9、ible pavement) or portland cement concrete (for rigid and interlocking block pavements). These topics are discussed in other chapters of this handbook. This chapter presents the concepts and methods of pavement thickness

10、 design. As </p><p>　　2．Pavement Types and Materials</p><p>　　2.1 Flexible versus Rigid Pavement</p><p>　　Traditionally, pavements are classified into two categories, namely flexibl

11、e and rigid pavements. The basis for classification is the way by which traffic loads are transmitted to the subgrade soil through the pavement structure. As shown in Fig. 2.1, a flexible pavement provides sufficient thi

12、ckness for load distribution through a multilayer structure so that the stresses and strains in the subgrade soil layers are within the required limits. It is expected that the strength of subgrade soil wo</p><

13、;p>　　A rigid pavement, by virtue of its rigidity, is able to effect a slab action to spread the wheel load over the entire slab area, as illustrated in Fig. 2.1. The structural capacity of the rigid pavement is largel

14、y provided by the slab itself. For the common range of subgrade soil strength, the required rigidity for a portland cement concrete slab (the most common form of rigid pavement construction) can be achieved without much

15、variation in slab thickness. The effect of subgrade soil properties </p><p>　　FIGURE 2.1 Flexible and rigid pavements.</p><p>　　2.2 Layered Structure of Flexible Pavement</p><p>　　2

16、.2.1 Surface Course</p><p>　　In a typical conventional flexible pavement, known as asphalt pavement, the surface course usually consists of two bituminous layers — a wearing course and a binder course. To pr

17、ovide a durable, watertight, smooth-riding, and skid-resistant traveled surface, the wearing course is often constructed of dense-graded hot mix asphalt with polish-resistant aggregate. The binder course generally has la

18、rger aggregates and less asphalt. The composition of the bituminous mixtures and the nominal top size </p><p>　　2.2.2 Base Course</p><p>　　Base and subbase layers of the flexible pavement make u

19、p a large proportion of the total pavement thickness needed to distribute the stresses imposed by traffic loading. Usually base course also serves as a drainage layer and provides protection against frost action. Crushed

20、 stone is the traditional material used for base construction to form what is commonly known as the macadam base course. In this construction, choking materials consisting of natural sand or the fine product resulting fr

21、om cr</p><p>　　Dry-bound macadam is compacted by means of rolling and vibration that work the choking materials into the voids of larger stones. For water-bound macadam, after spreading of the choking materi

22、als, water is applied before the entire mass is rolled. Alternatively, a wet-mix macadam may be used by premixing crushed stone or slag with a controlled amount of water. The material is spread by a paving machine and co

23、mpacted by a vibrating roller. </p><p>　　Granular base materials may be treated with either asphalt or cement to enhance load distribution capability. Bituminous binder can be introduced by spraying heated a

24、sphalt cement on consolidated and rolled crushed stone layer to form a penetration macadam road base. Alternatively, bituminous road bases can be designed and laid as in the case for bituminous surface courses. Cement-bo

25、und granular base material is plant mixed with an optimal moisture content for compaction. It is laid by paver and</p><p>　　TABLE 2.1 Example Composition of Dense Bituminous Paving Mixtures</p><p&

26、gt;　　2.2.3 Subbase Course</p><p>　　The subbase material is of lower quality than the base material in terms of strength, plasticity, and gradation, but it is superior to the subgrade material in these proper

27、ties. It may be compacted granular material or stabilized soil, thus allowing building up of sufficient thickness for the pavement structure at relatively low cost. On a weak subgrade, it also serves as a useful working

28、platform for constructing the base course. subbase course may be omitted if the subgrade soil satisfies the</p><p>　　2.2.4 Prepared Subgrade</p><p>　　Most natural soils forming the roadbed for

29、pavement construction require some form of preparation or treatment. The top layer of a specified depth is usually compacted to achieve a desired density. The depth of compaction and the compacted density required depend

30、 on the type of soil and magnitudes of wheel loads and tire pressures. For highway construction, compaction to 100% modified AASHTO density covering a thickness of 12 in. (300 mm) below the formation level is commonly do

31、ne. Compaction de</p><p>　　Due to the higher wheel loads and tire pressures of aircraft, many stringent compaction requirements are found in airport pavement construction.</p><p>　　In some insta

32、nces it may be economical to treat or stabilize poor subgrade materials and reduce the total required pavement thickness. Portland cement, lime, and bitumen have all been used successfully for this purpose. The choice of

33、 the method of stabilization depends on the soil properties, improvement expected, and cost of construction.</p><p>　　2.3 Rigid Pavement</p><p>　　Rigid pavements constructed of portland cement c

34、oncrete are mostly found in heavy-traffic highways and airport pavements. To allow for expansion, contraction, warping, or breaks in construction of the concrete slabs, joints are provided in concrete pavements. The join

