土木工程建筑道橋外文翻譯外文文獻(xiàn)英文文獻(xiàn)瀝青路面結(jié)構(gòu)設(shè)計(jì)的低成本農(nóng)村道路

1、外文文獻(xiàn) structural design of asphalt pavement for low cost rural roadsyuan goulin(袁國(guó)林)12 chen rongshen(陳榮生)1. college of transportation, southeast university, nanjing 210b9b, china2. college of civil engineering, nanjing university of technology, nanjing , china in developing countries，rural road const

2、ruction is mostly cumbered by shortage of funds. engineers concerns most in rural areas is how to build roads which not only cost less but also meet the traffic demands. especially in vast rural areas of china, there are a great variety of transportation patterns, and the traffic composition is very

3、 complex. compared with other countries，the traffic composition in china rural areas have its own features. therefore，there is no experience about the rural roads construction for reference. in recent years，the central government of china has increased the strength for rural road construction. at th

4、e same time，a lot of researches about rural road construction have been done by researchers in china, and some conclusions about china rural roads have been made. in the authors opinion，the selection of the pavement structure material is the key measure to reduce the construction cost of rural roads

5、 after the route has been determined. compared with concrete pavement，asphalt pavement relatively costs less and is the first choice for rural roads in china. and then，according to the research achievements about rural roads construction，the authors have done some preliminary researches on the struc

6、ture design for low-cost asphalt pavements for rural roads.1 traffic composition of rural road rural roads include county roads，town roads and village roads. the traffic on rural roads is usually mixed. on a county road, traffic volume is between 300 to 1500 veh/d in average，and in a county with a d

7、eveloped economy，it reaches 1000 to 2 000 veh/d. the traffic volume between county and town is 100 to 300 veh/d，and the traffic volume between towns is usually less than 100 to 300 veh/d. in a mixed traffic flow，trucks account for 40% to 70% of the traffic volume, which are mainly light trucks carry

8、ing less than 2. 5 tons(including agricultural vehicles such as electro-tricycles，walking tractors etc.)and medium-size trucks of 2. 5 to 5 tons. most of these light or medium trucks are overloaded. the proportion of heavy truck is less than 9%.on some roads to counties，the proportion of overloaded

9、trucks is 5% to 32 %，while on some county roads connecting to national or provincial trunk highways，the proportion of overloaded vehicles usually amounts to 20% to 32% .the traffic volume on rural roads is not heavy. however，considering the practical situation in china, as well as the exitence of ov

10、erloaded vehicles，100kn，or bzz-100 was adopted as standard axle load in the research. the pavement deflection or the flexural-tensile stress at the bottom of asphalt surface is taken as the design parameter. the axle load was calculated inaccordance with the following formula:pi和ni-the axle weight o

11、f an i-level axle in kn and the action frequency;ns和ps-the axle weight of standard axle in 100 kn and the action frequency;if the distance between axles is less than 3 m， axle loads are calculated asa double-axle or multi-axle loads，andc1=1+1.2m-1if the flexural-tensile stress at the bottom of semi-

12、rigid base is taken as the design parameter, the axle load is calculated in accordance with the following formula:nsni=c1c2pips8if the distance between axles is less than 3m，c1=1+2(m-1)2 traffic volume on rural roads minibuses are adopted as the standard vehicle for the design of rural roads. table

13、1 shows its external dimensions.table 1 external dimensions of the passenger car mlength width height front overhang distance between axles rear overhang 6.0 1.8 2.0 0.8 3.8 1.4 the typical vehicle types on rural roads are listed in table 2. and others such as non-power-driven vehicles，animal-drawn

14、vehicles，and bicycles can be taken into account in the calculation of traffic volume on rural roads，in view of their roadside interference. in accordance with the traffic composition and volumes，rural roads are divided into five grades. the traffic volume of each grade is shown in table 3. traffic v

15、olume specified in table 3 was obtained by taking the minibus as the standard vehicle type,and converting different types vehicles according to the vehicle conversion coefficients given in table 2.in table 3， ne refers to the cumulative equivalent axle load action frequency; ns refers to the equival

