JPH08135383A - Repairing work method of tunnel in use - Google Patents

Abstract

PURPOSE: To carry out a repairing work without stopping the overall running of a train in particular, in a repairing work method of an existing tunnel such as the widening of the tunnel and the repairing of the peripheral wall. CONSTITUTION: A reinforcement of a natural ground 5 by rock bolts; an excavation and exhaust of a repairing area; an erection of a mine timbering 1 to an excavated area; a partitioning which consists of an end plate with an air fence 7 to the clearance between the mine timbering 1 and a natural ground; and the installing of a face protective work 10 to the excavated face; are carried out. Furthermore, a series of works including the installing of a collapse protector to an existing arch in a nonexcavated part; the assembling of a PC plate 2a between the mine timberings; and the pouring and the filling of a backfilling mortar layer 3 to the clearance between the PC plate and the natural ground; are repeated as one cycle, so as to repair the full length of the tunnel.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a so-called repair work method for widening an existing tunnel and repairing an arch part or a side wall part in the tunnel. In particular, the present invention relates to a construction method capable of performing construction without stopping the passage of vehicles during the repair work period.

[0002]

2. Description of the Related Art For example, the PCL method (PRECAST CONCRETE) is used as a construction method for widening an existing tunnel.
There is LINING). This method is characterized by excavating and eliminating the arch part and side wall part of the existing tunnel to be widened, and installing a trolley equipped with an erector for assembling the arch part on the rail at the entrance side of the tunnel. , The arch-shaped panel made of precast concrete slab, that is, the panel functioning as the secondary lining, is installed, and in that state the transport vehicle is guided into the tunnel, and the above-mentioned panel is operated by operating the above-mentioned electrator on the vehicle. It is a construction method that is integrally attached to the arch part in the tunnel, backfill mortar is filled between the panel and the ground and fixed. This is a kind of panel construction method using a so-called PC plate. Therefore, it is evaluated as a construction method that contributes to shortening the construction period.

[0003]

However, this PCL
When the construction method is used, the passage of vehicles during the construction period is completely stopped. Further, there is a problem that it is necessary to deploy a very large-scale dedicated machine equipped with an erector for assembling the panel.

Needless to say, the railway network is an economic artery. Therefore, even if it is temporary, it is a great economic loss to completely stop its use. Therefore,
For the purpose of eliminating this economic loss, there has been a demand for the development of a construction method that allows repairs such as widening and repairs while allowing the passage of vehicles while ensuring sufficient safety.
It is an object of the present invention to provide an existing tunnel repair work method as a means for responding to such a request.

[0005]

Therefore, as means for achieving the above object, the present invention regulates the operation of a vehicle by performing a work process according to the following procedural method during an operation stop time of the vehicle. No, that is, the repair work for widening or repairing the existing tunnel is performed without completely stopping the passage of vehicles. (1) First, as a means for reinforcing the ground of an existing tunnel to be widened or repaired, a rock bolt was driven in the side wall portion or the arch portion. In other words, rock bolts were used to reinforce the ground of the side walls and arches of the existing tunnel to be widened or repaired. (2) When the reinforcement work was completed, the side wall part or the arch part was excavated according to the expansion or repair width, and the excavation scrap was carried out of the tunnel. That is, the side wall part or the arch part of the existing tunnel was excavated in accordance with the widening region or the repair region, and the excavation gap was carried out. (3) After the excavation and the excavation excavation work was completed, support work was built at a fixed pitch. Specifically, 0.
Support works were built at intervals of 8 to 1.5 meters. (4) When the supporting work was built, a partition made of an air fence was detachably attached to the gap between the outer circumference of the supporting work and the ground. Further, the face portion excavated for widening or repairing was provided with face protector made of an air tube as a means for preventing the face portion from collapsing. (5) Then, when the work of attaching the partition consisting of the siding and the face protection work by the air fence is completed, the mesh muscles are inserted between the support works, and one worker can easily hold it between the support works. It incorporates a preformed rectangular PC plate that can be embraced. Specifically, the high-strength concrete slabs were sequentially inserted in such a manner that they were hung between the supporting works, and the side wall portion or the arch portion or the entire circumference of the side wall portion and the arch portion was constituted by the high-strength concrete slab. That is, the PC plate was incorporated as a lining and formwork. Further, a protector was attached to the existing arch portion in the unexcavated portion as a means for preventing peeling and collapse of the existing arch portion, that is, the existing secondary lining. (6) When the work of assembling the PC plate and the attaching work of the protector are completed, the back filling mortar injection hose is connected to the socket that is embedded in the PC plate in advance, and the back surface of the high-strength concrete plate is connected through this injection hose. Mortar was injected and filled into the gap between the ground and the ground. That is, a secondary lining consisting of a high-strength concrete slab and a mortar layer was formed.

