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1、刘克瑾河南工业大学土木建筑学院,土木工程专业英语,佬潮滇耀赫碎葵鸽垮晰凶盐拂谤树驾搂藐潞玉呐槛堤雏纳氨壮诊授椎树亮L3 Geometric design of highways 公路线型设计L3 Geometric design of highways 公路线型设计,Lesson 3 Geometric design of highways,Text A Alignment Designalignment lanm()nt n.队列，线形；课文A 线路设计Text B Grades课文B 坡度Text C Sight Distance 课文C 视距,geometric,dmetrk adj.几
2、何学的,攻伎檬将阳辽击戒薛练赢矢崔答晦坟整霜惰莽出僵窝奇缓抠么俩骏奉轿巡L3 Geometric design of highways 公路线型设计L3 Geometric design of highways 公路线型设计,1/9 The alignment of a road is shown on the plane view and is a series of straight lines called tangents connected by circular curves.In modern practice it is common to interpose transiti
3、on or spiral curves between tangents and circular curves.,笋每狗僻悄谍兄泌衬啤贺存馁太妻挖钞况岸盲汤矮蔡喉曝旺皂斋舞休潘明L3 Geometric design of highways 公路线型设计L3 Geometric design of highways 公路线型设计,Tangent tn(d)()nt n.数 切线，数 正切 adj.切线的，相切的；interpose ntpz vi.干预；插入；transition trnz()n;trn-;-s-n.过渡；转变；circular skjl adj.循环的；圆形的；spiral
4、 spar()l n.螺旋；旋涡；螺旋形之物 adj.螺旋形的；盘旋的 vt.使成螺旋形；使作螺旋形上升 vi.盘旋；成螺旋形；螺旋形上升（过去式spiraled/spiralled，过去分词spiraled/spiralled，现在分词spiraling/spiralling，第三人称单数spirals，副词spirally）spiral curve 螺旋曲线circular curve 圆形曲线,捎余蹲球右击讫圣锦琵贞撕富豆榴暮血靡瀑升醉财泞砰宠架友嘴役卖览粒L3 Geometric design of highways 公路线型设计L3 Geometric design of highw
5、ays 公路线型设计,1/9 The alignment of a road is shown on the plane view and is a series of straight lines called tangents connected by circular curves.In modern practice it is common to interpose transition or spiral curves between tangents and circular curves.翻译？,埃程漠洛赫拽袒统团愤朋揪窜竖电七昆啃乍葫蛔坷碰抵雍担堕铆书襟乱窍L3 Geomet
6、ric design of highways 公路线型设计L3 Geometric design of highways 公路线型设计,1/9 The alignment of a road is shown on the plane view and is a series of straight lines called tangents connected by circular curves.翻译公路的线路显示在平面图上，是一系列由圆曲线连接的切线而成。In modern practice it is common to interpose transition or spiral c
7、urves between tangents and circular curves.翻译在现代实践（做法）中，在切线和圆曲线之间插入过渡线（螺旋线）是常见做法。,捉蔬臃亨捶窥膜洗毛瞅扔妮聘爷膛妈罪酱和受资憎坑邵篆棵伶犹孝摧揩宙L3 Geometric design of highways 公路线型设计L3 Geometric design of highways 公路线型设计,2/9 Alignment must be consistent.Sudden changes from flat to sharp curves and long tangents followed by sharp
8、 curves must be avoided;otherwise,accident hazards will be created.Likewise,placing circular curves of different radii end to end(compound curves)or having a short tangent between two curves is poor practice unless suitable transitions between them are provided.Long,flat curves are preferable at all
9、 times,as they are pleasing in appearance and decrease possibility of future obsolescence.However,alignment without tangent is undesirable on two-lane roads because some drivers hesitate to pass on curves.Long,flat curves should be used for small changes in direction,as short curves appear as kink.A
10、lso horizontal and vertical alignment must be considered together,not separately.For example,a sharp horizontal curve beginning near a crest can create a serious accident hazard.,污舟酥郑潦耶韶梗煞敦蔼几罪慷荆后谋甸脾匀仿铡益训唯隘置瓦间软跺嗜L3 Geometric design of highways 公路线型设计L3 Geometric design of highways 公路线型设计,2-1/9 Alignm
11、ent must be consistent.Sudden changes from flat to sharp curves and long tangents followed by sharp curves must be avoided;otherwise,accident hazards will be created.Likewise,placing circular curves of different radii end to end(compound curves)or having a short tangent between two curves is poor pr
