IMPROVEMENTS IN CONSTRUCTING TUBULAR TUNNELS OR SUBWAYS, AND APPARATUS FOR THAT PURPOSE
Year: 1874

page_text: LETTERS PATENT to James Henry Greathead, of No. 2, Storey's
Gate, Westminster, in the County of Middlesex, for the Invention
of "IMPROVEMENTS IN CONSTRUCTING TUBULAR TUNNELS OR SUBWAYS, AND
APPARATUS FOR THAT PURPOSE."
PROVISIONAL SPECIFICATION left by the said James Henry Greathead
at the Office of the Commissioners of Patents, with his Petition,
on the 16th May 1874.
い
I, JAMES HENRY GREATHEAD, of No. 2, Storey's Gate, Westminster,
in the County of Middlesex, do hereby declare the nature of the said
Invention for "IMPROVEMENTS IN CONSTRUCTING TUBULAR TUNNELS OR SUB-
WAYS, AND APPARATUS FOR THAT PURPOSE," to be as follows:-
My Invention relates to a method of constructing tubular tunnels or
subways, consisting of tubes of metal or other material built into holes.
bored under the surface of the ground, and to apparatus employed in
boring such holes, and in building therein the permanent tubular
casings.
\

page_text: For boring the holes for such tubular tunnels I provide a shield or
cap, consisting of a strong front part, from which extends backwards a
cylindrical flange somewhat larger than the outer diameter of the
intended tubular casing, so that it overlaps and encloses the most
advanced part thereof. The front has through it holes provided with
stuffing boxes, through which chisels or drills or other tools can
be passed, these tools being worked from inside the shield so as to disin-
tegrate or break up the material in front thereof.
In order to render the protruding tools available for cutting in
various directions they may be passed through spherical sockets in
stuffing boxes in the front of the shield, arranged so as to admit of their
being directed at various angles.
I also provide other holes through the front, and connect them
by pipes provided with cocks or valves to pumps and receptacles to
operate in the following manner :-I force through some of these
pipes a quantity of water, employing at the same time when necessary
the disintegrating tools above mentioned. The matter disintegrated is
carried in a state of suspension by others of the tubes into receptacles in
the rear of the shield, whence it is removed. When the suspended
matter has to be conveyed by the pipes over a considerable distance, its;
movement along these pipes may be aided by water jets introduced at
intervals, thus avoiding excessive pressure outside the shield.
In the case of driving the tunnel through loose dry material, such as
sand, air instead of water may be blown into the material outside the
shield, causing the loose particles to be forced back with the currents of
air returning through tubes in receptacles in the rear of the shield.
For tunnelling in comparatively loose soil under water the forcing of
water through the shield may in some cases be dispensed with when the
pressure of the exterior water is sufficient to force with it the disin-
tegrated material.
In driving through fissured rocks under water the rock may be disin-
tegrated by the use of the protruded tools, and the debris carried into
the interior of the shield by water, as above described.
€
In driving a tunnel through loose material near the surface the soil in
front may be displaced by water ejected through the shield, and the 3
shield may be forced forwards as its front becomes cleared. The front of

page_text: the sides of the tubular casing. This cement, while it fills up the void
so as to prevent settlement, serves also to fill, cover, and render tight
and secure the jointing of the blocks which constitute the casing.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said James Henry Greathead in the Great Seal Patent
Office on the 12th November 1874.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JAMES
HENRY GREATHEAD, of No. 2, Storey's Gate, Westminster, in the
County of Middlesex, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Sixteenth day of May, in the year of our Lord
One thousand eight hundred and seventy-four, in the thirty-seventh year
of Her reign, did, for Herself, Her heirs and successors, give and grant
unto me, the said James Henry Greathead, Her special license that I,
the said James Henry Greathead, my executors, administrators, and
assigns, or such others as I, the said James Henry Greathead, my
executors, administrators, and assigns, should at any time agree with,
and no others, from time to time and at all times thereafter during
the term therein expressed, should and lawfully might make, use,
exercise, and vend, within the United Kingdom of Great Britain and
Ireland, the Channel Islands, and Isle of Man, an Invention for "IMPROVE-
MENTS IN CONSTRUCTING TUBULAR TUNNELS OR SUBWAYS, AND APPARATUS FOR THAT
PURPOSE," upon the condition (amongst others) that I, the said James
Henry Greathead, my executors or administrators, by an instrument in
writing under my, or their, or one of their hands and seals, should
particularly describe and ascertain the nature of the said Invention, and
in what manner the same was to be performed, and cause the same to be
filed in the Great Seal Patent Office within six calendar months next
and immediately after the date of the said Letters Patent.
NOW KNOW YE, that I, the said James Henry Greathead, do hereby
declare the nature of the said Invention, and in what manner the
same is to be performed, to be particularly described and ascertained
in and by the following statement thereof, reference being had to the

