JPH09279978A - Large-section tunnel constructing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide such a construction method as being capable of performing smooth construction in a shorter period and at a lower cost. SOLUTION: Plural rectangular shield tunnels 13 are constructed neighboring one another in the peripheral direction to construct a tunnel structure 11 and then an inward mountain G2 is drilled to construct a large-section tunnel 10. When the tunnel structure 11 is constructed, the rectangular shield tunnels 13 are precedingly constructed and then backfilling material 17 for the precedingly constructed rectangular shield tunnels 13 is drilled, so that part of the rectangular shield tunnels 13 to be followingly constructed are lapped over the precedingly constructed rectangular shield tunnels 13.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for constructing a tunnel having a large cross section which is suitable for use in constructing a tunnel having a large cross section and a rectangular shape in a sectional view.

[0002]

2. Description of the Related Art As is well known, a shield construction method of excavating a ground with a shield excavator and constructing a tunnel having substantially the same diameter as the shield excavator behind the excavator is often used for construction of a tunnel. However, in the shield method, if a tunnel with a large cross section is to be constructed, the shield excavator used for the tunnel will naturally become large, and as a result, manpower and cost will be reduced in all aspects such as manufacturing, transporting and assembling the shield excavator. It becomes bulky.

For this reason, in recent years, a method of forming a large-sized tunnel structure from these small-diameter tunnels by constructing a large number of small-diameter tunnels along the shape of the large-section tunnel has been developed.

By the way, in particular, when an attempt is made to construct a large-section tunnel having a large space inside, as shown in FIG. 15, a tunnel structure 1 having a circular cross-section is constructed, and a space S having a predetermined dimension is formed inside thereof. Since the tunnel structure 1 is formed larger than the space S, the large-section tunnel T is formed.
If the site required to construct the building is large and the cost is high, or if the site cannot be secured, the space S with a predetermined size is required.
There is a problem that it is impossible to form.

Therefore, as shown in FIG. 16, by constructing a large-section tunnel T'having a rectangular cross-section, a minimum required land for securing a space S of a predetermined size may be secured. Since this can reduce the cost, various construction methods of such a large-section tunnel T'having a rectangular cross section have been developed.

[0006]

However, the conventional large-section tunnel and the method for constructing the same as described above have the following problems. When constructing the tunnel structure 2 as a lining body of the large-section tunnel T ′ having a rectangular cross-section as shown in FIG.
After constructing the horizontal portion 2a and the vertical portion 2b that form the four sides by assembling the segments in a square cross-section with a shield excavator, the horizontal portion 2a and the vertical portion 2b that are adjacent to each other are connected to each other by the joint portion A. Need to connect in. To this end, as shown in FIG. 17 (a), after constructing the horizontal portion 2a and the vertical portion 2b of the tunnel structure 2 separately, first, the ground G between the horizontal portion 2a and the vertical portion 2b is formed.
1 is ground improvement using chemical solution injection or freezing method. Subsequently, as shown in FIG. 17 (b), the connecting portion earth retaining material 3 incorporated at the end of the horizontal portion 2a when the horizontal portion 2a is constructed is extruded toward the vertical portion 2b. Then, after the connecting portion retaining material 3 reaches the vertical portion 2b, the segments 4 of the horizontal portion 2a and the vertical portion 2b are removed, and the connection bracket 5 is attached to the vertical portion 2b. After the horizontal portion 2a and the vertical portion 2b are integrally connected in this way, as shown in FIG. 17 (c), the reinforcing bars 6 and the like are arranged inside and the concrete 7 is cast into the tunnel structure. Body 2 is completed.

In such a construction method, first, the connecting portion earth retaining material 3 is pushed out, but when constructing the horizontal portion 2a, a backing filler (not shown) such as mortar is provided on the outer periphery thereof. Since it has been injected, earth retaining material 3 at the connection
Extrusion is difficult. Further, in order to stop the joint portion A from water and increase its strength, the ground G1 is designed to be improved by a chemical solution injection, a freezing method, or the like. Needless to say, such ground improvement requires time and cost, Moreover, it is difficult to obtain a perfect water-stopping effect. Furthermore, the horizontal part 2
When connecting a and the vertical portion 2b, the ground of the joint portion A is excavated and the reinforcing bars are laid and assembled there. At this time, the segments 4 forming the side surfaces of the horizontal portion 2a and the vertical portion 2b are formed. Must be partially dismantled and removed. Since these segments 4 originally hold the tunnel space against the earth pressure and groundwater pressure of the natural ground, it is necessary to provide other supporting works etc. when removing the segment 4, which is troublesome. Takes. In addition, in order to install such a support and the like in a long section in the axial direction of the horizontal portion 2a and the vertical portion 2b, the support and support becomes a large scale. It is necessary, and this also causes a long construction period and an increase in cost.

