| 30 deg. | 30 |
______________|________|________|________|____________|

____________________________________________________________________
| | | | | |
Combined | | | | | |
assumed | _h_ | _l_ | [phi] | _D_{E}_ | _D_{W}_ |
conditions. | | | | | |
______________|________|________|________|____________|____________|
| | | | | |
I_{3} | 20 | 30 | 50 deg. | 40 | 60 |
I_{4} | 20 | 30 | 40 deg. | 40 | 60 |
II_{3} | 15 | 15 | 50 deg. | 40 | 60 |
II_{4} | 15 | 15 | 40 deg. | 40 | 60 |
III_{3} | 15 | | 50 deg. | 15 | 15 |
III_{4} | 15 | | 40 deg. | 15 | 15 |
IV_{3} | 30 | | 50 deg. | 30 | 30 |
IV_{4} | 30 | | 40 deg. | 30 | 30 |
______________|________|________|________|____________|____________|

APPROXIMATE PRESSURES ON TUNNELS, PER SQUARE FOOT.

_________________________________________________________________________
| | | | || | | |
Pressure | I_{1}| I_{3}| I_{3}| I_{3} || I_{2}| I_{4}| I_{4}| I_{4}
per square|Earth.|Earth.|Water.|Combined.||Earth.|Earth.|Water.|Combined.
foot, at | | | | || | | |
__________|______|______|______|_________||______|______|______|_________
| | | | || | | |
A | 3,240| 3,690| 1,500| 5,190 || 2,325| 2,880| 2,250| 5,130
B | 2,745| 3,105| 1,500| 4,605 || 1,845| 2,385| 2,250| 4,635
C | 2,160| 2,475| 1,500| 3,975 || 1,350| 1,800| 2,250| 4,050
D | 450| 540| 1,500| 2,040 || 450| 450| 2,250| 2,700
E | 360| 360| 1,625| 1,985 || 450| 450| 2,438| 2,888
F | 270| 270| 1,750| 2,025 || 450| 360| 2,626| 2,986
G | 225| 225| 1,875| 2,100 || 360| 270| 2,814| 3,084
__________|______|______|______|_________||______|______|______|_________
_________________________________________________________________________
| | | | ||