JP3964233B2 - Shield tunnel structure and construction method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a structure of a shield tunnel in which an opening such as a branch tunnel is formed on an inner peripheral surface of a main tunnel dug by a shield machine, and a construction method thereof.
[0002]
[Prior art]
As shown in FIGS. 9 and 10, the shield tunnel structure is formed by forming a start port 101 as an example of an opening in the main tunnel 100 dug by a shield machine and using a branch shield machine from here. There is one formed by excavating the branch tunnel 102.
[0003]
Conventionally, when the branch tunnel start port 101 is provided in the main tunnel 100, for example, as shown in FIGS. 9 and 11, the reinforcing ring body 103 is assembled so as to surround the start port 101, and in this state, the main tunnel 100 The starting port 101 was formed in the inner peripheral surface of the.
[0004]
The reinforcing ring body 103 is arranged at equal intervals between the rings 104 arranged on both sides in the tunnel axial direction at the inner peripheral portion of the main tunnel 100 and serving as the tunnel starting port 101. It is composed of a beam member 106 connected to the ring and the defect ring 105 so as to be positioned on both the upper and lower sides of the part that will be the starting ring 101.
In the case of a steel segment, for example, the start port 101 is formed by fusing the skin plate at the bottom of the segment with gas or the like.
[0005]
[Problems to be solved by the invention]
In the conventional shield tunnel structure described above, the reinforcing ring body 103 is assembled so as to surround the vicinity of the starting port 101 before the starting port 101 is formed. Assembling takes time and effort, and the construction period is long and the cost is high.
In addition, when the start opening 101 is provided in the segment that forms the inner peripheral surface of the main tunnel, for example, in the case of a steel segment, the skin plate must be blown by gas, or in the case of a concrete segment, In addition, there is a problem that it takes time to form the start port 101 itself.
[0006]
The present invention has been made in view of the above circumstances, can easily reinforce the vicinity of the opening, and can easily form the opening itself, thereby shortening the construction period and reducing the cost. It is an object of the present invention to provide a shield tunnel structure that can be used.
[0007]
[Means for Solving the Problems]
In order to solve the above problems, the present invention employs the following means.
That is, the structure of the shield tunneling according to claim 1 has a structure of a shield tunnel openings are formed branch tunnel or the like to the inner circumferential surface of the main line tunnels excavation by the shield machine, the opening of such a branch tunnel A pair of reinforcing column members are provided on both front and rear outer sides in the main tunnel axial direction of the main part, and upper and lower reinforcing beam members are disposed so as to straddle the reinforcing column members at upper and lower ends of the pair of reinforcing column members. Is provided,
The reinforcing column member is constituted by a segment,
The segment in the vicinity of the branch tunnel opening is configured in an arc plate shape with a wall block forming the inner peripheral wall of the main tunnel and an opening block where the branch tunnel opening is formed, and the pair of reinforcing columns Between the members,
The reinforcing beam member is set in a reinforcing material assembling portion provided in a segment of the reinforcing column member and a wall block of a segment in the vicinity of the branch tunnel opening,
The opening block is made of a high toughness concrete material that can be excavated by a shield excavator .
In this case, when forming an opening for a branch tunnel or the like, the opening of the branch tunnel or the like can be obtained by an extremely easy operation such as assembling a reinforcing beam member to a reinforcing material assembling portion provided in a segment where the opening is to be formed. The vicinity of the part can be reinforced in advance. In addition, in a small-diameter cross-section tunnel, in order to provide an opening in the middle of the tunnel, the space in the tunnel is narrow and cannot be reinforced, but in this case, the opening can be reinforced easily.
Moreover, since a pair of reinforcing pillar members provided on both the front and rear outer sides of the opening of the branch tunnel or the like in the main tunnel axial direction are directly formed by segments, the vicinity of the opening is formed when forming the opening of the branch tunnel or the like. The work of installing a reinforcing column member to reinforce the vicinity of the opening becomes unnecessary, and accordingly, the construction period can be shortened and the cost can be reduced. Further, in forming the opening of the branch tunnel or the like, the reinforcing column member is configured in advance by segments provided on both the front and rear sides in the main tunnel axial direction of the opening of the branch tunnel or the like. The vicinity of the opening of the branch tunnel or the like can be reinforced in advance by an extremely easy operation such as setting the upper and lower reinforcing beam members on the upper and lower ends and the wall block of the member. Therefore, the construction period can be shortened and the cost can be reduced.
