JP4380098B2 - Expansion method of existing tunnel - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for enlarging an existing tunnel, and more particularly to a method for enlarging a cross section of an existing tunnel while ensuring traffic of a vehicle.
[0002]
[Prior art]
In existing tunnels, such as those that have not passed the current building limits after the years of construction have passed, as a method of enlarging the cross-section while ensuring vehicle traffic, a protector has been installed in the existing tunnel. In addition to securing the passage of vehicles, etc. on the inside, excavating machinery was installed on the protector to remove the lining layer of the existing tunnel and excavate natural ground.
[0003]
However, in such a method for expanding an existing tunnel, a heavy machine such as an excavating machine is mounted on the protector. Therefore, the protector uses a highly rigid member over the entire line. The proportion of expenses increased and became very uneconomical.
[0004]
By the way, a protector for passing a vehicle is installed in an existing tunnel, and an example of an enlargement method of an existing tunnel in which a heavy machine such as an excavating machine is not mounted is disclosed in, for example, JP 2000-356090 A. ing.
[0005]
The expansion method proposed in this publication discloses that the section of the widening tunnel is divided into an advanced mine part adjacent to the cross section of the existing tunnel and a reverse mine part including the existing tunnel cross section. The intermediate wall as a temporary primary lining layer is constructed on the partition surface that divides the advanced mine and the reverse mine, and the reverse mine is excavated while leaving this intermediate wall. The gist is to remove and construct a widening tunnel that includes advanced and reverse shafts.
[0006]
In such a method for expanding an existing tunnel, a protector for securing vehicle traffic is installed in the existing tunnel when excavating the advanced mine, and after passing through the advanced mine, this protector is used as a tunnel on the advanced mine side. It will be transferred.
[0007]
However, such an existing tunnel expansion method also has the following technical problems.
[0008]
[Problems to be solved by the invention]
That is, a protector for securing vehicle traffic installed in an existing tunnel is usually extended over the entire length of the tunnel, but this is applied to an existing tunnel as in the enlargement method disclosed in the public gazette. If it is transferred from the inside to the advanced mine, it will be necessary to disassemble, relocate, and reassemble the protector, and it will take time to transfer, resulting in a decrease in construction efficiency.
[0009]
This invention is made | formed in view of such a conventional problem, The place made into the objective is to provide the expansion method of the existing tunnel which can avoid the fall of construction efficiency.
[0010]
[Means for Solving the Problems]
In order to achieve the above object, the present invention provides a method for expanding the cross-sectional area of an existing tunnel while securing the passage of a vehicle, and performing a reinforcement work on the lining layer of the existing tunnel from the inner surface side as necessary. And a step of installing a simple protector that protects vehicle traffic in the existing tunnel, and a step of excavating a widened portion having an arc-shaped cross section while providing a primary lining layer adjacent to the side of the existing tunnel. And after excavation of the widened portion, the side portion of the lining layer is cut and removed, and the widened portion and the existing tunnel are communicated with each other, and a temporary support column is provided at the side cut portion of the lining layer. And a step of forming a temporary partition wall between the newly installed floor slab and the ceiling portion of the widened portion on which the temporary primary lining layer is applied, while forming a new floor slab on the lower surface of the widened portion. And ensure vehicle traffic on the widened section side. While removing the simple protector and removing the temporary support struts, the arch portion of the lining layer is destroyed and the vicinity thereof is excavated to shape between the widened portion and the existing tunnel. And a step of forming an enlarged tunnel cross section and a step of forming a secondary lining layer in the enlarged tunnel cross section.
[0011]
According to the method for enlarging an existing tunnel configured as described above, the protector for protecting vehicle traffic is removed without being transferred if the vehicle traffic is secured on the widened portion side. Reduction in work efficiency due to replacement is avoided.
[0012]
The reinforcement work can be configured by placing a cable bolt from the inside of the lining layer toward the natural ground side and injecting a backfill material into the natural ground where the outer surface of the lining layer is in contact. .