35、t spacing, which determines the length of individual slab panels, depends on the use of steel reinforcements in the slab. The jointed plain concrete pavemen (JPCP), requiring no steel reinforcements and thus the least ex

36、pensive to c</p><p>　　The base course for rigid pavement, sometimes called subbase, is often provided to prevent pumping (ejection of foundation material through cracks or joints resulting from vertical move

37、ment of slabs under traffic). The base course material must provide good drainage and be resistant to the erosive action of water. When dowel bars are not provided in short jointed pavements, it is common practice to con

38、struct cement-treated base to assist in load transfer across the joints.</p><p>　　3．Considerations for Highway and Airport Pavements</p><p>　　The two pavement types, flexible and rigid pavement,

39、 have been used for road and airport pavement construction. The choice of pavement type depends on the intended functional use of the pavement (such as operating speed and safety requirements), types of traffic loading,

40、cost of construction, and maintenance consideration.</p><p>　　The main differences in design considerations for highway and airport pavements arise from the characteristics of traffic using them. Over the ty

41、pical design life span of 10 to 20 years for flexible pavements, or 20 to 40 years for rigid pavements, a highway pavement will be receiving highly channelized wheel load applications in the millions. Consideration of th

42、e effects of load repetitions — such as cumulative permanent deformation, crack propagation, and fatigue failure — becomes important. T</p><p>　　Another important difference is in the magnitude of wheel load

43、s. Airport pavements receive loads far exceeding those applied on the highway. An airport pavement may have to be designed to withstand equivalent single wheel loads of the order of 50 t (approximately 50 tons), whereas

44、the maximum single wheel load allowed on the road pavement by most highway authorities is about 10 t (approximately 10 tons). Furthermore, the wheel tire pressure of an aircraft of about 1200 kPa (175 psi) is nearly tw&l

45、t;/p><p>　　公路和機(jī)場路面設(shè)計（節(jié)選）</p><p><b>　　T. F. Fwa</b></p><p><b>　　新加坡國立大學(xué)</b></p><p><b>　　1.緒論</b></p><p>　　路面的設(shè)計和建造是為了能夠給行人和

46、貨物在其上面進(jìn)行全天候持久的安全迅速活動提供一個舒適合意的水平環(huán)境。路面的這些功能要求可以通過在設(shè)計和施工過程中仔細(xì)考慮如下幾個方面來實(shí)現(xiàn)：（a）合理選擇路面類型；（b）合理選擇各路面層材料和路基土處理；（c）合理進(jìn)行各路面層厚度劃分；（d）地下排水系統(tǒng)設(shè)計；（e）路面排水系統(tǒng)和幾何尺寸設(shè)計；（f）路面的抵抗能力。</p><p>　　公路和機(jī)場路面在結(jié)構(gòu)設(shè)計上的兩個主要考慮因素是材料設(shè)計和厚度設(shè)計。材料設(shè)計要合

47、理選擇各路面層材料，滿足瀝青混合料（柔性路面）或者水泥混凝土（剛性路面）配合比設(shè)計要求。這些問題將在本手冊的其他章節(jié)中進(jìn)行討論。本章介紹路面厚度設(shè)計的概念和方法。顧名思義，厚度設(shè)計是指確定每個路面層的厚度，形成一個穩(wěn)定的路面結(jié)構(gòu)，使得在規(guī)定的設(shè)計年限內(nèi)滿足設(shè)計交通量的要求。排水系統(tǒng)設(shè)計可檢驗(yàn)整個路面結(jié)構(gòu)在它的排水要求和一體化設(shè)施方面是否滿足相關(guān)要求。</p><p>　　2. 路面類型和材料</p>

48、<p>　　2.1柔性路面和剛性路面</p><p>　　傳統(tǒng)上，根據(jù)通過路面結(jié)構(gòu)傳遞到路基土上的交通荷載，路面分為兩類，即柔性路面和剛性路面。如圖2.1所示，柔性路面具有足夠的厚度來承受多層結(jié)構(gòu)傳遞的分布荷載，使得路基土層的應(yīng)力應(yīng)變值控制在容許范圍內(nèi)。柔性路面地基土的強(qiáng)度將直接關(guān)系到總厚度。路面結(jié)構(gòu)層的設(shè)計充分利用到了應(yīng)力隨著土層的加深而減少這一原理。</p><p>　　剛

