【正文】
olves maintaining the center line of each individual roadway at profile grade while raising the outer edge and lowering the inner edge to produce the desired superelevation is attained some distance beyond the point of curve. If a vehicle travels at high speed on a carefully restricted path made up of tangents connected by sharp circular curve, riding is extremely unfortable. As the car approaches a curve, superelevation begins and the vehicle is tilted inward, but the passenger must remain vertical since there is on centrifugal force requiring pensation. When the vehicle reaches the curve, full centrifugal force develops at once, and pulls the rider outward from his vertical position. To achieve a position of equilibrium he must force his body far inward. As the remaining superelevation takes effect, further adjustment in position is required. This process is repeated in reverse order as the vehicle leaves the curve. When easement curves are introduced, the change in radius from infinity on the tangent to that of the circular curve is effected gradually so that centrifugal force also develops gradually. By careful application of superelevation along the spiral, a smooth and gradual application of centrifugal force can be had and the roughness avoided. Easement curves have been used by the railroads for many years, but their adoption by highway agencies has e only recently. This is understandable. Railroad trains must follow the precise alignment of the tracks, and the disfort described here can be avoided only by adopting easement curves. On the other hand, the motorvehicle operator is free to alter his lateral position on the road and can provide his own easement curves by steering into circular curves gradually. However, this weaving within a traffic lane (but sometimes into other lanes) is dangerous. Properly designed easement curves make weaving unnecessary. It is largely for safety reasons, then, that easement curves have been widely adopted by highway agencies. For the same radius circular curve, the addition of easement curves at the ends changes the location of the curve with relation to its tangents。D302004[S].人民交通出版社,2004[20][S].人民交通出版社,2006[21] . 