Page 272 - Moving the Earth_ The Workbook of Excavation

PONDS AND EARTH DAMS

6.8 THE WORK

FIGURE 6.6 Working back a heavy pile.

Trucking. A flattened windrow, such as is shown in Fig. 6.7, may be used as a truck road if it
is dry and substantial enough, and is connected with dry land at one end. The dragline, or back-
hoe, may be started at the far end and worked toward the exit. It may dig to final grade, leave a
shelf for further dragline work, or it may load the dry material in the trucks and cast the wet stuff
from the bottom to build up a new windrow.
Abnormal delays may be experienced in the trucking. It is usually not practical to build turn-
arounds or two-lane roads, so the trucks must back in the full distance from shore, and no other truck
can enter until the previous one has left, thus leaving the shovel idle each time. There is also danger
of trucks going too close to the edge, or encountering soft spots, so that they get stuck or overturn.
If the windrow can be connected with dry land at both ends, scrapers may be used to remove
the dry upper part.
Material may be trucked away economically if the pond is to be large in proportion to the size
of the shovel, so that several shovel handlings would be required; if there is insufficient space in
the digging area to pile the spoil; if fill is needed elsewhere on the project; or if the spoil can be