The features of this repair work method are:
As described above, the above-mentioned series of work is defined as one cycle during the suspension time of operation of the vehicle, and is sequentially repeated from the entrance side of the existing tunnel to the exit side of the tunnel to perform the repair work on the entire length of the existing tunnel. Especially. In other words, it allows trains to pass between cycles so that construction can be performed without stopping the passage of trains during the repair work period.

Further, in order to shorten the cycle time of the above-mentioned series of work, excavation of the arch or the side wall and carrying-out of the slip, construction work of supporting work,
The work process for installing a partition consisting of a siding plate with an air fence in the gap between the outer periphery of the support work and the ground and attaching the face protection work to the excavated face face should be performed in the following procedure. did.

First, the support work was built by excavating one pitch of the support work construction interval. Then, a blocking means for preventing collapse is attached to a new arch portion formed by excavation, that is, a new ground arch portion in the gap between the outer periphery of this support work and the ground. After that, one more pitch was excavated to build the support work. Then, this support work,
That is, the partition consisting of the siding plate by the air fence and the face protector are attached to the gap between the outer periphery of the second support work and the ground.

In addition, at the site where there is spring water in the tunnel, before the backfilling mortar injection and filling work, along the ground side of the arch and the side wall, that is, along the cutting surface and at a constant interval. Was installed and a drain pipe was attached. Then, after the installation, backfill mortar was injected and filled so that the spring water was guided and discharged to the gutter of the tunnel roadbed.

[0010]

In the method for repairing an existing tunnel according to the present invention, the construction is carried out based on the procedure described above. Therefore, the allowable time zone for construction work is set in advance from the train passage time on the repair line. Specifically, a construction section was set up to accommodate the time zone from the passage of the last train at night to the passage of the first train. And (1) to
The one-cycle work process of (6) was completed during that time period, and the heavy machinery used was evacuated from the tunnel. As a result, the desired repair work could be performed without stopping the operation of the vehicle during the construction period.

Further, in the work steps of excavating the arch or the side wall, constructing the supporting work, installing the partition consisting of the siding plate by the air fence, and further installing the face protector, first the supporting work is carried out. After constructing the support work by excavating by one pitch of the construction interval of the work, after installing the blocking means for preventing collapse on the new ground arch part formed by excavation in the gap between the outer periphery of this support work and the natural ground. According to the procedure of constructing a supporting work by excavating one pitch, and installing a partition consisting of a seed plate by the air fence and a face protector in the gap between the outer circumference of this supporting work and the ground. It is possible to perform backfilling mortar injection and filling work for the gap between the high-strength concrete slab and the ground for two pitches between the front and rear supports, that is, for two spans at the same time. That. As a result, the cycle time of a series of work procedures could be shortened. In other words, it was possible to perform more efficient repair work during the limited construction time, that is, during the vehicle operation suspension time.

[0012]

[Embodiment] Further, this repair work method will be concretely explained based on an embodiment shown in the drawings. In addition, in this embodiment, description will be given based on a case where the present invention is applied to widening work of an arch portion in an existing tunnel including a secondary lining of a brick structure. Incidentally, FIG. 13 is a partial perspective view showing the tunnel cross-sectional structure after the widening work, and 100 is the existing secondary lining of the brick structure. In addition, 1 is a supporting work set for repairing, 2 is a secondary lining that constitutes a newly widened arch portion made of high-strength concrete slab 2a, 3 is a backfill mortar layer, and 4 is ground. It is a rock bolt that was placed to reinforce the mountain.