Moreover, by positioning the cutter device at the tip of the shield machine at the location to be the opening, and driving the shield machine in this state, the opening can be directly excavated by the cutter device. In order to form the film, it is not necessary to cut the segments with gas or the like in advance.
[0008]
The structure of the shield tunnel according to claim 2 is a structure of a shield tunnel in which an opening such as a branch tunnel is formed on an inner peripheral surface of a main tunnel dug by a shield machine, and the opening of the branch tunnel or the like is formed . A pair of reinforcing column members are provided on both front and rear sides in the main tunnel axis direction, and upper and lower reinforcing beam members are provided at both upper and lower ends of the pair of reinforcing column members so as to straddle the reinforcing column members. The reinforcing column member is constituted by a segment, and the segment in the vicinity of the branch tunnel opening is an arc plate formed by a wall block that forms the inner peripheral wall of the main tunnel and an opening block that forms the branch tunnel opening. The reinforcing beam members are arranged between the pair of reinforcing column members and the segments in the vicinity of the segments of the reinforcing column members and the branch tunnel opening. Is set to the reinforcing member assembly portion provided in the instrument of wall blocks,
The opening block is configured to be detachable from the wall block .
In this case, when digging a branch tunnel with a shield tunneling machine, the vicinity of the opening of the branch tunnel or the like is reinforced with a reinforcing column member and a reinforcing beam member, and then the opening block is removed from the wall block to The opening can be easily and safely formed. In this case as well, as in the case of the first aspect, it is not necessary to cut or segment the segments in advance with a gas or the like in order to form the opening. Moreover, the removal work of the opening part block for forming the opening part is easy to disassemble, and the work can proceed safely and easily. In addition, since the vicinity of the opening is reinforced by the reinforcing pillar member and the reinforcing beam member, there is no need to separately incorporate the opening reinforcing component on the inner surface of the tunnel, and the thickness of the secondary lining is reduced. Or can be omitted.
[0010]
According to a third aspect of the present invention, there is provided a shield tunnel structure according to the third aspect, characterized in that a firing material is assembled between the reinforcing column member and the reinforcing beam member.
In this case, the strength in the vicinity of the opening of the branch tunnel or the like can be increased by the fire striking material, and if it is sufficient to have the same strength as that of the reinforcing body not having the fire striking material, the reinforcing pillar is correspondingly increased. The thickness of the material constituting the member or the reinforcing beam member can be reduced.
[0013]
The shield tunnel structure according to claim 4 is the shield tunnel structure according to any one of claims 1 to 3 , wherein a reinforcing steel plate is detachably attached to a segment in the vicinity of the branch tunnel opening on the inner peripheral surface side of the tunnel. It is characterized by being attached to.
In this case, before the vicinity of the opening of the branch tunnel or the like is reinforced by the reinforcing column member and the reinforcing beam member, the segment itself has sufficient strength by the reinforcing steel plate and the vicinity of the opening of the branch tunnel or the like is formed. After reinforcing with the reinforcing column member and the reinforcing beam member, the opening of the subsequent branch tunnel or the like can be easily formed by removing the reinforcing steel plate. That is, it is possible to satisfy both the securing of strength for safety and the ease of forming the opening at the same time.
[0014]
The construction method of the shield tunnel according to claim 5 is characterized in that the primary lining of the main tunnel is performed simultaneously with the excavation of the main tunnel by the structure of the shield tunnel according to any one of claims 1 to 4. Yes.
In this case, a main tunnel in which an opening such as a branch tunnel is formed on the way can be constructed by a construction method almost the same as that for constructing a tunnel without a branch tunnel.
[0015]
The shield tunnel construction method according to claim 6 is characterized in that, in the shield tunnel construction method according to claim 5, an opening such as a branch tunnel is formed after the primary lining of the main tunnel is performed. It is said.
In this case, after the construction of the main tunnel, an opening such as a branch tunnel can be formed at an arbitrary time.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
<First Embodiment>
1 to 4 show a first embodiment of the present invention.
