Page 357 - Moving the Earth_ The Workbook of Excavation

ROADWAYS

ROADWAYS 8.19

FIGURE 8.13 Sidehill cut with excavator.

The fill is kept higher than the cut, particularly if used for footing. Poles or platforms can be
used for extra support under both tracks, or under the outside track only.
When the ground is soft or wet, the slope is very steep, soil layers slope with the hillside, or
smooth bedrock is just under the cut, the smallest backhoe which can handle the digging should
be used. The weight of a large machine, together with the vibration of its work, may cause a slide.
Shovel spoil can most conveniently be sidecast, but also can be loaded into trucks backed up
to it. If the road is long and narrow, trucking out all the spoil will be very slow work.
Rock exposures along the road line should be blasted, as a shovel cannot be readily moved up
and down steep slopes to bypass them. Use of a shovel is indicated when soil is too soft or rocky
for effective dozer work, when cuts are deep, and when spoil is to be used at a distance.
The work is ordinarily left rough to be finished off by a dozer or grader.

Side Cuts. When the notch is to be largely or entirely a cut and the spoil is to be used nearby on
the job, dozer sidecasting is used only until the shelf is of ample width to hold the machinery. The
material is then pushed or carried along the shelf to the fill area.
Big dozers can be used for pushes up to 200 feet on the level, and farther downhill with fair
efficiency. When the cut is too narrow to allow machines to pass each other, their production can
be stepped up, at some additional cost, by using two or more dozers in relays. One, working from
the back of the cut, will push a load partway to the fill and spread it a bit in dumping it. The dozer
below it will back over the heap and push it to the end of its beat.

Scrapers. The possibility of using scrapers should be considered. Their use on short runs is dis-
cussed later.
Tractor scrapers are impossible to back, so in a narrow road they require an additional road to
bring them back from the fill. This may have to go back to the beginning of the hillside, or enter
it at some intermediate point. In either case, the scraper’s travel distances are apt to be much
greater than those of the bulldozer.
If some spoil is being sidecast and some hauled away, a dozer can work on widening and serve
as a pusher.
In the first stages of enlarging a notch, it may be difficult to keep the road sloping into the hill
because of scrapers sinking and gouging into the loose fill. This pitch may be preserved or
restored by running a grader or an angling dozer close to the wall, and casting out. As the cut
widens and enters solid ground for its full width, it will become possible to keep it trimmed on the
bottom by proper manipulation of the scrapers.