 , in feet. |  . |  , in pounds per squarefoot. |  , in pounds per squarefoot. | ||
|---|---|---|---|---|---|
 . |  . | . | . | ||
| 15 | 45° | 1 485 | 2 300 | 405 | 300 |
| 15 | 30° | 1 035 | 2 100 | 540 | 600 |
| 30 | 45° | 3 240 | 2 800 | 450 | 400 |
| 30 | 30° | 2 325 | 2 600 | 450 | 750 |
If the height,
, of earth covering is 200 or 300 ft., the values given by [Figs. 17] and 18 are much larger than those given in Columns
, which presumably represent Mr. Meem’s pressures for any height greater than 40 ft.
In saturated earth, it has been customary, perhaps, to regard the earth as if it were gravel composed of solid spheres, like marbles, so that the water has free access in any direction. Thus, in the case of a retaining wall backed by such material, the water has full access practically to every part of the wall, and the wall is subjected to the full water pressure corresponding to its depth. It is likewise subjected to a thrust from the earth, corresponding to
and
