IMPROVEMENTS IN THE CONSTRUCTION OF SUBMARINE TUNNELS
Year: 1856

page_text: (This Invention received Provisional Protection, but notice to proceed with the
application for Letters Patent was not given within the time prescribed
by the Act.)
PROVISIONAL SPECIFICATION left by Alexandre Vacherot at the Office
of the Commissioners of Patents, with his Petition, on the 26th April
1856..
I, ALEXANDRE VACHEROT, of Paris, in the Empire of France, Architect, do
hereby declare the nature of the said Invention for "IMPROVEMENTS IN THE
CONSTRUCTION OF SUBMARINE TUNNELS," to be as follows:
The
This Invention relates to a simple and economic construction of tunnels for
submarine communications, or for forming viaducts under water suitable for
crossing large rivers, straits, or arms of the sea, without materially obstructing
the current or interfering in any way with the navigation thereof.
tunnel itself is composed of a number of sections or short lengths, which
are constructed and completed previous to being submerged, and when sub-
merged they are rivetted together, to form the entire length of the tunnel; or
the junction of the sections may be effected by a species of self-acting hinged
catch or catches, or shecks, which will fall into their places when the section
is brought in contact with its neighbour; by which arrangement-the services of
a diver may be dispensed with, as the sections unite themselves... Each of these
sections consist of two D-shaped chambers of sheet or wrought iron, open at
both ends, and placed one inside the other, the inner one being of the desired

page_text: capacity of the tunnel; and the space which intervenes between the inner and
outer chamber or casing is filled in with concrete, or any suitable hydraulic
cement or mortar which bas the property of hardening when under water.
The inner casing is made of much stronger material than the outer one, and
both are well braced and strengthened by suitable diagonal and other bracings
and girders. These sections or lengths are deposited by suitable tackle upon
the ordinary bed or submerged surface of the ground, and their subsequent
leveling or adjustment is effected by a number of rods which project outside
the base or flat bottom of the sections, & are connected or jointed each to a
foundation stone, in such a manner that when the section is lowered to the
bottom of the water, the foundation stones will adjust themselves individually
to the surface of the bed, whilst at the same time the rods which are passed
through suitable tubes or sockets in the base of the section will slide therein,
and thus protrude more or less at different parts, according to the nature of the
ground. The entrance of the rods to the sockets is packed, to prevent the
admission of water into the tunnel, and the rods are enclosed in india-rubber
tubes or cases, which protect them from the action of the water, and thus
obviate the rapid oxidation or corrosion which would otherwise occur. The
rods at each end of the sections are firmly fixed (not jointed) to stones, which
are made pointed, and these rods protrude laterally, or at an angle, downwards,
and afford a firm bearing or stay against any external lateral pressure or strain
on either side of the tunnel. The adjustment of the level of the various sections
is effected by acting on the internal ends of the adjusting rods by screws or
other powerful pressure, so as to force them outwards, and thus elevate those
parts of the section requiring to be elevated. The rods having been all
adjusted, their insido protruding ends are cut off flush with the sockets, and
they are then secured firmly and prevented from rising by plates bolted over
them, or by other suitable means. Before each section is lowered into the
water, both its ends are tightly closed by plates and india-rubber, or other
packing, so as to prevent the entrance of water therein, and the inner one of
these covers is removed when the section has been joined on to its neighbour,
which has been previously adjusted in the manner herein-before described.
In this way the work is proceeded with until the whole length of tunnel is
completed. An inclined cutting is made on each shore or bank to coincide
with the level of the tunnel, and a strong embankment of masonry is erected
to serve as a sea wall, and also as a mouth or entrance to the tunnel. It will
thus be seen that the bed of the sea or river is left unaltered, and that the
tunnel rests upon it by a number of adjusted feet or supports. The outer
casing of the tunnel may be coated over with bitumen, to preserve it for a time

page_text: from corrosion, but when the hydraulic mortar, concrete, or cement has had
time to harden, the outer casing will be no longer requisite, as the tunnel will
consist, as it were, of one entire stone. A portion at each end of the sections
is left without the cement or hydraulic mortar lining before being lowered, in
order to admit of its being securely jointed to the next section, and when joined
this space is filled up like the rest of the section.