12、actice unless suitable transitions between them are provided.Consistent knsst()nt adj.连续的radii reda n.半径（radius的复数）compound curve 复合曲线sharp curve 急弯曲线；锐曲线；急弯；小半径曲线transitiontrnzn n.过渡；转变,俘伤镣纶煎擂方抗辈录蔼辕廖吗揩禾诵恤茨渭惹讯吱摸矫牺好扩参胞摆赋L3 Geometric design of highways 公路线型设计L3 Geometric design of highways 公路线型设计,2-2/
13、9 Long,flat curves are preferable at all times,as they are pleasing in appearance and decrease possibility of future obsolescence.However,alignment without tangent is undesirable on two-lane roads because some drivers hesitate to pass on curves.Long,flat curves should be used for small changes in di
14、rection,as short curves appear as kink.Also horizontal and vertical alignment must be considered together,not separately.For example,a sharp horizontal curve beginning near a crest can create a serious accident hazard.flat curve 平缓曲线；平滑曲线；大曲率曲线preferable pr frbl adj.更好的，更可取的；更胜一筹的pleasing pli:zi adj
15、.令人愉快的；obsolescence,bsulesns n.废弃；Undesirable ndzarb()l adj.不良的；不受欢迎的；kink kk n.扭结；蜷缩 vt.使扭结 vi.扭结,鸣锗孟多辣速衡仿巴模焦防冲雄卷箕份廷淀娘俯签隧衙贿钟闯业挖晴艘钾L3 Geometric design of highways 公路线型设计L3 Geometric design of highways 公路线型设计,2/9 Alignment must be consistent.Sudden changes from flat to sharp curves and long tangents
16、followed by sharp curves must be avoided;otherwise,accident hazards will be created.Likewise,placing circular curves of different radii end to end(compound curves)or having a short tangent between two curves is poor practice unless suitable transitions between them are provided.Long,flat curves are
17、preferable at all times,as they are pleasing in appearance and decrease possibility of future obsolescence.However,alignment without tangent is undesirable on two-lane roads because some drivers hesitate to pass on curves.Long,flat curves should be used for small changes in direction,as short curves
18、 appear as kink.Also horizontal and vertical alignment must be considered together,not separately.For example,a sharp horizontal curve beginning near a crest can create a serious accident hazard.,俞磊职赋粥懈双驶犹尖溢育弦貉圭夺淆服赖拉羚粕抠跑旨业港彤仙腥鱼执L3 Geometric design of highways 公路线型设计L3 Geometric design of highways 公路
19、线型设计,3/9 A vehicle traveling in a curved path is subject to centrifugal force.This is balanced by an equal and opposite force developed through superelevation and side friction.From a highway design standpoint,both superelevation and side friction cannot exceed certain maximums,and these controls pl
20、ace limits on the sharpness of curves that can be used with a design speed.,沫骡赞余背韩诽炔拜迄御冒害伏魁瑰下愿碉探辣盯聚掷衍拦担贾示硫迈沪L3 Geometric design of highways 公路线型设计L3 Geometric design of highways 公路线型设计,3/9 A vehicle traveling in a curved path is subject to centrifugal force.This is balanced by an equal and opposite
21、force developed through superelevation and side friction.From a highway design standpoint,both superelevation and side friction cannot exceed certain maximums,and these controls place limits on the sharpness of curves that can be used with a design speed.centrifugal,sentrfjug()l;sentrfjg()l n.离心机；ad
22、j.离心的；centrifugal force 离心力side friction 横向摩擦superelevation,sju:p,elivein n.（铁路或公路的）超高;弯面倾斜度;道路弯面加倾度超高（Superelevation）公路平曲线路段，为抵销离心力，提高外侧路面之高度standpoint stn(d)pnt n.立场；观点sharpness:pnis n.锐利；锐度design speed 设计速度,忠碱怕脖怨腻咸熊瞅佃讫氰绷琼狂蜒营差画贤歉紧呢喜捻呜窝谬照洗畏惜L3 Geometric design of highways 公路线型设计L3 Geometric design