The present invention has been made in consideration of the above points, and provides a method of constructing a large-section tunnel capable of smoothly performing the construction and shortening the construction period and reducing the cost. Is an issue.

[0009]

The invention according to claim 1 is
After constructing a plurality of rectangular shield tunnels adjacent to each other in the circumferential direction in the circumferential direction to construct a tunnel structure that serves as a lining body for a large-section tunnel, excavate the ground inside the tunnel structure. By constructing a tunnel having a large cross section by forming a space here, when constructing the tunnel structure, first, a hole is excavated in the ground with a shield excavator having a rectangular cross section, Assemble the segment into a rectangular shape in cross section in the hole and pre-construct one shield tunnel by filling the void between the surrounding ground and the segment with the backfill filler, and then to the one shield tunnel that was pre-constructed. When another shield tunnel is built next to it, the backfilling of the previously constructed shield tunnel together with the ground adjacent to the one shield tunnel. After drilling the wood with a shield excavator,
By assembling the segment here in a rectangular cross-sectional view, by filling the back ground filler between the surrounding ground and the shield tunnel previously constructed and the segment, a part of the other shield tunnel to be constructed later It is characterized by being superposed on the previously constructed one shield tunnel.

According to a second aspect of the present invention, in the method for constructing a large cross-section tunnel according to the first aspect, after the tunnel structure is constructed, the previously constructed shield tunnel and the later constructed shield tunnel are adjacent to each other. By removing the segment of the portion to be removed and further removing the backfill filler in this portion, the inside of the tunnel structure is penetrated in the circumferential direction of the cross section, and thereafter, the reinforcing bar is provided in the segment of the tunnel structure, The feature is that reinforcement materials such as steel are placed and concrete is poured.

According to a third aspect of the present invention, in the method for constructing a large-section tunnel according to the second aspect, the work of penetrating the inside of the tunnel structure, the work of arranging the reinforcing material, and the work of placing concrete are performed. It is characterized in that the tunnel structure is made continuous in the excavation direction by performing at least every other segment in the excavation direction of each shield tunnel and repeating each of the operations in the remaining portion.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION First and second embodiments of a method for constructing a large cross section tunnel according to the present invention will be described below with reference to FIGS.

[First Embodiment] FIG. 1 shows a state in which a large-section tunnel 10 is being built. This large-section tunnel 10 resists earth pressure from surrounding rocks. It is composed of a tunnel structure 11, which is a lining body, and an internal space (space) 12 formed by excavating the natural ground G2 inside the tunnel structure 11.

The tunnel structure 11 includes side wall portions 11a, 11a on both sides located in a substantially vertical plane and the side wall portions 11a and 11b.
Each of a and 11a has an upper surface 11b and a lower surface 11c which are respectively provided between the upper and lower ends and are located in a substantially horizontal plane, and has a generally square cross-section in cross section. The tunnel structure 11 has a configuration in which a plurality of rectangular shield tunnels (shield tunnels) 13 each having a rectangular cross section are arranged in the circumferential direction and these are integrated. Then, in such a tunnel structure 11, reinforcing bars (not shown) are arranged at the connecting portions of the rectangular shield tunnels 13, 13 adjacent to each other, and concrete (not shown) is placed inside the reinforcing bars. There is. Here, regarding the radial dimension of the large-section tunnel 10, for example, the internal space 12 has a width of about 8 m and a length of about 9 m, and the rectangular shield tunnel 13 has a thickness of about 3 m.

Next, a method of constructing such a large section tunnel 10 will be described. To this end, first, the rectangular shield tunnels 13, 13, which form the tunnel structure 11,
Among them, the rectangular shield tunnels 13A and 13B forming the upper surface 11b and the lower surface 11c are sequentially constructed in advance. To this end, a cutter provided on the front surface of a shield excavator (not shown) having a rectangular cross section is used to drill rectangular holes 15A, 15B in the ground, and steel segments 16, 16,
Are assembled in a rectangular shape in cross section, and a backfill filler 17 such as concrete, mortar, or fiber concrete is filled between the outer peripheral surface of the assembled segments 16 and the inner peripheral surface of the hole 15.

