二級(jí)公路設(shè)計(jì)專業(yè)外文翻譯-公路隧道-wenkub
2023-05-19 17:20:05 本頁(yè)面
【正文】 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 super elevation along the spiral, a smooth and gradual application of centrifugal force can be had and the roughness avoided. 河南理工大學(xué)本科畢業(yè)設(shè)計(jì) 專業(yè)外文翻譯 3 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。 本科畢業(yè)設(shè)計(jì)（ 論文） 專業(yè)名稱 ： 土木工程 專業(yè) （ 道路與橋梁 ） 年級(jí)班級(jí)： 道橋 085 班 學(xué)生姓名： 宋鵬 指導(dǎo)教師： 廖明成 河南理工大學(xué) 土木 工程學(xué)院 二 ○ 一二年五 月十 八 日 專業(yè)外文翻譯 河南理工大學(xué)本科畢業(yè)設(shè)計(jì) 專業(yè)外文翻譯 1 Geometric Design of Highways The road is one kind of linear construction used for travel. It is made of the roadbed, the road surface, the bridge, the culvert and the tunnel. In addition, it also has the crossing of lines, the protective project and the traffic engineering and the route facility. The roadbed is the base of road surface, road shoulder, side slope, side ditch foundations. It is stone material structure, which is designed according to route39。 hence the decision regarding their use should be made before the final location survey. They point of beginning of an ordinary circular curve is usually labeled the PC (point of curve) or BC (beginning of curve). Its end is marked the PT (point of tangent) or EC (end of curve). For curves that include easements, the mon notation is, as stationing increases: TS (tangent to spiral), SC (spiral to circular curve), CS (circular curve to spiral), and ST (spiral go tangent). On twolane pavements provision of a wilder roadway is advisable on sharp curves. This will allow for such factors as (1) the tendency for drivers to shy away from the pavement edge, (2) increased effective transverse vehicle width because the front and rear wheels do not track, and (3) added width because of the slanted position of the front of the vehicle to the roadway centerline. For 24ft roadways, the added width is so small that it can be neglected. Only for 30mph design speeds and curves sharper than 22176。它是由路基、路面、橋梁、涵洞和隧道 組成。路基作為行車部分的基礎(chǔ)，必須保證 它 有足夠的強(qiáng)度和穩(wěn)定性， 可以 防止水及其他自然災(zāi)害的侵蝕。路面質(zhì)量的好環(huán)，直接影響到行車的安全性、舒適性和 通行 ?，F(xiàn)代設(shè)計(jì)時(shí)常在直線與圓曲線之間插入緩和曲線。然而，雙向道路線形全由曲線構(gòu)成也是不理想的，因?yàn)橐恍{駛員通過(guò)曲線路段時(shí)總是猶豫。 行駛在曲線路段上的車輛受到離心力的 作 用，就需要一個(gè)大小相同方向相反的由超高和側(cè)向磨擦提供的力抵消它 ，這些控制值對(duì)于某一規(guī)定設(shè)計(jì)車速可能采用曲線的曲率作了限制。通常的做法是維持道路每一條中線設(shè)計(jì)標(biāo)高不變，通過(guò)抬 高外側(cè)邊緣，降低內(nèi)側(cè)邊緣以形成 所需的 超高，對(duì)于直線與圓曲線直接相連的線形，超高應(yīng)從未到達(dá)曲線之前的直線上開(kāi)始，在曲線頂點(diǎn)另一端一定距離以外達(dá)到全部超高。由于剩余超高發(fā)揮作用，乘客須作進(jìn)一步的姿勢(shì) 的調(diào)整 。火車必須遵循精確的運(yùn)行軌道，采用緩和曲線后，上述那種不舒服的感覺(jué)才能消除。 主要是出于安全原因 ，公路部門(mén)廣泛采用了 緩和曲線。對(duì)于雙向道路，急彎處應(yīng)增加路面寬度，這主要基于以下因素：（ 1）駕駛員害怕駛出路面邊緣；（ 2）由于車輛前輪和后輪的行駛軌跡不同，車輛有效橫向?qū)挾燃哟?；?3）車輛前方相對(duì)于公路中線傾斜而增加的寬度。豎向線形由直線和豎向拋物線或圓曲線組成，稱為縱坡線。在山區(qū) ，坡度要使得挖填平衡以使總成本最低。 由上坡向下坡變化的路段應(yīng)設(shè)在挖
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