Page 168 - Moving the Earth_ The Workbook of Excavation

BASEMENTS

4.8 THE WORK

FIGURE 4.8 Four-pile excavation.

line, are pushed up on the east and west piles, respectively, with ramps cut out of the bank and
partly refilled as in the previous example. The section between these two cuts is pushed onto piles
to the north and south, with ramps cut out of the bank beyond the digging line, each pile being
supplied mainly from soil on its side of the center.
By this plan, the whole surface of the excavation can be worked down as a unit, the dozer
always pushing dirt to the nearest pile. The four directions of push may be taken in rotation, or
varied according to the operator’s inclination.
Advantages of this method are efficiency, in that pushing distance is kept to a minimum, and
adaptability to grading plans. The four spoil piles are shown to be about equal, but their relative
sizes may be changed without varying the method. Access and space for material are not as good
as with the open-front method. A larger-amount of dirt is dug out for ramps and must be pushed
back later.
Grading. If the topsoil has been pushed well back, it is possible to rough-grade the fill at the
same time that it is pushed out of the basement, or immediately afterward. This has the advantage
of making all four sides accessible to the builders.
Ordinarily, it is easier to spread several small piles than one big one. For this reason, it is wise
to stop excavating occasionally and to spread the piles which have been built up.
The grade should be kept at least 1 foot above its final level, to provide excess soil for back-
filling around the foundation.
If the digging is wet, the spoil may be too sloppy to spread immediately.
Irregular Basement. Figure 4.9 shows a basement of irregular shape. This may be dug by the
open-front method by cutting back the jog as indicated in (A), and by pushing dirt for the small
south room into the main basement, to be piled on the east side.