16、ent axle load action frequency in the designed traffic lane in the beginning operation period of rural roads; y refers to the average annual growth rate of traffic volume; refers to lane coefficient, and 1.0 for a single lane and 0. 6一0. 7 for a dual lane.3 strength of roadbedthe modulus of resilien

17、ce of roadbed varies greatly. for convenience，the strength of roadbed can be divided into four classes according to its moisture content and modulus of resilience，as shown in table 4. the parameters in table 5 are determined by combining design principles with practical experience. by applying elast

18、ic multilayer theory to the pavement structure specified in table 5，the influence of ne on the pavement thickness of rural roads was analyzed，and the result show that for given h，h2，e0，the roadbase thickness for neighboring traffic classes changes in a range of 4-5 cm. this result indicates that the

19、 classification of traffic volume on rural roads shown in table 3 is reasonable and feasible in terms of the design and construction of asphalt pavement structures. by using the elastic multilayer theory，the asphalt pavement structure of ordinary rural road in table 5 is analyzed. when ne，the cumula

20、tive equivalent axle load action frequency，the thickness of road surface(h =3 cm)，and the thickness of subbase(h2 = 20 cm ) remain the same , the influence of neighboring roadbed strength classifications on the thickness of roadbase is 3 cm一5 cm. this conclusion indicates that the strength classific

21、ation of roadbed is reasonable and applicable to the design and construction of asphalt pavement structure.4 determination of thicknesses of asphalt pavement structure sensitivity analysis of the design parameters of roadbed and pavement structures is to find out the relationship between structural

22、strength of asphalt pavement structure and the design parameters of each layer, and determine the most sensitive layer in the pavement structure. the asphalt pavement structure of rural roads is generally composed of a road surface, a roadbase，and a subbase，as shown in table 6. the pavement structur

23、e was analyzed according to elastic multiplayer theory under the double circular uniform load，with an assumption that there is continuous contact between the adjacent layers of the asphalt pavement structure. the basic parameters used in the calculation and analysis of asphalt pavement structure are

24、 listed in table 7. by analyzing the effects of the change of all the parameters of pavement structure on the distortion of the road surface，roadbase，and roadbed , the following conclusions have been drawn.(1)increasing the thickness of the road surface effectively decreases the road surface deflect

25、ion，but raises the cost. the comparatively economical and effective method is to increase the thickness of the subbase, which is superior to increasing the thickness of roadbase，while increasing the thickness of the road surface is the last choice.(2)as the thickness of pavement structure increases，

26、the change of road surface deflection will trend to be gentle. when the thickness of road surface reaches a certain value，the variance in the road surface deflection will not be obvious，and then it is ineffective to enhance the bearing capacity of asphalt pavement structure by increasing the thickne

27、ss of road surface. it is recommended that the thicknesses of the roadbase and the subbase should be equal to or largerthan 18 and 20 cm, respectively，in design of asphalt pavement structures of rural roads. fig. 1 shows the effects of the changes in the thickness of each layer on road surface defle

28、ction.(3)road surface deflection is very sensitive to the change of modulus of the roadbed. the increase in the modulus of roadbase or subbase is also effective to decrease the deflection of the road surface. on the other hand，the deflection of the road surface decreases gradually when the modulus o

29、f the surface increases，being the least effective factor. when the modulus of the road surface increases to a certain value， decrease in road surface deflection is not apparent. fig. 2 shows the effect of the modulus of each layer on road surface deflection. from the above discussion，we conclude tha

30、t the most sensitive layer for road surface deflection is subbase，and the next is roadbase. to decrease the road surface deflection of low-cost rural roads，the strength and stability of the roadbed should be enhanced, and the materials with a certain thickness and relatively high density should be u

31、sed to pave the subbase. the traffic volume or the accumulative equivalent axle load action times(frequency)within the designed life of road is used to determine the type and thickness of the asphalt pavement road surface, and the results are listed in table 8，where veh/d means the number of the equ

