JP2004244842A - Existing tunnel repairing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a repairing method for extremely reducing fear of corrosion over the future by completely protecting a bolt body of a structurally unfixed part when repairing an existing tunnel, particularly, an existing tunnel having a lining on a tunnel inner peripheral surface by a lock bolt. <P>SOLUTION: When repairing the existing tunnel having the lining on the tunnel inner peripheral surface, a bore hole (h) is bored in the surrounding natural ground M by penetrating through the lining F. The lock bolt 1 is formed by respectively arranging an injection port of a fixing material on one end side of a sheath 7 arranged on the outer periphery of the bolt body 2, and a delivery port of the fixing material on the other end side, and is inserted into the bore hole. The bolt body 2 between at least the lining and a natural ground surface layer part is constituted to be covered with the sheath 7. After filling the fixing material G between the bolt body and the sheath by injecting the fixing material from the injection port, the fixing material G is filled and solidified in the sheath outside bore hole (h) and the surrounding natural ground M from the delivery port. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for repairing an existing tunnel, and more particularly to a method for repairing an existing tunnel having a lining on the inner peripheral surface of the tunnel.
[0002]
[Prior art]
Conventionally, when performing repair for the purpose of reinforcing an existing tunnel, for example, the present applicant has previously proposed the use of a lock bolt in Patent Document 1 as a reinforcing material. In that case, a major problem when repairing existing tunnels, especially tunnels constructed by conventional construction methods, is the cavities and voids that exist between the linings on the inner periphery of the tunnel and the natural ground. .
[0003]
That is, many recently constructed tunnels spray concrete on the pit wall and place lining concrete on the inside through a waterproof layer, so there is almost no gap on the back side of the lining, A tunnel constructed by the conventional so-called conventional construction method digs a mountain, supports the pit wall with a sheet pile made of timber, casts concrete or piles bricks with a predetermined thickness inside, Since it is a lining, there is usually a cavity outside the lining.
[0004]
On the other hand, there are roughly two types of rock bolt construction methods, the filling type and the injection type, but in either case, the presence of the cavity or void is not covered with the fixing material at the same time as the construction failure. A problem arises in the long-term reinforcement effect in that a part, that is, a part unprotected against water, is generated.
[0005]
In the end, the cavity is often filled by backfilling, but it is difficult to completely fill the cavity so as to eliminate the influence of spring water. It is inevitable that the so-called water path remains. Therefore, it is inevitable that a part of the rock bolt is defenseless against the spring water. In other words, it can be evaluated structurally that the cavity is filled with the backfill material, but it cannot be filled without leaving a small water channel.
[0006]
In other words, if backfilling is performed, the structure of the entire tunnel is evaluated, but normally, as a backfilling material, a soft material such as air mortar is injected so as not to place a burden on the existing lining. A state that is evaluated as being general and having no gap as an overall structure is not necessarily a state in which there is no water channel around the lock bolt.
[0007]
Therefore, there is a part that is not covered with the part corresponding to the above water channel in the placed rock bolt, and when there is corrosive spring water, A bolt body rusts and becomes thin. Then, in the back part of the old tunnel lining that should be repaired, the lock bolt that should form the arch that integrated the lining and the ground is cut off, and even if repair is done, it is appropriate The rock bolt effect, that is, the effect of forming an arch utilizing ground stress around the tunnel space cannot be expected. Furthermore, there are the following problems during the construction of rock bolts. For example, when a fixing material is injected into the bore hole into which the lock bolt is inserted through the injection tube or the like in advance, the size of the cavity, particularly the height direction, can be increased. The more it becomes, the more difficult it becomes to insert the injection tube into the natural ground, and there is a problem that the efficient work cannot be performed.
[0008]
On the other hand, there are three types of injection lock bolt construction methods as shown in FIGS. Each figure shows an example in which an injection-type rock bolt is applied to an existing tunnel having a gap between the existing tunnel lining F and the ground M on the outside.
