Improvements in or Connected with Apparatus for the Construction of Subterraneous or Subaqueous Tunnels or Passages.
Year: 1889

page_text: Date of Application, 17th Jan., 1889
Complete Specification Left, 7th Oct., 1889-Accepted, 9th Nov.,
1889
PROVISIONAL SPECIFICATION.
Improvements in or Connected with Apparatus for the Construction
of Subterraneous or Subaqueous Tunnels or Passages.
I, JAMES YATE JOHNSON, of 47 Lincoln's Inn Fields, in the County of Middlesex,
Gentleman, do hereby declare the nature of this invention which has been com-
municated to me from abroad by Louis Coiseau of 48 Rue de Bondy, Paris in the
Republic of France, Engineer to be as follows:-
This invention relates to apparatus constructed with a view to overcoming the
difficulties attending the formation of tunnels or passagos in wet sandy or other loose
soil or in or on the beds of rivers and other like situations and consists mainly in
the construction and arrangement of a water tight shield which is also applicable
to the construction of tunnels under houses and buildings of all descriptions where it
is necessary to avoid any disturbance or subsidence of the surface. By the employment
of this apparatus the workmen are also enabled to carry on their operations in perfect
safety.
The said shield is arranged to admit of the employment of compressed air for the
purpose of keeping out the water and supporting the surrounding or superincumbent
soil. The external forn or configuration of the shield corresponds with that of the
tunnel in transverse section being constructed with an outer metal casing of cylindrical
shape for example made smooth externally to enable it to slide readily through the
soil. This hollow cylinder is divided by two partitions into three compartments. The
first or front compartment next to the face of the excavation forms the working
chamber, and is supplied with air under pressure through suitable pipes. The second
or middle chamber forms a lock and the third being open to the atmosphere or
charged with air at a pressure intermediate between that in the working chamber and
atmospheric pressure as hereinafter explained forms the building or construction
chamber in which the masonry or other permanent lining of the tunnel is placed in
position.
The compartments are divided horizontally by floors supporting the workmen and
apparatus and the middle and construction chainbers are also divided vertically by
partitions forming with the floors a series of cells and strengthening the structure.
In constructing a tunnel under a river for example a portion of the tunnel is first
excavated in the ordinary way until infiltrating water is met with. The shield is then
set up at the face of the tunnel and the masonry or other permanent lining is placed
in position behind it. When the lining composed of metal segments or cylinders
lined with brick work for example is completed in the portion of the tunnel previously
excavated the shield is advanced by means of hydraulic rams placed between the end
of the lining and the back of the shield. In forcing the plungers or pistons of the
rains to the end of their stroke the front edges of the shield are caused to penetrate the
soil which therenpon fills the working chamber. This soil must be removed before
the shield can be again pushed forward and with this object compressed air is forced
into the compartments of the working chamber and the workmen pass through suitable
doors from the construction or rear chamber into the lock or middle chamber.
the soil to be removed consists of sand, gravel slime or such material as can be
removed by a stream or current of water there is no need for the workmen to enter
the working chamber the sand or the like being discharged by means of an ejector
apparatus composed of moveable pipes or nozzles passing through the partition and
which the workmen simply move about in the working chamber the said pipes com-
municating through flexible pipes provided with stop cocks with closed receptacles or
simply with the exterior of the chambers. The difference in the pressures in the
When

page_text: working chamber and the exterior or atmosphore of the tunnel is sufficient to produce
a current which draws away the sand from the former.
In cases where the soil can be removed from the tunnel entirely by the aid of
water it is simply necessary to admit a sufficient quantity of water to and from the
working chamber by the aid of suitable valves. The partition is provided with
glazed holes to enable the progress of the operation to be seen by the aid of electric
or other lamps.
When the soil contains stones or is of such a nature as not to admit of being washed
away by a current the workmen are first shut up in the intermediate or middle com-
partments which are charged with compressed air at the same pressure as the working
chamber. By means of suitable doors in the partition the workmen can then pass into
the working chamber and dig out the face of the tunnel or remove any obstructions
that oppose the advance of the shield. The soil thus dug out or loosened in the
working chamber is shovelled or thrown into the intermediate chamber whence it is
thrown (after closing the doors leading to the working chamber) into trucks or
receptacles in the construction chamber or in the tunnel.