北京:中國建材工業(yè)出版社,2003[22] Goddard, system ,1991[23] mittee Report on surface Word Road Congress Montreal,1995[24] Jacobs M M J,De bont A H,Molenaar A A A, in asphalt concrete pavements[C] [M].Proc 7th Int Conf on Asphalt Pavements,199276外文資料翻譯Geometric Design of HighwaysA Alignment Design The alignment of a road is shown on the plane view and is a series of straight lines called tangents connected by circular. In modern practice it is mon to interpose transition or spiral curves between tangents and circular curves. Alignment must be consistent. Sudden changes from flat to sharp curves and long tangents followed by sharp curves must be avoided。同時,也難以忘記,那段日子:每天白天去實(shí)習(xí),晚上回來借同學(xué)電腦做畢業(yè)設(shè)計(jì)的日子。謝 辭畢業(yè)是終點(diǎn),也是起點(diǎn),歷經(jīng)五個月的時間,在這個離別氣息凝重的季節(jié),我的畢業(yè)論文總算定稿了,在指導(dǎo)老師的幫助和包容下終于基本完成了。 結(jié) 論本次畢業(yè)設(shè)計(jì)的目的在于培養(yǎng)我們綜合應(yīng)用所學(xué)知識的能力,是對各個教學(xué)階段的繼續(xù)、深化、拓寬和升華。故:石灰土:故 查三層體系上層底面拉應(yīng)力系數(shù)諾謨圖,得:故:上述計(jì)算結(jié)果滿足設(shè)計(jì)要求。 —— 瀝青混凝土或半剛性材料的極限抗拉強(qiáng)度(MPa); —— 抗拉強(qiáng)度結(jié)構(gòu)系數(shù)。表53 軸載換算結(jié)果匯總表車型(次/日)(次/日)東風(fēng)EQ140后軸111470三湘ck6640后軸112517黃海DD680前軸4911510后軸11510解放sp9200后軸7851510合計(jì): (3)設(shè)計(jì)年限累計(jì)當(dāng)量標(biāo)準(zhǔn)軸載數(shù)設(shè)計(jì)年限內(nèi)一個車道通過的累計(jì)當(dāng)量標(biāo)準(zhǔn)軸次數(shù)按下式計(jì)算:式中:——設(shè)計(jì)年限內(nèi)一個車道通過的累計(jì)標(biāo)準(zhǔn)當(dāng)量軸次(次)——設(shè)計(jì)年限(年),——路面營運(yùn)第一年雙向日平均當(dāng)量軸次(次/日)——設(shè)計(jì)年限內(nèi)交通量平均增長率(%),——與車道數(shù)有關(guān)的車輛橫向分布系數(shù),1)當(dāng)以設(shè)計(jì)彎沉為指標(biāo)及驗(yàn)算瀝青層層底拉應(yīng)力時:2)當(dāng)以半剛性材料結(jié)構(gòu)層的層底拉應(yīng)力為設(shè)計(jì)指標(biāo)時: 結(jié)構(gòu)一:半剛性基層瀝青路面4cm細(xì)粒式瀝青混凝土 + 6cm中粒式瀝青混凝土 + 7cm粗粒式瀝青混凝土 + 22cm水泥穩(wěn)定碎石 基層+ ?二灰土底基層,以二灰土為設(shè)計(jì)層。2) 在跨越排水溝槽出、通過農(nóng)田排灌去到處、平原區(qū)路線通過較長的低洼或泥沼地帶、傍山或沿溪路線暴雨時徑流易集中地帶以及邊溝排水需要時,均要設(shè)置涵洞。 土石方數(shù)量計(jì)算及調(diào)配(1) 土石方數(shù)量計(jì)算 橫斷面面積計(jì)算:橫斷面上各轉(zhuǎn)折點(diǎn)坐標(biāo)(),則斷面面積為: 土石方數(shù)量計(jì)算: 式中 V— 體積,即土石方數(shù)量 —分別為相鄰兩斷面的面積 L—相鄰斷面之間的距離土石方數(shù)量表見附表。查《規(guī)范》得知,當(dāng)路基填土高度小于6m時,路基邊坡按1:。2) 豎曲線幾何元素計(jì)算變坡點(diǎn)樁號為K0+,兩相鄰路段的縱坡為= % ,= %,豎曲線半徑R=19000m① 計(jì)算豎曲線要素=-() = ,為凹形。然后進(jìn)行計(jì)算,看拉的坡滿不滿足控制點(diǎn)的高程和規(guī)范要求,如不滿足時就進(jìn)行調(diào)坡。 縱坡設(shè)計(jì)(1) 縱坡設(shè)計(jì)的一般要求 1) 縱坡設(shè)計(jì)必須滿足《標(biāo)準(zhǔn)》的有關(guān)規(guī)定,除特殊條件一般不采用使用極限值。其它交點(diǎn)的計(jì)算結(jié)果見“直線、曲線及轉(zhuǎn)角表”。