Row | Tunnel Shape | Diameter | Height Placement | Ration of h/d |
1 | Circular | 16 | 12 | 0.75 |
2 | 18 | 1.125 | ||
3 | 24 | 1.5 | ||
4 | 30 | 1.875 | ||
5 | 36 | 2.25 | ||
6 | 42 | 2.625 |