Reseach On The Geometric Problems In Road Cross-sectional Design

With the rapid development of the national economy and the gradually acceleratepace of highway construction, road survey and design industry has made a thrivingdevelopment, while there have been also some new changes, such as significantly shortendesign cycles, increased number of conditions that the road interfere with each other andso on. In case of a single line, there is a relatively mature method to design the road’scross-section. However, in the condition of a number of design lines interfere with eachother, there is no uniform and reliable method in the industry. It is difficult to achieveparallel cross-sectional design automatically, which is greatly affect the efficiency ofhighway’s design; addition, In order to arrange the cross-sectional drawings morereasonable to facilitate browsing, it is necessary to arrange them automatically whileoutputting the drawings. In this paper, cross-sectional design of parallel lines andcross-section drawing’s arrangement, the two typical geometric problems are researcheddeeply.A method for parallel cross-sectional design with error consistency is proposed. First,calculate the cross points of all stakes, which is interfere with others, on the main designlines; then, calculate the cross points of the stakes on the second line by intersecting withthe main line’s cross line; finally, calculated geometric shape of the parallel cross-sectionswith different slope changing strategies.A technology for cross-sectional drawing automatic typesetting is proposed. Breakingthe traditional methods based on the bounding box to limit the layout, and making full useof the highway section view expressed only cross-sectional shape of the outer contour witha small number and simple type of lines, the geometric position of each cross-section iscalculated according to intersection line element in the adjacent cross-section drawings.The two geometric problems discussed in the paper are successful applied to developthe new generation of commercial highway CAD system, which has been used in the large highway projects and been widely praised by the road designers.