FIG. 1 shows the structure of a shield tunnel according to the present invention. In the figure, reference numeral 1 denotes a main tunnel whose inner peripheral surface is covered with a plurality of steel segments. The main tunnel 1 is dug by a shield machine, and a start port 2A, which is an example of an opening of the branch tunnel 2, is formed on the inner peripheral surface of the main tunnel.
[0017]
A pair of reinforcing column members 4 are provided on both the front and rear sides of the start opening 2A of the branch tunnel 2 in the main tunnel axial direction. The reinforcing column member 4 reinforces the start opening 2A of the branch tunnel 2 together with a reinforcing beam member 12 described later.
[0018]
The reinforcing column member 4 is constituted by a special segment 6A. As shown in FIGS. 1 to 3, the special segment 6 </ b> A constituting the reinforcing column member 4 is set to have a width W narrower than that of the other segments 6, and the thickness T of the main girder plate 7 is also different. It is set to be thicker than that of the segment 6, and has sufficient rigidity to reinforce the vicinity of the start port 2A. The special segment 6A constituting the reinforcing column member 4 is also similar to the other segments 6 such as the skin plate 8 serving as the bottom, the main girder plate 7 standing on the left and right sides of the skin plate 8, and the skin plate 8 And a rib member 10 that is passed between the main plate 7 and the joint plate 9 that stands up at the end of the main plate.
[0019]
Upper and lower reinforcing beam members 12 are provided at both upper and lower ends of the pair of reinforcing column members 4 so as to straddle the reinforcing column members 4.
In the illustrated example, the reinforcing beam member 12 is made of grooved steel, and is provided in advance in the segment 6A constituting the reinforcing column member 4 and the other segment 6B disposed in the vicinity of the start opening 2A. By being set in the assembling part 13, it is fixed at a predetermined position.
The reinforcing material assembling portion 13 is constituted by a groove 13 a formed at a predetermined position of the main girder plate 17 of the segment 6. In addition to the groove 13a, the reinforcing member assembling portion 13 provided in the segment 6A constituting the reinforcing column member 4 is provided with mounting plates 13b located on both sides of the groove 13a. The reinforcing column member 12 is bolted.
[0020]
A striking material 14 is assembled between the reinforcing column member 4 and the reinforcing beam member 12. In the case of the illustrated example, the fire striking material 14 is made of groove steel, and is assembled by being bolted to the reinforcing column member 4 and the reinforcing beam member 12 respectively.
[0021]
Although not shown here, if the reinforcing beam members 12 are not sufficiently supported only by the reinforcing column members 4 arranged on both sides of the start opening 2A, the reinforcing column members 4 on both sides are not supported. A plurality of partially cutout segments such as the missing ring 104 described in the above-described prior art may be arranged between them, thereby supporting the reinforcing beam member 12.
[0022]
As shown in FIG. 4, the segment 6B in the vicinity of the start 2A of the branch tunnel 2 includes a wall block 15 that forms the inner peripheral wall of the main tunnel 1, and a start port block 16 that forms the branch tunnel start. Consists of.
In FIG. 4, the illustration of the reinforcing beam member 12, the reinforcing assembling portion 13 that receives the reinforcing beam member 12, and the fire striking material 14 is omitted to avoid the complexity of the drawing.
[0023]
The wall block 15 has a structure in which a part of a normal steel segment is cut out along the start opening 2A.
That is, the wall block 15 is passed between the skin plate 8 serving as the bottom, the main girder plate 7 standing on the left and right sides of the skin plate 8, the joint plate 9 standing on the end of the skin plate 8, and the main girder plate 7. One of the left and right main girders 7 is formed to be curved in a concave curved shape so that the middle part thereof follows the outer shape of the start opening 2A.
[0024]
On the other hand, the start port block 16 is made of a high toughness concrete material that can be excavated by a shield excavator. High toughness concrete is composed of mortar, fine powder, high-performance water-reducing material, and reinforcing fibers (steel fibers or resin fibers). It is a material that has sufficient resistance to earth pressure, has the strength to take the jack reaction force when the shield machine is advanced, and can be excavated by the cutter of the shield machine. is there.
[0025]
Next, an actual tunnel construction method in the above shield tunnel structure will be described.
