What is the difference in mechanical characteristics between the main road surface and the tunnel external connection?

1. Height difference: The pavement height of the external wiring of the tunnel is generally higher than that of the main line, in order to avoid water from entering the tunnel. This causes the slope of the road surface outside the tunnel to be steeper than that of the main line.

2. Straight line and curve structure: the roads on the main line are generally straight lines or transition curves, while the roads on the external wiring of the tunnel often have more sharp turns and steep slopes to adapt to the limitations of terrain and traffic conditions.