In tunnelling through the bed of a river for example the edge of the shield may
be stopped by coming in contact with an obstacle such as a ships anchor embedded in
the bottom of the river in such a position as to be inaccessible to the workmen in the
middle chamber. In this case a workman is equipped with a divers helmet and dress
with the exception of the lead soled boots and other weights being thus enabled to
move about freely in any direction the dress not being inflated owing to a peculiar
combination consisting in causing air to circulate in the helmet at a pressure
corresponding to that of the water. The air escapes through a special pipe leading to
the middle chamber. A door is opened in the front partition admitting water to the
intermediate compartment and the workman provided with the specially arranged
dress passes from the intermediate compartment into the working chainber and removes
the obstacle.
Whilst one gang of men is employed in digging out the soil another gang may
work at the construction of the lining at the back of the shield. Blocks of wood may
be placed bebind the shield to prevent it from being forced backwards by the pressure
and the hydraulic rams may then be released and placed in readiness to advance the
shield by another stroke.
The space loft at the back of the shield between the sides of the tunnel and the
permanent lining is filled up with clay or other materials injectod by means of water
and a pump for example. A certain opening or interval is necessarily loft between the
inner surface of the casing of the shield and the outer surface of the permanent lining
of the tunnel and in order to prevent water froin penetrating through this opening
to the interior of the tunnel a flexible pipe is placed in the interval and is expanded
with air or liquid so as to form a tight joint at this part.
The work may be carried on almost entirely under ordinary atmospheric pressure
as far as the workmen are concerned especially when the soil is of such a nature as to
be removed by means of the ejectors but in constructing a tunnol at a considerable
depth such as 100 feet of water for example with the water constantly pressing
against the face of the shield the action of the rams is supplemented by compressed
air forced into a chamber formed at the back of the shield by erecting a hollow
partition across the tunnel at a certain distance behind the shield. This partition being
suitably fixed in position the space immediately behind the shield is charged with air
at a pressure intermediate between atmospheric pressure and the pressure resulting
from the head of water. By these means facility is afforded for constructing tunnels
under great pressures of water without inconvenience to the workmen.
Dated this 17th day of January 1889.

page_text: COMPLETE SPECIFICATION.
Improvements in or Connected with Apparatus for the Construction
of Subterraneous or Subaqueous Tunnels or Passages.
I, JAMES YATE JOHNSON of 47 Lincolns Inn Fields in the County of Middlesex,
Gentleman do hereby declare the nature of this Invention which has been com-
municated to me from abroad by Louis Coiseau of 48 Rue de Bondy Paris in the
Republic of France Engineer, and in what manner the same is to be performed to be
particularly described and ascertained in and by the following statement :-
This Invention relates to apparatus constructed with a view to overcoming the
difficulties attending the formation of tunnels or passages in wet sandy or other
loose soil or in or on the heds of rivers and other like situations and consists mainly
in the construction and arrangement of a water tight shield which is also applicable
to the construction of tunnels under houses and buildings of all descriptions where it
is necessary to avoid any disturbance or subsidence of the surface. By the employ-
ment of the combination of apparatus hereinafter described the workmen are
also enabled to carry on their operations in perfect safety. The said shield is arranged
to admit of the employment of compressed air for the purpose of keeping out the
water and supporting the surrounding or superincumbent soil.
The external form or configuration of the shield corresponds with that of the
tunnel in transverse section and watertight compartments are provided enabling com-
pressed air to be employed for driving out the water and acting as supports for
the soil in combination with other arrangements whereby the work is facilitated as
hereinafter described.
And in order that my said Invention may be fully understood I shall now proceed
moro particularly to describe the same and for that purpose shall refer to the several
figures on the annexed sheet of drawings the same letters of reference indicating
corresponding parts in all the figures.
Figure 1 of the accompanying drawings represents in longitudinal vertical section
an example of the workings in the construction of a submarine or subaqueous tunnel.
with the improved apparatus according to this invention and Figure 2 represents the
shield viewed from behind and partly in section in order to shew the arrangement of
the compartments therein.
A is the outer shell or casing of the shield which is made smooth externally in
order to facilitate its advance by sliding being made of a form corresponding to that of
the tunnel in transverso section. In the example illustrated the tunnel is represented
as being circular in transverse section but it is evident that any other suitable form
may be employed. The cylinder or casing A is connected to two diaphragms or
transverse partitions B and C, and to horizontal partitions or floors E. The cylinder A
is also connected to vertical longitudinal partitions F and to strengthening rings or
webs R.
This hollow cylinder is divided by the two partitions or diaphragms B and C into
three compartments. The first or front compartment next to the face of the excavation
forms the working chamber and is supplied with air under pressure through suitable
pipes. The second or middle chamber forms a lock and the third being open to the
atmosphere or charged with air at a pressure intermediate between that in the working
chamber and atmospheric pressure as hereinafter explained forms the building or
construction chamber in which the masonry or other permanent lining of the tunnel
such as brickwork combined with a metal casing or a metal casing alone is placed in
position.
