Improvements in the Construction of Submarine Tunnels.
Year: 1898

page_text: Date of Application, 16th July, 1898-Accepted, 20th Aug., 1898
COMPLETE SPECIFICATION.
Improvements in the Construction of Submarine Tunnels.
We, CARL PAULITSCHKY, Civil Engineer, and Madame ROSA PAULITSCHKY, Married
Woman, both of IV Gusshaus Str. 21, Vienna, in the Austrian Empire, do hereby
declare the nature of our invention and in what manner the same is to be
performed, to be particularly described and ascertained in and by the following
statement:
Our invention relates to improvements in the construction of submarine tunnels
constructed at considerable depth from the surface of the sea.
The establishment of a serviceable system of transit by means of railway carriages
or other vehicles between two continents separated by a channel, straits, or the like is
admittedly fraught with much difficulty, for it is in the first place imperative to avoid
all interference with navigation, an interference which would inevitably exist were an
embankment, road or bridge built across the sea; while, on the other hand, the
cutting of a subterranean passage through the ground, below the sea bottom, is at
the best a risky undertaking, as one is for ever liable to come upon layers of
permeable matter, or indeed upon accumulations of water, which would infallibly
cause the whole of the expensive works already carried out to be flooded and
destroyed, the sudden and unforeseen rush of water probably involving serious loss of
life. It is, indeed, impossible to provide for or guard against all the conceivable
emergencies and catastrophes that may arise under those circumstances since an
accurate survey of the ground at the bottom of the sea is utterly impracticable.
Now the object of our invention is to obviate these drawbacks and dangers, and to
devise means for establishing an intercourse between two continents separated by the
sea-such as Great Britain and France for example-under far better conditions than
it would be feasible by the performance of any of the diverse projects which have
been hitherto framed for the purpose. Here is a brief enumeration of these schemes:
(1) A subterranean tunnel below the sea ground; (2) an iron bridge supported by
piers of masonry and raised high above the sea level; (3) an elevated dyke or mole
forming the groundwork of a railway or road; and (4) a tunnel built either of metal
tubes or of brickwork upon the sea bottom. All these projects, however, are attended
with too many and too serious inconveniences to be by any chance likely to be ever
carried into practical effect. To cut an underground tunnel at the sea bottom is as
we have before explained altogether too risky a matter. The construction of an iron
bridge upon solid walls or piers, while it does not indeed present any insurmountable
technical difficulty, loses inuch of its practical value through the obvious fact that
piers or pillars erected at distances of from 300 to 500 metres apart could not but
seriously obstruct and endanger navigation especially in foggy weather; while when
squalls ог gales are about, they would make a train traffic across the channel equally
unsafe. A continuous pier, mole or jetty, extending right across the channel, even
though openings were provided in it at pre-determined distances, for ships to pass
through, would, it stands to reason, block navigation to an even more considerable
extent than would bridge; again a tubular tunnel through a structure erected upon
the bottom of the sea, while it may possibly admit of a train service being organized,
makes it still very doubtful, whether such a structure will be capable of holding out
for any appreciable length of time; for it is a notorious fact that ordinary cast iron

page_text: tubes, no matter of how powerful a construction, or how strong may be the foundation
whereon they rest, are apt to crack and split at comparatively short notice, and hence
promptly become unfit for use; besides, quite apart from the almost unconquerable
technical difficulties attaching to such a construction, railway trains could hardly be
relied on to circulate through it in a satisfactory manner owing to the wide differences
of level existing at the sea bottom.
The means of transit which the present invention affords is calculated to remove
all the difficulties and disadvantages above set forth, while on the other hand every
one of its features militates in favour of its adoption. Its advantages are as
follows:
(1) The tunnel does not extend through any unexplored or unfathomable ground,
but is built in solid ground-work the dimensions of which are exactly determined
beforehand;
(2) All the conditions and circumstances under which the tunnel is to be built
may be weighed and computed in anticipation ;
(3) As it is to be sunk to a sufficient depth below the sea level to lie in a
layer or zone where the water is perfectly calm, and being moreover thoroughly
water tight, it will enable trains to move to and fro with absolute safety, without
interfering with navigation; and
(4) Drainage and ventilation are easy and simple in construction, while the cost of
keeping the works in repair is reduced to a minimum.
