JP7178783B2 - Egg-shaped tunnel with branch structure and its construction method - Google Patents

Description

TECHNICAL FIELD The present invention relates to an egg-shaped tunnel having a substantially egg-shaped tunnel cross section and a branch structure (confluence structure) of a main tunnel and a sub-tunnel, and a construction method thereof.

For example, the parent-child shield machine described in Patent Document 1 uses a shield machine to construct a single-track section, a double-track section, and a transition section between them in a subway tunnel. A slave machine with a main cutter is installed in the center of a master machine having an elliptical outer shell, and two crescent-shaped main cutters of the master machine are installed on both sides of the slave machine.
When constructing a tunnel, excavation is performed by rotating each main cutter while the parent and child machines are combined. At construction sites for double-track sections, parts that cannot be excavated by the main cutters are excavated by protruding sub-cutters. At the construction site of a single track section, the main cutter of the parent machine is stopped, and the segment ring is constructed behind as a shield while excavating the child machine. In this parent-child shield machine, only one child machine in the center can start from the parent machine, and a tunnel branching in two directions cannot be constructed.

The egg-shaped tunnel 100 shown in FIG. 8 includes an egg-shaped shield 103 that encloses a relatively large-diameter main tunnel 101 and a relatively small-diameter sub-tunnel 102 . In order to branch and extend the main tunnel 101 and the sub-tunnel 102 from the confluence portion of the egg-shaped tunnel 100, a structure is required in which the main tunnel 101 and the sub-tunnel 102 are arranged in contact or close to each other without overlapping. be.

For example, in an underground railway tunnel, when branching the access road from the ground level to the underground station installed on the main track in the tunnel, the passage including escalators and stairs that join the underground station from the ground level will be branched as the access road. . In addition, in an underground road tunnel, the approach road from the ground is branched to the main road in the tunnel.

JP-A-10-77779

However, if the underground tunnel described above is a horizontal egg-shaped tunnel 100 as shown in FIG. Weak and difficult to withstand soil loads. For this reason, it is necessary to raise the strength by erecting columns between the main tunnel and the sub-tunnel or by increasing the thickness of the segments, which causes the problem of increased construction costs. In addition, if the diameter of the main tunnel 101 is increased to increase the height of the main tunnel 101 in order to increase the earth load resistance, and the diameter of the egg-shaped shield 103 is partially increased, the center O of the shield 103 is laterally displaced. There is a problem that it becomes laterally long and large, resulting in high cost.

SUMMARY OF THE INVENTION The present invention has been made in view of such problems, and provides an egg-shaped tunnel having a branch structure that is high in strength, can withstand soil loads, and can reduce construction costs, and a construction method therefor. With the goal.

An egg-shaped tunnel having a branch structure according to the present invention is an egg-shaped tunnel having a shield with an egg-shaped cross section, and includes a main tunnel having a relatively large diameter installed inside the shield and a main tunnel installed inside the shield. a relatively small-diameter sub-tunnel branched in parallel with the tunnel, wherein the main tunnel and the sub-tunnel are arranged in parallel and close to each other at the branch in the shield, and at least the main tunnel is located closer to the branch than the branch at the confluence. is also enlarged in diameter and integrally formed so as to communicate with the sub-tunnel.
According to the present invention, since the diameter of the main tunnel is expanded from the diverging portion at the confluence portion in the shield of the egg-shaped tunnel, it can be integrally formed with the sub-tunnel without changing the position, and the egg-shaped tunnel is not flattened and is resistant to soil. The load is high and the strength is high, so the manufacturing cost can be reduced. Moreover, since the diameter is expanded at the confluence, a wide space can be secured.