The number of horizontal partitions or platforms E is regulated according to the
height of tunnel and the nature of the soil and the vertical partitions F extending
from the working chambers in front to beyond the diaphragm E form with the floors
a series of cells and strengthen the structure.
These cells or compartments are provided with a number of appliances connected

page_text: with the work of excavation as hereinafter explained in the description of the modes
of working with the improved apparatus.
In constructing a tunnel under a river for example a portion of the tunnel is first
excavated in the ordinary way until infiltrating water is met with. The shield is then
set up at the face of the working and the masonry or other permanent liuing (com-
posed of metal the sections or segments O for example) or simply consisting of metal
rings is placed in position behind it. When the lining composed of metal segments
or cylinders as in the example illustrated is placed in position, the brickwork is com
pleted in the portion of the tunnel previously excavated and the shield is advanced
by means of bydraulic rams P placed between the end of the lining and the back of
the shield. In forcing the plungers or pistons of the rams outwards to the end of
their stroke the front edges of the shield are caused to penetrate the soil to an extent
corresponding to the stroke of the pistons say to a distance equal to the width of one
of the lining segments or rings O. The working chambers or cells in the front of
the shield are at the same time filled with soil which must be removed before the shiokl
can be again pushed forwards. With this object compressed air is forced into the
compartments of the working chamber and the workmen pass through doors D from
the construction chamber at the back into the lock or middle chamber. When the soil
to be removed consists of sand, gravel, slime or other like materials that can be
removed by a stream or current there is no need for the workmen to enter the working
chambers the sand or the like being drawn out or discharged by means of an
apparatus G consisting of moveable or flexible pipes with nozzles projecting through
the partition C into the working chambers. These apparatus are provided with stop
cocks, which, when opened, connect them with closed receptacles or trunks S or simply
with the exterior of the chambers. The difference in the pressures in the working
chamber and the exterior or atmosphere of the tunnel is sufficient to produce a current
which draws away the sand or soil from the former.
In cases where the soil can be removed from the tunnel entirely by the aid of
water it is simply necessary to admit a continuous supply of a sufficient quantity of
water to the working chambers in order to cause the soil to be carried away by the
water when the outlet orifice is opened. The partition C at the back of the front
chambers is provided with glazed holes H to enable the progress of the operation to
be seen by the aid of electric or other lamps L.
When the soil contains stones or is of such a clayey or tenacious nature for example
as not to admit of being washed away by a current of water the workmen are first
shut up in the lock or middle compartments by closing the doors D in the partition B
and these compartments are charged with compressed air by opening cocks com-
municating with the working chambers until an equilibrium of pressure is obtained.
By means of doors D' in the partition C the workman can then pass into the working
chambers and dig out the face of the tunnel (as represented in the lower cell in
Figure 1) or remove any obstructions that oppose the advance of the shield. The
soil thus dug out or loosened in the working chamber is shovelled or thrown into the
trunks S in the intermediate chamber.
When the trunks S are full the covers at their inner ends are closed down and the
covers at their lower or outer ends are opened so as to allow their contents to descend
into trucks or receptacles in the construction chamber or in the tunnel the doors D'
communicating with the working chambers being first closed and the doors D opened
in order to allow the compressed air to escape. The doors D are then closed and the
doors D¹ opened and the work of excavation recommenced as before until the working
chambers are cleared. In tunnelling through the bed of a river for example the edge
of the shield may be stopped by coming in contact with an obstacle such as the ships
anchor 1 represented in Figure 1 as being embedded in the bottom of the river in
such a position as to be wholly or partly inaccessible to the workmen. Under these
conditions the men in the intermediate chamber between the partitions B and C which
in this case is filled with water up to the level of the door D or level at which
the compressed air escapes are unable to get at the anchor or remove it with any
-tools.

page_text: In this emergency a workman is equipped with a divers helmet and dress with the
exception of the lead soled boots and other weights being thus enabled to move about
freely in any direction as the dress does not require weights not being inflated owing
to a combination consisting in causing the air to circulate in the helmet or head
piece at a pressure corresponding to that of the water. The air escapes through a
pipe U leading to the air space in the middle chamber. A door is opened in the front
partition admitting water to the intermediate compartment and the workman provided
with the specially arranged dress passes from the intermediate compartment into the
working chamber and removes the obstacle.