The main features of our invention are as follows: A number of annular tunnel
sections or lengths each consisting of 3, 4, 5, or more wrought or cast iron or other
metal rings are tightly fitted together, and groups or sets of such tunnel sections are
hermetically closed in by means of water tight plates or partitions removable from
within. These tunnel sections, or groups of tunnel sections, thus joined and closed,
are of a less specific gravity than water and will consequently float thereon. Upon
being floated and brought up to a point of the water surface above and coinciding
with the position which they are eventually to occupy, they are sunk by being
sufficiently weighted for the purpose, until they reach and firmly settle upon an
embankment previously erected by the aid of blocks of rock, the surface or bed of
which has been properly levelled with concrete and ballast. The divers at the bottom
of the sea then fit together these sets of tubes and seal the joints hermetically so as
to form sections of the tunnel in course of construction of greater or less length, an
operation which does not present any very great difficulty, inasmuch as the portions
of the tunnel may be suspended by means of chains from the ships or rafts which
serve to convey them from one point of the sea to another. Thus the tunnel
sections are readily manipulated on the water, and the divers are able rapidly to
install them in the requisite positions, in strict alignment and exactly on the pre-
determined level. After having thus formed upon the bed of the submarine
embankment a section of the contemplated tunnel of somewhat considerable length,
the partitions dividing the several sets of tubes, which go to form that tunnel section,
from each other, are removed, and the metal body constituting the partial tunnel is
lined internally with masonry or hydraulic concrete (cement stone) so FLS
effectually to keep out the water. It will be understood that instead of the
masonry, concrete or cement, any other suitable material which will ensure strength
and tightness may be employed, while it also goes without saying that the sectional
outline of the tunnel must needs be such as to admit of the construction of a service-
able railway line, track or roadway in its interior.
"
In order that the subject of our invention may be more clearly understood, we
shall now proceed to describe the same in detail with reference to the accompanying
drawings in which,
Fig. 1 is a section of the works across any given channel or straits. indicating the
levels of the sea, and including a longitudinal section of the submarin tunnel.
Fig. 2 is a cross section on line X Y.

page_text: Figs. 4 5 6 7 and 8 are sections representing the details of construction of the body
of the tunnel;
Fig. 9 is a longitudinal section of the line or road carried from one sea shore to the
other, the lengths being drawn on a scale about one hundred times less than the
heights (or depths); and
Fig. 10 shows the line nearing the shore on a scale approaching the full size more
or less.
A and B are the shores or coasts on both sides of an intercontinental channel canal
or other water course.
level.
C indicates the high water sea level, and D, the low water sea
In constructing a tunnel in accordance with our invention, the first stage is to
determine the axis of the tunnel, which operation is performed by means of anchored
metal cords or cables c c¹ c² attached to buoys d d¹ d² floating on the surface of the
water at distances of from 300 to 500 metres apart. The depth of the water is then
ascertained along this axis at the points where the cables are anchored, and so the
depth is likewise determined at points such as e, f, e¹, f¹, e², f2
,
situated about 30 metres from the axial line on either side thereof (see Fig. 3). By
such means a longitudinal section and cross sections of the sea bottom are obtained,
quite similar to those which are taken preparatory to the performance of earth works
on terra firma. The longitudinal section the level-line of the bed of the embank-
ment which is to serve as the base or foundation of the tunnel body is then drawn ;
this is supposed to be the line marked A¹ B¹ C¹ in Fig. 1. This line should be
situated sufficiently far below the sea level D to enable ships of any tonnage to pass
over the tunnel unimpeded after its completion, or at all events over the greater
part of such tunnel. From this lowest part of the tunnel it should slope upwards in
the direction of the sea board on both sides. This lowest or central portion may be
horizontal as shown in the drawings, though it is preferable to give it a slight
gradient from the middle towards both extremities, the object of such a course being
to enable the water resulting from condensation and filtration to drain off to the two
pumping stations erected at the terminals of the slopes. After having determined
the level, or gradient, as the case may be, of the tunnel bed, the completion of the
embankment is proceeded with, the materials necessary for the purpose-preferably
pieces of rock or pebble stone more or less elongated in shape-being sunk all along
the line, as marked by the buoys.
The length of this embankment or bedding at its base m m¹ (Fig. 2) should be
approximately three times greater than that which it would be were the works carried
out on land; the width m m³, which evidently varies with the depth of the embankment
and the slope to be provided for, according to the nature of the materials employed,
is (in other words) so determined as to enable the bed or platform n n' to have also
a very considerable breadth imparted to it; so that eventually the axis of the iron
tunnel to be laid out may be shifted from the centre of the embankment to either
the right or left, and by preference-strictly in a straight line,-while the
embankment shall in practice be capable of slightly deviating from the mathematically
correct alignment.
When the embankment has been built, and its shape finally settled by means of
the sounding line, so as to ensure as near an approach as possible to the shape or
outline defined in the project, the levelling of the bed or platform is proceeded with
preferably by means of heavy ballast and a layer or course of strong concrete or
cement masonry as at E, Fig. 2. This work is performed in the ordinary diving
bells employed in pneumatic foundations, that is caissons provided with chimneys,
shafts or shoots for the reception of the materials brought up to the spot by craft
anchored in a convenient position for discharging them. Care should be taken to
make the surface of the concrete coincide with the longitudinal outline or section
described in the project whilst making it horizontal in the transverse direction. The
embankment with its concrete crown or crest consequently forms a very firm base,
as uniform as possible throughout, and ready to receive the body of the iron
tunnel T.