Next, the grounds adjacent to the previously constructed rectangular shield tunnels 13A and 13B are excavated to construct rectangular shield tunnels 13C and 13D therein. As shown in FIG. 2A, the shield excavator 20 used at this time is provided with a cutter (not shown) for excavating the ground on the front surface, and a concrete cutting mechanism capable of cutting concrete or the like on the side surface. 21 is provided. When the shield excavator 20 excavates the natural ground at the position where the rectangular shield tunnels 13C and 13D shown in FIG. 1 are to be constructed and drills the holes 15C and 15D, a concrete cutting mechanism provided on the side surface thereof. At 21, part of the backfill filler 17 on the side surfaces of the rectangular shield tunnels 13A and 13B constructed in advance (the portions (reference numerals (a) and (b) in FIG. 1) are cut. After that, the segments 16, 16, ... Are respectively assembled into the holes 15C, 15D in a predetermined shape, and the backfill filler 17 is filled on the outer sides thereof to construct the rectangular shield tunnels 13C, 13D. In this state, the rectangular shield tunnels 13C and 13D
Is firmly integrated with the rectangular shield tunnels 13A and 13B previously constructed by the backfill filler 17.

Next, the side surface 11 of the tunnel structure 11 is formed.
rectangular shield tunnels 13E, 1 constituting a, 11a
Build 3F. As shown in FIG. 2B, the shield excavator 22 used at this time is provided with a cutter (not shown) for excavating the ground on the front surface, and concrete cutting capable of cutting concrete or the like on the upper and lower surfaces thereof. Mechanisms 23, 23 are provided. This shield excavator 22
Then, the rectangular shield tunnels 13E and 13F shown in FIG.
When excavating the natural ground at the position where to construct the holes 15E and 15F, the concrete cutting mechanisms 23 and 23 provided on the upper and lower surfaces thereof are used to construct the rectangular shield tunnels 13A, 13B, 13C, which are constructed in advance. A part of the backfill filler 17 on the upper surface or the lower surface of 13D (reference numeral (c) in FIG. 1,
Cut (d), (e), and (f). After this,
In the holes 15E and 15F, the segments 16 and
The rectangular shield tunnel 13 is formed by assembling 16, ...
E, 13F is built. In this state, the rectangular shield tunnels 13E, 13F have the rectangular shield tunnels 13A, 13B, 13 previously constructed by the backfill filler 17.
This means that a part of them is polymerized with C and 13D to be firmly integrated.

Then, reinforcing bars (not shown) and concrete (not shown) are placed in the constructed tunnel structure 11 as follows. First, as shown in FIG. 3, in the tunnel structure 11, in a portion where the rectangular shield tunnels 13, 13 are adjacent to each other, the segment 16 located at the connecting portion is removed. At this time, the segment 16 is removed for every other segment ring in the direction in which the rectangular shield tunnels 13 are continuous. When the segments 16 are removed in this manner, the backfill fillers 17 of the rectangular shield tunnels 13 and 13 adjacent to each other are exposed. Then, as shown in FIG.
5 is formed. At this time, by using core boring or the like, the portion 25 that contacts the outer peripheral side and the inner peripheral side of the tunnel structure 11 is used.
The openings a and 25b are formed in a substantially arched shape. In this way, the openings 25 are formed for every other segment ring, and the openings 25 are formed into a substantially arched shape, so that the openings 25 are stable and can be rebared during construction. It is possible to resist the soil water pressure and reaction force from the surrounding ground without reinforcement. By thus forming the opening 25 between the rectangular shield tunnels 13, 13 which are adjacent to each other, the tunnel structure 11 is continuously penetrated in the circumferential direction of the cross section.

Subsequently, as shown in FIG. 5, the opening 2 of the connecting portion of the rectangular shield tunnels 13 and 13 adjacent to each other.
After reinforcing bars (reinforcing material) 26 are laid out in 5, concrete 27 is further placed.