32、ivalent the passenger cars per day. for a low traffic volume rural road with ne 500 000，graded broken stones(or gravel)can be used as a flexible base. the flexible base has good strength and effectively prevents reflection cracks of the asphalt pavement road surface, provided the graded broken stone

33、s(or gravel ) meets the requirements for high density(degree of compaction ,100%. to ensure the sufficient strength and stability of the flexible base，its thickness is not less than 15 cm，the thickness of the aggregate subbase is not less than 20 cm，a semi-rigid base usually has a good bearing capac

34、ity for the rural roads with ne)500 000，or those with low traffic volumes but relatively,the minimum thickness of semirigid base or subbase is 16-18 cm5 calculation of the thickness of road surface5.1 deflection(1)road surface deflection road surface deflection is a vertical distortion caused by ver

35、tical load on the road surface. it not only reflects the whole strength and stiffness of asphalt pavement structure and roadbed，but also has a close internal relation with the service condition of the pavement.(2)design deflection the design deflection is the index representing the stiffness of the

36、pavement structure. it is also the deflection of the pavement which is established according to the accumulative equivalent axle load estimated to pass over a lane in the expected design life, road types, road classification，and the types of road surface and roadbase. the design deflection is not on

37、ly the main basis for the design thickness of the pavement structure，but also the necessary index for the examination and acceptance of the project. through theoretical analysis and experimental study，formulas for the design deflection value which are applicable to the pavement structure design of l

38、owcost rural roads are as follows:semi-rigid base:ld=629ne-0.2asflexible base:ld=1134ne-0.2aswhere a, is the type coefficient of the road surface. the type coefficient of asphalt concrete road surface is 1.0;that of hot-mix asphalt macadam and that of emulsified asphalt macadam road surface are all

39、1. 1; and that of asphalt surface treatment road surface is1 .2.(3)allowable deflection allowable deflection is the maximum deflectionallowed at the end of the roads service life under lim-iting conditions in poor season. through thoreticalanalysis and experimental study，the calculation for-mulas fo

40、r the allowable deflection of road surfacewhich are applicable to the pavement structure designof low-cost rural roads are as follows2:ld=786ne-0.2asld=1418ne-0.2aswhen designing the asphalt pavement structure of low-cost rural roads, we should use formula (6) or (7 ) according to the types of roadb

41、ase to determine the thickness of asphalt pavement structure.5.2 tensile stress because the asphalt pavement structure of lowcost rural roads is not substantial enough and the heavy vehicles are allowed to pass over them, the maximum tensile stress should be checked by computing the stresses of the

42、semi-rigid base and subbase. the tensile stress at the bottom of semi-rigid base or subbase，would be less than or equivalent to the allowable tensile stress of the materials of the semirigid base or subbase , namely，mr=spksfor the stabilized aggregate base with an inorganic binder-ks=0.35ne0.11ac,ac

43、=1.2for the stabilized fine-grained soil base with an inorganic binder:ks=0.35ne0.11ac,ac=1.25.3 pavement thickness to make it simple and convenient for engineers to determine the desired thickness of rural road pavement, the curves of the thickness of the roadbase of low-cost rural roads according

44、to typical pavement structures and accumulative frequency of equivalent axle load are shown in figs. 3，4 and 5. (1)when the accumulative frequency of equivalent axle load is within times per lane，asphalttreated or asphalt penetrated surfaces with thickness of 1. 5 cm一cm is recommended for road surfa

45、ce. for various accumulative equivalent axle loads and the moduli(eo)of roadbed，the equivalent thickness of roadbase is shown in fig. 3.(2)when the accumulative frequency of equivalent axle load is within 500 001)一1 000 000 times per lane，asphalt macadam or asphalt concrete with thickness of 3 cm -5

46、 cm is recommended. for various accumulative equivalent axle loads and moduli(eo)of roadbed，the equivalent thickness of roadbase is shown in fig. 4.(3)when the accumulative frequency of equivalent axle load is within 1000 000-2 000 000 times per lane，asphalt concrete road surface of 5 cm-7 cm thick

