Figure - 1 is a tunnel section. The vertical direction (elevation) is the vertical axis, represented by H; the horizontal direction (distance from the center line of the line) is the horizontal axis, represented by B.
The ordinate of the center of the circle is equal to the design elevation of the route minus the distance from the design elevation line to the center of the tunnel multiplied by the cross slope ratio, plus the height from the center of the circle to the road surface. Expressed by formula (1-1). ?
O=S-b×i h＝S-4.11×0.02 1.69 ?(1--1)?
The abscissa of the center of the circle is equal to 10m (assuming that the abscissa of the line center is 10 meters) . Add the distance from the center of the line to the center of the tunnel.