[0001] This invention concerns a process to excavate the inverted lower arch in existing
tunnels. To be more exact, this invention concerns a process suitable for the excavation
and restoration of the inverted lower arch in existing tunnels without interrupting
the flow of vehicles normally passing along the tunnels where work is to be done.
[0002] The process of the invention is generally employed equally well in work to enlarge
existing tunnels or only repair the existing inverted arch.
[0003] The process may also be employed for the excavation and preparation of a new inverted
arch in existing tunnels.
[0004] The invention concerns also the apparatus which employs the above process.
[0005] The state of the art covers the problems connected with the excavation and rehabilitation
of the inverted lower arch in existing tunnels. These problems arise substantially
from the need to interrupt any flow of vehicles within the tunnels until the excavation
and rehabilitation work has been completed.
[0006] Such work generally becomes necessary where existing tunnels are to be enlarged,
and in cases where the inverted arch has to be re-made because it has collapsed or
been damaged or for other reasons.
[0007] It follows that alternative plans have therefore to be made which normally envisage
the doubling of the tunnel in which work has to be done.
[0008] The outcome can be summed up as involving long times for design work and approval
of the new plans, the necessity of expropriation of land, environmental problems and
the unavoidable performance of new works upstream and downstream for the necessary
rectification of the lay-out.
[0009] The present applicant has the purpose of overcoming the problems linked to the state
of the art and of perfecting a process able to carry out the excavation and rehabilitation,
or excavation and preparation, of the inverted arch in existing tunnels without interrupting
the flow of vehicles passing into the tunnels.
[0010] A further purpose of the invention is to provide an apparatus able to carry out the
above process.
[0011] The invention is set forth in the main claims 1 and 14, while the dependent claims
describe various features of the invention.
[0012] The process of the invention provides for the use, within an existing tunnel, of
a protective shield through which the traffic is made to pass. This protective shield
forms part of the state of the art.
[0013] The shield can stretch along the whole length of the tunnel or be restricted to the
portion substantially affected by the works. This portion, in the case of a railway
line, to which we shall refer in the description that follows, is suitably supported
to enable trains to pass through while work is proceeding below it.
[0014] The support structures are suitable prepared on each occasion downstream of the portions
on which work is being carried on, according to methods belonging to the state of
the art.
[0015] The excavation works on the inverted arch are conducted with an apparatus which passes
along the tunnel and is positioned between the protective hield and the inner wall
of the tunnel.
[0016] This apparatus carries out the following works continuously for excavation and rehabilitation
of an existing inverted arch:
- the making of two lateral excavations parallel to the railway line so as to enable
the apparatus itself to pass through;
- excavation of the existing inverted arch for complete demolition of the same;
- removal of debris of the excavated inverted arch from the excavation zone;
- removal of all the excavation debris towards the outside of the tunnel or, at any
rate, onto means able to carry the debris out of the tunnel, and
- the casting of a new inverted arch.
[0017] When the casting of the new inverted arch has ended, steps are taken to remove the
protective shield and to set the railway line and all the service works finally in
order.
[0018] According to the invention the apparatus suitable to carry out the above process
consists of a vault-wise structure bearing below itself the equipment to excavate
the inverted arch.
[0019] This excavation equipment works beneath the railway line and comprises a rotary drum
excavation tool that extends substantially along the whole width of the inverted arch.
[0020] With the advance of the vault-wise structure on its own runways, this excavation
tool carries on continuously the excavation of the inverted arch, the debris of which
is removed by means of the excavation tool itself. For this purpose it comprises incorporated
means for removal of debris from the excavated zone so as to transfer the debris onto
means for final removal from the tunnel.
[0021] The excavation tool possesses not only a rotary motion but also a vertical motion
so that it can be adjusted to the thickness of the inverted arch to be excavated.
[0022] Shuttering operates in cooperation with the excavation tool in a coordinated manner
in the casting of material to form a new inverted arch in the excavation zone. This
shuttering is suitably conformed to constitute a support too for the railway lines
above.
[0023] Auxiliary means may also be comprised to remove excavated material which may not
have been collected by the excavation tool.
[0024] The vault-shaped structure is equipped with lateral excavation means to make channels
parallel to the railway line which make possible the free forward movement of the
excavation tool and the removal of debris from the tunnel; these lateral excavation
means obviously work in advance of the excavation tool.
[0025] The apparatus of the invention can be included advantageously in a working train
carrying out enlargement of existing tunnels; it can work just as well independently
if only the repair of an inverted arch is required.
[0026] These and other special features will be described better in the description of the
invention that follows.
[0027] The attached figures, which are given as a non-restrictive example, show the following:-
Fig.1 is a front diagrammatic view of an excavation apparatus according to the invention;
Fig.2 is a section of the apparatus of Fig.1 along the line A-A;
Fig.3 is an enlarged partial section of the apparatus of Fig.1 along the line B-B;
Fig.4 is a front diagrammatic view of a tunnel with the excavation already performed;
Fig.5 is a front diagrammatic view of a tunnel with a new inverted arch.