A construction method for an egg-shaped tunnel having a branch structure according to the present invention is a construction method for an egg-shaped tunnel in which a main tunnel with a relatively large diameter and a sub-tunnel with a relatively small diameter are installed in parallel within a shield having an egg-shaped cross section, At the bifurcation in the egg-shaped tunnel, the diameter of the main cutter of the main line shield machine is reduced to excavate the main tunnel, and the sub-tunnel is excavated at a position close to the main cutter by the sub-cutter of the branch shield machine. At the confluence part in the die tunnel, at least the main cutter is expanded in diameter and excavated so that it overlaps with the sub-cutter at a position shifted in the front-rear direction, and the main tunnel and the sub-tunnel are integrally formed. .
According to the present invention, the main cutter of the shield machine for the main line and the sub-cutter of the shield machine for the branch line can be excavated in close proximity to each other at the bifurcation of the egg-shaped tunnel, and the main cutter can be excavated at the confluence. Since the diameter is expanded and the sub-cutter is overlapped with the sub-cutter at a position shifted in the front-rear direction, the main tunnel and the sub-tunnel can be constructed as an integrated confluence.

Further, the sub-cutter of the branching shield machine is extendable, and it is preferable that the sub-cutter is contracted in diameter at the branching portion and excavated with the sub-cutter extended at the confluence portion.
At the confluence of the egg-shaped tunnels, the diameter of the main cutter and the sub-cutter are respectively expanded and excavated, so that the main tunnel and the sub-tunnel can be constructed integrally to secure a large space.

A construction method for an egg-shaped tunnel having a branch structure according to the present invention is a construction method for an egg-shaped tunnel in which a main tunnel with a relatively large diameter and a sub-tunnel with a relatively small diameter are installed in parallel within a shield having an egg-shaped cross section, At the bifurcation in the egg-shaped tunnel, the main tunnel is excavated by the main cutter of the shield machine for the main line, and the sub-tunnel is excavated by the sub-cutter of the bifurcation shield machine at a position close to the main cutter, and the egg-shaped tunnel joins. Part 2 is characterized in that the main tunnel and the sub-tunnel are integrally formed by extending at least the extendable main sub-cutter provided on the main cutter and excavating the portion outside the outer peripheral surface of the main cutter.
According to the present invention, since at least the main sub-cutter can excavate the outside of the excavation area of the main cutter and the sub-cutter, a wider integrated space can be secured at the confluence.

According to the egg-shaped tunnel having the branch structure and construction method thereof according to the present invention, the size of the main tunnel can be increased or decreased between the branch and the confluence without changing the central position of the large-diameter tunnel on the outer shell of the egg-shaped tunnel. As a result, it is possible to suppress the lateral length of the structure, to achieve high strength and high resistance to soil load, to set a wide space at the confluence, and to reduce the manufacturing cost.

FIG. 4 is an explanatory view of the egg-shaped tunnel broken at the confluence according to the embodiment of the present invention; Figure 2 is a cross-sectional view of a bifurcation in the egg-shaped tunnel shown in Figure 1; FIG. 2 is a cross-sectional view of a junction in the egg-shaped tunnel shown in FIG. 1; FIG. 4 is an explanatory diagram showing an excavation method at a bifurcation of an egg-shaped tunnel; FIG. 4 is an explanatory diagram showing an excavation method at a confluence of egg-shaped tunnels; It is explanatory drawing which shows the excavation method of the junction part of an egg-shaped tunnel by a modification. It is an explanatory view similar to FIG. 1 showing a modification in which an egg-shaped tunnel is constructed in a road tunnel. 1 is a cross-sectional view of a conventional egg-shaped tunnel; FIG.

Hereinafter, an egg-shaped tunnel and a construction method thereof according to an embodiment of the present invention will be described with reference to FIGS. 1 to 5. FIG.
FIG. 1 shows an egg-shaped tunnel 1 according to an embodiment of the present invention, which is applied to a railway tunnel such as a subway. An underground subway station 2 is installed in the egg-shaped tunnel 1 shown in FIG. The egg-shaped tunnel 1 has an underground space in which a main tunnel 3 and a sub-tunnel 4 extending separately meet at an underground station 2. - 特許庁The main tunnel 3 has a relatively large diameter and substantially circular cross section, and the sub tunnel 4 has a relatively small diameter and substantially circular cross section.

