外文翻譯--公路和機(jī)場(chǎng)路面設(shè)計(jì)

1、外文翻譯一公路和機(jī)場(chǎng)路面設(shè) 計(jì)中文2942字本科生畢業(yè)設(shè)計(jì)（論文）外文資料翻譯翻譯資料名稱（外文）:Highway and Airport Pavement Design翻譯資料名稱（中文）:公路和機(jī)場(chǎng)路面設(shè)計(jì)學(xué) 院： 建筑工程學(xué)院系專 業(yè)：土木工程（道橋）班 級(jí)：學(xué) 號(hào)：姓 名：指導(dǎo)教師：完成日期:2012 年0 2月 20 日2Highway and Airport Pavement Design (Excerpt)T. F. FvvaNational University of Singapore1. IntroductionPavements are designed and cons

2、tructed to provide durable all-weather traveling surfaces for safe and speedy movement of people and 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

3、phases: (a) selection of pavement type, (b) selection of materials to be used for various pavement layers and treatment of subgrade soils, (c) structural thickness design for pavement layers, (d) subsurface drainage design for the pavement system, (e) surface drainage and geometric design, and (f) r

4、idability of pavement surface.The two major considerations in the structural design 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 flexib

5、le 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 design. As the name implies，thickness design refers to the procedure of deterinin

6、ing the required thickness for each pavement layer to provide a structurally sound pavement structure with satisfactory performance for the design traffic over the selected design life. Drainage design examines the entire pavement structure with respect to its drainage requirements and incorporates

7、facilities to satisfy those requirements.2. Pavement Types and Materials2.1 Flexible versus Rigid PavementTraditionally, pavements are classified into two categories, namely flexible and rigid pavements. The basis for classification is the way by which traffic loads are transmitted to the subgrade s

8、oil through the pavement structure. As shown in Fig. 2.1, a flexible pavement provides sufficient thickness 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 s

9、oil would have a direct bearing on the total thickness of the flexible pavement. The layered pavement structure is designed to take advantage of the decreasing magnitude of stresses with depth.A rigid pavement, by virtue of its rigidity, is able to effect a slab action to spread the wheel load over

10、the entire slab area, as illustrated in Fig. 2.1. The structural capacity of the rigid pavement is largely 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

11、be achieved without much variation in slab thickness. The effect of subgrade soil properties oil the thickness of rigid pavement is therefore much less important than in the case of flexible pavement.|(a) Typical Cross Section of Flexible Pavement (b) Load Transmission in Flexible PavementHighway Pa

12、vementAirportPavementWheel LoadTack CoalPrime CoatWearing CourseBinder Course1-2 In2-4 in3-6 inBase Course4-12 in6-12 inSubbase Course12-18 inPrepared SubgradeMM*Natural Subgrade&24 in12-36 in12-60(1 in =25.4 mm)Concrete Slab6-12 In10-24 inBase or Subbase4-6 in4-12 inPrepared SubgradeG-12ln9-18

13、inNatural Subgrade1 In = 254 mm)(c) Typical Cross Section of Rigid PavementHighway Airport Pavement Pavement(d) Load Transmission in Rigid PavementWheelFIGURE 2.1 Flexible and rigid pavements.2.2 Layered Structure of Flexible Pavement2.2.1 Surface CourseIn a typical conventional flexible pavement, k

14、nown as asphalt pavement, the surface course usually consists of two bituminous layers 一 a wearing course and a binder course. To provide a durable, watertight, smooth-ridings and skid-resistant traveled surface, the wearing course is often constructed of dense-graded hot mix asphalt with polish-res

15、istant aggregate. The binder course generally has larger aggregates and less asphalt- The composition of the bituminous mixtures and the nominal top size aggregates for the two courses are determined by the intended use, desired surface texture (for the case of wearing course), and layer thickness.

16、A light application of tack coat of water-diluted asphalt emulsion may be used to enhance bonding between the two courses. Table 2.1 shows selected mix compositions listed in ASTM Standard Specification D3515 1992- Open-graded wearing courses, some with air void exceeding 20%, have also been used to

17、 improve skid resistance and reduce splash during heavy rainfall by acting as a surface drainage layer.2.2.2 Base CourseBase and subbase layers of the flexible pavement make up a large proportion of the total pavement thickness needed to distribute the stresses imposed by traffic loading. Usually ba

18、se course also serves as a drainage layer and provides protection against frost action. Crushed stone is the traditional material used for base construction to form what is commonlv known as the macadam base course. In this construction, choking materials consisting of natural sand or the fine produ

19、ct resulting from crushing coarse aggregates are added to produce a denser structure with higher shearing resistance. Such base courses are called by different names, depending on the construction method adopted.Dry-bound macadam is compacted by means of rolling and vibration that work the choking m