page_text: The construction of the tunnel itself is now commenced. In order to mark the
strictly correct axis of the embankment upon the surface of the water in a conspicuous
manner-the embankment in its complete and final form being taken as a criterion-
there are embedded in the layer of concrete a somewhat considerable number of iron
rings to which metal cords are attached which are likewise connected to the buoys on
the surface of the water. It goes without saying, that in proportion as the con-
struction of the embankment proceeds further the buoys which have originally been
employed to mark the final line of the proposed tunnel may be removed.
Now this is the manner in which the body of the tunnel is constructed :-
In view of the considerable weight of the rings or sections of the tunnel it is advis-
The rings R
able to erect special foundries in the immediate vicinity of the shores.
(see Figs. 4 to 8) shall be constructed of wrought or cast iron, steel, or any other
suitable metal or material; the dimensions and sections are determined so as to
admit of the provision of an inner lining, leaving the clear space necessary for the
passage of the trains. The width is thus approximately from 8 to 5 metres, and the
height or depth, from 5 to 6 metres. The thickness of the walls of the rings in ques-
tion should be sufficient to resist the pressure of a water column of say 30 metres
(with due regard to an adequate co-efficient of safety as usual). The rings R are
preferably very wide at their base, so as to have a firm resting surface upon the
embankment. They may moreover be made up of a number of parts hermetically
joined together, so as to facilitate their conveyance from the shore to the spot where
they are to be fixed.
At the top parts of the rings R there are secured or cast
integral with them, a number of ears or lugs such as p q for example, which will
serve to facilitate the joining and fixing operations.
The extremities of the rings are so shaped as to fit those of the adjoining rings as
accurately and closely as possible. To this end the arrangement shown in detail in
Fig. 5 may be adopted although that represented in Figs. 7 and 8 is to be preferred.
Of the two extreme edges of each ring one, 1 is contracted conically, while the other
2, is correspondingly enlarged. z is an indiarubber ring or band passed beforehand
on to the terminal of the tunnel section or ring r¹.
In order to lower the tunnel sections in the water (after they have been pre-
viously fitted together in groups of two, three, four or more), metal ropes are passed
through the ears p and q and they are brought up on to the surface of the sea, and
made to float in the axial line of the submarine embankment. The sets of rings thus
fitted together are now weighted sufficiently to make them sink down upon the con-
crete bed of the embankment (see Fig. 2). The divers then adjust them in position
in the manner hereinabove stated, by inserting them into each other (see Figs.
and 8) when, owing to the indiarubber packing rings, z the requisite water tightness
will for the time being be ensured at the joints, which are moreover strengthened by
means of screws such as 8, or by clamp irons or anchors employed to consolidate the
structure as a whole; and finally the joints are hermetically sealed outside and, in
addition, lined with lead internally.
After having thus constructed a certain length of the tunnel body upon the bedding
or platform of the embankment, the partitions t (Fig. 7), which separate the several
groups of annular tunnel sections from each other are removed, and an internal line
such as 2 (Fig. 4) is made of masonry, concrete, or hydraulic mortar, or cement. In
the middle of the tunnel platform there is as usual provided a bath or trough for
collecting the condensation and filtration water as it drains off; and there are further
provided lateral boards or side walks for the use of the gangers or road labourers.
At points from 300 to 500 metres apart there are provided safety niches or shelters.
as indicated at N (Fig. 4), and should the space available within the rings R not
admit of this, rings of greater width should be employed at those points. On the
whole, then, the interior arrangement of the tunnel is very similar to that of an
ordinary subterranean tunnel or subway.
The metal body of the tunnel thus constructed and previously covered with an
external coating to protect the metal from rust, is now additionally covered with a
layer of ballast or if desired a casing of hydraulic cement, the depth or thickness o

page_text: which may vary according to requirements; and lastly the whole is covered over with
pieces of rock or stone of more voluminous size. The body of the tunnel will after
this form one integral block with the embankment (see Fig. 2).
From the foregoing remarks it will be understood that the sole object of the metal
portion is to facilitate the construction of a submarine tunnel of masonry, and to
serve as a consolidating skeleton or framework for the same.
Should the depth of the water at either of the shores to be connected be
insufficient to enable the tunnel to be started from the very shore at a sufficiently low
level to suit the requirements of navigation; or if the people of either country
insisted upon it that their territory should not be entered upon by trains through
tunnels, but that the trains as they arrived, should be exposed to view, we propose
to establish the intercontinental connection in the manner clearly illustrated in
Figures 9 and 10.