First, FIG. 1 shows a state in which heavy machinery used for widening and repairing is installed in a tunnel of the widening and repairing route. The order of arranging the heavy equipment on the drawings is not particularly specified. Next, an outline of the division of roles of these heavy machinery will be described. First, from the upper left, A is a road header. It is responsible for excavating the arch part that should be widened. Next, B is a carrier dump, which conveys the excavation scrap excavated by the load header A to the outside of the tunnel. C is a carrier dump, which is a high-strength concrete slab 2a mainly used during the construction work of the support work and during the support work.
It is intended to be used as a kind of aerial work vehicle to be used when incorporating or filling back-filling mortar. D is a back-filling mortar filling pump, and E is a mixer car that plays a role as a mortar supply device that supplies back-filling mortar to the filling pump D. The mixer truck E has a role as a carrier for loading backfilled mortar into the tunnel from a mortar manufacturing plant (not shown) installed outside the tunnel.

Further, F on the left side of the lower part of FIG. 1 is a spraying device for super rapid hardening cement in an emergency, specifically, super quick hardening premix concrete. This is a so-called emergency countermeasure work vehicle at a construction site, which responds to the occurrence of spring water or landslides. G is a hydraulic wheel jumbo, which is a lock bolt 4 as a reinforcing means for the arch part or the side wall part.
It is equipped with a punching machine that shares the work such as placing.
Reference numeral H denotes a carrier vehicle equipped with a mortar pump, which shares the work of fixing the lock bolt 4 and the work of carrying the support 1 and the high-strength concrete slab 2a serving as the secondary lining into the tunnel. It should be noted that all of these heavy equipments are on standby at the evacuation site installed outside the tunnel except during repair work, and are always on standby so that the desired work process can be started promptly at all times.

Next, the working procedure will be described based on the order of steps. First, FIG. 2 shows the lock bolt 4 as a reinforcing means on the ground 5 of the arch portion and the side wall portion by the hydraulic wheel jumbo G shown in FIG. It is sectional drawing at the time of finishing the driving operation. That is, it indicates the end of the work process of the reinforcement work by the lock bolt 4.

FIG. 3 is a sectional view showing a work process of excavating the widened region of the arch portion by the load header A. As described above, in this embodiment, the excavation area is limited to the arch portion as illustrated because of the widening of only the arch portion.

FIG. 4 shows a case in which the carrier dump C is used to construct a lining / formwork between the erection support 1 (1) after the erection is completed and the erection support 1 is installed in the arch after the widening excavation work. It is a tunnel sectional view at the time of finishing the assembling work of the functioning high-strength concrete slab 2a. For shoring work 1,
The one obtained by bending the H-shaped steel was used. Also,
In the example, the tunnels were built at a pitch of 1.2 meters in the longitudinal direction.

FIG. 5 is an arch part showing a work process in which a partition consisting of a plenum 8 by an air fence 7 is attached to the support 1 after the building work and the gap 6 between the support 1 and the ground 5. FIG. In the embodiment, a rubber hose-shaped air fence 7 is filled with compressed air (7 Kg / cm ² ) through a compressor (not shown) and inflated. Then, on the outer side (on the right side in the figure), the crate plate 8 is detachably attached via a stopper 9, so that the air fence 7 forms the crate plate 8 into a partition structure. That is, the metal stopper 9 is clamped to the flange 1a of the supporting structure 1 so that the air fence 7 serves as a detachable partitioning structure composed of the chest plate 8.

The partition formed by the siding plate 8 by the air-borne fence 7 is a high-strength concrete slab 2 which serves as a secondary lining.
When the back-filling mortar layer 3 is filled in the gap 6 between the back surface of a and the ground 5, the role of preventing leakage of the mortar layer 3 is shared. Incidentally, reference numeral 16 in the drawing
Is an injection confirmation hole of mortar, the role of which will be described later.

FIG. 6 is a construction sectional view of a face protection work 10 for preventing the face part from collapsing in the arch part excavated for widening. The structure is an inverted L-shaped air structure made of H-shaped steel on the lower surface of the support structure 1 located on the most distal side (the right side in the drawing) as shown in the figure and the support structure 1 in front of it. The tube fixing bracket 11 was attached. And
The air bag 12 is provided between the horizontal plate 11a provided at the tip (right side in the figure) of the air tube fixing bracket 11 and the face of the cutting face, that is, the arc-shaped excavation face composed of the excavation face.
Face protector 10 was applied. The injection of air into the air bag 12 is the same as in the case of the air fence 7.