缺點(diǎn): 路線不夠優(yōu)美,平曲線半徑太小,幾乎接近最小半徑,使得路線與周圍環(huán)境不協(xié)調(diào);選擇路線大部分是占用農(nóng)田,地勢平緩,不利于道路的排水;比選路線要經(jīng)過一片水塘,地質(zhì)狀況不好,還需要進(jìn)行地質(zhì)處理,導(dǎo)致建設(shè)經(jīng)費(fèi)增加。正線方案正是考慮到線形設(shè)計(jì)的重要性,結(jié)合水文地質(zhì)等因素,做出的正確選擇。雙向四車道一級公路應(yīng)能適應(yīng)將各種汽車折合成小客車的年平均日交通量為15000—30000輛。(7) 豎曲線最小長度為70m。 3)標(biāo)準(zhǔn)軸載:BZZ100 4)設(shè)計(jì)交通量:折合小客車年平均日交通量,交通量年增長率6 %北京BJ130 1470東風(fēng)EQ140 2517三湘CK6640 3037黃海DD680 510解放SP9200 510 設(shè)計(jì)依據(jù)《路基路面工程》.《公路勘測設(shè)計(jì)》.《公路工程技術(shù)標(biāo)準(zhǔn)》(JTG B012003).人民交通出版社,2004.《公路路線設(shè)計(jì)規(guī)范》(JTG D202006).人民交通出版社,2008.《公路瀝青路面設(shè)計(jì)規(guī)范》(JTG D502006).人民交通出版社,2007.《公路工程路基設(shè)計(jì)規(guī)范》(JTG D302004).人民交通出版社,2004.《公路小橋涵手冊》(JTG D502006).人民交通出版社,2007. 設(shè)計(jì)任務(wù)及主要內(nèi)容 設(shè)計(jì)任務(wù)(1) 路線選線和路線方案的比選,確定總體路線較優(yōu)方案。地形對工程施工和材料運(yùn)輸影響不大。項(xiàng)目的建成后必能對當(dāng)?shù)芈糜钨Y源開發(fā)、城鎮(zhèn)經(jīng)濟(jì)發(fā)展起到積極的促進(jìn)作用;該公路的建設(shè),在給人們旅游帶來很大便利的同時,更帶動了沿線優(yōu)勢產(chǎn)業(yè)發(fā)展,對當(dāng)?shù)鼐C合實(shí)力的提升有著非常重要的意義。 設(shè)計(jì)成果 該路段為偃師顧縣至黃蟒崖段公路,路線起點(diǎn)為K0+000,路線終點(diǎn)為K3+。第一部分是緒論,是對沿線氣象、地質(zhì)等的綜合概述;第二部分是總路線設(shè)計(jì),目的是根據(jù)所給資料,確定本次設(shè)計(jì)的任務(wù)以及主要內(nèi)容,并根據(jù)年平均日交通量,確定公路等級和車道數(shù)量;第三部分是路線設(shè)計(jì),包括平面設(shè)計(jì)、縱斷設(shè)計(jì)和橫斷設(shè)計(jì);第四部分是路基路面設(shè)計(jì);第五部分是結(jié)論、謝詞、參考文獻(xiàn)以及外文翻譯。以各類現(xiàn)行規(guī)范為主,結(jié)合各地區(qū)地形條件、氣候條件和地質(zhì)條件綜合考慮進(jìn)行開放式設(shè)計(jì),是我國道路設(shè)計(jì)工作者普遍采用的方法。降水多集中在每年的9三個月份。全長共設(shè)置了兩個平曲線,半徑分別是1000m和2000m;四個豎曲線,半徑分別為19000m、10000m、22000m和15000m。降水多集中在每年的9三個月份。砂石料、石灰、粉煤灰等地材均來源于當(dāng)?shù)?,料源分布廣,儲量豐富。(2) 一般平曲線最小半徑為400m,極限平曲線最小半徑為250m,不設(shè)超高的最小半徑為2500m。根據(jù)標(biāo)準(zhǔn)和下表所述折算系數(shù),折算交通量。路線也應(yīng)與地形相適應(yīng)。從縱斷面上來看,道路起伏不大。2) 兩圓曲線間以直線徑相連接時,直線的長度不宜過短; 《標(biāo)準(zhǔn)》規(guī)定,設(shè)計(jì)速度大于或等于60Km/h時,同向圓曲線間最小直線長度(以m計(jì))以不小于6V(以Km/h計(jì))為宜。2) 設(shè)緩和曲線的單曲線中樁坐標(biāo)計(jì)算ZH ~ HY任意點(diǎn)坐標(biāo):X =Y =式中 L — 緩和曲線上任意點(diǎn)至ZH點(diǎn)的曲線長度 x — 緩和曲線上任意點(diǎn)的切線橫距 x = ……— 轉(zhuǎn)角符號,右轉(zhuǎn)為“+”,左轉(zhuǎn)為“”,下同。(2) 坡長限制 1) 最短坡長的限制,主要是從汽車行駛平順性的要求考慮的。當(dāng)設(shè)計(jì)速度為80Km/h時,凸豎曲線一般最小半徑為4500m,極限最小半徑為3000m;凹型豎曲線一般最小半徑為3000m,極限最小半徑凸型為2000m;豎曲線最小長度為70m。 第4章 道路橫斷面設(shè)計(jì)和路基結(jié)構(gòu)設(shè)計(jì) 道路橫斷面組成一級公路的橫斷面組成主要包括:行車道、中間帶、路肩、邊坡、排水設(shè)施等。加寬值bx按加寬計(jì)算公式計(jì)算=Lc時,為圓曲線上的超高值D0內(nèi)側(cè)D0C表中 C—外側(cè)路緣帶邊緣 D—中央分隔帶邊緣—左側(cè)路緣