成昆线赵坪一号隧道全长3,000多米,于1966年10月铺轨通车。1973年以来,发现有的地段整体道床与人行道之间出现裂缝,宽度达20毫米,中心水沟横向断裂,线路下沉,最大下沉量为18毫米,甚至达45毫米,在列车荷载 Cheng-Kun Zhao Ping Tunnel No. 1 full-length more than 3,000 meters, in October 1966 opened to traffic. Since 1973, cracks have been found in some sections of the total ballast bed and sidewalks, with a width of 20 mm. The central gutter has been transversely fractured and the line has sunk. The maximum subsidence amount is 18 mm or even 45 mm. When the train load