A subway main line 6 extends in the main tunnel 3 and is connected to and integrated with an underground station 2. - 特許庁The sub-tunnel 4 indicates an access road 7 that extends from the underground station 2 to the ground level. Generally, the access road 7 includes stairs, escalators, and passages (not shown) that connect the underground station 2 with an above-ground entrance/exit. there is
In the shield (segment ring) 9 of the egg-shaped tunnel 1, the region where the main tunnel 3 and the sub-tunnel 4 are arranged close to each other in parallel is the branching portion (see FIG. 2). The area forming the underground station of the space where 4 is integrated is the junction (see FIG. 3). Therefore, the egg-shaped tunnel 1 has a branched structure of the main tunnel 3 and the sub-tunnel 4 .

2 and 3 are vertical cross-sectional views showing the egg-shaped tunnel 1, and FIG. 2 is a cross-sectional view taken along line AA of FIG. 3 is a cross-sectional view taken along the line BB in FIG. 1, showing the confluence.
In FIG. 2, the shield 9 of the egg-shaped tunnel 1 is horizontal in cross section, that is, has a horizontally elongated egg-shaped shape. there is The main tunnel 3 and the sub-tunnel 4 are each formed to have a substantially circular cross section, and the partition 10 (segment ring) of the main tunnel 3 and the partition 11 (segment ring) of the sub-tunnel 4 are arranged close to each other.

3, in the underground station 2, the bulkhead 10 of the main tunnel 3 is constructed by expanding its diameter to a position close to a portion of the shield 9, and the bulkhead 11 of the sub-tunnel 4 also contacts a portion of the shield 9. It is constructed by expanding the diameter to the position. Therefore, since the outlines of the partition 10 of the main tunnel 3 and the partition 11 of the sub-tunnel 4 overlap each other, they are connected and integrated.
At the confluence in the shield 9, the upper and lower regions P1 and P2 deviated from the expanded bulkhead 10 of the main tunnel 3 and the bulkhead 11 of the sub-tunnel 4 are excavated by a fixed auger screw 25 as will be described later to form the shield. The space in 9 is made into the underground station 2 as a whole. In the underground station 2, as shown in FIG. 1, a main line 6 extending through the main tunnel 3, and a platform 13, offices, etc. installed inside the sub-tunnel 4 are installed.

Next, a method for constructing the egg-shaped tunnel 1 according to this embodiment will be described with reference to FIGS. 4 and 5. FIG.
The tunnel boring machine 15 shown in FIGS. 4 and 5 includes a main shield machine 16 (parent machine) having an outer shell 12 with an oval cross section and a relatively large-diameter main-line shield machine 17 and a relatively small-diameter branch shield machine 17 inside the main shield machine 16 (parent machine). Shield machines 18 (child machines) are arranged in parallel in the horizontal direction. The main line shield machine 17 is a subsidiary machine for excavating the main tunnel 3 having a relatively large diameter and a substantially circular cross section, and the branching shield machine 18 is a subsidiary machine for excavating the sub tunnel 4 having a relatively small diameter and a substantially circular cross section. .

The main line shield machine 17 is provided with a rotatable main cutter head 21 having, for example, four telescopic cutters 20 arranged radially at intervals of 90 degrees on a faceplate on the front. The extensible cutter 20 has an extensible spoke 20a with a bit at its tip that can be extended and contracted radially outward by an extensible jack. Sometimes held in a stretched state.
Similarly, the branching shield machine 18 has a rotatable sub-cutter head 23 on the front surface of which two extendable cutters 22 are radially arranged at intervals of, for example, 180 degrees. The extensible cutter 22 has an extensible spoke 22a with a bit at its tip that can be extended and contracted radially outward by an extensible jack. Sometimes held in a stretched state.

When excavating at the diverging portion, the main line shield machine 17 and the branching shield machine 18 are provided with a driving jack as a driving mechanism behind the main cutter head 21 and the sub cutter head 23, an earth discharging mechanism, and a ring-shaped segment. It is equipped with an erector device to be assembled, a reaction force receiver for starting, etc. The parent shield machine 16 is also equipped with similar equipment when excavating at the confluence.
At the junction, the rear side of the main cutter head 21 of the main line shield machine 17 is arranged to prevent interference between the extended telescopic cutter 20 of the main line shield machine 17 and the telescopic cutter 22 of the branching shield machine 18 . The sub-cutter head 23 of the shield machine 18 for branching is installed by shifting it. Alternatively, the secondary cutter head 23 of the branching shield machine 18 may be installed in front of the main cutter head 21 of the main line shield machine 17 .