49、性路面依靠其剛度，能夠有效傳遞作用在整塊混凝土板塊上的車輛荷載，如圖2.1所示。剛性路面的結(jié)構(gòu)承載力大部分都是由混凝土板塊自身提供。在地基土強(qiáng)度的一般變化范圍內(nèi)，硅酸鹽水泥混凝土面板（最常見的剛性路面結(jié)構(gòu)）的剛度要求無需板塊厚度發(fā)生多大變化就能滿足。因此，路基土性能對剛性路面厚度的影響要比柔性路面小得多。</p><p>　　圖2.1 柔性和剛性路面</p><p>　　2.2 柔性路面結(jié)

50、構(gòu)層次</p><p><b>　　2.2.1 面層</b></p><p>　　瀝青路面是一種典型的傳統(tǒng)柔性路面，它的面層通常由兩個瀝青層組成，即磨耗層和聯(lián)結(jié)層。為了保證路面的耐久性、不透水、平穩(wěn)行車和防滑，磨耗層一般由熱拌瀝青混凝土和耐磨碎石組成，而聯(lián)結(jié)層則一般由大量的碎石和少量的瀝青組成。這兩層的瀝青混合料的組成以及骨料的最大公稱直徑是由使用目的、所希望的表面結(jié)

51、構(gòu)（針對磨耗層而言）、層厚來決定的。由水稀釋乳化瀝青組成的粘結(jié)層的一個簡易運(yùn)用就是增強(qiáng)磨耗層和聯(lián)結(jié)層之間的粘結(jié)性。表2.1顯示了列在ASTM標(biāo)準(zhǔn)規(guī)格D3515[1992] 上的經(jīng)選定的混合成分。有些空隙率超過20%的開級配磨耗層也可作為強(qiáng)降雨天氣時的地面排水層，用于提高抗滑性和防止濺水。</p><p><b>　　2.2.2 基層</b></p><p>　　柔性路

52、面的基層和底基層占總路面厚度的大部分，它們用來分配交通荷載所產(chǎn)生的應(yīng)力。通常基層也可作為排水層，并提供保護(hù)免受霜凍作用。碎石是基層施工的常用材料，構(gòu)成俗稱的碎石基層。在本階段施工過程中，填充材料選用天然砂或者良好級配的壓碎碎石集料，形成具有更高抗剪承載力的密實(shí)結(jié)構(gòu)。根據(jù)施工方法的不同，這樣的基層有不同名稱。</p><p>　　表2.1 濃瀝青攤鋪混合料組成示例</p><p>　　干結(jié)碎

53、石通過軋制和振動，使填充料填塞到大塊石頭間的空隙，達(dá)到壓實(shí)的目的。而對于水結(jié)碎石，在填充材料填塞空隙后，水在整塊被軋制前就得到應(yīng)用。另外，通過用適量的水預(yù)拌碎石或礦渣，濕混碎石也可被使用。這些材料先用攤鋪機(jī)攤鋪，然后再用振動壓路機(jī)壓實(shí)。</p><p>　　顆?；鶎硬牧峡蛇x用瀝青或者水泥以提高荷載分配能力。為建造滲透碎石路面基層，在固結(jié)并壓實(shí)的碎石層上面噴灑熱拌瀝青混凝土?xí)r可采用瀝青結(jié)合料。瀝青路面基層的設(shè)計和攤

54、鋪可以作為瀝青面層的示例。水泥穩(wěn)定基層粒料在達(dá)到壓實(shí)時的最佳含水量后采用廠拌法，通過攤鋪機(jī)攤鋪，養(yǎng)護(hù)足夠的時間。貧混凝土基層也被成功運(yùn)用到柔性路面。</p><p><b>　　2.2.3 底基層</b></p><p>　　跟基層材料相比，底基層材料的強(qiáng)度、塑性和級配要求都要更低，但是在這些性能上，底基層更具優(yōu)勢?？赡芤?yàn)椴捎昧藟簩?shí)粒料或穩(wěn)定土，路面結(jié)構(gòu)造價相對較低

55、，但厚度卻足以滿足要求。對于柔弱底基層，它也可以作為構(gòu)建基層的有用的施工平臺。如果路基土滿足底基層材料的特定要求，也可以不構(gòu)建底基層。</p><p>　　2.2.4 素土夯實(shí)層</p><p>　　用于路面建筑的絕大部分天然土路床要求進(jìn)行素土夯實(shí)或者特殊處理。某一指定深度的頂層通常需要壓實(shí)來獲得理想的壓實(shí)密度。壓實(shí)深度和壓實(shí)密度的要求要根據(jù)土壤類型、車輪荷載大小以及輪胎壓力而定。在公路建

56、筑上，壓實(shí)至100%修改過的 AASHTO（美國國家公路與運(yùn)輸協(xié)會標(biāo)準(zhǔn)）密度時，覆蓋厚度為12英寸 (300毫米)，通常的做法都是低于這個正常水平的。對于重交通路面，壓實(shí)深度可能要求高達(dá)24英寸（600毫米）。例如，對于粘性路基，瀝青研究所（1991）要求達(dá)到最低的95%AASHTO標(biāo)準(zhǔn) T180次 (D法)密度時，厚度為頂級12英寸（300毫米），在所有填方中最少90%要低于頂級12英寸（300毫米）。對于無粘性路基，相應(yīng)的壓實(shí)要求是