47、is recommended. for various accumulative equivalent axle loads and moduli(eo)of roadbed , the equivalent thickness of roadbase is shown in fig.s.in figs.3-5，ld is the designed deflection, lo is the representative deflection of roadbed，e, is the modulus of resilience of the roadbase，in mpa , eo is th

48、e modulus of resilience of the roadbed，in mpa ,and h, in cm，is the equivalent thickness of the base (roadbase and subbase)，which can be obtained through calculation and in-site investigation for a trilevel-pavement roads(including road surface，base and roadbed).if a designed road has four layers，i.e

49、. a subbase is added，according to the regression analysis of the extrapolated results of a number of multi-layer flexible systems and the available research findings，the thickness of the roadbase , h,，in cm, can be calculated from the following equation:h1=h-h22.4e2e16 concluding remarks compared wi

50、th concrete pavement, asphalt pavements have a lower construction cost, which is suitable for the roads in relatively underdeveloped rural areas in china. the research in this paper proposed a method for structural design of low cost asphalt pavements. the method is to provide an guideline for the d

51、esign of asphalt pavement structure in rural areas.references1yuan g l , zhang f , chen s w , et al. research on technical indexes of rural highway construction in jiangsu province j .highway, 2005(6):135一139(in chinese). 2 research institute of highway , the ministry of communications. final report

52、 on low cost inter-township and rural road construction techniquesr.beijing; resdarch institute of highway, 2003(in chinese). 3 liu q q. how to reduce the construction cost of the rural highway j .journal of highway and transportation research and development, 2005(2):41一44(in chinese). 4 jtg b014-9

53、7. specification for design of highway asphalt pavement s (in chinese ). 5 jtg bo1-2003. technical standard of highway engineering s (in chinese).6 deng x j. engineering for sub-grade and pavement m.2nd ed. beijing; peoples communications press, beijing, 2004(in chinese ).中文譯文瀝青路面結(jié)構(gòu)設(shè)計(jì)的低成本農(nóng)村道路袁國(guó)林1，陳榮

54、生21。交通運(yùn)輸學(xué)院，東南大學(xué)，南京210b9b，中國(guó)2。土木工程學(xué)院，南京工業(yè)大學(xué)，南京，中國(guó)在發(fā)展中國(guó)家,農(nóng)村道路建設(shè)主要是因缺乏資金而受阻。工程師最關(guān)心的農(nóng)村問題是如何修建的公路不僅成本低,而且滿足交通需求。特別是在廣大農(nóng)村地區(qū),有各種各樣的交通方式,交通成分非常復(fù)雜。與其他國(guó)家相比,在中國(guó)農(nóng)村地區(qū)交通組成有其自身的特征. 因此,沒有足夠經(jīng)驗(yàn)對(duì)農(nóng)村公路建設(shè)提供參考依據(jù)。近年來,中國(guó)的中央政府增加了對(duì)農(nóng)村公路建設(shè)的力量。與此同時(shí), 在中國(guó)，研究人員已經(jīng)完成了關(guān)于中國(guó)農(nóng)村道路的大量研究和一些結(jié)論。在作者的觀點(diǎn),選擇不同的路面結(jié)構(gòu)材料是關(guān)鍵措施，從而降低農(nóng)村道路的工程造價(jià)。相比,瀝青混凝土路面

55、相對(duì)費(fèi)用少、是第一個(gè)在中國(guó)農(nóng)村道路的選擇。然后,根據(jù)農(nóng)村道路建設(shè)研究成果,作者也做了一些對(duì)低成本瀝青路面結(jié)構(gòu)設(shè)計(jì)的初步研究。1 農(nóng)村道路交通組成 農(nóng)村道路包括縣公路、城市道路和村的道路。 農(nóng)村道路上，交通通常是喜憂參半。一個(gè)平?？h的道路，交通量平均為的300至1500輛/ 天；一個(gè)經(jīng)濟(jì)發(fā)達(dá)的縣,已經(jīng)達(dá)到了1000到2000 輛/ 天。通信量縣、鎮(zhèn)之間是100到300輛/ 天，交通量之間通常低于城鎮(zhèn)是100至300輛/ 天。在一個(gè)混合交通流、卡車占有40%到70%的交通量,主要為輕型卡車攜帶小于2.5噸(包括農(nóng)業(yè)車輛如拖拉機(jī)等)、行走、中型卡車2.5 - 5噸。大部分的輕或中等卡車超載。重型卡車