After this, as shown in FIG.
Other than the part where the reinforcing bars and concrete 27 were placed,
For the remaining portion of the tunnel structure 11, the segment 16 is removed and the opening 28 is formed in the same manner as described above. Then, as shown in FIG.
The reinforcing bars 26 and the concrete 27 are laid on the No. 8 concrete. As a result, over the entire length of the tunnel structure 11, the arrangement of the reinforcing bars 26 and the placing of the concrete 27 at the connecting portions of the rectangular shield tunnels 13, 13 adjacent to each other are completed.

After that, if necessary, a reinforcing bar (not shown) is arranged in the segment 16 of the tunnel structure 11,
Be sure to place concrete (not shown).

Thereafter, as shown in FIG. 1, the ground G2 inside the tunnel structure 11 is excavated and an internal space 12 is formed therein to construct the large-section tunnel 10 of a predetermined shape. Complete.

As described above, in the method of constructing the large-section tunnel 10, the tunnel structure 11 is constructed by constructing a plurality of rectangular shield tunnels 13 adjacent to each other in the circumferential direction.
After the construction, the large section tunnel 10 is constructed by excavating the inner ground G2. When constructing the tunnel structure 11, first,
After constructing the rectangular shield tunnel 13 in advance, by excavating the backfilling material 17 of the rectangular shield tunnel 13 constructed in advance, a part of the rectangular shield tunnel 13 constructed in the subsequent process is superposed on the rectangular shield tunnel 13 constructed in advance. It is configured to let. Further, by removing the segment 16 in a portion where the rectangular shield tunnel 13 constructed earlier and the rectangular shield tunnel 13 constructed later are adjacent to each other and removing the backfill filler 17, the inside of the tunnel structure 11 is circumferentially extended. The structure is such that the reinforcing bars 26 are laid in the tunnel structure 11 and then concrete 27 is placed therein. Thereby, the tunnel structure 11 of the large cross-section tunnel 10 having sufficient rigidity can be constructed. Backfilling material 1 for the rectangular shield tunnel 13 previously constructed in this way
Since the rectangular shield tunnel 13 that was previously constructed and the rectangular shield tunnel 13 that was constructed later are integrated by excavating 7 and constructing the rectangular shield tunnel 13 afterward, the rectangular shield tunnels 13, 1 that are adjacent to each other are integrated.
Even when the three are joined together, it is possible to counteract the earth pressure and groundwater pressure of the ground without performing ground improvement by injecting a chemical solution as in the past and without using support works. Therefore, the large cross-section tunnel 10 can be constructed smoothly and efficiently, and thus, the effect of shortening the construction period, reducing the cost, and improving the safety can be obtained.

Further, the penetration work between the rectangular shield tunnels 13 adjacent to each other, the reinforcing work of the reinforcing bars 26, and the placing work of the concrete 27 are performed at least every other segment ring in the axial direction of the tunnel structure 11. The tunnel structure 11 is configured to be continuous in the axial direction by repeating each of the above-mentioned operations in the remaining portion. As a result, during each of the above-mentioned operations, the tunnel structure 11 is stabilized by the portions where the rectangular shield tunnels 13 adjacent to each other have not yet been penetrated or the portions where the concrete 27 has already been cast. It is possible to plan and to work safely.

Although the reinforcing bars 26 are arranged in the openings 25, 28 in the first embodiment, steel members may be arranged to reinforce the openings 25, 28. . In this case, as shown in FIG. 8, the upper and lower portions 25a 'and the lower surface 25b' of the opening 25 'are formed in a straight line shape without forming a substantially arch shape. In order to form this opening 25 ', a reinforcing steel rod 29a having a diameter slightly smaller than each hole is inserted into a plurality of holes formed by, for example, core boring. Then, both end portions of the reinforcing steel rod 29a are fixed to the segment 16 of the one rectangular shield tunnel 13 and the segment 16 of the other rectangular shield tunnel 13 by substantially U-shaped steel rod fixing jigs 29b. To do. Each steel rod fixing jig 29b can be fixed with bolts or the segment 1
It is also possible to weld if 6 is made of steel. In this way, the upper and lower parts 25 of the opening 25 '
By reinforcing a ', 25b' with the reinforcing steel rods 29a, 29a, ..., the reinforcing strength is increased as compared with the case where it is formed in a substantially arch shape (see FIG. 4), and it is resistant to surrounding earth pressure and water pressure. can do. Moreover, the reinforcing steel rods 29a, 29a,
Since the upper and lower portions 25a 'and 25b' can be made linear when using ..., the opening 25 'is made larger than in the case where these portions are made substantially arched (see FIG. 4). be able to. Furthermore, these reinforcing steel rods 29
It is also possible to use a, 29a, ... Instead of the reinforcing bar. The reinforcing steel rod 29a does not matter about its cross-sectional shape, material, etc., and for example, a hollow pipe material may be used and may be appropriately selected according to the required reinforcing strength.

