The weekly clarion. [volume] (Jackson, Miss.) 1863-1882, 1870-11-10

The New Chicago River Tunnel.
A correspondent of the Providence OR.
I'D Journal furnishes the following de-
scription of the new submarine tunnel at
Chicago. The tunnel under the river at
Washington street is an object of much
interest to the stranger, as a work of re-
markable utility, unique of its kind and
most sagaciously planned and arranged.
| The demand for such roadway, connect
ing the divisions of the city which the
river separates, had become a necessity
at the time when it was commenced for
Notwithstanding the great multiplication
of bridges, travel was most vexatiously
delayed and embarrassed by the continual
opening of the draws. 1t was completed
on the first of January, 1869, at cost of
1928, 500, and has fully subserved the
purposes contemplated, afording a very
convenient means of transit, both for car
riages and pedestrians. The avenue for
vehicles dips from the open street, one
block back from the side of the river.
The extreme length of the roadway
formed of Nicolson pavemenD, is 1903
feet. The length between the arches is
$50 feet. The distance between the en-
frances on either side for foot passengers
is $40 feet. The grade of descent east
ward is one foot in eighteen, and west
ward::one foot in sixteen. The height of
the chamber beneath the river is 1888
feet At 10 feet from the river centre
separate double wagon ways begin, each
eleven feet in width. Parallel with the
carriage way is the foot passage, sepa-
rate chamber eleven feet high at the CEN
tire. 1t is entered from within passenger
houses by descending short flights of
steps. The floor is even and the descent
gradual. The gas lights are forty feet
apart. There are ventilation shafts by
which the air is kept fresh.
The labors of the men employed in
making the excavations further down the
river at LaSalle street are watched daily
by curious throng, and present very
novel spectacle. They are indeed of the
mud, muddy, these besmeared, bedrag-
gled wallowers in the noisome deposit left
by waters with which the drainage of the
city has been so long mingled. They
toll ON day after day, knee deep in the
Shiny ooze, slowly removing accumula-
tons of filthy sediment, the amount of
which must seem discouraging to contem-
plate. Before us lies great basin from
which the water has been pumped, laying
bare the muddy bottom two-thirds of the
way across the stream. A gang of labor
ers are continually shoveling the mud into
buckets which are drawn out by steam
power.
The loads are emptied into scows and
conveyed away to make land for railroad
purposes. The open area are enclosed
by three sides of Golfer dam, built of
double water-tight walls of heavy plank,
which form massive bulwarks to shut out
the river. The spaces between the walls,
three or four feet wide, are filled with
mud, giving great stability. The struc-
ture is shored up and braced from within
in the strongest manner by masses of
heavy timber. The middle bulkhead,
placed lengthwise with the stream, rests
against the mouths of the closed cylindri-
cal chambers of the northern or compile
ted portion of the tunnel. The founda-
ton for this was prepared, and its oven
like compartments of masonry built up
within the walls of cofer-dam, which
was the counterpart of the one above de-
scribed. The river now flows above this
masonry, and all vessels passing up or
down must sail over it, though the chan
mel is quite narrow.
The bed is at present nearly prepared
upon which to lay the masonry for the
first section of the south part of the struc-
ture. The mud is dug out to a depth of
twenty-four feet The depth of the
water above the place was formerly
twenty feet, so that the submarine road
way at this point viii be about forty-four
feet below the surface of the river. A
section comprising thirty-eight feet of the
horizontal length of the structure is built
up and finished at one time. The length
of the bulkheads extending to the shore
is at present one hundred and eighty
feet. The work was begun in the centre
of the river by letting down large crib
or coffer-dam, in shape like square box,
thus making a well in the middle of the
river, then pumping out the water, dig
ging out the bottom, and laying a section
of masonry within the box, whose trans
verse sides were elongated from time to
time, laying bare more and more of the
river bed as Che progress of the work re-
quired, until they reached the shore.
The total length of the tunnel when
completed, including the approaches from
Randolph street on the south and from
Michigan street on the north, will be
nineteen hundred and thirty feet As
in the Washington street tunnel, there
will be an open passage way for vehicles.
and separate chamber for pedestrians.
For the construction of the masonry
about eight million bricks viii be re-
CURED and a very large amount of stone
The completed portion may now be en-
tered, although the pathway is muddy
one. In two weeks time il viii be made
more passable- The laying of the MAJ
sonry was commenced on the 9th of
February last. The FIRST piles were
driven, preparatory to building the Golfer
dam on the 18th Of November. The time
fixed by the contractors, previous to
which they propose to have the tunnel
completed, Il the 4th Of July next. IL
III found that depth Of eight feet of de-
posit has accumulated on the bottom Of
4