FIG. 7 shows the exfoliation of the old secondary lining made of the existing brick structure, that is, the tip side of the mounting portion of the face protector 10 shown in FIG. 6, that is, the cutting work for widening has not been performed yet. It is sectional drawing which shows the attachment construction of the protector 13 for preventing a fall. As for the structure, the suspension rod 4a is connected to the lock bolt 4 previously constructed to protect the natural ground.
The protector 13 was suspended using a. A corrugated board made of synthetic resin is used as the protector 13, and the protector 13 covers the arch portion, that is, the entire circumferential area corresponding to the ceiling of the tunnel.

The face protector 10 shown in FIG.
Also, the role of the protector 13 shown in FIG. 7 is to prevent a collapse accident of the ground 5 and the old secondary lining part from the arch part before the train is passed and also during the construction work. It is for. FIG. 8 is a sectional view of the tunnel in which the work of attaching the protector 13 has been completed.

Further, in this embodiment, the high-strength concrete slab 2a incorporated between the supports 1 and 1 is prepared by mixing a thermosetting melamine resin into a composition containing cement, finely divided silica and a special additive and heat treating the mixture. The special precast concrete slab obtained by doing was adopted. Moreover, the shape is about 120 cm in length, 5 cm in thickness, about 20 cm in width,
A PC plate having a weight of about 25 kg and formed to be easily carried by one worker was prepared. That is, one worker can easily install between the front and rear flange portions 1a and 1a (see FIGS. 5 and 6) of the erected supports 1 and 1, respectively, to quickly form the arched secondary lining 2. It is a PC version 2a that can be constructed.

9 (A) and 9 (B), in order to facilitate the work of assembling the high-strength concrete slab 2a between the supports 1 and 1, mounting metal fittings 2c and 2c provided as jigs on the PC slab 2a are shown. It is the top view (A) and front view (B) which show an example. As shown in the figure, the anchor bolts 2b,
Mounting brackets 2c and 2 having an elongated plate shape via 2b
c was held. Then, the mounting brackets 2c and 2c
And the flanges 1a and 1a (see FIG. 6) of the supporting structure 1 are inserted between the ends of the concrete slab 2a and the concrete plate 2a so as to be fixed. As a result, one worker can quickly
Moreover, the assembly work can now be done efficiently.

Although not shown in the drawings, each high-strength concrete slab 2a was previously embedded with a back-filling mortar injection socket, and was installed between the support works 1 and 1 in the same manner as described above. The injection socket was used to perform backfilling concrete filling work. In addition, the assembling work of the high-strength concrete slab 2a was performed by using the carrier dump C as described in FIG.

By the way, in the filling and filling work of the backfilling mortar, it is easy to leave a void at the top of the arch. Therefore, in the embodiment, as a means for eliminating the generation of the voids, as shown in FIGS. 5 and 10, an injection of about 2 inches is preliminarily performed on the top of the partition composed of the seed plate 8 by the air fence 7 forming the partition. When a confirmation hole 16 is provided and mortar is injected from the injection socket, it is confirmed that the mortar continuously leaks from the confirmation hole 16 and the injection work is completed.

As the back-filling mortar, a special lightweight mortar commonly called scum mortar was used. That is, mortar was used which has high fluidity, can be injected and filled, has an appropriate viscosity, has high particle dispersibility, is difficult to separate, and has excellent adhesiveness as a mortar grounding material.

Although not shown in the drawing, a mesh streak is interposed between the spans prior to the filling and filling work of the back-filling mortar between the supports 1 and 1, and then the backing is performed. The filling mortar was injected and filled. That is, a backfill mortar layer reinforced with mesh rebar was used to enhance its strength and adhesiveness.

FIG. 11 shows a drain pipe 1 as a measure against spring water.
Fig. 5 is a sectional view of a rehabilitated tunnel showing a piping example of No. 5, which is installed between the ground 5 and the backfill mortar layer 3 and has a structure in which water is guided to a side groove (not shown) along the side wall of the tunnel. And FIG. 12 is an enlarged sectional view taken along line XX of FIG. Further, FIG. 13 is a partially cutaway perspective view showing the tunnel cross-sectional structure after the completion of the widening repair work as described at the beginning.