Whilst one gang of men is employed in digging out the soil another gang or
gangs may work at the construction of the lining at the back of the shield the
rivetters erecting the casing O of iron plates which is employed to keep out the water
which might otherwise percolate through the brickwork and the bricklayers putting
in the brickwork all these operations being performed under atmospheric pressure.
Blocks of wood placed behind the shield and bearing against the brickwork lining or
against beams or girders imbedded therein may be employed to prevent the shield
from being forced backwards by the pressure and when the materials have been cleared
out of the working chamber and the lining constructed up to the back of the shield
the hydraulic rams P may be released and placed in readiness to advance the shield
to the extent of another stroke of the rams. With this object the pressure in the
working chambers is reduced or even entirely removed before the rams P are caused
to act. The shield is then secured by packing the space behind it as before.
The space left at the back of the shield at M between the sides of the tunnel or
excavation and the permanent lining is filled up with puddled clay or other materials
injected through a pipe or hose N by means of a pump Q for example. A certain
opening or interval is necessarily left between the inner surface of the casing of the
shield and the outer surface of the permanent lining of the tunnel and in order to
prevent water from penetrating through this opening to the interior of the tunnel
a flexible pipe T is placed in the interval and is expanded with air or liquid so as to
form a tight joint at this part.
The work may be carried on almost entirely under ordinary atmospheric pressure
as far as the workmen are concerned especially when the soil is of such a nature as
to bo removed by means of the nozzles or ejectors and the tunnel is being constructed
under a head of water of moderate pressure and which does not act entirely on the
surface of the working chamber at the time when the shield is being pushed forwards
but in constructing a tunnel at a considerable depth such as 100 feet of water for
example with the water constantly pressing against the face of the shield the power
of the rams is inadequate and is supplemented by compressed air forced into a
chamber formed at the back of the shield by erecting a hollow partition (forming a
lock) across the tunnel at a certain distance behind the shield as represented at V
Figure 1.
This partition V being suitably fixed in position the space between it and the back
of the shield can be charged with air under such pressure that the rams simply
require to overcome the resistance arising from the friction between it and the soil.
When the shield has thus been advanced by the raus it is secured by packing placed
behind it and the pressure in the working chamber can be reduced to a point
intermediate between atmospheric pressure and the pressure resulting from the head
of water. By these means facility is afforded for constructing tunnels without
inconvenience to the workmen under great pressures of water or at depths of 100 feet
and upwards.
In all the operations there is only a small number of men working in compressed
air and it is only in special cases that they are required to work under pressure at all,
their safety as well as the safety of the men working under atmospheric pressure being
also complete the shield being of sufficient strength to enable it to resist all the
pressures to which it is exposed and resulting from the weight of the superincumbent
soil or of the water. Any tunnelling or other like excavating operations under the

page_text: limits of pressure in which men can work may be conducted with advantage by the
aid of this improved apparatus.
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed I declare that what I
claim is :-
-
1. A shield constructed with a lock or intermediate chamber in order to enable
compressed air to be employed in the construction of tunnels or passages substantially
as herein before described with reference to the accompanying drawings.
2. A shield divided by floors and partitions into cells or compartments into which
(together or separately) compressed air can be introduced substantially as hereinbefore
described with reference to the accompanying drawings the said division facilitating
the support of the earth and enabling roof props to be dispensed with.
3. For working in the working chamber or cells of a shield employed in the con-
struction of tunnels and the like a non inflated diving-dress enabling the operator
to work under water without the aid of leads or weights by means of the arrangement
for supplying air to the head piece substantially as hereinbefore described with reference
to the accompanying drawings.
4. In combination with the improved shield or apparatus for the construction of
tunnels and the like the employment of clay applied by the means hereinbefore set
forth for filling the space or void left by the shield between the lining and the
surface of the tunnel substantially as hereinbefore described with reference to the
accompanying drawings.
5. The employment of a tube or pipe filled or expanded with air or liquid for making
a tight joint betwoon the lining of the tunnel and the casing of the shield substantially
as herein before described with reference to the accompanying drawings.
6. In combination with a shield for the construction of tunnels and the like the
employment of a partition (V) forming an intermediate air pressure chamber between
the shield and the atmosphere in order to facilitate the work of construction
substantially as hereinbefore described with reference to the accompanying
drawings.
7. The general arrangements and combinations of parts constituting the improved
apparatus for the construction of subterraneous or subaqueous tunnels or passages
substantially as hereinbefore described.
Dated this 7th day of October 1889.
J. H. JOHNSON & Co.,
Agents.