been removed, refill the holes and level the area to
prevent the accumulation of water.
STRIPPING
Stripping consists of removing and disposing of
objectionable topsoil and sod. It may either follow or
be done with clearing and grubbing. Actual
earthmoving begins with stripping; surface soil and
rocks are removed from the area to be excavated.
Deeply embedded rocks and large boulders may have
to be blasted before they can be removed.
The material removed by stripping is called spoil.
Unless otherwise directed, you should dump spoil
along the area to be excavated within range of the
earthmoving equipment. If the spoil will not be put to
use, such as turfing or finishing the shoulder of a road
or runway, it should be wasted along the edges of the
project, as shown in figure 15-64. Take care not to
disturb necessary drainage.
Equipment, commonly used in stripping, consists
of a dozer, a scraper, and a grader. As mentioned
earlier, the dozer is the most often used when
removing trees. Dozers can handle all short-haul
excavations (up to 300 feet). For long-haul
excavations (over 300 feet), scrapers should be used.
A scraper may be used also on fine soils for shallow
stripping. A grader is used mainly for shaping and
finishing a stripped surface. It is adaptable also for
ditching, for sidecasting, and for sloping banks.
DRAINAGE
Drainage is the construction of facilities needed
to allow excess surface and subsurface water to flow
from the construction site. Properly designed and
constructed drainage systems are one of the most
important parts of a construction project. Without
proper drainage, rainwater and water running off the
surrounding ground could turn the area into a lake. It
is also necessary to drain off surface water that would
soak down and wet the subgrade.
The elements, determining drainage needs for a
road or project site, are the amount of annual rainfall
in the area and the routes or areas that can be used to
collect or channel excess surface and subsurface
water, such as lakes, ponds, streams, or voids (i.e.,
gullies).
The type of soil is critical to the design and
construction of a road. It is poor judgment to construct
a road over or through clay, sand, or other undesirable
material if it cannot be properly compacted. It is best
to bypass this type of material.
If a road surface is to endure continued use for
years, it must have firm support from the subgrade. All
organic materials, such as living or decayed
vegetation, should be removed from the area of the
subgrade unless the road is for emergencies or is
temporary (detour or military road). In designing and
building a road, consider the type of drainage, the type
of soil, and the amount of clearing or grubbing
necessary.
To facilitate drainage, excavate diversion ditches
to conduct all surface water into natural channels or
outfall ditches. Outfall ditches are constructed to
drain low or boggy spots. At the point or the end of
the system when the accumulated runoff discharges
into the disposal point, the runoff is technically known
as discharge. The discharge point in the system is
called the outfall. This preliminary work is done at the
same time the area is cleared and grubbed.
The finished drainage system usually consists of
ground slopes, ditches, culverts, gutters, storm drains,
and underground water drains. Open channels should
Figure15-64.-Stripping.
15-40