[0013]
After forming the temporary primary lining layer, a temporary waterproof sheet material that is removed before the construction of the secondary lining layer can be provided on the inner surface side.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments of the invention will be described in detail with reference to the accompanying drawings. 1 to 12 show an embodiment of an existing tunnel expansion method according to the present invention.
[0015]
The method for expanding the existing tunnel 10 shown in the figure is to enlarge the cross-sectional area while securing the passage of the general vehicle 11 in the existing tunnel 10. First, the first step as shown in FIG. 1 is performed.
[0016]
In the first step, the reinforcement work 14 for the lining layer 12 of the existing tunnel 10 is performed. In the case of the present embodiment, the existing tunnel 10 is formed in an approximately horseshoe-shaped cross section, and the lining layer 12 includes a ceiling-side arch part and side wall parts connected to both sides thereof, and bottom plates are provided at both ends of the side wall part. 16 is formed.
[0017]
In the case of the present embodiment, the reinforcement work 14 is performed by placing a cable bolt 14a from the inside of the lining layer 12 toward the ground, and injecting the backfill material 14b into the ground where the outer surface of the lining layer 12 contacts. It consists of two different reinforcement works.
[0018]
In this case, a plurality of cable bolts 14a are laid on the natural ground side through the arch portion of the lining layer 12 so as to penetrate the bolt material, and fixed to the natural ground side with a hardening material such as mortar. Then, the outer periphery side of the arch portion of the lining layer 12 is reinforced.
[0019]
Further, the backfilling material 14b is made of, for example, a poorly blended mortar, and through which a through hole is formed in the arch portion of the lining layer 12, injected into the ground, and hardened. The layer 12 is reinforced.
[0020]
The reinforcement work 14 for the lining layer 12 is appropriately performed as necessary. For example, as a result of examining the state of the lining layer 12 in advance, if the reinforcement is not necessary, the reinforcement work 14 is not performed. In addition to the combined use of the placement of the cable bolt 14a and the injection of the backfill material 14b, either one of them can be selected.
[0021]
Such reinforcement work 14 is performed over the entire length of the existing tunnel 10, and when this is completed, the second step shown in FIG. 2 is then performed. This second step is a step of installing a simple protector 18 for protecting the passage of the general vehicle 11 in the existing tunnel 10.
[0022]
In the case of the present embodiment, the simple protector 18 is installed in the existing tunnel 10 such that the cross section with one end opened is formed in a concave shape by a steel plate or the like, and the opening side is positioned on the bottom plate 16. The general vehicle 11 passes through the inside.
[0023]
Since the simple protector 18 does not mount a heavy machine such as an excavating machine on the upper portion thereof, there is no need to provide a large work space on the outer peripheral side of the protector 18, and the inner surface side space of the lining layer 12 of the existing tunnel 10 is effectively used. It can be utilized and does not require high rigidity unlike a protector used in this type of conventional construction.
[0024]
When the installation of the simple protector 18 is finished and the passage of the general vehicle 11 within the existing tunnel 10 is secured, the third step shown in FIG. 3 is then performed. The third step is a step of excavating the widened portion 20 having an arc-shaped cross section adjacent to the side of the existing tunnel 10.
[0025]
In the present embodiment, the dotted semicircular portion shown in FIGS. 1 and 2 is an enlarged tunnel cross section, and this enlarged tunnel cross section 22 corresponds to the cross section of the existing tunnel 10. In FIG. 5, the left half is substantially overlapped with each other.
[0026]
When such an enlarged tunnel cross section 22 is formed, the widened portion 20 mainly enlarges the right side portion of the existing tunnel 10, and as a result, the widened portion 20 of the present embodiment Will be excavated.
[0027]
Excavation of the widened portion 20 is formed through the entire length on the right side of the existing tunnel 10 so as to be parallel to the tunnel axis of the existing tunnel 10. At this time, the excavation range of the widened portion 20 is performed such that the outer surface of the right side wall of the lining layer 12 of the existing tunnel 10 is almost exposed and the upper end slightly covers the arch portion, and is almost half of the cross section 22 of the enlarged tunnel. It becomes size.
