Improvements in Tunnel Linings.
Year: 1899

page_text: Date of Application, 30th May, 1899-Accepted, 1st July, 1899
COMPLETE SPECIFICATION.
Improvements in Tunnel Linings.
I, THOMAS HENRY MURPHY, of 1401, Monadnock Building, Chicago, Illinois,
U.S.A., Manufacturer, do hereby declare the nature of this invention and in what
manner the same is to be performed, to be particularly described and ascertained
in and by the following statement:
My invention relates to improvements in tunnel linings to be used in the con-
struction of tunnels and sub-ways in connection with the use of a shield which is
employed in the process of excavation in a well-known manner.
Heretofore shields have been used most successfully in connection with a tunnel
lining comprising cast iron sections in the form of segment boxes bolted together
in a circle and receives the direct pressure of the rams which are employed to push
the shield forward into the heading and cut out the excavation. This lining has
been expensive and requires considerable time to erect.
Various attempts have been made to use grouting concrete or loose bricks laid
together without mortar as an outer lining to receive the thrust of the shield,
enclosing an inner lining of brick masonry, as it has been found wholly impracticle
to receive the shield pressure upon newly laid masonry.
The grouting concrete when used as an outer lining requires time to set, and
when pressed upon before setting will check or crack the green or newly laid
masonry and render the lining of the tunnel faulty.
The object of my invention is to provide a combined outer tunnel lining and
shield abutment ring, or a concrete lining may be secured and completely protected
both against the pressure and destructive actions of extensions or unexcavated
material until the inner lining containing lime or cement has been thoroughly dry
and set.
My invention consists in an outer tunnel lining made of wooden blocks or sections
locked together and placed one upon the other and secured thereto, the circum-
ferential joints being preferably laid with sheets of water-proof material as burlap
soaked in tar which will when tightly compressed by the rams. provide a non-
yielding abutment to receive the pressure of the shield and also a water-tight
outer lining for the masonry.
My invention further consists in securing inwardly projecting bolts to the
wooden lining having bond plates upon their inner end to hold the concrete or

page_text: other inner lining more securely to the outer lining as will hereinafter appear with
reference to the accompanying drawings, wherein :-
Figure 1, is a perspective view of a series of blocks lining and connecting pieces
laid together to form my improved outer lining;
Figure 2, a transverse section upon a reduced scale of a tunnel formed in
accordance with my invention, and
Figure 3, a perspective detail of a segmental lining strip and fragments of two
adjacent strips.
The tunnel lining as shown in Figure 1 comprises an outer lining of wooden
blocks matched and interlocked at their ends and placed in rings or in a continuous
ring circumferentially within the bore of the tunnel, the wooden blocks 1, as shown,
having a V-shaped protrusion 2 at one end and a corresponding V-shaped in-
denture at the outer end to match and interlock each other and thus provide a
self-supporting cylindrical shell, against which the outer unexcavated loose and
liquid material of the tunnel bore may be supported, the circumferential seams
between the layers of wooden block may be protected and be made water-proof by
a layer of water-proof material 4, as burlap formed in segmental sections with
rabbeted ends 5, soaked in tar and placed between each layer of blocks, and com-
pressed together with the blocks by means of rams in a solid cylindrical mass,
the burlap layer breaking joint with the blocks and the blocks and burlap sections
being built up continuously, one following the other, the pistons and the rams
being released and adjusted successively and continually, thus enabling the shield
to be pushed forward without intermission.
The continuous method of laying the outer lining and moving the shield forward
uninterruptedly is of great advantage both for expediting the work and for keeping
the constant pressure upon the outer lining to render it perfectly water-tight before
the inside lining is laid.
The rings of blocks being thus tightly compressed by the rams may be tied
together by lagging placed longitudinally within the outer lining and spiked to the
blocks either as a sheathing or at suitable distances apart. The entire shell
forming the inner lining is thus made compact watertight of pieces of any required
size or sizes to thus use up waste material, the whole lining securely bound together
to provide a strong continuous self-supporting shell should the shell be removed
or the pressure taken from all the rams.
The inner lining may be laid within a lining such as described, in a secure and
workmanlike manner. Suitable bolts being passed through and held between the
wooden blocks and secured thereto in a suitable manner, the inner end of said bolts
projecting within the outer lining and provided with a bound or bond plate 8, thus
providing an anchorage for an inner lining of concrete or grouting, which may be
readily shaped to any desired design of cross-section, either to suit the purposes of
the tunnel or to provide sub-conduits for drainage, gas, water and electric
conductors in a simple, inexpensive and expedious manner.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed, I declare that what
I consider novel and desire to claim is: ---
1. A tunnel lining comprising an outer circle of segmental wooden blocks placed
end for end and one upon the other and secured together in rings to receive the
rams of a tunneling shield and connected together in a suitable manner longi-
tudinally to provide a self-sustaining outer shell to closely follow the shield and
an inner lining of suitable material as masonry or concrete to be protected by
said outer lining until set substantially as described.
2. A tunnel lining comprising a cylindrical shell of wooden sections forming
continuous rings intermediate sheets of water-proof material, and longitudinal
lagging strips secured to and acress the wooden ring sections to connect them
together substantially as described.
3. In a tunnel lining an outer shell comprising a series of wooden sections inter-

page_text: posed sheets of water-proof material, bond plate bolts secured to and projecting
outwardly from said outer shell and an inner lining secured by said bolts sub-
stantially as described.
Dated this 29th day of Mar 1800.
H. D. FITZPATRICK,
100, Wellington Street, Glasgow, Agent.