page_text: accompanying Drawings, and to the figures and letters marked thereon,
that is to say :-
-
My Invention relates to a method of constructing tubular tunnels or
subways, consisting of tubes of metal or other material built into holes
bored under or partially under the surface of the ground, and to
apparatus employed in boring such holes, and in building therein the
permanent tubular casings.
The chief object of my Invention is to facilitate or render practicable
the construction of tunnels or subways under water or in other positions
where, from the loose nature or the soil or from the large quantity of
water contained in it, it may be tedious, expensive, or dangerous to
execute them by the ordinary methods of construction. In driving
tunnels under water, whether by means of tunnelling or by means of
open cofferdams, the difficulty and danger arise generally from the
necessity of exposing a surface of the wet, soft, or loose materal, and at
the same time taking away all support from it by pumping out the
water. By my method, as will be seen from the following description,
it is not necessary to expose any surface in such manner, and the
excavation can be carried forward with great expedition and certainty.
For boring the holes of tubular tunnels, and inserting the tubular
lining, I provide a shield or cap consisting of a strong front part, from
which extends backwards a cylindrical flange somewhat larger than the
outer diameter of the intended tubular casing, so that it overlaps and
encloses the most advanced part thereof. By causing this cap or shield
to advance, sliding on the end of the tubular casing, at the same time
that the material is displaced immediately in front of it, I am from time
to time enabled to insert the casing of the tube inside the overlapping
plate or cylinder of the shield in the known manner.
The permanent casing of the tunnel may be of brickwork built in the
ordinary way, or it may be of iron or other metal, or of iron frames filled
in with cement, concrete, or other material made in Voussoir segments
bolted together.
Instead of metal the casing may be formed of Voussoir segments of
artificial stone, cement, concrete, or other material previously moulded,
and secured together in their places by dowelling. When Voussoir
segments are used I secure a number of the blocks last erected by

page_text: temporary clamps taking into recesses formed in the moulded blocks.
When the blocks have settled in their places, and have been secured
there by cement as I shall presently describe, these temporary clamps
may be slackened and removed, and employed to secure blocks erected
afterwards.
In joining together the segments of the tubular casing leather or
other yielding material may be introduced, so as to render the joints
water-tight, and also by bearing against the interior periphery of the
shield to prevent ingress of water as the same is moved forward. As
the shield is advanced its cylindrical flange being withdrawn leaves a
void space all round the portion of the tunnel tube which it enclosed.
I fill this void in the known manner by forcing in liquid cement through
holes in the sides of the tubular casing. This cement, while it fills up
the void so as to prevent settlement, serves also to fill, cover, and
render tight and secure the jointing of the blocks which constitute the
casing.
I will now describe the method according to which I operate, and
the apparatus employed for that purpose, referring to the accompanying
Drawings.
Fig. 1 represents a longitudinal section of part of the tubular casing
of a subway carried through a water-bearing material with its shield.
The tubular casing in this case is composed of cast-iron segments D, D,
bolted together and lined with brickwork B, B. Closely overlapping
the advanced end of the iron tube is the cylinder P, P, of the shield.
At J, J, are packings or cups to prevent the passage of water between
the cylinder P, P, of the shield and the casing D, D. Inside this
cylinder and near its front is a face or diaphragm F, F, connected
securely and tightly with the cylindrical plate, so as to form together
with it a water-tight head to the tubular subway capable of sliding upon
the casing. At several places in the face F, F, are fixed nozzles N, N,
open towards the front and connected at the back with a pipe W, W,
extending back through the whole or a portion of the tube already
completed. At one or more places also in the face F, F, a pipe or
- pipes G, G, are provided also open to the front, and extending back
into the completed tube, and connected with tanks or receptacles R, R.
Again at other convenient places in the face F, F, are chisels C, C,
passing through stuffing boxes in spherical sockets S, S, which admit of

page_text: the tools being directed at various angles, and of being slid to and fro.
Inside the shield and in rear of the face F, F, are hydraulic presses H,
H, H, with their supply pipe A, A. W¹, A¹, and G₁ are sliding. joints
for the several pipes. A current of water is made to flow through the
pipe W, W, in the direction shewn by the arrows, and through the
openings or nozzles N, N, when it comes in contact with the sand, gravel,
or other material in front of the face F, F. At the same time when
necessary the sand or gravel is loosened or stirred up by means of the
chisels or tools C, C, actuated by men or mechanical power from within
the shield. This water returns through the pipe or pipes G, G, in the
direction indicated by the arrows, carrying with it a portion of the sand
or other material.
When sand or light material of like character is dealt with the deposit
tanks R, R, may be dispensed with, the material being carried by the
water to the point of discharge, which in the case of a tunnel laid on an
ascending gradient may be at any convenient point in its course.
As a
space is thus cleared immediately in front of the face the shield is forced
forward by means of the presses H, H, abutting against the casing of
the tube already placed. When the shield has in this manner been
advanced a sufficient distance another ring of the casing is introduced
in the rear of the hydraulic presses, and bolted to the advanced end of
the casing previously inserted. The joints and packings are then made
good, and the several pipes lengthened so as to be ready for the next
advance of the "shield."
In practice it would probably be most convenient to cause the flow of
water through the nozzles N, N, to be intermittent at short intervals,
thus alternately excavating a space in front of the shield, and relieving
the face from the outside pressure, so as to diminish the resistance to
the advance of the shield.
Fig. 2 represents a longitudinal section of the shield and part of the
tubular casing of a subway near the surface of a water-bearing stratum.
The tubular casing in this case is composed of Voussoir segments D, D,
of concrete, cement, or artificial stone, dowelled into one another, and
temporarily held together by clamps K, K. The shield is similar to that
shewn in Fig. 1 (the reference letters being also the same), with the
exception that in this case the sand, gravel, or other excavated material
does not return through, a pipe into the interior of the tube, but is