[0028]
When the widened portion 20 is excavated and formed, the primary lining layer 24 by concrete spraying is sequentially formed on the inner surface of the excavation as the excavation progresses. When the widened portion 20 is formed, the fourth step shown in FIG. 4 is then performed.
[0029]
This fourth step is a step of cutting and removing the side portion of the lining layer 12 of the existing tunnel 10 (the portion indicated by the phantom line in FIG. 4) to allow the widened portion 20 and the existing tunnel 10 to communicate with each other. The cutting removal range of the lining layer 12 is a portion where the outer peripheral surface is exposed when the widened portion 20 is formed, and includes the entire right side wall and a part of the arch portion that follows, for example, Then, it is removed by cutting into blocks with a wire saw or the like.
[0030]
After the predetermined portion of the lining layer 12 is removed, the fifth step shown in FIG. 5 is then performed. The fifth step is a step of installing the temporary receiving support column 26 at the cutting and removing position on the side portion side of the lining layer 12.
[0031]
A plurality of temporary support columns 26 are installed at predetermined intervals along the tunnel axis direction of the existing tunnel 10. Once the temporary support column 26 is installed, the sixth step shown in FIG. 6 is then performed.
[0032]
The sixth step is a step of forming the new floor slab 28 on the lower surface of the widened portion 20 and sticking the waterproof sheet material 30 on the primary lining layer 24 provided on the excavation surface of the widened portion 20.
[0033]
When the application of the waterproof sheet material 30 is completed, the seventh step shown in FIG. 7 is then performed. The seventh step is a step of installing a temporary partition wall 32 between the ceiling portion of the widened portion 20 to which the primary lining layer 24 and the waterproof sheet material 30 are attached and the new floor slab 28.
[0034]
The temporary partition 32 is formed along the tunnel axis of the existing tunnel 10. In this case, if the total length of the existing tunnel 10 is relatively short, the existing tunnel 10 may be integrally formed over the entire length without being divided in the middle. If the total length of the existing tunnel 10 is relatively long, an appropriate length may be used. It may be formed by being divided by.
[0035]
After the temporary partition 32 is formed, the eighth step shown in FIG. 8 is then performed. In the eighth step, when the temporary partition wall 32 is formed, the stability of the widened portion 20 is ensured, so that the passage on the widened portion 20 side of the general vehicle 11 becomes possible, and as a result, it is installed on the existing tunnel 10 side. This is a process of removing the simple protector 18 that has been removed.
[0036]
Next, the ninth step shown in FIG. 9 destroys the arch portion of the lining layer 12 of the existing tunnel 10 projecting inward of the enlarged tunnel cross section 22 while removing the temporary receiving struts 26, and This is a step of forming a predetermined enlarged tunnel section 22 by excavating and shaping between the sections of the widened portion 20 and the existing tunnel 10.
[0037]
In this case, when a natural ground is exposed by excavation, a primary lining layer is formed on the portion by spraying concrete as necessary. Next, a tenth step shown in FIG. 10 is performed.
[0038]
This tenth step is a step of removing the bottom slab 16 below the existing tunnel 10 and forming a floor slab 34 connected to the new floor slab 28 by placing concrete. When the floor slab 34 is formed, Underneath, a drain pipe 36 is buried.
[0039]
Next, an eleventh step shown in FIG. 11 is performed. The eleventh step is a step of forming a secondary lining layer 38 by sticking a sheet to the shaped expanded tunnel cross section 22, and in this case, placing concrete as shown in FIG. Before the machine 40 is used and the secondary lining layer 38 is formed, the waterproof sheet material 30 and the temporary partition wall 32 are removed.
