1、 Overview The project is designed for a section of expressway in a certain area. The implementation of the project will play a positive role in driving the economic development of the area and facilitating the life of local people; It is also an important channel to connect the local and the outside world. The four lane expressway standard is adopted for the whole line: the calculated driving speed is 80 km/h, the subgrade width is 24.5 m, and the design load of bridges and culverts is highway Class I. The whole line of this section is 2.960 km long, with 50586.7 m3 of excavation, 27790.3 m3 of filling, m3 of protection works, m3 of pavement, 1 bridge of 252 meters, 5 culverts, 1 interchange, covering an area of 235.4 mu. The whole line is equipped with supporting traffic works and facilities along the line. The total budget is 55.928844 million yuan, with an average of 18.89488 million yuan per kilometer. 2、 Route 1. Horizontal alignment design The basic idea of the horizontal alignment design of the project is to deal with the intersection relationship between the expressway and local roads, so that the route is consistent with the existing landscape; Deal with the relationship between expressway and local reservoir, pay attention to the selection of route location and reservoir location, and coordinate the route landscape and flood control; Deal with the relationship between the route location and the local towns, so that the construction of the expressway can more conveniently serve the local economy; Dealing with the relationship between the interchange and the upper and lower expressways is more convenient for the masses and reduces the interference of demolition. The whole line is dominated by curves, which greatly conforms to the terrain conditions and meets the layout of large-scale planning projects; Grasp the linear indicators flexibly, so that they are not only larger than the low limit value of the standard, but also not demanding high indicators; The technical indicators of adjacent curves shall be continuous and balanced to ensure the safety and comfort of driving. There are 3 intersections in this section. The radius of the horizontal curve is between 410 and 500. The curves are arranged in accordance with the hillside. Transition curves are set according to the requirements of Technical Standards for Highway Engineering, and the minimum length of transition curve is 150 meters. The minimum radius of horizontal curve of the whole line is 410m, and there is one horizontal curve in total, and the maximum radius is 500m, and there is one horizontal curve in total. The minimum straight line length between curves is 160m. 2. Vertical section alignment design The basic idea of the vertical section alignment design of this section is: in the vertical section design, in line with the design concept of protecting the natural environment, try to make the route conform to the ups and downs of the natural terrain; Fully consider the intersection relationship with local roads in the longitudinal plane, and properly handle the relationship between the upper span and the lower crossing; The filling height of subgrade shall be controlled as far as possible to reduce the land occupied by demolition; The location and elevation of grade change point, grade rate and grade length shall be optimized under the condition of meeting the horizontal and vertical combination, and the radius of vertical curve shall be as large as possible. The maximum longitudinal slope of this section is 2.3%, the minimum longitudinal slope is 0.35%, and the minimum slope length is 200m. Among the six vertical curves, three are convex, with a minimum radius of 7000 meters, which is greater than the general minimum value of 4500 meters specified in the Technical Standards for Highway Engineering; Three are concave, with a minimum radius of 4500, which is 3000 meters higher than the general minimum value specified in the Technical Standards for Highway Engineering.
