Note: Descriptions are shown in the official language in which they were submitted.
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_eld of the Inven-tion
The invention relates to tunnel linings.
Background of the Invention
Descri~tion of the Prior Art
U.K. Patent No. 14462~02 describes and illustrates
a tunnel llning consisting of rings of arcuate segments
a nuinber of which are preformed, internally smdokh
segments to provide the lower or invert of the lining
and a num~er of which have recesses on the inner surfaces
and are fixed toge-ther by bolts to form the upper part
of the lining. The smooth segments are in-terconnected
by simple dowel connections between adiacent circumferentlal
ends of the segments which locate the ends of the segments
in register with one another but do not secure the ends
of the segments together. It has been found that when such
a lining is erected behind a tunnelling shield, and as
the shield is withdrawn from the lining there is a tendency
for the smooth invert segments to drop away from the other
segments because the dowel connections do not hold the
segments positively in place. It has also been found
with this form of tunnel lining ring that as the loads
on the tunnel lining increase over the mon-ths after
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construction, the lining tends to squat in the vertical plane and
to adopt an increasing out of circular form. The simple dowel
connections between the smooth segments of the invert are not cap-
able of resistiny such squat.
United Kingdom Patent 2,004,931 describes and illustrates
a tunnel lining comprising rings of arcuate segments of smooth
internal surface which are locked positively together at their
circumferential ends by tapered pins driven into recesses in the
adjacent segment ends through overlapping tensile hoops bridging
the re esses to lock the segment ends together in compression.
This construction can be built to true circular form and since the
segments are locked together there is no risk of the lowermost
segments dropping away after extraction of the shield and so the
circularity of the ring is maintained as the loads on the ring
increase.
However, in certain conditions, neither of the above
forms of lining may be considered suitable and it is an object of
this invention to provide a lining which preserves the rigid
invert structure of United Kingdom Patent 2,004,931 whilst per-
mitting an 01ement of choice for the remaining part of the lining.
Summary of the Invention
The invention provides a tunnel lining comprising a number
of side-by-side sections each having a pluraltty of arcuate segments
of generally smooth internal surface forming a lower part of the
section with the segments being secured together end-to-end by
overlapping tensile hoops projecting from the respective segment
end and retaining devices driven into the overlapping hoops and an
arch of a further form of segment bridging the upper ends of the
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lower part of the section, the arch comprising a plurality of
arcuate segments having end flanges, bolts securing the end flanges
of adjacent segments together, sockets in the upper ends of the
segments of the lower part of the section and further bolts extend-
ing through the flanges at the lower ends of the arch and screwed
into the sockets in the upper ends of the lower part of the
section to secure the flanges to said upper ends.
Brief Description of the DrawingS
Figure 1 is an end view of a section of a tunnel lining;
and
Figure 2 is a section along the line 2 2 on Figure 1.
Description of the Preferred Embodiments
Referring firstly to Figure 1 of the drawings, the
tunnel lining section shown constitutes one of a number of sections
laid along the tunnel and comprises a lower part indicated general-
ly by the reference numeral 10 having three (or optionally more)
arcuate concrete smooth internal surface tunnel lining segments Ll
laid end to-end around the lower part of the tunnel. The joints
indlcated at 12 between adjacent ends of the segments 11 are of
the ~orm described and illustrated in United Kingdom Patent
2,00~r931. sriefly, each segment end has a pair of spaced semi-
cylindrical grooves e~tending partway across the segment
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end from the inner side thereof. One of -the grooves
has a pair of tensile hoops bridging the groove and
projecting from the segment end to receive a
corresponding hoop on the adjacent segment and the other
groove has a single tensile hoop projecting from the
segmen-t end to engage be-tween a corresponding pair of
hoops on the other segment end. Either tapered pins
or equivalent fastening devices are driven into the
overlapping hoopsto draw and hold the segment ends together
in compression. Where required a waterproof membrane
or o-ther sealing element may be disposed between the
adjacent ends of the segments. The resulting assembly
of seyments 11 provides a smooth internal lower surface
for the tunnel lining.
15The segment ends 13 at the upper ends of the
lower par-t 10 of the lining each have a pair of spaced ~-
cast-in ~rew threaded sockets 14 and the upper arch
of the lining comprises a pair of further arcuate
concrete lining segmen-ts 15. The lower ends 16 of the
arch of further segments are formed with in-ternal
flanges 17 through which bolts (not shown) extend into
the sockets 14 -to secure the lower ends of the segments
16 to the upper ends 14 of the segments 11. The adjacent
ends of the two seyments 15 at -the -top of the lining are
each formed with further flanges 18 which are bolted
toyether with a ke~ segment 19 between the ends of -the
segments,
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Thus the upper part of the lining does not have a
smooth internal surface as provided by the lower part of the
lining but, since the entire or at least the main flow of fluid
through the lining will take place through the lower part of
the lining only the lower part of the lining need have a
smooth internal surface. The upper part of the lining can be
formed from any conventional construction of which the bolted
lining system just described is but one example. In the case
where the lining is not intended for waterflow but for purposes
such as supporting the ground in a railway tunnel/ a simple
arch construction may be used for supporting the tunnel roof
instead of the lining arrangement.
The tunnel lining segments can be secured together
along the tunn~l by any convenient system such as that described
and illustrated in our United Kingdom patent No. 2,004,931.
It will be understood that the number of smooth
inner surface lining segments provided in the lower part of the
lining and the construction of the upper part of the lining
can be varied from that described above to suit the requirements
of the particular lining to be constructed.
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