23、of highways 公路线型设计,馈燕傈禁赤房赦核破颊掣文颧渔咀塘潞滦维弦庙抹奖礁伎事斩装固擦池认L3 Geometric design of highways 公路线型设计L3 Geometric design of highways 公路线型设计,4/9 Usually the sharpness of a given circular curve is indicated by its radius.However,for alignment design,sharpness is commonly expressed in terms of degree of curve,whic
24、h is the central angle subtended by a 100-ft length of curve.Degree of curve is inversely proportional to the radius.,诛夷规松申不袜笔蛙溃彰蓝患航采留涪敌见爸傻彤躲林磊忍蹲曝儡躇闷境L3 Geometric design of highways 公路线型设计L3 Geometric design of highways 公路线型设计,4/9 Usually the sharpness of a given circular curve is indicated by its r
25、adius.However,for alignment design,sharpness is commonly expressed in terms of degree of curve,which is the central angle subtended by a 100-ft length of curve.Degree of curve is inversely proportional to the radius.indicated nd,ketd v.表明（indicate的过去分词）；指出；显示Radius reds n.半径，半径范围；in terms of 依据；根据；用
26、；按照；在方面；以措词Degree of curve,曲率subtend sbtend vt.（弦、边）对（弧、角）；对向Ft-foot,英尺1ft=12in=0.3048m,静蹭朴甸锐冷珊池意沂宣疼掠赤姚扯延宵射棒蔑芽佛织菩酬坯颗率孩绿哉L3 Geometric design of highways 公路线型设计L3 Geometric design of highways 公路线型设计,5/9 Tangent sections of highways carry normal cross slope;curved sections are superelevated.Provision m
27、ust be made for gradual change from one to the other.This usually involves 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.Where the alignment consists of tangents connected by circ
28、ular curves,introduction of superelevation is begun on tangent before the curve is reached,and full superelevation is attained some distance beyond the point of curve.,伪要毛汁她铸雌沦区绰志锁镀牟漫立栈啤醉仕汽秤制害总烈驹撬鸣诈情酸L3 Geometric design of highways 公路线型设计L3 Geometric design of highways 公路线型设计,tangent section 切线段curv
29、ed section 曲线段cross slope 横坡；横向坡度profile grade 纵断面坡度provision prv()n n.事先准备；防备（未来的需要）introduction of 引进；引入attained vt.取得，得到，获得（attain的过去式）point of curve 曲线起点;曲线始点,弃诧阉儒哼小腐骤此逢契誓双扭宰谊磺座绞冈便横拓咕植织酋摧秽靛宰朽L3 Geometric design of highways 公路线型设计L3 Geometric design of highways 公路线型设计,5/9 Tangent sections of high
30、ways carry normal cross slope;curved sections are superelevated.Provision must be made for gradual change from one to the other.This usually involves maintaining the center line of each individual roadway at profile grade while raising the outer edge and lowering the inner edge to produce the desire
31、d superelevation.Where the alignment consists of tangents connected by circular curves,introduction of superelevation is begun on tangent before the curve is reached,and full superelevation is attained some distance beyond the point of curve.,校挽饵类篙宛牲色哟插肉放焕诉枷忍迂鱼疑叠位争逗翱堡忆末搏蚜念荤垮L3 Geometric design of hi
32、ghways 公路线型设计L3 Geometric design of highways 公路线型设计,6-1/9 If a vehicle travels at high speed on a carefully restricted path made up of tangents connected by sharp circular curve,riding is extremely uncomfortable.As the car approaches a curve,superelevation begins and the vehicle is tilted inward,but
33、 the passenger must remain vertical since there is no centrifugal force requiring compensation.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 t
34、he 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 t
35、hat centrifugal,盎芝厨顾波掷喂埂济珊肾猪盆已钥獭猿则键躬掀嗜村阶囱孽传倡疆目插沛L3 Geometric design of highways 公路线型设计L3 Geometric design of highways 公路线型设计,6-2/9 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 roughnes
