《公路线形设计》外文文献(中英对照)

外文文献翻译

（含：英文原文及中文译文）

文献出处：Y Hassan. Geometric Design of Highways[J] Advance s in Transportation Studies, 2016, 6(1):31-41.

英文原文

Geometric De s ign of Highway s

YHassan

A.Alignment De s i gn

The alignment of a road is shown on the plane view and is a s erie s of straight line s called tangen ts connected by circular curve s. In modem practice it is common to interpo s e tran s ition or s piral curve s between tangent s and circular curve s.

The line s hape should be continuou s, s udden changes from flat line to small radiu s curve or s udden change of long line end connected to s mall radius curve s hould be a v oided, otherwise a traffic accident may occur. Similarly, arc s with different radii end-to-end (complex curves) or s hort straight line s between two arcs with different radii are bad line s unle ss an easing curve is in s erted between arcs. The long, s mooth curve is alwa ys a good line becau s e it is beaut 血lly lined and will not be abandoned in the future. However, it is not ideal that the two-way road line s hape is compo s ed entirely of curve s, becau s e s ome driver s alway s he s itate to pas s through curved road s egment s. The long and s low curve is used in the

smaller comer s. If you u s e a s hort curve, you will s ee "kinks." In addition, the de s ign of the flat and v ertical s ections of the line s hould be con s idered comprehen s ively and s hould not be only one. No matter which, for example, when the s tarting point of the flat curve is near the vertex of the vertical curve, s eriou s traffic accident s will o ccur.

Vehicle s driving on curved s ection s are s ubjected to centrifugal force, and they need a force of the s ame magnitude in the oppo s ite direction due to the height and lateral friction to off s et it. From the viewpoint of highway de s ign, the high or horizontal friction cannot exceed a certain v alue. The

m 邸imum, the s e control v alues for a certain design s peed may limit the curvature of the curve. In generai the curvature of a c 订c u lar curve is repre s ented by it s radius. For the linear de s ign, the curvature is often de s cribed by the curvature, ie, the central angle corre s ponding to the 100-foot curve, which is in v er s ely proportional to the radiu s of the curve.

A normal road arch is s et in a s traight s ection of the road, and the curve section is s et to a super high, and an exces s i v ely gradual road s ection must be s et between the norn 叫s ection and the s uper high s ection. The usual practice is to maintain the de s ign elevation of each midline of the road unchanged.

B y raising the outer edge and lowering the inner edge to form a s uper high, for the line s hape where the s traight line is d 汀ec tly connected with the c 虹le curve, the s uper high s hould ne v er s tart on the straight line before reaching the curve. At the other end of the curve at a