57、100%和95%。</p><p>　　由于飛機(jī)的輪載和輪壓更大，因此在機(jī)場路面施工時，對壓實(shí)要求更為嚴(yán)格。</p><p>　　在某些情況下，處理或者加固軟弱不良路基材料是一種經(jīng)濟(jì)的做法，并且可以減少所需的總路面厚度。硅酸鹽水泥、石灰、瀝青等的成功運(yùn)用就是為了達(dá)到這樣的效果。選擇怎樣的加固方法要根據(jù)土壤性質(zhì)、預(yù)期改善效果和建設(shè)成本而定。</p><p><b

58、>　　2.3 剛性路面</b></p><p>　　在交通繁忙的公路和機(jī)場路面，硅酸鹽水泥混凝土剛性路面結(jié)構(gòu)幾乎隨處可見?？紤]到混凝土板的膨脹、收縮、翹曲或者開裂，混凝土路面設(shè)有接縫。接縫間距取決于混凝土板中鋼筋的選用，它能決定單獨(dú)每板塊的長度。接縫式素混凝土路面結(jié)構(gòu)（JPCP）是一種很流行的建筑形式，它不需要鋼筋，因而造價最低。根據(jù)混凝土板厚度的大小，普通混凝土路面的標(biāo)準(zhǔn)接縫間距是10—20英

59、尺（3—6米）。當(dāng)混凝土板塊接縫間距大于6米時，需要增設(shè)鋼筋防止開裂，從而進(jìn)入到使用接縫式鋼筋混凝土路面（JRCP）和連續(xù)鋼筋混凝土路面（CRCP）階段。連續(xù)鋼筋混凝土路面通常多含0.6%的鋼筋，用來減少除結(jié)構(gòu)和伸縮縫以外的接縫數(shù)量。</p><p>　　剛性路面基層，有時又叫做底基層，通常用于防止出現(xiàn)唧泥（在交通作用下，混凝土板垂直運(yùn)動，基礎(chǔ)材料通過裂縫或者接縫噴出的現(xiàn)象）?；鶎硬牧媳仨毦哂辛己玫呐潘阅懿⑶夷?/p>

60、夠抵抗水的腐蝕作用。當(dāng)短縫路面沒有傳力桿時，通常的做法是構(gòu)建水泥穩(wěn)定基層來協(xié)助傳遞橫穿接縫的荷載。</p><p>　　3. 公路和機(jī)場路面注意事項(xiàng)</p><p>　　柔性路面和剛性路面這兩種路面類型已經(jīng)廣泛運(yùn)用到了公路和機(jī)場路面建筑。選擇哪種路面類型要根據(jù)路面的預(yù)期使用功能（例如運(yùn)行速度和安全要求）、交通荷載類型、工程造價和維修代價而定。</p><p>　　公

61、路和機(jī)場路面設(shè)計考慮因素方面主要的不同在于使用它們的交通特點(diǎn)各異。柔性路面的標(biāo)準(zhǔn)設(shè)計年限是10-20年，剛性路面是20-40年，在它們各自的設(shè)計年限內(nèi)，公路路面將受到數(shù)于百萬計的高渠化輪載作用。考慮到重復(fù)荷載的影響——例如累積永久變形、裂紋擴(kuò)展和疲勞破壞——變得重要，路面結(jié)構(gòu)設(shè)計必須考慮到整個設(shè)計年限范圍內(nèi)的荷載作用總效應(yīng)。相比之下，機(jī)場路面的負(fù)荷頻率要小得多。所謂的飛機(jī)著陸、起飛漂移，大差異的機(jī)輪裝配配置，不同飛機(jī)的布局設(shè)計，這些因素

62、使得作用在機(jī)場路面的輪載渠化程度比公路路面低。因此在機(jī)場路面的結(jié)構(gòu)設(shè)計中，以最關(guān)鍵的飛機(jī)為標(biāo)準(zhǔn)是很有必要的。</p><p>　　另外一個重要的不同就在于輪載的大小。機(jī)場路面受到的荷載遠(yuǎn)大于作用在公路上的。機(jī)場路面要設(shè)計能夠承受50噸（或接近50噸）的等效單輪荷載，然而大部分公路部門所允許的最大公路路面單輪荷載只有10噸（或接近10噸）。此外，一架飛機(jī)的輪胎壓力大約是1200KP（175磅），接近于兩倍的標(biāo)準(zhǔn)卡車