The watchman and southron. [volume] (Sumter, S.C.) 1881-1930, 1911-02-04
THE SAND-CLAY ROAD.
Construction, Grade and Location.
(By Prof. M. Goode Homes, Dept. Of
Civil Engineering University OF

II
Civil Engineering University OF
South Carolina.)
| In the majority of cases. the road
needs to be relocated both as regards
grades and distance. This point
should be carefully looked into before
proceeding with the sand-clay con-
struction; for a failure to do so may
mean a failure Of the road. OF a loca-
tion such that a maximum amount of
good is not obtained with a minimum
amount Of service. When a sand-ciay
surface Is added to a road, 1t should
be made as a permanent improvement
In order TO preserve the investment;
thus we see that the road should he
so located that 1t will not ever be
necessary to again make a change. In
order to obtain this, the grades should
never be more than 3 1-2 per cent,
else the surface OF the road will wash
into the gullies. On the other hand
the grades should never be less than
II
sufficient fall to give proper drainage
The grades should vary from one to
two per cent. Proper grades may he
obtained by cutting and filling, or by
winding around the hills or zigzagging
up the slope. The location of the road
should be such that the distance be-
tween the controlling points are as
short as possible, and the line as
straight as possible. without intro
ducing excessive grades. The reloca-
ton OF a road and the establishment
Of the grade line should never be un-
dertaken except by a competent road
engineer, who should also set the
grade and slope stakes. In making
fills. the embankments should be
formed Of successive layers not more
than IL inches thick. In order that
each layer may be thoroughly COM
pacted.
! Drainage.
| II the country Is Of sand, deep and
porous enough. to absorb quickly the
heaviest rains. no special attention
need be given to drainage. other than
to provide q proper crown to the sur
face OF the road to shed the water
quickly to the sides. When the above
condition does not exist. 1t Is extreme
ly essential to provide a proper sys-
ii nf ~
attained by side bitches along each
edge of the roadway. They should be
\ about four or Ave feet wide, and one
to one and a half feet deep. sloping
| three to one the side next to the road
and about one to one on the outer
| side. These side ditches should have
outlets as frequently as possible which
carry the water entirely away from
the road. Whenever necessary, cul-
verts should be provided to carry the
water under the roadway; never let
| ting IL flow across the surface. The
| crown Of the roadway should be suf-
| hcient to quickly shed all water fall
Ing on 1t to the side bitches. When
the road runs through section that
Is low and level. so that the surface
Of the road is kept continually wet
from seepage, 1t is necessary to dig
wide and rather deep bitches on each
side of the road and raise the level Of
the roadway sufficiently high to shed
all the water from the surface. In
some cases IL will be necessary TO
supplement the side bitches with a
line OF tile subdrain.
Sand-Clay on Sandy Subgrade.
| The roadbed should be graded true
to the lines and grades established by
the engineer. All spongy material,
vegetable matter. trees roots, and
stumps should be carefully removed.
and the space thus made filled in with
sound material and the surface Of the
roadbed made solid and firm. The
portion OF the roadbed intended for
the sand-clay should be excavated to
a depth equal TO the required thick
ness OF the sand-clay. That is, a
trench should be made in the road the
width and depth being the same as
that of the sand-clay, and the bottom
OF the trench shaped to a true sur
face conforming to the crown of the
finished roadway. All soft places in
this trench should be thoroughly COM
pacted. This trench is now filled with
clay, which i'm turn is covered with a
layer OF clean, sharp and sound sand.
The clay may be obtained, when the
country is underlaid with a stratum
OF suitable clay. by digging a big