20、aterials into the voids of larger stones. For water-bound macadam, after spreading of the choking materials, 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

21、 a paving machine and compacted by a vibrating roller.Granular base materials may be treated with either asphalt or cement to enhance load distribution capability. Bituminous binder can be introduced by spraying heated asphalt cement on consolidated and rolled crushed stone layer to form a penetrati

22、on macadam road base. Alternatively, bituminous road bases can be designed and laid as in the case for bituininous surface courses.Cement-bound granular base material is plant mixed with an optimal moisture content for compaction. It is laid by paver and requires time for curing. Lean concrete base

23、has also been used successfully under flexible pavements.TABLE 2.1 Example Composition of Dense Bituminous Paving MixturesMix Designation and Nominal Maximum Size of AggregateSieve Size2 in.(50 mm)1 妁 in,(37.5 mm)1 in.(25.0 mm)3/4 in.(19,0 mm)1/2 in.(125 mm)3/8 in.(9,5 mm)2% in1002 in.90-10090-10010

24、01 妁 in.90-1001001 in90-1001003/4 in.51090-1001001/2 in.35-6556-8090-1001003/8 in.56-8090-100No, 417-4723-5329-5935-6544-7455 - 85No. 810-361S-41144523-4928-5832-67No. 16No, 30No. 503-154-16S-175-195-217-23No. 100No, 2000-50-61-72-S2-102-10Note: Nviinbers in table refer to percent passing by weightS

25、昭ASTM» Standard Specification D3515-AnBook ofATMStandards. VbL 04.03 Road and Paving Materials; Travelled Surface Characteristics, 1992 With permission.223 Subbase CourseThe subbase material is of lower quality than the base material in terms of strength, plasticity, and gradation, but it is su

26、perior to the subgrade material in these properties. 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 platform for constructing the base

27、 course, subbase course may be omitted if the subgrade soil satisfies the requirements specified for subbase material.224 Prepared SubgradeMost natural soils forming the roadbed for pavement construction require some form of preparation or treatment. The top layer of a specified depth is usually com

28、pacted to achieve a desired density. The depth of compaction and the compacted density required depend 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 nun) below the formati

29、on level is commonly done. Compaction depth of up to 24 in. (600 mm) may be required for heavily trafficked pavements. For example, in the case of cohesive subgrade, the Asphalt Institute 1991 requires a minimum of 95% of AASHTO T180 (Method D) density for the top 12 in. (300 mm) and a minimum of 90

30、% for all fill areas below the top 12 in. (300 mm). For cohesionless subgrade, the corresponding compaction requirements are 100 and 95%, respectively.Due to the higher wheel loads and tire pressures of aircraft, many stringent compaction requirements are found in airport pavement construction.In so

31、me instances 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 the method of stabilization depends oil the soil properties Improvement

32、 expected, and cost of construction.2.3 Rigid PavementRigid pavements constructed of portland cement concrete are mostly found in heavy-traffic higiiways and airport pavements. To allow for expansion, contraction, warping, or breaks in construction of the concrete slabs, joints are provided in concr

33、ete pavements. The joint 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 expensive to construct, is a popular form of Construction-

34、Depending on the thickness of the slab, typical Joint spacings for plain concrete pavements are between 10 and 20 ft (3 and 6 in). For slabs with joint spacing greater than 6 in, steel reinforcements have to be provided for crack control, giving rise to the use of jointed reinforced concrete pavemen

35、ts (JRCP) and continuously reinforced concrete pavements (CRCP). Continuously reinforced concrete pavements usually contain higher than 0.6% steel reinforcement to eliminate the need to provide joints other than construction and expansion joints.The base course for rigid pavement, sometimes called s

36、ubbase, is often provided to prevent pumping (ejection of foundation material through cracks or Joints resulting from vertical movement 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 sh

37、ort jointed pavements it is common practice to construct cement-treated base to assist in load transfer across the joints.3. Considerations for Highway and Airport PavementsThe two pavement types, flexible and rigid pavement, have been used for road and airport pavement constructioiL The choice of p

38、avement type depends on the intended functional use of the pavement (such as operating speed and safety requirements), types of traffic loading, cost of construction, and maintenance consideration.The main differences in design considerations for highway and airport pavements arise from the characte

39、ristics of traffic using them. Over the typical 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 the effects of load repetitions 一 such a

40、s cumulative permanent deformation, crack propagation, and fatigue failure 一 becomes important. The total number of load applications in the entire design life of a highway pavement must therefore be known for pavement structural design. In contrast, the frequency of aircraft loading on airport pave

41、ment is much less. There are also the so-called wander effect of aircraft landing and taking off and the large variation in the wheel assembly configurations and layout of different aircraft. These make wheel loading on airport pavements less channelized than on highway pavements. Identification of