[0040]
When the formation of the secondary lining layer 38 is completed, the sidewalk 42 is installed in the twelfth step shown in FIG. 12, and the expansion of the existing tunnel 10 is completed. In this embodiment, if the total length of the existing tunnel 10 is relatively short, the steps shown in FIG. 1 to FIG. 12 can be sequentially performed and expanded, or if the total length of the existing tunnel 10 is relatively long. The entire length may be divided by an appropriate length, and for example, the steps from FIG. 1 to FIG. 10 may be repeated a plurality of times.
[0041]
Now, according to the expansion method of the existing tunnel 10 configured as described above, the protector 18 for protecting the passage of the vehicle 11 is removed without being transferred if the passage of the vehicle 11 is secured on the widened portion 20 side. Therefore, a reduction in work efficiency associated with the transfer as in the conventional enlargement method is avoided.
[0042]
In the above-described embodiment, the case where the widened portion 20 is formed on the right side of the existing tunnel 10 is exemplified. However, the embodiment of the present invention is not limited to this, and for example, the widened portion is formed on the left and right sides of the existing tunnel 10. The present invention can also be applied to an enlargement method for forming a portion.
[0043]
【The invention's effect】
As described above in detail, according to the method for expanding an existing tunnel according to the present invention, it is possible to avoid a decrease in construction efficiency.
[Brief description of the drawings]
FIG. 1 is an explanatory view of an initial process showing an embodiment of a method for expanding an existing tunnel according to the present invention.
2 is an explanatory diagram of a process performed subsequent to FIG. 1. FIG.
3 is an explanatory diagram of a process performed subsequent to FIG. 2. FIG.
4 is an explanatory diagram of a process performed subsequent to FIG. 3. FIG.
FIG. 5 is an explanatory diagram of a process performed subsequent to FIG. 4;
6 is an explanatory diagram of a process performed subsequent to FIG. 5. FIG.
7 is an explanatory diagram of a process performed subsequent to FIG. 6. FIG.
8 is an explanatory diagram of a process performed subsequent to FIG. 7. FIG.
FIG. 9 is an explanatory diagram of a process performed subsequent to FIG. 8;
10 is an explanatory diagram of a process performed subsequent to FIG. 9. FIG.
11 is an explanatory diagram of a process performed subsequent to FIG. 10. FIG.
12 is an explanatory diagram of a process performed subsequent to FIG. 11. FIG.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 Existing tunnel 11 General vehicle 12 Covering layer 14 Reinforcement work 20 Widening part 22 Expanded tunnel cross section 24 Primary lining layer 26 Temporary receiving column 28 New floor slab 30 Waterproof sheet material 32 Temporary partition wall 38 Secondary lining layer

Claims (3)

In a method of enlarging the cross-sectional area of an existing tunnel while ensuring vehicle traffic,
A step of reinforcing the lining layer of the existing tunnel as needed from the inner surface side;
Installing a simple protector for protecting vehicle traffic in the existing tunnel;
Excavating the widened portion of the arc-shaped cross section while providing a primary lining layer adjacent to the side of the existing tunnel;
After excavation of the widened portion, the side portion of the lining layer is cut and removed, and the widened portion and the existing tunnel are connected to each other, and a temporary support column is installed at the side portion of the lining layer. Process,
Forming a new floor slab on the lower surface of the widened portion, and installing a temporary partition wall between the new floor slab and the ceiling portion of the widened portion provided with the temporary primary lining layer;
By securing vehicle traffic on the widened portion side, removing the simple protector, removing the temporary support struts, destroying the arch portion of the lining layer and excavating the vicinity thereof, the widened portion Forming an enlarged tunnel cross section by shaping between the portion and the existing tunnel;
And a step of forming a secondary lining layer in the cross section of the enlarged tunnel. The reinforcing work consists of placing a cable bolt from the inside of the lining layer toward the natural ground side, and injecting a backfill material into the natural ground where the outer surface of the lining layer contacts. The method for expanding an existing tunnel according to claim 1. The method for enlarging an existing tunnel according to claim 1, wherein after the temporary primary lining layer is formed, a temporary waterproof sheet material that is removed before the construction of the secondary lining layer is provided on the inner surface side.

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