[Second Embodiment] Next, as a large-section tunnel to be constructed, a tunnel having an upper and lower two-layer structure will be described as an example. As shown in FIG. 9, the large-section tunnel 30 to be constructed is formed inside the tunnel structure 31 as a lining body that resists earth pressure from the surrounding ground and the tunnel structure 31. Upper and lower two-stage internal space (space) 3
It is composed of 2, 33.

The tunnel structure 31 includes side wall portions 31a, 31a on both sides located in a substantially vertical plane and the side wall portions 31.
a upper surface 31b and a lower surface 31c which are respectively provided between the upper and lower ends of a and 31a and which are located in a substantially horizontal plane, and an upper and lower internal spaces 32 and 33 which are provided between intermediate portions of the side walls 31a and 31a. The partition surface 31d and the partition surface 31d are formed into a generally Japanese letter-shaped cross section. The tunnel structure 31 has a configuration in which a plurality of rectangular shield tunnels (shield tunnels) 35 are arranged adjacent to each other in the circumferential direction of the cross section, and these are integrated.

Each rectangular shield tunnel 35 is made up of a steel segment 36 and a backfill filler 37 filled between the segment 36 and the ground.

In the tunnel structure 31, a reinforcing bar 39 is arranged all around, and concrete 40 is placed inside the reinforcing bar 39.

Next, a method of constructing such a large cross section tunnel 30 will be described. For this purpose, as shown in FIG. 10, first, the side wall portions 31a, 31a of the tunnel structure 31 are formed.
And rectangular shield tunnels 35A, 35B, 35 at the intersections of the upper surface 31b, the lower surface 31c, and the partition surface 31d.
C, 35D, 35E and 35F are sequentially constructed in advance. At this time, with a cutter provided in front of a shield excavator (not shown) having a rectangular cross section, rectangular holes 41A, 41 are formed in the ground.
Drilling holes B, 41C, 41D, 41E, 41F,
After that, the steel segments 36, 36, ... Are assembled into a predetermined shape, and the assembled segments 36, 36 ,.
Outer peripheral surface and holes 41A, 41B, 41C, 41D, 41
Between the inner peripheral surface of E, 41F, concrete or mortar,
A backfill filler 37 such as fiber concrete is filled.

Here, the rectangular shield tunnels 35A, 3
5B, 35C, 35D, 35E, and 35F are assembled with the segment 36 so that the concave portion 42 is formed in a portion in contact with the rectangular shield tunnels 35G, 35H, 35J, and 35K forming the side wall portions 31a and 31a of the tunnel structure 31. This part is the backfill filler 37 compared to other parts.
Is becoming thicker.

Next, the side wall portion 31 of the tunnel structure 31 is formed.
rectangular shield tunnels 35G, 3 constituting a, 31a
5H, 35J, 35K, and a rectangular shield tunnel 3 that constitutes the upper surface 31b, the lower surface 31c, and the partition surface 31d.
5L, 35M, and 35N are sequentially constructed as follows. At this time, the rectangular shield tunnels 35G, 3
The shield excavator 22 (see FIG. 2) used when constructing the 5H, 35J, and 35K is provided with concrete cutting mechanisms 23 and 23 on the upper and lower surfaces. Then, the front ground of the shield excavator 22 is excavated by a cutter (not shown), and the concrete cutting mechanisms 23, 23 are used to adjoin the adjacent rectangular shield tunnels 35A, 35B as shown in FIG. , 35C, 35D, 3
The backfill filler 37 of 5E and 35F is cut. After this, as shown in FIG. 12, behind the segments 36, 36,
The rectangular shield tunnels 35G, 35H, 35 are assembled by assembling the ...
J, 35K is built.