First, the main tunnel 1 is dug using a shield machine. The inner peripheral surface of the main tunnel 1 is formed by assembling arcuate plate-like segments 6 (in the illustrated example, steel segments). At this time, special segments 6 </ b> A constituting the reinforcing pillar member 4 are assembled in advance on both the front and rear sides of the start opening 2 </ b> A of the branch tunnel 2 in the main tunnel axial direction. Further, as shown in FIG. 4, the segment 6B in the vicinity of the place where the start port 2A is formed includes a wall block 15 forming the inner peripheral wall of the main tunnel 1 and a start port where a branch tunnel start port is formed. What consists of block 16 is used.
[0026]
After the main tunnel 1 is completed, or when the main tunnel 1 is dug to a certain extent, reinforcement in the vicinity of the start opening 2A of the branch tunnel 2 is performed.
That is, the upper and lower reinforcing beam members 12 are respectively attached to the reinforcing member assembling portions 13 provided in advance in the segment 6B in the vicinity of the portion where the special opening 6A constituting the reinforcing column member 4 and the start opening 2A are formed. Assemble each.
Specifically, the reinforcing beam member 12 is fitted into the groove 13a constituting the reinforcing assembling portion 13, and the fitted reinforcing beam member 12 is used by using the mounting plate 13b provided on the special segment 6A. Use bolts.
Further, the fire stroking material 14 is assembled between the reinforcing column member 4 and the reinforcing beam member 12 so as to straddle both the members 4 and 12. In this way, the vicinity of the start port 2A can be further reinforced by assembling the firing material 14.
[0027]
After reinforcing the vicinity of the start port 2A of the branch tunnel 2 in this way, the branch tunnel 2 is dug by a shield machine.
At this time, as described above, the segment 6B in the vicinity of the place where the starting port 2A is formed is composed of the wall block 15 and the starting port block 16, and the starting port block 16 is made of high toughness concrete. Therefore, the starting port 2A can be formed by directly excavating the starting port block 16 with a shield machine. Therefore, the conventional work for gas-cutting the skin plate or attaching concrete, which has been conventionally performed to form the starting port, is no longer necessary, and the excavation work of the branch tunnel 2 that intersects the main tunnel 1 can be performed. Easy to proceed.
[0028]
<Second Embodiment>
FIG. 5 is a perspective view of an essential part showing a second embodiment of the shield tunnel structure according to the present invention.
The feature of the second embodiment is that a wall block 15 that forms the inner peripheral wall of the main tunnel 1 and a branch tunnel start port are formed as a segment 6B used in the vicinity of the start port 2A of the branch tunnel 2 shown in FIG. This is a point using a segment main body 20 composed of a starting port block 16 and a reinforcing steel plate 21 detachably attached to the inner peripheral surface of the tunnel of the segment main body 20.
[0029]
That is, the segment 6B having a structure in which the reinforcing steel plate 21 is detachably attached to the inner peripheral surface of the segment shown in FIG. 4 is used.
In addition, as a method of detaching the reinforcing steel plate 21 from the segment main body 20, a combination of bolting and male / female fitting as shown in FIG. 5 may be considered.
[0030]
When such a segment 6B is used, before reinforcing the vicinity of the start opening 2A of the branch tunnel 2 with the reinforcing column member 4, the reinforcing beam member 12, and the like, the reinforcing steel plate 21 provides sufficient strength to the segment 6B itself. In addition, after reinforcing the vicinity of the start opening 2A of the branch tunnel 2 with the reinforcing column member 4, the reinforcing beam member 12 and the like, the reinforcing steel plate 21 is removed, so that the subsequent branch tunnel 2 The starting port 2A can be easily formed. In other words, it is possible to satisfy both the securing of strength for safety and the ease of forming the starting port at the same time.
[0031]
In the second embodiment, since the segment 6B reinforced by the reinforcing steel plate 21 is used, it is not always necessary to use a high-toughness concrete material as the material of the starting port block 16, and ordinary concrete is used. It is also possible to use it.
[0032]
<Third Embodiment>
FIG. 6 is a perspective view of an essential part showing a third embodiment of the shield tunnel structure according to the present invention, and FIG. 7 is an exploded perspective view thereof.
In the third embodiment, as in the first embodiment described above, a wall that forms the inner peripheral wall of the main tunnel 1 as a segment 6B used in the vicinity of the start opening 2A of the branch tunnel 2 shown in FIG. A block 25 and a start port block 26 in which a branch tunnel start port is formed is used. Here, a structure in which the start port block 26 is detachably assembled to the wall block 25 is used. ing.
