土木工程 建筑 道橋 外文翻譯 外文文獻 英文文獻 瀝青路面結構設計的低成本農村道路

1、外文文獻 structural design of asphalt pavement for low cost rural roadsyuan goulin(袁國林)12 chen rongshen(陳榮生)1. college of transportation, southeast university, nanjing 210b9b, china2. college of civil engineering, nanjing university of technology, nanjing 210009, china in developing countries，rural road

2、 construction 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 i

3、s very 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.

4、 at the 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

5、 roads 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

6、 structure 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 wi

7、th a developed 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

8、 carrying 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 overl

9、oaded 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

10、 of overloaded 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 we

11、ight of 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

12、 semi-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.

13、table 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-

14、drawn 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. tra

15、ffic volume 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 e

16、quivalent 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 re

17、silience 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

18、 elastic 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 th

19、at the 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

20、cumulative 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 cla

21、ssification 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 struc

22、tural 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 st

23、ructure 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 structu

24、re are 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 d

25、eflection，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 incr

26、eases，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 t

27、hickness 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

28、 deflection.(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 mod

29、ulus of 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 conclu

30、de that 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 shoul

31、d be used 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 t

32、he equivalent 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

33、 stones(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

34、 capacity 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

35、by vertical 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 o

36、f the 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

37、not only 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 desig

38、n of lowcost 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 ar

39、e all 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-mu

40、las for 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

41、 roadbase 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 o

42、f the 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=0.35ne0.1

43、1ac,ac=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 acco

44、rding 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 500000 times per lane，asphalttreated or asphalt penetrated surfaces with thickness of 1. 5 cm一cm is recommended f

45、or road surface. 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 thickne

46、ss of 3 cm -5 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 c

47、m-7 cm thick 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 m

48、pa , eo is the 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 fo

49、ur layers，i.e. 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 remark

50、s compared with 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 guidel

51、ine for the design 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.

52、 final report 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).

53、 4 jtg b014-97. 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構設計的低

54、成本農村道路袁國林1，陳榮生21。交通運輸學院，東南大學，南京210b9b，中國2。土木工程學院，南京工業(yè)大學，南京210009，中國在發(fā)展中國家,農村道路建設主要是因缺乏資金而受阻。工程師最關心的農村問題是如何修建的公路不僅成本低,而且滿足交通需求。特別是在廣大農村地區(qū),有各種各樣的交通方式,交通成分非常復雜。與其他國家相比,在中國農村地區(qū)交通組成有其自身的特征. 因此,沒有足夠經(jīng)驗對農村公路建設提供參考依據(jù)。近年來,中國的中央政府增加了對農村公路建設的力量。與此同時, 在中國，研究人員已經(jīng)完成了關于中國農村道路的大量研究和一些結論。在作者的觀點,選擇不同的路面結構材料是關鍵措施，從而降低農

55、村道路的工程造價。相比,瀝青混凝土路面相對費用少、是第一個在中國農村道路的選擇。然后,根據(jù)農村道路建設研究成果,作者也做了一些對低成本瀝青路面結構設計的初步研究。1 農村道路交通組成 農村道路包括縣公路、城市道路和村的道路。 農村道路上，交通通常是喜憂參半。一個平?？h的道路，交通量平均為的300至1500輛/ 天；一個經(jīng)濟發(fā)達的縣,已經(jīng)達到了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(包括農業(yè)車輛如拖拉機等)、行走、中型卡車2.5 - 5

56、噸。大部分的輕或中等卡車超載。重型卡車的比例小于9%。某些道路上的比例對縣、超載的卡車是5%至32%,而在一些縣公路連接到國家或省級公路的比例軀干,超載的比例通常數(shù)量的20%提高到32%。 交通量對農村道路不會很重。然而,考慮到中國的實際情況,以及車輛超載,要滿足 100 kn,和 bzz-100標準軸載作用次數(shù)。人行道撓度和底部的拉應力作為瀝青路面設計參數(shù)。軸載荷計算方式,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,軸載荷進行了計算：c1=1+1.2m-1如果彎拉型壓力的半剛性基層底部作為設計參數(shù)計算、軸重依下列公式：nsni=c1c2p

57、ips8如果兩軸之間的距離小于3米：c1=1+2(m-1)2 對農村公路交通量 農村道路以面包車為車輛的設計標準。表1顯示了其外部尺寸。典型的車輛類型農村道路都列在表2。如電動車,摩托車 和自行車可以考慮為邊對農村道路交通量的計算的路邊干擾。根據(jù)交通組成和卷,農村道路被分成5個等級。每一等級通信量見表3。交通量在表3規(guī)定經(jīng)以小巴為標準的車輛類型,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的頻率ns指的等效軸重行動的頻率在設計交通車道上開始運行期間;r指的年增長率交通量指系數(shù),一個車道為為1.0,雙車道為0.6一0.7。3路基強度路基回彈模量的變化極大。

58、為方便起見,路基的強度可以分為四類根據(jù)其含水率和模量的韌性,顯示在表4。表5的參數(shù)確定設計原則相結合的實踐經(jīng)驗。采用多層彈性理論對路面結構表5中指定的影響,在暗夜精靈,農村道路鋪裝厚度進行了分析,結果表明,在給定的h,h2,e0、路面基層厚度變化為周邊交通類一個范圍內的4 - 5厘米。測試結果表明,該分類農村道路運輸量對顯示在表3是合理的、可行的設計和施工條件對瀝青路面結構。采用多層彈性理論,瀝青路面結構的普通鄉(xiāng)村公路表5中進行了分析。當北東向、累積的等效軸重行動頻率,路面的厚度(h = 3厘米的厚度)、基層(h2 = 20厘米)保持不變,鄰近的路基強度的影響分類基層的厚度為3 cm一5厘米。這一結論表明,路基強度分類是合理的、適用于設計與施工的瀝青路面結構。4厚度測定瀝青路面結構設計