[0009]
FIG. 6A shows a lock bolt (bolt body) B made of steel bar or the like, and the injection tube T1 and the exhaust tube T2 are inserted into the borehole h, and the opening of the borehole h is closed with the packer P. A type in which a fixing material (not shown) is filled into the borehole h and surrounding surrounding mountains from the injection tube T1 while discharging the air in the borehole h from the exhaust tube T2.
[0010]
In FIG. 6B, only the injection tube T1 is attached to the hollow lock bolt B and inserted into the bore hole h, the opening of the bore hole h is closed with the packer P, and the inside of the bore hole h is inserted from the hollow hole of the lock bolt B. A type in which the fixing material is filled into the bore hole h and surrounding surrounding mountains from the injection tube T1 while discharging the air.
[0011]
FIG. 6 (c) shows that only the hollow lock bolt B is inserted into the bore hole h, and the fixing material is released from the hollow hole of the lock bolt while discharging the air in the bore hole h from the gap between the bore hole h and the lock bolt B. Is filled in the borehole h and surrounding surrounding mountains.
[0012]
In the types shown in FIGS. 6 (a) and 6 (b), since the tube diameter that can be used for injection is limited to about 10 to 15 mm due to the limitation of the hole diameter, cement mortar or cement milk having high fluidity is used as the fixing material. If it is not used, it cannot be constructed efficiently. In addition, if the fixing material has high fluidity, the possibility that the fixing material escapes into the ground after the completion of the injection and causes poor fixing of the bolt depending on the condition of the crack in the ground. If the fluidity of the fixing material is lowered to prevent this, the frequency of tube clogging becomes very high. Once the injection tube is closed, the bolts must be pulled out, the tubes must be reattached and re-installed, which significantly increases work time and member loss.
[0013]
In FIG. 6 (c), a standard hollow lock bolt includes a material having a relatively large hollow hole diameter of about 20 mm, and the hollow hole is used as an injection port. Compared with the cases of FIGS. 6 (a) and 6 (b), it is possible to inject using a fixing material having remarkably low fluidity. As a result, for example, there is an advantage that the fixing material does not fall even from an upward hole, and the fixing material does not easily escape from a crack in the natural ground. However, the bolt is exposed in the unfixed portion of the cavity, and the point unprotected against spring water cannot be solved.
[0014]
[Patent Document 1]
JP2001-20098A
[0015]
[Problems to be solved by the invention]
The present invention has been proposed in view of the above problems, and provides a method for repairing an existing tunnel in which a bolt body in an unfixed part is completely protected structurally and there is very little risk of corrosion in the future. Objective.
[0016]
[Means for Solving the Problems]
In order to achieve the above object, an existing tunnel repair method according to the present invention has the following configuration. That is, when repairing an existing tunnel having a lining on the inner peripheral surface of the tunnel, a bore hole is drilled in the surrounding natural ground through the lining and fixed to one end side of the sheath provided on the outer periphery of the bolt body. A lock bolt having a material injection port and a fixing material discharge port provided at the other end is inserted into the bore hole, and at least the bolt body between the lining and the ground surface layer is formed by the sheath. The fixing material is injected from the injection port and filled with the fixing material between the bolt main body and the sheath, and then the fixing material is inserted into the bore hole outside the sheath from the discharge port and into the surrounding ground. It is characterized by being filled and solidified.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, a method for repairing an existing tunnel according to the present invention will be specifically described based on an embodiment shown in the drawings.
[0018]
FIG. 1 shows an example of a lock bolt used in a method for repairing an existing tunnel according to the present invention. FIG. 1 (a) is a longitudinal sectional view, FIG. 1 (b) is an enlarged view of a part thereof, and FIG. 1 (c). Is a bottom view.
[0019]
The lock bolt 1 in the illustrated example is provided with a bolt main body 2 having a rolling screw 21 on the entire outer peripheral surface, and a threaded engagement with the rolling screw 21 at the distal end portion 2a and the base end portion 2b of the bolt main body 2, respectively. A conical tip cap 3 and a nut 4, a dome head 5 and a bearing plate 6 provided so as to penetrate the bolt body 2 in the vicinity of the nut 4, and a bolt body between the dome head 5 and the tip cap 3. 2 and so on.