page_text: washed away from the face of the shield outwards by the pressure of the
water discharged from the nozzles N,
N.
Fig. 3 represents a longitudinal section of a portion of a cast-iron
tube or subway and the shield with its air locks, which I will now
describe employed in the removal of boulders or other obstructions.
O, O, are two partitions erected inside the shield with an air pipe a, a,
running through them having valves at V and V¹, and d, d, are doors
in these partitions. The interior of the shield is thus provided with two
air-tight chambers L, M, forming an air lock; E is an opening or door
in the face of the shield. On a boulder or obstruction being met with
it will by the action of gravity gradually find its way to the bottom of
the shield in front of the face, or if necessary it can be brought to that
position by the tools C, C. If air be then forced into the chamber M,
so as to have a pressure equal to that of the water on the outside, the
door E may be opened; the water will not rise above the level of the
top of the door, and through the opening E the boulder or obstruction
may be removed. The chamber L is for the purpose of affording a
means of ingress and egress to the chamber M without reducing the
pressure of the air in M in the known manner.
Fig. 4 represents a longitudinal section of a shield and part of a tube
of brickwork D, D, the shield being similar to that shewn in Fig. 1 (and
similarly lettered), with the exception that the face F, F, is made funnel
shaped, and the water is ejected through an annular space N, N, to
return through G into the pipe or pipes G, G.
Fig. 5 represents a longitudinal section of a shield and a portion of a
tube of brickwork D, D. The general arrangement of the shield is the
same as that in Fig. 1, but a modified form of the chisels is here shewn
at C, C, which may be worked by causing their shanks to revolve, and
the pipe G is made to pass through a stuffing box S, and is armed at its
advanced end with tools C, C, which may be worked by causing the
pipe to revolve. The face is made double, F, F, and F', F¹, to admit of
the chisels and pipe being taken out for repairs through the compart-
ments Z, Z, Z.
Fig. 6 represents to an enlarged scale a section, and Fig. 7, a front
view of the clamps K, K, shewn in Fig. 2.
Fig. 8 represents a section, and Fig. 9, a front view of a segment of
the tubular casing for a subway composed of an iron frame I, I, filled
in with cement, concrete, or artificial stone Y.

page_text: Fig. 10 represents to an enlarged scale a section of the spherical
stuffing box S, S, of the chisels C, C, in the several Figures already
described.
In operating with the apparatus described above when the excavated
material in the pipe G, G, has to be conveyed over a considerable
distance, or up an ascent, its movement along the pipes may be aided
by water jets introduced at intervals, thus avoiding excessive pressure
outside the shield.
In the case of driving the tunnel through loose dry material, such as
sand, air instead of water may be blown into the material outside the
shield, causing the loose particles to be forced back with the currents
of air, returning through tubes into receptacles in the rear of the
shield.
In tunnelling in comparatively loose soil the forcing of water through
the face of the shield may in some cases be dispensed with, the loose
material being removed by means of a sand pump or otherwise through
tubes sliding in stuffing boxes when necessary in the face while the
shield is at the same time forced forward by the presses.
In driving through fissured rock under water the rock may be disin-
tegrated by the use of the protruded tools, and the debris carried away
into the interior of the shield by water, as already described.
In some cases the face of the shield may be divided into cells or com-
partments provided with closely fitting doors, one or more of which
could be opened at a time for working on the material in front, or
3 clearing it of larger impediments, such as boulders. In such cases air
may be forced into the material in front, so as to displace and keep out
the water.
Having thus described the nature of my Invention, and in what
manner the same is to be performed, I hereby declare that I make no
general claim to the use of a sliding shield in the construction of
tubular subways, nor to any means of advancing such shield, or of insert-
ing and making good the tubular structure behind it; but I do claim,—
First. The method substantially as heren described of displacing the
material in front of the shield, used in constructing a tubular subway by
the action of fluid combined when necessary with the agency of tools
worked from within the shield.

page_text: Second. The use in the shield employed in the construction of a
tubular subway of an air lock constructed and operating substantially as
herein described.
In witness whereof, I, the said James Henry Greathead, have here-
unto set my hand and seal, this Ninth day of November, in the
year of our Lord One thousand eight hundred and seventy-
four.