Further, the rectangular shield tunnels 35L, 35
The shield excavator (not shown) used when constructing the M and 35N is equipped with a cutter for excavating the ground in the front, and a concrete cutting mechanism (not shown) on both left and right sides.
Is provided. Then, as shown in FIG. 11, the shield excavator (not shown) is used to excavate the forward ground, and the concrete cutting mechanisms (not shown) provided on both left and right sides adjoin the adjacent rectangular shield tunnels 35A, 35.
B, 35C, 35D, 35E, 35F backfill filler 37
To cut. Thereafter, as shown in FIG. 12, the segments 36, 36, ... Are assembled at the rear side, and the backfill filler 37 is filled on the outer side thereof to construct the rectangular shield tunnels 35L, 35M, 35N.

In this state, the previously constructed rectangular shield tunnels 35A, 35B, 35C, 35D, 35E, 35.
F, and the rectangular shield tunnels 35G, 35 that were constructed afterwards
This means that the H, 35J, and 35K and the rectangular shield tunnels 35L, 35M, and 35N that were constructed afterward were firmly integrated.

After that, as shown in FIG. 9, the tunnel structure 3 constructed in the same manner as in the first embodiment.
Reinforcing bars 39 and concrete 40 are placed and filled in 1. As shown in FIG. 13, after removing the segments 36, 36 at the portions where the rectangular shield tunnels 35, 35, ... Are adjacent to each other,
The backfill filler 37 at that portion is removed to form the opening 43. In this way, the tunnel structure 31 is penetrated so as to be continuous in the circumferential direction of the cross section. After this, as shown in FIG. 9, reinforcing bars 39 are laid in the tunnel structure 31 over the entire circumference in the cross-sectional direction, and concrete 40 is poured and filled. Note that the removal of the segment 36, the formation of the opening 43, the reinforcement of the reinforcing bar 39, and the filling of the concrete by casting are performed every other segment ring in the direction in which the tunnel structure 31 is continuous, and then the remaining Do the same for the parts. Thereby, the tunnel structure 31
It means that the full length of was built.

After that, the ground inside the tunnel structure 31 is excavated and the internal spaces 32 and 33 are formed therein, thereby completing the construction of the large-section tunnel 30 having a predetermined shape.

In the method of constructing the large section tunnel 30 described above, by applying the same method as in the first embodiment, the large section tunnel 30 having an upper and lower two-layer structure can be constructed, and at that time. Further, similar to the first embodiment, it is possible to obtain the effects of shortening the construction period, reducing the cost, and improving the safety. Moreover, the rectangular shield tunnels 35A, 35B, 35C, 35D, 35 to be constructed in advance are constructed.
The recesses 42 are formed in the E and 35F segments 36, and the backfill filler 37 in the recesses 42 is cut when the 35G, 35H, 35J, and 35K are constructed in a subsequent step. As a result, the amount of the backfill filler 37 used can be reduced as compared with the case where the thickness of the backfill filler 37 is increased as a whole. Moreover, the rectangular shield tunnels 35G, 35H, 35J, 35K, 35L, 35M,
When constructing 35N later, the rectangular shield tunnels 35A, 35B, 35C, 35D, 35 constructed earlier are constructed.
Since E and 35F are on both sides, the reaction force in the shield excavator can be easily obtained, and the excavation direction can be easily controlled.

In the second embodiment, it is possible to use a steel material as the reinforcing material instead of the reinforcing bar 39. Also, for example, rectangular shield tunnels 35A, 3
5B, 35C, 35D, 35E, and 35F are constructed in advance, and then rectangular shield tunnels 35L, 35M, and 35N are constructed afterwards, and then rectangular shield tunnels 35G and 35 are constructed.
The configuration may be such that H, 35J, and 35K are constructed.

Although the large-section tunnel 10 has a single-layer structure and the large-section tunnel 30 has an upper-lower two-layer structure in the above-described first or second embodiment, it has a structure of three or more layers in addition to this. May be. Further, the cross-sectional shape is not limited to the perfect rectangular shape, and may be another shape such as a part having a curved shape. Also,
The segments 16 that make up the tunnel structures 11, 31;
Regarding 36, it does not matter about its cross-sectional structure or material. Further, as to the reinforcement bar arrangement and concrete placement in the segments 16 and 36, only the connecting portion may be used as in the first embodiment, or the entire cross section may be used as in the second embodiment. You may give it.