[0020]
The bolt body 2, the tip cap 3, the nut 4, the dome head 5, and the bearing plate 6 are each formed of a metal such as steel, and the sheath 7 is a synthetic resin tube 71 such as polyethylene resin and its synthetic resin in this example. It consists of a metal pipe 72 such as a steel pipe fitted and connected to the lower end of the pipe 71. The end of the synthetic resin pipe 71 opposite to the metal pipe 72 is fitted and fixed to the short cylindrical portion 3a provided on the tip cap 3, and the end of the metal pipe 72 opposite to the synthetic resin pipe 71 is the dome head. 5 are connected to each other by being integrally fixed to each other by welding or the like.
[0021]
The dome head 5 is formed in a hollow, flat and substantially spherical shape, and has a function as a fixing material injection port into the sheath 7, and the dome head 5 is provided with a fixing material injection hole 11. . The sheath 7 is provided with a discharge hole 12 as a fixing material discharge port on the distal end side. In the case of the figure, the discharge hole 12 is provided in the short cylindrical portion 3a of the distal end cap 3. It may be provided in the vicinity or between the sheath 7 and the tip cap 3. Further, the bearing plate 6 is formed in a flat funnel shape having an opening projecting downward at the center, and an exhaust hole 13 is provided in the vicinity of the opening.
[0022]
FIG. 2 is a cross-sectional view of the tunnel T in which the existing tunnel is reinforced and repaired using the lock bolt 1 described above, and FIG. 3 is a partial enlarged view thereof. In this example, an existing lining F formed of concrete or the like is shown. A plurality of lock bolts 1 are laid in the radial direction of the tunnel cross section through the gap A between the ground and the ground M.
[0023]
In constructing the reinforcement repair as described above, first, as shown in FIG. 4 (a), the bore hole h is formed in the ground M through the lining F and the gap A, and the same figure is formed in the bore hole h. Insert the lock bolt 1 as shown in FIG. At that time, at least the bolt main body 2 between the lining F and the natural ground surface layer portion (the natural ground inner surface) is covered with the sheath 7, for example, as shown in the illustrated example, the lining F and the natural ground surface layer portion M1. When there is a gap A between them, at least the bolt body 2 located in the gap A is covered with a sheath 7. In this example, the substantially entire length of the bolt body 2 including the gap is covered with a sheath 7 composed of a synthetic resin tube 71 and a metal tube 72.
[0024]
In this state, the fixing material G is injected from the injection hole 11 provided in the dome head 5, and the fixing material G flowing into the dome head 5 from the injection hole 11 is formed from the synthetic resin pipe 71 and the metal pipe 72. The bolt main body 2 located inside the sheath 7 is covered with the fixing material G in order from the bottom. At that time, the air in the sheath 7 is sequentially discharged into the bore hole h from the discharge hole 12 provided in the distal end cap 3.
Furthermore, when the fixing material G is injected and the entire space between the sheath 7 and the bolt body 2 is filled with the fixing material G as shown in FIG. When the fixing material G is further injected from this state, the fixing material G flows from the discharge hole 12 into the bore hole h, and the outer peripheral surface of the sheath 7 is moved downward from the upper side in the bore hole h to the fixing material. G is sequentially filled so as to cover, and a part of the fixing material G penetrates into the natural ground.
[0025]
When the fixing material G is filled in the entire bore hole h on the natural ground M side, the flat funnel shape continues through the bore hole h on the lining F side while continuing to descend so as to cover the outer peripheral surface of the sheath 7 in the gap A. Into the bearing plate 6. At that time, the air in the bore hole h on the natural mountain M side and the lining F side is discharged to the outside from the exhaust hole 13 provided in the bearing plate 6, and the fixing material G flowing into the bearing plate 6 is discharged into the exhaust hole 13. The injection of the fixing material G is stopped when it has flowed out.