42、the most critical aircraft is therefore necessary for structural design of airport pavements.Another important difference is in the magnitude of wheel loads. Airport pavements receive loads far exceeding those applied on the highway. An airport pavement may have to be designed to withstand equivalen

43、t single wheel loads of the order of 50 t (approximately 50 tons), whereas 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 twice the

44、 value of a normal truck tire. These differences greatly influence the material requirements for the pavements.公路和機(jī)場(chǎng)路面設(shè)計(jì)（節(jié)選）T. F. Fwa新加坡國(guó)立大學(xué)1緒論路面的設(shè)計(jì)和建造是為了能夠給行人和貨物在其上面進(jìn)行全天候持久的安 全迅速活動(dòng)提供一個(gè)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(jì)和施工過程中仔細(xì)考慮如下幾個(gè)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(jì)；（e）路面排

45、水系統(tǒng)和幾何尺寸設(shè)計(jì)；（f）路面的抵抗能力。公路和機(jī)場(chǎng)路面在結(jié)構(gòu)設(shè)計(jì)上的兩個(gè)主要考慮因素是材料設(shè)計(jì)和厚度設(shè) 計(jì)。材料設(shè)計(jì)要合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(jì)要求。這些問題將在本手冊(cè)的其他章節(jié)中進(jìn) 行討論。本章介紹路面厚度設(shè)計(jì)的概念和方法。顧名思義，厚度設(shè)計(jì)是指確定 每個(gè)路面層的厚度，形成一個(gè)穩(wěn)定的路面結(jié)構(gòu)，使得在規(guī)定的設(shè)計(jì)年限內(nèi)滿足 設(shè)計(jì)交通量的要求。排水系統(tǒng)設(shè)計(jì)可檢驗(yàn)整個(gè)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。2.路面類型和材料2.1柔性路面和剛性路面?zhèn)鹘y(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

46、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(jì)充分利用到了應(yīng)力隨著 土層的加深而減少這一原理。剛性路面依靠其剛度，能夠有效傳遞作用在整塊混凝土板塊上的車輛荷載, 如圖21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(wú)需板塊厚度發(fā)生多大變化就能滿足。因此，路基土性能對(duì)剛性路 面厚度的影響要比柔性路面小得多。(a)柔性路面橫藪面粘結(jié)層一透層一磨耗層聯(lián)結(jié)層基層底基

47、層聿土夯實(shí)層夫然路基1-2 in3-6 in/ 2-4 in/ 4-12 in6-12 in12-18 in12-36 in/ / 6-24 in12-60 n/(b)荷載在柔性路面的傳遞公路路面機(jī)場(chǎng)路面(1 in = 25.4 mm)公路路面機(jī)場(chǎng)路面-輪載混凝土板& 12 In10-24 In基層或者底基層4-6 In4-12 inn tut n素土夯實(shí)層6-12 in9-18 in天然路基(1 in = 25.4 mm)(c)剛性路面橫截面(d)荷栽在剛性路面的傳遞圖2.1柔性和剛性路面2.2柔性路面結(jié)構(gòu)層次2.2.1面層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(gè)瀝青層組

48、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)構(gòu)(針對(duì)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(gè)簡(jiǎn)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D35151992上的經(jīng)選定的混合成分。有些空隙率 超過20%的開級(jí)配磨耗層也可作為強(qiáng)降雨天氣時(shí)的地面排水層，用于提高抗滑 性和防止濺水。2.2.2基層柔性路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

49、荷載 所產(chǎn)生的應(yīng)力。通?；鶎右部勺鳛榕潘畬?，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(jí)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。2.1濃瀝青攤鋪混合料組成示例組合名稱和碎石的最大公稱粒徑篩孔尺寸2 in.(50 mm)1 妁 in,(37,5 mm)1 in.(25.0 mm)3/4 in.(19mm)1/2 in.(125 mm)3/8 in.(9,5 mm)2% i口1002 in.90-10090-1001001妁id90-1001001 in.6D90-

50、1001003/4 in.52 in.35-6556-8090-1001003/8 in.56090-100No, 417-4723-5329-5935-65447455-85No. 810-361S-41144523-4928-5832-67No. 16No, 30No. 503-154-165-175-195-217-23No. 100No, 2000-5461-72-82-102-10注：表中數(shù)據(jù)指的是通過篩孔重雖百分比。文獻(xiàn)：ASTM,標(biāo)準(zhǔn)規(guī)范D3515-84,ASTM標(biāo)準(zhǔn)年鑒，4. 03卷一道路和攤鋪材料；行車 路面待性，1992。許可。干結(jié)碎石通過軋制和振動(dòng)，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(duì)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(dòng)壓路機(jī)壓實(shí)。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(jì)和攤鋪可以作為瀝青面層的示例。水