| Per cent. | ||
| Percentage of | moisture in natural earth | 19 |
| “ “ | voids in natural earth | 52 |
| “ “ | grit and gravel in natural earth | 38 |
| “ “ | compression on dam over earth at borrow pit | 16 |
| “ “ | compression on dam over earth in wagons | 43 |
| Degrees. | |
| Angle of repose of natural moist earth | 44 |
| Angle of repose of earth, dust dry | 36 |
| Angle of repose of saturated earth | 23 |
CONSTRUCTION DETAILS.–The materials forming the bulk of the dam were hauled by four-horse teams, in dump wagons, holding 3 cu. yds. each. The wagons loaded weighed about six tons and were provided with two swinging bottom-doors, which the driver could operate with a lever, enabling the load to be quickly dropped while the team was in motion. If the material was quite dry, the load could be dumped in a long row when so desired.
After plowing the surface of the ground and wasting any objectionable surface soil, the material was brought to common earth-traps for loading into wagons, by buck or dragscrapers of the Fresno pattern. In good material one trap with eight Fresno-scraper teams could fill 25 wagons per hour. The average length of haul for the entire work was about 1,320 ft.
The original plans and specifications were adhered to throughout, with the single exception that the central puddle wall was not carried above elevation 1,160, as shown on [Figs. 11] and [12], more attention being given to the inner face puddle. This modification in the original plans was made because of the character of the materials available and the excellent results obtained in securing an homogeneous earthen concrete, practically impervious.
FIG. 11.–DIMENSION SECTION OF TABEAUD DAM.
The top of the embankment was maintained basin-shaped during construction, being lower at the axis than at the outer slopes by 1-10, to the height below the finished crown. This gave a grade of about 1 in 25 from the edges toward the center, resulting in the following advantages:
(1) Insuring a more thorough wetting of the central portion of the dam; any excess of water in this part would be readily taken care of by the central cross drains.
(2) In wetting the finished surface prior to depositing a new layer of material, water from the sprinkling wagons would naturally drain towards the center and insure keeping the surface wet; the layers being carried, as a rule, progressively outward from the center.