[0028] The figures give an example, as we said above, of the excavation of an inverted arch
in an existing railway tunnel, which in this case contains two railway lines.
[0029] Railway lines 11-111 are shown in the tunnel 10 for the passage of trains 12-112.
[0030] Provisional support means 14 to support rails 15, as in the state of the art, are
provided in the zone involved in the excavation of an existing inverted arch 13.
[0031] These provisional support means 14, which may consist of bundles of rails or other
suitable systems, are positioned in succession along the railway lines 11-111 so as
to enable the excavation work to advance continually.
[0032] The railway consisting of two lines 11-111 is protected by a protective shield 16
within which the trains 12-112 can pass.
[0033] The protective shield 16 may have a minimum indispensable length equal to the portion
of the tunnel 10 involved in the works and may include its own runways 17 positioned
on supports 18 arranged at the sides of the railway.
[0034] If so required, the protective shield 16 may also have a length differing from the
portion of the tunnel 10 involved and will have overall dimensions suited to that
of the trains 12-112 passing through it.
[0035] The apparatus to excavate the inverted arch 13 consists of a vault-shaped structure
19 able to run within the tunnel 10 on its own runways 20 positioned on supports 18.
[0036] The vault-shaped structure 19 comprises lateral arms 21 to support excavation equipment
22; these lateral arms 21 can be adjusted vertically, by jacks 23 for instance, so
as to adapt the action of the excavation equipment 22 to the thickness of the inverted
arch 13.
[0037] The vertical displacement of the arms 21 can be carried out continuously during the
whole excavation work.
[0038] The excavation equipment 22 consists of a drum 24 capable of being rotated about
its own axis according to the arrow 25 by a motor 26, advantageously a hydraulic motor.
[0039] The drum 24 extends substantially along the whole width of the inverted arch 13 and
has an outer conformation suitable to obtain the desired final profile of the inverted
arch 13 as an element to complete the circumference of the tunnel 10. In the example
shown the outer conformation of the drum 24 conforms to a double cone.
[0040] The drum 24, which is hollow within, includes on its outside excavation tools 27,
which cooperate with slits 28 made in the periphery of the drum 24 so as to enable
the materail excavated to fall within the drum 24. This fall takes place by gravity
and the material is held momentarily by vanes 29 suitably arranged inside the drum
24.
[0041] When the material reaches the neighbourhood of the upper part of the drum during
rotation thereof, it falls from the drum 24 and the vanes 29 onto a discharge means
within the drum; this discharge means is positioned parallel to the axis of the drum
24 and in this case is a first conveyor belt 30 driven by a motor 31 in the direction
of the arrow 32.
[0042] According to a varaint at least one stationary worm is included within the drum 24
and is arranged in such a way that it skims the inner surface of the drum 24. The
excavated material is discharged sideways by the friction caused by the relative movements
of the rotary drum and stationary worm. All embodiments provide for discharge of the
material on one side or on the opposite side or on both sides.
[0043] The first conveyor belt 30 emerges laterally from the drum 24 and cooperates with
a second conveyor belt 33 that removes the excavated material towards the outlet of
the tunnel 10.
[0044] The second conveyor belt 33, being positioned beneath the plane of the railway lines
11-111, can cooperate conveniently with elements that discharge onto vehicles which
carry the material out of the tunnel 10 if there is enough space available.
[0045] The lateral end portions of the drum 24 and of the first conveyor belt 30 and also
the lower ends of the support arms 21 and the second conveyor belt 33 can move in
service channels 34 excavated beforehand parallel to and at the sides of the railway.
These service channels 34 are obtained advantageously by the action of excavation
arms (not shown in the figures) solidly fixed to the vault-shaped structure 19.
[0046] These excavation arms obviously work in the direction of forward movement 35 of the
vault-shaped structure 19 in advance of the action of the equipment 22 that excavates
the inverted arch 13.
[0047] Shuttering 36 works in cooperation and coordination with the movement of the excavation
equipment 22 so as to make possible the casting of material 37 which will form the
new inverted arch 113. This shuttering 36 may be conformed advantageously to provide
a support for the railway lines 11-111 above; for this purpose it may consist, for
instance, of two halves 136-236 which can be coupled together telescopically and actuated
by an inner screw 40.
[0048] A discharge worm screw 41 may be connected advantageously to the shuttering 36 and
be suitable for lateral removal of debris not collected by the drum 24.
[0049] Fig.4 shows the situation in the zone where excavation work on a pre-existing inverted
arch 13 takes place.
[0050] Fig.5 shows the situation after the new inverted arch 113 has been cast, together
with the positioning of ballast 38, the arch 113 blending with the inner lining 39
of the tunnel 10.