56、的比例小于9%。某些道路上的比例對(duì)縣、超載的卡車是5%至32%,而在一些縣公路連接到國(guó)家或省級(jí)公路的比例軀干,超載的比例通常數(shù)量的20%提高到32%。 交通量對(duì)農(nóng)村道路不會(huì)很重。然而,考慮到中國(guó)的實(shí)際情況,以及車輛超載,要滿足 100 kn,和 bzz-100標(biāo)準(zhǔn)軸載作用次數(shù)。人行道撓度和底部的拉應(yīng)力作為瀝青路面設(shè)計(jì)參數(shù)。軸載荷計(jì)算方式,依照下面的公式:pi和ni為車軸重量和頻率ns和ps為總車軸重量和頻數(shù)如果兩軸之間的距離小于3米,軸載荷進(jìn)行了計(jì)算：c1=1+1.2m-1如果彎拉型壓力的半剛性基層底部作為設(shè)計(jì)參數(shù)計(jì)算、軸重依下列公式：nsni=c1c2pips8如果兩軸之間的距離小于3米：c

57、1=1+2(m-1)2 對(duì)農(nóng)村公路交通量 農(nóng)村道路以面包車為車輛的設(shè)計(jì)標(biāo)準(zhǔn)。表1顯示了其外部尺寸。典型的車輛類型農(nóng)村道路都列在表2。如電動(dòng)車,摩托車 和自行車可以考慮為邊對(duì)農(nóng)村道路交通量的計(jì)算的路邊干擾。根據(jù)交通組成和卷,農(nóng)村道路被分成5個(gè)等級(jí)。每一等級(jí)通信量見表3。交通量在表3規(guī)定經(jīng)以小巴為標(biāo)準(zhǔn)的車輛類型,并將不同類型車輛的車輛折算系數(shù)記錄在所給的表2，表3中,ne指的是累積的等效軸重行動(dòng)的頻率ns指的等效軸重行動(dòng)的頻率在設(shè)計(jì)交通車道上開始運(yùn)行期間;r指的年增長(zhǎng)率交通量指系數(shù),一個(gè)車道為為1.0,雙車道為0.6一0.7。3路基強(qiáng)度路基回彈模量的變化極大。為方便起見,路基的強(qiáng)度可以分為四類根據(jù)

58、其含水率和模量的韌性,顯示在表4。表5的參數(shù)確定設(shè)計(jì)原則相結(jié)合的實(shí)踐經(jīng)驗(yàn)。采用多層彈性理論對(duì)路面結(jié)構(gòu)表5中指定的影響,在暗夜精靈,農(nóng)村道路鋪裝厚度進(jìn)行了分析,結(jié)果表明,在給定的h,h2,e0、路面基層厚度變化為周邊交通類一個(gè)范圍內(nèi)的4 - 5厘米。測(cè)試結(jié)果表明,該分類農(nóng)村道路運(yùn)輸量對(duì)顯示在表3是合理的、可行的設(shè)計(jì)和施工條件對(duì)瀝青路面結(jié)構(gòu)。采用多層彈性理論,瀝青路面結(jié)構(gòu)的普通鄉(xiāng)村公路表5中進(jìn)行了分析。當(dāng)北東向、累積的等效軸重行動(dòng)頻率,路面的厚度(h = 3厘米的厚度)、基層(h2 = 20厘米)保持不變,鄰近的路基強(qiáng)度的影響分類基層的厚度為3 cm一5厘米。這一結(jié)論表明,路基強(qiáng)度分類是合理的、適用于設(shè)計(jì)與施工的瀝青路面結(jié)構(gòu)。4厚度測(cè)定瀝青路面結(jié)構(gòu)設(shè)計(jì)參數(shù)的靈敏度分析路基和路面結(jié)構(gòu)之