[0026]
Thereafter, the fixing material G filled in the sheath 7 and the bore hole h is solidified to fix the lock bolt 1 so as to connect the existing lining F and the natural ground M. If a plurality of the lock bolts 1 are provided in the radial direction of the tunnel cross section as shown in FIG. 2, a firm arch-shaped reinforcement region can be formed on the outer periphery of the tunnel.
[0027]
As described above, when there is a gap A at least between the lining F and the natural ground surface layer portion M1, particularly between the lining F and the natural ground surface layer portion M1 as shown in the illustrated example, the inside of the space A The bolt body 2 located at the position of the sheath is covered with a sheath 7, and a fixing material is filled and solidified between the bolt body 2 and the sheath 7, in the bore hole h outside the sheath, and in the surrounding natural ground M. Thus, even if there is a portion where the fixing body is not covered on the outside of the sheath 7 by the air gap A, the bolt body 2 is at least double protected by the sheath 7 and the fixing materials on both the inside and outside thereof. Thus, it is possible to satisfactorily prevent the bolt body 2 from being rusted by the spring water and the corrosive components contained in the spring water.
[0028]
The air gap A is filled with a backfill material such as air mortar as necessary in a conventionally known manner, and the filling operation is performed either before or after the operation of placing the lock bolt 1 is performed. Well, in any case, the bolt body 2 is protected at least twice as described above even if a water channel remains between the backing material and the lining or between the backing material and the ground. Therefore, there is no risk of corrosion.
[0029]
Moreover, in the said embodiment, although the sheath 7 was comprised with the synthetic resin pipe | tube 71 and the metal pipe 72, you may comprise only a synthetic resin pipe | tube or only a metal pipe over the full length of the sheath 7. FIG. The sheath 7 may be one having a large number of protrusions 7a projecting outward on the peripheral surface as shown in FIG. 5 (a), or one gently bent in a zigzag manner as shown in FIG. 5 (b). If such a sheath is used, the fixing strength can be increased.
[0030]
【The invention's effect】
As described above, according to the method for repairing an existing tunnel according to the present invention, the bolt body 2 of the lock bolt 1 can be protected at least twice by the sheath 7 and the fixing material G, so that the existing tunnel lining F and ground M It is possible to prevent the bolt body 2 from rusting as much as possible even when there is a gap or a water gap between them, and it is possible to greatly improve durability and reliability. .
[Brief description of the drawings]
FIG. 1A is a longitudinal sectional view showing an example of a lock bolt used in the present invention.
(B) is an enlarged view of a part thereof.
(C) is the bottom view.
FIG. 2 is a cross-sectional view of a tunnel in which an existing tunnel is reinforced and repaired according to the present invention.
FIG. 3 is an enlarged view of a part of FIG.
FIG. 4 is an explanatory diagram showing an example of a construction process of the tunnel repair method according to the present invention.
FIGS. 5A and 5B are longitudinal sectional views showing examples of changing the sheath. FIGS.
FIGS. 6A to 6C are explanatory views showing a construction example of a conventional injection type rock bolt.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Lock bolt 2 Bolt main body 3 Tip cap 4 Nut 5 Dome head 6 Bearing plate 7 Sheath 71 Synthetic resin pipe 72 Metal pipe 11 Injection hole 12 Discharge hole 13 Exhaust hole T Tunnel F Covering A Cavity M Ground mountain M1 Ground mountain surface layer part G Fixing material h Bore hole

Claims (1)

When repairing an existing tunnel with a lining on the inner peripheral surface of the tunnel, a bore hole is drilled in the surrounding ground through the lining, and a fixing material is attached to one end of the sheath provided on the outer periphery of the bolt body. Lock bolts each having a fixing material discharge port at the inlet and the other end are inserted into the bore hole, and at least the bolt body between the lining and the ground surface layer is covered with the sheath. After the fixing material is injected from the injection port and the fixing material is filled between the bolt body and the sheath, the fixing material is filled into the bore hole outside the sheath and the surrounding ground from the discharge port. A tunnel repair method characterized in that it is solidified.

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