1 - Process to excavate the inverted lower arch in existing tunnels, tracks (11-111)
for vehicles passing within the tunnels (10) being protected by a protective shield
(16) placed between the tracks (11-111) and the inner walls of the tunnels (10), the
portion of the tracks (11-111) involved in the excavation being made to cooperate
with provisional, temporary support means (14), the process being characterized in
that it provides for performance of the working steps connected with the excavation
of the inverted lower arch (13) in existing tunnels (10) without interrupting the
normal flow of traffic passing within the existing tunnels (10) in which work is to
be done, the working steps connected with the excavation being organized and carried
out within the circular space contained between the protective shield (16) and the
extrados of the tunnel (10) and below the portion of track (11-111) momentarily upheld
by the temporary support means (14).
2 - Process as claimed in Claim 1, whereby the working steps connected with the excavation
of the inverted lower arch (13) in existing tunnels (10) consist of:
- excavation of lateral service channels (34) parallel to the tracks (11-111),
- excavation of the existing inverted arch (13);
- removal of the debris of excavation of the inverted arch (13) from the excavation
zone;
- discharge of the debris of all the excavations towards the outside of the tunnel
(10), and
- casting the new inverted arch (113),
the working steps being carried out continuously in a desired momentary succession
by an apparatus able to move along the tunnel (10).
3 - Process as claimed in Claim 1 or 2, whereby the excavation of the inverted arch
(13) may be a coordinated step in an operation to enlarge existing tunnels (10).
4 - Process as claimed in Claim 1 or 2, whereby the excavation is carried out so as
to lay a new inverted arch (13).
5 - Process as claimed in any claim hereinbefore, whereby the excavation of the inverted
arch (13) is carried out on a frontage corresponding to the width of the inverted
arch (13) itself.
6 - Process as claimed in any claim hereinbefore, whereby the position for excavating
the inverted arch (13) may be varied according to the thickness thereof.
7 - Process as claimed in any claim hereinbefore, whereby the removal of the excavated
material of the inverted arch (13) takes place laterally to the tracks (11-111).
8 - Process as claimed in any claim hereinbefore, whereby the removal of the excavated
material of the inverted arch (13) takes place substantially at the same time as the
excavation of the same.
9 - Process as claimed in any claim hereinbefore, whereby the removal of the excavated
material of the inverted arch (13) is carried out by the means that perform the excavation.
10 - Process as claimed in any claim hereinbefore, whereby the discharge of the excavated
material of the inverted arch (13) takes place on a plane located below the tracks
(11-111).
11 - Process as claimed in any claim hereinbefore, whereby when the work of excavation
of the inverted arch (13) has ended, the excavation possesses a definitive configuration.
12 - Process as claimed in any claim hereinbefore, whereby the excavation of' the
service channels (34) is carried out at the same time as, but in a position in advance
of, the excavation of the inverted arch (13).
13 - Process as claimed in any claim hereinbefore, whereby shuttering (36) for casting
(37) the new inverted arch (113) is employed as a support for the railway tracks (11-111).
14 - Apparatus to excavate the inverted lower arch (13) in existing tunnels (10),
which employs the process of the claims hereinbefore and is characterized in that
it consists of:
- a vault-shaped structure (19) able to move on its own runways (20),
- arms (21) to support the excavation equipment,
- excavation equipment (22) and
- means to excavate service channels (34).
15 - Apparatus as claimed in Claim 14, in which the support arms (21) can be adjusted
vertically.
16 - Apparatus as claimed in Claim 14 or 15, in which the excavation equipment (22)
consists of:
- a hollow rotary drum (24),
- means (26) to actuate the drum (24),
- excavation tools (27),
- means (30) to remove debris, and
- means (31) to actuate the removal means (30).
17 - Apparatus as claimed in any of Claims 14 to 16 inclusive, in which the rotary
drum (24) comprises on its periphery slits (28) that cooperate with the excavation
tools (27).
18 - Apparatus as claimed in any of Claims 14 to 17 inclusive, in which the rotary
drum (24) comprises internal vanes (29) for temporary storage of excavation debris.
19 - Apparatus as claimed in any of Claims 14 to 18 inclusive, in which the debris
removal means (30) are located within the rotary drum (24).
20 - Apparatus as claimed in any of Claims 14 to 19 inclusive, in which the debris
removal means (30) consist of a conveyor belt.
21 - Apparatus as claimed in any of Claims 14 to 19 inclusive, in which the debris
removal means (30) consist of at least one stationary worm.
22 - Apparatus as claimed in any of Claims 14 to 21 inclusive, in which the length
of the rotary drum (24) is coordinated with the width of the inverted arch (13) to
be excavated.
23 - Apparatus as claimed in any of Claims 14 to 22 inclusive, in which the shuttering
(36) has a telescopic structure (136-236).
24 - Apparatus as claimed in any of Claims 14 to 23 inclusive, in which the shuttering
(36) comprises screw-type actuation means (40).
25 - Apparatus as claimed in any of Claims 14 to 24 inclusive, in which the shuttering
(36) comprises lateral worm screw means (41) to discharge excavated debris.