FIGS. 14 (A), (B), and (C) show a rock bolt for reinforcing the ground on the side wall side and the arch of the existing tunnel. Other examples of the excavation work taken to shorten the cycle time until the filling and filling of the mortar into the gap and the work of attaching the partition made of the seed plate 8 by the air fence 7 are shown in the order of steps. First, (A) shows a case in which only one pitch of the construction method P of the support work 1 is excavated and the next support work 1 is built. (B) shows that a new arch portion formed by the excavation, that is, a blocking means 17 is attached to the ground arch 5 and the gap 6 on the outer periphery of the supporting work 1 that has been built as described above, as a means for preventing the collapse of the ground arch portion. The figure shows the excavation for one pitch and the construction work for the next support 1 (right side in the figure) is completed. As the blocking means 17, a hose-shaped bag body is provided in the gap 6 between the outer periphery of the support structure 1 and the ground 5, and then the bag body is filled with mortar to inflate the ground arch. It was used as a means to prevent the collapse of parts. (C) is a filling plate 8 by an air fence 7 in a gap 6 between the outer periphery of the right side supporting work 1 and the natural ground 5 after the above construction is completed.
The state where the partition consisting of is attached is shown.

After carrying out the above procedure, each support work 1,
1 and 1 High strength concrete plate 2
Assembling a and 2a (shown by phantom lines) causes left and right 2
Injecting and filling backfilling mortar into the pitch interval (2P) is possible. As a result, the cycle time is shortened, and more efficient repair work can be performed in a limited time zone.

The method for repairing the existing concrete according to the present invention is to perform the repair work by widening it according to the procedure described above with reference to the embodiments, so that the following effects can be exhibited. it can. (1) There is no need to stop traffic during the construction period. That is, the construction section is set in advance corresponding to the time zone in which the vehicle does not pass through the construction section. That is, a construction section is set in which the construction work can be performed within the time zone in which the vehicle does not pass. More specifically, by setting the number of support spans that can be installed within the time period when the vehicle does not pass, how to construct the support work from excavation work, construction of the lining plate by incorporating the concrete slab, and By performing a series of operations such as backfilling mortar injection and filling, it can be constructed without being controlled by vehicle traffic. (2) In addition, the construction method according to the present invention does not require a dedicated large-scale machine as seen in the conventional PCL construction method, and requires a small number of people to install a high-strength concrete slab, which is an important part of construction work. It can be easily carried out by the worker, and since the partition construction consisting of the siding plate by the air fence is performed for each span to perform the filling and filling work of the backfilling mortar, one span and one span can be reliably performed. And it can be repaired under a safe working environment. (3) During excavation work, if blocking means is provided for every other support work and two spans are excavated, the injection and filling of mortar can be performed once for two spans, and the work cycle time can be shortened. . In addition to the protection work for the excavated face, there are few measures to prevent the collapse of the arch in the unconstructed area. As a result, it is possible to develop a safe, efficient, and quick construction work without interrupting the important role of the railway network, that is, by utilizing the limited vehicle suspension period.

[Brief description of drawings]

FIG. 1 is a tunnel cross-sectional view showing an example of deployment of heavy equipment used in a case of performing a widening work on an arch portion of an existing tunnel by a repair work method according to the present invention.

FIG. 2 is a sectional view of a tunnel in which a rock bolt as a ground reinforcement means is installed.

FIG. 3 is a tunnel cross-sectional view showing an excavation work process of a widened region (arch portion).

FIG. 4 is a sectional view of the tunnel at the time when the support work is built and the high-strength concrete slab assembling work process is completed between the support works.

FIG. 5 is a vertical cross-sectional view showing a work step of attaching a seed plate by an air fence that partitions a gap between each support work and the ground.

FIG. 6 is a construction cross-sectional view of a face protection work for an excavated face.

FIG. 7 is a cross-sectional view showing a structure of a protector mounting construction portion as a collapse prevention means of the old secondary lining in the unconstructed area.

FIG. 8 is a cross-sectional view of the tunnel in which the protector has been attached and installed.

FIG. 9A is a plan view of a high-strength concrete slab provided with a mounting bracket, and FIG. 9B is a front view thereof.

FIG. 10 is a vertical cross-sectional front view of the top of the tunnel showing the installation position of the injection confirmation hole of the mortar.

FIG. 11 is a sectional view of a repair tunnel showing an example of attaching a drain pipe as a measure against spring water.

12 is an enlarged cross-sectional view taken along line XX of FIG.