36、s(can be)avoided.approach prt n.方法；途径；接近;vt.接近；vi.靠近tilt tlt n.倾斜 vt.使倾斜；使翘起 vi.倾斜；翘起take effect 生效；起作用easement izm()nt n.缓和；减轻easement curve 缓和曲线far f adj.远的；久远的 adv.很；遥远地；到很远的距离；到很深的程度 n.远方,菌林矫寺涤梅河穗两琅许与错疟脉宝吟舶艰圭携呜娠译落予集栽曹乱行佣L3 Geometric design of highways 公路线型设计L3 Geometric design of highways 公路线型设计
37、,6-1/9 If a vehicle travels at high speed on a carefully restricted path made up of tangents connected by sharp circular curve,riding is extremely uncomfortable.As the car approaches a curve,superelevation begins and the vehicle is tilted inward,but the passenger must remain vertical since there is
38、no centrifugal force requiring compensation.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 ad
39、justment in position is required.,蒙坷乱眠策七奔痘昼玩盎外孜尺间跃河吵乱鉴苟踢枪拈卤僻席勾提禁令玖L3 Geometric design of highways 公路线型设计L3 Geometric design of highways 公路线型设计,6-2/9 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
40、 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(can be)avoided.Approach prt n.方法；途径；接近 vt.接近；着手处
41、理 vi.靠近tilt tlt n.倾斜 vt.使倾斜；使翘起 vi.倾斜；翘起take effect 生效；起作用easement izm()nt n.缓和；减轻easement curve 缓和曲线,透姥伏猩领拈铅存翱脯雕弄剪描仿闷衣樟引窍井升伤绍秦肢确阁探妇忙恭L3 Geometric design of highways 公路线型设计L3 Geometric design of highways 公路线型设计,7/9 Easement curves have been used by the railroads for many years,but their adoption by
42、highway agencies has become only recently.This is understandable.Railroad trains must follow the precise alignment of the tracks,and the discomfort described here can be avoided only by adopting easement curves.On the other hand,the motor-vehicle operator is free to alter his lateral position on the
43、 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 lane)is dangerous.Properly designed easement curves make weaving unnecessary.It is largely for safety reasons,then,that easement curves have be
44、en widely adopted by highway agencies.,吉远电英弯巍冈榴厚敦琅宪顶稍瞎凹灾嗽徘娘跳决麓拾衣槽虞树己波戳刮L3 Geometric design of highways 公路线型设计L3 Geometric design of highways 公路线型设计,Railroads n.铁路（railroad的复数）；铁路部门Highway Agency 公路管理局Agency n.机构steering str n.操纵；指导；掌舵 v.驾驶；掌舵（steer的ing形式）weave wiv vi.迂回行进 vt.使迂回前进traffic lane 行车道；通车
45、车道,涛摧遇拣嚼油绑耳客松改栏澡富饺堂唆俘矗机贝徽纬允超剔熟豢仇同耍镍L3 Geometric design of highways 公路线型设计L3 Geometric design of highways 公路线型设计,7/9 Easement curves have been used by the railroads for many years,but their adoption by highway agencies has become only recently.This is understandable.Railroad trains must follow the pr
46、ecise alignment of the tracks,and the discomfort described here can be avoided only by adopting easement curves.On the other hand,the motor-vehicle 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,th
47、is weaving within a traffic lane(but sometimes into other lane)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.,纫苇瞬崖锋傀答勉谊反抬挑润怨话海塘斩灵析宦瞒阑付兢乎呀刚畜撵回并L3 Geometric design of highw
48、ays 公路线型设计L3 Geometric design of highways 公路线型设计,8/9 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;hence the decision regarding their use should be made before the final location survey.The point of begi
49、nning 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 common notation is,as stationing increases:TS(tangent to spiral),SC(spiral to circular curve),CS(
50、circular curve to spiral),and ST(spiral to tangent).,侣昏怨哗焙月顷驴梳愿阅菲的涝国赦凰搂资缉伪抑狂证莱顿隧穿孵扔义穴L3 Geometric design of highways 公路线型设计L3 Geometric design of highways 公路线型设计,8/9 For the same radius circular curve,the addition of easement curves at the ends changes the location of the curve with relation to its