Starting from the shore A, we would extend a railway line, fully exposed, along a
pier or embankment G, sufficiently high to enable one or a number of openings P
to be provided in it for the passage of coasting vessels. At a point F of this em-
bankment, the railway would reach and enter the tunnel H descending from that
point with a gentle gradient (say from 10 to 15 per mille.) to a depth sufficient for
the largest ships freely to pass over it. From this lowest depth-situated we will
say at the point I-the tunnel H should extend horizontally or with a very gradual
slope (1 per inille. for example) to a point. K situated in the middle or thereabouts of
the straits or channel to be spanned. Hence the tunnel may further continue to
extend either horizontally or with a gradual rise to a point L situated in proximity
to the opposite shore B, where the terminal connection with terra firma is effected
in the same manner as has just been described with reference to the shore A,
unless it is preferred to adopt the method specified hereafter and illustrated in
Figure 9.
At the points I and L of the tunnel-marking the greatest depths-we propose to
erect light-houses, and in conjunction with these, exhaust and ventilation stations
to keep the tunnel well drained and supplied with respirable air. By means of piers
or jetties such as M raised above the high water level, these lighthouses are connected
with the shore or the embankment G affording access to the tunnel H. All these
structures rising above the water would be lighted with electricity at night, while
the interior of the tunnel H and that of each of the lighthouses would be kept so
illuminated night and day without intermission. The electric light required for the
purpose would be supplied from stations installed on both shores and working each
independently of the other, whereby the simultaneous extinction of all the lights
would be rendered impossible; care being taken to illuminate the openings P for the
passage of coasters, guard ships, etc., with particular brilliancy, and if necessary
with coloured lights so that they may be descried and located by the shipping during
the night and through the densest fogs.
The trains, also, should in preference be propelled by electricity.
The stretch of sea situated between the lighthouses 0, 0,-which in the main
would be the identical part which prior to the construction of the tunnel had been
opened to navigation-will after such construction be likewise available for the
passage of ships of the largest tonnage.
As will be seen from Figure 9, we have assumed that next to the right hand shore B
there is a great depth of water. Where this supposition is verified, the main
embankment G (unless it be necessary to retain it for some such reason as we have just
now mentioned) may be dispensed with, and the tunnel H may be carried across at a
given angle or gradient from the point L to the land which it would enter in the
shape of an entrenchment. Thus at very little distance from the coast there
would be left a depth of water sufficient for all ordinary purpose of navigation. The
lighthouse O placed at the point L which forms the limit of the deep waters may be
replaced by a lightship, while, if necessary, the use of either a lightship or a light-
house may be altogether avoided.

page_text: Having now particularly described and ascertained the nature of our said
invention and in what manner the same is to be performed, we declare that what
we claim is:-
1. The special construction of submarine tunnels, consisting of fitting together a
number of annular tunnel sections of wrought or cast iron, steel or any other
suitable material, hermetically sealing their joints, and closing in groups or sets of
such annular sections at the ends, likewise hermetically, by means of water-tight
partitions removable from within; lowering the parts of the tunnel thus constructed
on to a submarine embankment of rock having formed on it beforehand a level
cemented bed or platform; fitting together the inetal tunnel sections hermetically
at the sea bottom and erecting them in the proper position upon the said platform
or bed; removing the partitions; providing the metal body of the tunnel with an
inner lining of masonry; covering such body externally with a protective layer
or casing of masonry or concrete, or protecting it in any other similar manner,
and finally consolidating the entire structure with blocks of rock or stone, so that the
tunnel and the foundation embankment may present one integral body or block.
2. A tunnel constructed and arranged substantially as described and shown.
3. The specially constructed submarine tunnels consisting in connecting therewith
a railway line or lines on shore by means of an embankment provided with openings,
permitting the tunnel to be sunk sufficiently deep to obviate any interference with
navigation, the tunnel entrances or terminals being situated upon the said embankment
at a convenient elevation above the high water level as set forth.
4. The specially constructed submarine tunnel consisting in combining with it a
short railway by means of a trench or excavation permitting the tunnel to be sunk
deep enough to allow of unimpeded navigation, the terminals of the tunnel being
situated at the entrance of such trench at a sufficient elevation above the high water
line as set forth.
5. The specially constructed tunnel, the terminals of which are connected with
terra firma by either of the described methods; one or both of the extremities of
the tunnel being connected with the shore substantially as set forth.
118 foth tra
11y 1000..
PHILLIPS & LEIGH,
No. 22, Southampton Buildings, Chancery Lane, London, W.C.,
Agents for the Applicants.