[0033]
In other words, the wall block 25 and the start-up block 26 used here are based on steel segments having a skin plate and a main girder plate, and the main girder plates of the blocks 25 and 26 are bolted. 27 and nut 28 are detachably assembled.
In this case, when the branch tunnel is dug by the shield machine, the vicinity of the start opening 2A of the branch tunnel is reinforced by the reinforcing column member and the reinforcing beam member, and then the connection by the bolt 27 and the nut 28 is released. As shown in FIG. 7, the start port block 26 can be removed from the wall block 25, whereby the start port 2A of the branch tunnel can be formed easily and safely.
[0034]
<Fourth embodiment>
FIG. 8 is a perspective view of an essential part showing a fourth embodiment of the shield tunnel structure according to the present invention.
In the fourth embodiment, as in the third embodiment described above, as a segment 6B used in the vicinity of the start opening 2A of the branch tunnel 2, a wall block 25 that forms the inner peripheral wall of the main tunnel 1, The segment main body 30 having a structure in which the start opening block 26 in which the branch tunnel start opening is formed is detachably assembled to each other is used. Here, a reinforcing steel plate is further provided on the inner peripheral surface side of the tunnel of the segment main body 30. The one to which 32 is detachably attached is used.
[0035]
When such a segment 6B is used, before reinforcing the vicinity of the start opening 2A of the branch tunnel 2 with the reinforcing column member 4, the reinforcing beam member 12, and the like, the reinforcing steel plate 32 provides sufficient strength to the segment 6B itself. In addition, after reinforcing the vicinity of the start opening 2A of the branch tunnel 2 with a reinforcing column member and a reinforcing beam member, the reinforcing steel plate 32 is removed, and then the start port block 26 is replaced with the wall block 25. It is possible to easily form the start port 2A of the branch tunnel 2 by removing from the above. That is, also in this embodiment, it is possible to satisfy both the securing of strength for safety and the ease of forming the starting port at the same time.
[0036]
Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and other configurations may be adopted as necessary without departing from the spirit of the present invention. Can do.
For example, in the above-described embodiment, the example using the steel segment as the segment has been described. However, the present invention is not limited to this, and the present invention is also applied to a concrete segment or a composite segment. It goes without saying that it is possible.
In the above embodiment, the start of the branch tunnel has been described as an example of the opening formed on the inner peripheral surface of the main tunnel. Furthermore, there are also openings for joining with ancillary facilities such as human hole facilities, and it goes without saying that the present invention can be applied to these.
[0037]
【The invention's effect】
As described above, according to the present invention, when forming an opening such as a branch tunnel, it is extremely easy to assemble the reinforcing beam member to the reinforcing material assembling portion provided in the segment where the opening is formed. By an easy operation, the vicinity of the opening such as a branch tunnel can be reinforced in advance. In addition, since a pair of reinforcing pillar members provided on both the front and rear outer sides of the main tunnel axis direction of the opening portion of the branch tunnel or the like is configured by the direct segment, the reinforcing column is formed in the vicinity of the opening portion when forming the opening portion of the branch segment. The work of installing the member and reinforcing the vicinity of the opening is not necessary, and accordingly, the construction period can be shortened and the cost can be reduced.
The segment in the vicinity of the branch tunnel opening is composed of a wall block that forms the inner peripheral wall of the main tunnel and an opening block in which the branch tunnel opening is formed. If it is made of high-toughness concrete material that can be excavated in, the cutter device at the tip of the shield machine is located at the location to be the opening, and the shield machine is driven in this state, so that the opening is directly opened by the cutter device. It can be formed by excavation, and the work of previously cutting the segments with gas or the like is not necessary.
The segment in the vicinity of the branch tunnel opening is made up of a wall block that forms the inner peripheral wall of the main tunnel and an opening block in which the branch tunnel opening is formed. If the tunnel is dug with a shield machine, the vicinity of the opening of the branch tunnel is reinforced with the reinforcing pillar member and the reinforcing beam member, and then the opening block is removed from the wall block. Thus, an opening such as a branch tunnel can be easily and safely formed.