When constructing the large cross-section tunnels 10, 30, the rectangular shield tunnels 13A, 13B, 35 are used.
A, 35B, 35C, 35D, 35E, 35F are constructed in advance, and rectangular shield tunnels 13C, 13D, 35G,
Although 35H, 35J, 35K, 35L, 35M, and 35N are constructed to be constructed in the subsequent stage, the position of the shield tunnel to be constructed in advance or constructed in the subsequent stage is not limited to the above-mentioned form and may be appropriately determined. In addition, when constructing a shield tunnel in advance or in a trailing stage, all shield tunnels may be constructed in parallel at the same time, or may be constructed in sequence, in which case the construction order is not questioned. is not. Similarly, regarding the removal of the segments 16 and 36 of the connection portion and the removal of the backfill fillers 17 and 37,
The order of construction does not matter, and work efficiency should be given priority.

When constructing the rectangular shield tunnels 13 and 35, as shown in FIG. 2A, the shield excavator 20 provided with the concrete cutting mechanism 21 on the side surface.
Alternatively, the shield excavator 22 having the concrete cutting mechanisms 23, 23 on both the upper and lower surfaces shown in FIG. 2B is used, but a shield excavator of a type other than this may be used if necessary. . For example, one equipped with a concrete cutting mechanism on both sides as well as one side, as shown in FIG.
A shield excavator 50 shown in Fig. 14 having concrete cutting mechanisms 51, 51 on both sides of the upper surface,
The shield excavator 52 shown in (b) may be one that has concrete cutting mechanisms 53 and 54 at two positions, an upper surface and a side surface.

[0042]

As described above, according to the method of constructing a large-section tunnel according to the first aspect, a tunnel structure is constructed by constructing a plurality of rectangular shield tunnels adjacent to each other in the circumferential direction. After that, it is configured to construct a tunnel having a large cross section by excavating the inner ground, and when constructing the tunnel structure, first construct one of the shield tunnels first and then construct the preceding. By excavating the backfill filler that constitutes the shield tunnel together with the ground, a part of the shield tunnel that is constructed in a subsequent manner is superposed on the shield tunnel that was constructed in advance. Then, according to the method for constructing a large-section tunnel according to claim 2, a segment of a portion where the shield tunnel that was previously constructed and a shield tunnel that was constructed later are adjacent to each other is removed, and further the backfill filler in this portion is removed. By doing so, the inside of the tunnel structure is penetrated in the circumferential direction of the cross section, and after that, reinforcing bars are laid in the tunnel structure and concrete is further placed. This makes it possible to construct a large-section tunnel having sufficient rigidity. In this way, the shield tunnel that was constructed in advance and the shield tunnel that was constructed in the subsequent stage are integrated, so even when these adjacent shield tunnels are joined together, ground improvement by chemical solution injection is required as in the past. Therefore, it is possible to smoothly and efficiently construct a tunnel structure having a large cross-section tunnel, and it is possible to obtain the effects of shortening the construction period, reducing costs, and improving safety.

According to the method for constructing a large cross-section tunnel according to claim 3, the work of penetrating the inside of the tunnel structure, the work of arranging the reinforcing bars, and the work of placing concrete are carried out in the excavation direction of each shield tunnel. The tunnel structure is configured to be continuous in the excavation direction by performing at least every other segment and repeating the above-described operations in the remaining portions. As a result, during each of the above-mentioned operations, it is possible to stabilize the tunnel structure by the part that has not yet penetrated the tunnel structure or the part that has already been reinforced and the concrete has been laid. Yes, you can work safely.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view showing a first mode of a large-section tunnel being constructed by applying a method for constructing a large-section tunnel according to the present invention.

FIG. 2 is a front view showing a shield excavator used for constructing the large-section tunnel.

FIG. 3 is a view showing a process of constructing the large cross-section tunnel, and is a front cross-sectional view and a side cross-sectional view showing a state in which a segment of a portion where shield tunnels are adjacent to each other is removed.

FIG. 4 is a front sectional view and a side sectional view showing a state in which the backfill filler is removed.

FIG. 5 is a front sectional view and a side sectional view showing a state in which reinforcing bars are reinforced and concrete is placed.

FIG. 6 is a side sectional view showing a state following FIG.

FIG. 7 is a side sectional view showing a state where the construction of the tunnel structure is completed.

FIG. 8 is a front cross-sectional view and a side cross-sectional view showing another example of the method for reinforcing the opening with the backfill filler removed.

FIG. 9 is a vertical cross-sectional view showing a second mode of a large-section tunnel constructed by applying the method for constructing a large-section tunnel according to the present invention.

