Determination and construction of subgrade slope protection type
The total length of an expressway is 147km. The whole line is designed according to the standard of four lane expressway in mountainous areas, with a design speed of 60km/h and a subgrade width of 22.5m. An expressway crosses Ailao Mountain and Wuliang Mountain in Hengduan Mountains. The mountains along the expressway are undulating, with high mountains and deep valleys, steep terrain and criss crossing valleys. Due to the constraints of alignment, longitudinal slope and other aspects, there are many high fill and deep cut subgrades, of which only the 13th contract section has a vertical height of more than 60m. There are more than 10 high slopes; In addition, it is located in the fold fault zone, and the mountain is broken with poor stability. Therefore, if the reinforcement and protection measures for various slopes are not effective, it will lead to various slope diseases. Therefore, it is very important to select a reasonable slope protection form according to different geological conditions after slope excavation. This paper discusses how to determine the type of slope protection according to the geological conditions of the slope, the height of the sub platform, the slope ratio and other factors, as well as the problems that should be paid attention to in the construction of an expressway.