Further, if a fire striking material is assembled between the reinforcing column member and the reinforcing beam member, the strength in the vicinity of the opening of the branch tunnel or the like can be increased by the fire striking material.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing a structure of a shield tunnel according to a first embodiment of the present invention.
FIG. 2 is a perspective view showing a main part of the shield tunnel structure shown in FIG. 1;
FIG. 3 is a perspective view showing the operation of the shield tunnel structure shown in FIG. 1;
4 is a perspective view showing a segment in the vicinity of a starting point of a branch tunnel having the shield tunnel structure shown in FIG. 1. FIG.
FIG. 5 shows a second embodiment of the present invention and is a perspective view showing a segment in the vicinity of a start point of a branch tunnel.
FIG. 6 shows a third embodiment of the present invention and is a perspective view showing a segment in the vicinity of a start point of a branch tunnel.
7 is an exploded perspective view of the segment shown in FIG. 6. FIG.
FIG. 8 shows a fourth embodiment of the present invention and is a perspective view showing a segment in the vicinity of a start point of a branch tunnel.
FIG. 9 is a side view showing the structure of a conventional shield tunnel.
10 is a cross-sectional view taken along line ZZ in FIG.
11 is a perspective view showing a reinforcing body used in the structure of the conventional shield tunnel shown in FIG.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Main line tunnel, 2 ... Branch tunnel, 2A ... Starting port (opening part), 4 ... Reinforcing pillar member, 6A, 6B ... Segment, 12 ... Reinforcing beam member, 14 ... Fire hitting material, 15, 25 ... Wall block , 16, 26 ... start port block (opening block), 20, 30 ... segment main body, 21, 32 ... steel plate for reinforcement.

Claims (6)

A shield tunnel structure in which an opening such as a branch tunnel is formed on the inner peripheral surface of a main tunnel dug by a shield machine,
A pair of reinforcing column members are provided on both front and rear outer sides in the main tunnel axial direction of the opening portion of the branch tunnel or the like, and the upper and lower ends of the pair of reinforcing column members straddle the reinforcing column members. Upper and lower reinforcing beam members are provided,
The reinforcing column member is constituted by a segment,
The segment in the vicinity of the branch tunnel opening is configured in an arc plate shape with a wall block forming the inner peripheral wall of the main tunnel and an opening block where the branch tunnel opening is formed, and the pair of reinforcing columns Between the members,
The reinforcing beam member is set in a reinforcing material assembling portion provided in a segment of the reinforcing column member and a wall block of a segment in the vicinity of the branch tunnel opening,
The opening block is made of a high toughness concrete material that can be excavated by a shield excavator.
Structure of the shield tunnel, characterized in that is. A shield tunnel structure in which an opening such as a branch tunnel is formed on the inner peripheral surface of a main tunnel dug by a shield machine,
A pair of reinforcing column members are provided on both front and rear outer sides in the main tunnel axial direction of the opening portion of the branch tunnel or the like, and the upper and lower ends of the pair of reinforcing column members straddle the reinforcing column members. Upper and lower reinforcing beam members are provided,
The reinforcing column member is constituted by a segment,
The segment in the vicinity of the branch tunnel opening is configured in an arc plate shape with a wall block forming the inner peripheral wall of the main tunnel and an opening block where the branch tunnel opening is formed, and the pair of reinforcing columns Between the members,
The reinforcing beam member is set in a reinforcing material assembling portion provided in a segment of the reinforcing column member and a wall block of a segment in the vicinity of the branch tunnel opening,
The structure of a shield tunnel, wherein the opening block is configured to be detachable from the wall block . In the structure of the shield tunnel according to claim 1 or 2,
A structure of a shield tunnel, wherein a fire striking material is assembled between the reinforcing column member and the reinforcing beam member . In the structure of the shield tunnel according to any one of claims 1 to 3 ,
The shield tunnel structure characterized in that a reinforcing steel plate is detachably attached to the inner peripheral surface side of the segment in the vicinity of the branch tunnel opening. The shield tunnel construction method according to any one of claims 1 to 4, wherein a primary lining of the main tunnel is performed simultaneously with the excavation of the main tunnel . 6. The shield tunnel construction method according to claim 5, wherein an opening such as a branch tunnel is formed after the primary lining of the main tunnel is performed .

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