FIG. 10 is a diagram showing a process of constructing the large cross-section tunnel, which is a front cross-sectional view showing a state in which some shield tunnels are pre-constructed.

FIG. 11 is a front cross-sectional view showing a state in which a hole has been drilled in the ground for constructing another shield tunnel in a trailing direction.

FIG. 12 is a front sectional view showing a state in which a shield tunnel constructed in advance and a shield tunnel constructed in the same manner are integrated together.

FIG. 13 is a front sectional view showing a state in which the segment is removed and the backfill filler is removed at the joint between adjacent shield tunnels.

FIG. 14 is a front view showing another example of the shield excavator used in the method for constructing a large-section tunnel according to the present invention.

FIG. 15 is a vertical cross-sectional view showing an example of a conventional large-section tunnel.

FIG. 16 is a vertical cross-sectional view showing an example of a conventional large cross-section tunnel having a rectangular cross section.

FIG. 17 is a process drawing showing the method for constructing the large cross-section tunnel shown in FIG.

[Explanation of symbols]

10,30 Large-section tunnel 11,31 Tunnel structure 12,32,33 Internal space (space) 13,35 Rectangular shield tunnel (shield tunnel) 15A, 15B, 15C, 15D, 15E, 15F, 4
1A, 41B, 41C, 41D, 41E, 41F Hole 16,36 Segment 17,37 Backfilling filler 20,22 Shield excavator 26,39 Reinforcing bar (reinforcing material) 27,40 Concrete

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kazuo Miyazawa 1-3-2 Shibaura, Minato-ku, Tokyo Shimizu Construction Co., Ltd. (72) Hiroyuki Kubo 1-3-2 Shibaura, Minato-ku, Tokyo Shimizu Construction (72) Inventor Hisao Arai 1-3-2 Shibaura, Minato-ku, Tokyo Shimizu Construction Co., Ltd. (72) Inventor Fusao Kawakami 1-3-2 Shibaura, Minato-ku, Tokyo Shimizu Construction Co., Ltd. (72) Inventor Yasuhiko Shigeta 1-3-2 Shibaura, Minato-ku, Tokyo Shimizu Construction Co., Ltd. (72) Inventor Atsue Onoue 1-3-2 Shibaura, Minato-ku, Tokyo Shimizu Construction Co., Ltd. (72) Invention Hisashi Takenaka 1-3-2 Shibaura, Minato-ku, Tokyo Shimizu Construction Co., Ltd.

Claims (3)

[Claims] 1. A tunnel structure which is a lining body of a large cross section tunnel is constructed by arranging a plurality of rectangular shield tunnels adjacent to each other in the circumferential direction. A structure is constructed by constructing a tunnel having a large cross section by excavating the ground and forming a space here. When building the tunnel structure, first, a hole is made in the ground with a shield excavator having a rectangular cross-section. Excavation, the segment is assembled into a rectangular shape in a sectional view, and one shield tunnel is pre-constructed by filling the void between the surrounding ground and the segment with a backfill filler, and then the pre-constructed When the other shield tunnel is built next to the one shield tunnel, the shield tunnel that was previously built together with the ground adjacent to the one shield tunnel is constructed. After excavating the backfill filler with a shield excavator, the segments are assembled into a rectangular shape in cross section, and the backfill filler is filled between the surrounding ground and the previously constructed shield tunnel and the segment. A method for constructing a large-section tunnel, characterized in that a part of the other shield tunnel to be constructed later is superposed on the one shield tunnel constructed in advance. 2. The method for constructing a large cross-section tunnel according to claim 1, wherein after the tunnel structure is constructed, the shield tunnel of the preceding construction and the shield tunnel of the subsequent construction are adjacent to each other in the segment. By removing and further removing the backfill filler in this portion, the inside of the tunnel structure is penetrated in the circumferential direction of the cross section, and thereafter, a reinforcing material such as a reinforcing bar or a steel material is provided in the segment of the tunnel structure. A method for constructing a large cross-section tunnel, which is characterized by placing and then placing concrete. 3. The method for constructing a large cross-section tunnel according to claim 2, wherein a work of penetrating the inside of the tunnel structure,
Arrangement work of the reinforcing material, and placing work of concrete, at least every other segment in the excavation direction of each of the shield tunnel, by performing each of the operations repeatedly in the remaining portion thereafter, A method for constructing a large-section tunnel, characterized in that the tunnel structure is continuous in the excavation direction.