yesterday, the reporter learned from the provincial highway construction authority, S102 line Xining ring road safety through mutual aid to Datong highway tunnel in December 1st successfully.
Dandong tunnel is located in Huzhu Tu Autonomous County Mountain card ditch, the limit is 10 meters wide, 5 meters in height, a total length of 1010 meters, according to the two single hole double lane two-way highway traffic design, the design speed of 60 kilometers per hour, 80 million 165 thousand yuan of investment. The Loess covering area of the tunnel entrance slope, there are steep loess, crushing, inlet and outlet water, shallow buried section of poor surrounding rock, rock strength is very low, covering layer is thinner, holes difficulties and many other negative factors. Since the project started, the construction unit adopts unilateralpilot tunnel construction method, overcome the import and export of bias against the slope construction problem of hole, has achieved victory through the tunnel. After crossing the highway, the vehicle does not need to go through the road when the vehicle passes through the clamping ditch, which can directly pass through the clamping groove, which greatly shortens the distance and time.