FIG. 13 is a partially cutaway perspective view showing a tunnel cross-sectional structure after widening work.

FIG. 14 shows another procedure for excavating the arch part or the side wall part, constructing the supporting work, and installing a partition made of a mortar plate by an air fence in the gap between the outer periphery of the supporting work and the ground. It is a process drawing of an example.

[Explanation of symbols]

 1 ………… Supporting work 1a …… Flange part 2 ………… Secondary lining (new) 2a …… High-strength concrete slab 2b …… Insert anchor bolt 2c …… Mounting metal fitting 3 ………… Back filling mortar layer A… …… Roadheader (excavator) B ………… Carrier dump (for excavation transfer) C ………… Carrier dump (high work vehicle) D ………… Back filling mortar filling pump E ………… Mixer truck F… …… Emergency spraying work vehicle G ………… Hydraulic wheel Jumbo (piercing machine) H ………… Transport vehicle with mortar pump 4 ………… Lock bolt 4a …… Suspension rod 5 ………… Solid ground 6 ………… Gap Part 7 ………… Air fence 8 ………… Damping plate 9 ………… Stopper 10 …… Face protector 11 …… Fixed bracket 11a… Horizontal plate 12 …… Air bag 13 …… Protector 15 …… Drain piping 16: Injection confirmation hole 17: Blocking means

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Norio Shinomiya 2-4-24 Shibata, Kita-ku, Osaka City, Osaka Prefecture West Japan Railway Company (72) Inventor Yasutada Ikeda Shibata, Kita-ku, Osaka City, Osaka Prefecture 2-4-24 West Japan Passenger Railway Co., Ltd. (72) Inventor Kazuhiro Yasui 2-4-24 Shibata Shibata, Kita-ku, Osaka-shi, Osaka Prefecture West Japan Passenger Railway Co., Ltd. (72) Inventor Toshio Tamura Shinjuku, Tokyo 1-25-1 Nishi-Shinjuku, Taisei Construction Co., Ltd. (72) Inventor Hideo Tanaka 1-25-1 Nishi-Shinjuku, Shinjuku-ku, Tokyo Taisei Construction Co., Ltd.

Claims (4)

[Claims] 1. A repair work method for expanding or repairing an existing tunnel, comprising the following work steps. (1) The work process of placing a rock bolt as a means for reinforcing the ground of the side wall portion or arch portion of the existing tunnel to be widened or repaired, and (2) the side wall portion or arch portion to be widened or repaired. Excavation work according to the widening or repair area and work process for carrying out excavation slip, (3) Work process for constructing support work at a constant pitch in the excavation part, and (4) Support work A step of installing a partition made of a siding plate by an air fence in the gap between the outer periphery of the ground and the ground, and installing a face protector for the excavated face, and (5) a side wall portion between the support works. A work process in which a high-strength concrete slab that functions as a lining and a formwork is installed in the arch part, and a protector that prevents the existing arch part from collapsing in the unexcavated part is attached, 6) A working step of injecting and filling backfill mortar into the gap between the back surface of the high-strength concrete plate and the ground to form a secondary lining composed of the high-strength concrete plate and the mortar layer, (7) above (1) A method for rehabilitating an existing tunnel, characterized in that the work steps from (6) to (6) are defined as one cycle, and the construction is repeated from the entrance side to the exit side of the existing tunnel to be rehabilitated. 2. The excavation work of the arch portion or the side wall portion, the construction work of the support work, the installation of a partition made of a mortar plate by an air fence in the gap between the outer periphery of the support work and the ground, and the excavation. In the work process of attaching the face protection work to the face part, first, the support work is constructed by excavating the support structure by one pitch, and the excavation is performed in the gap between the outer periphery of this support work and the ground. After installing the blocking means to prevent the collapse of the arch part, excavation for 1 pitch was further carried out to build the support work,
The method for repairing an existing tunnel according to claim 1, characterized in that a partition composed of a siding plate by the air fence and a face protector are attached in a gap between the outer periphery of the support work and the ground. 3. The method for repairing an existing tunnel according to claim 1, wherein a drain pipe for spring water is attached to the excavated surface of the arch part or the side wall part toward the inner groove of the tunnel. 4. The method for repairing an existing tunnel according to claim 1, wherein mesh filling is embedded in the injection filling layer of the backfilling mortar.