Next, a tunnel excavation method using the tunnel excavator 15 will be described.
After a tunnel excavator 15 is excavated into the ground from a vertical shaft, a side tunnel is excavated to excavate an egg-shaped tunnel 1 for constructing an underground station 2. - 特許庁That is, the main shield machine 16 of the tunnel excavator 15 excavates the junction, and then the main tunnel 3 and sub tunnel 4 of the branch are excavated in the outer shell 12 by the main line shield machine 17 and the branch shield machine 18 . Alternatively, the main line shield machine 17 and the branch shield machine 18 may first excavate the branch section, and then the tunnel excavator 15 may excavate the confluence section.

When excavating the bifurcation, as shown in FIG. 4, the main tunnel 3 is excavated by the main cutter head 21 with the telescopic spokes 20a of the telescopic cutter 20 contracted in the main line shield machine 17 in the main shield machine 16. do. Behind the main cutter head 21 a circular segmented ring of the main tunnel 3 is constructed with a reduced diameter. Further, in the branching shield machine 18, the auxiliary tunnel 4 is excavated by the auxiliary cutter head 23 while the diameter of the telescopic spoke 22a of the telescopic cutter 22 is reduced. Behind the secondary cutter head 23 a circular segmented ring of secondary tunnels 4 of reduced diameter is constructed.
Since the main line shield machine 17 and the branch shield machine 18 excavate in parallel positions close to each other in the parent shield machine 16, they do not interfere with each other. It should be noted that, in excavation at the diverging portion, the main cutter head 21 and the sub-cutter head 23 may be displaced in the front-rear direction and excavated in the same manner as in the excavation at the confluence portion.

In the excavation of the egg-shaped tunnel 1, excavation of the confluence section is performed when the area of the underground station 2 is reached. That is, as shown in FIG. 5, in the main line shield machine 17, the telescopic spokes 20a of the telescopic cutter 20 are extended within the range of the outer shell 12 to excavate the main tunnel 3 having an enlarged diameter. The branching shield machine 18 also stretches the telescopic spokes 22a of the telescopic cutter 22 to excavate the sub-tunnel 4 with an enlarged diameter, and constructs a circular segment ring of the sub-tunnel 4 behind it.
In this embodiment, since the sub-cutter head 23 is installed behind the main cutter head 21, the main tunnel 3 and the sub-tunnel 4 can be excavated without interfering with each other and partially overlapping.

As a result, the enlarged excavation area of the main tunnel 3 and the excavation area of the sub-tunnel 4 are laterally communicated and integrated. Moreover, in these cases, the center of rotation of the main cutter head 21 and the sub-cutter head 23 does not move and excavation is performed with the diameter expanded within the range of the outer shell 12, and the outer shape of the shield 9 does not widen in the lateral direction. Therefore, the shield 9 suppresses a change in segment height and does not expand laterally.
Therefore, the shield 9 including the main tunnel 3 and the sub-tunnel 4 can withstand the earth load, and the construction cost can be reduced. It is possible to prevent the rotation center of the main line shield machine 17 from laterally moving and the egg-shaped tunnel 1 from expanding laterally as in the conventional technology.

An unexcavated area that is not included in the expanded excavation area of the main line shield machine 17 (the space of the main tunnel 3) and the excavation area of the branch shield machine 18 (the space of the sub tunnel 4) in the outer shell 12 of the confluence section. P1 and P2 can be excavated by an auger screw 25 fixedly arranged on the tunnel boring machine 15 . As a result, the entire inside of the outer shell 12 at the junction can be constructed in the space of the underground station 2 .
In the ground opposite to the main tunnel 3 and sub-tunnel 4 with respect to the egg-shaped tunnel 1 constructing the underground station 2, only the main line shield machine 17 is excavated to extend the main tunnel 3 forward. . Alternatively, a plurality of sub-tunnels 4 may be constructed by excavating branching shield machines 18 not only behind the egg-shaped tunnel 1 but also on the front side.

As described above, according to the egg-shaped tunnel 1 and the construction method thereof according to the present embodiment, when constructing the egg-shaped tunnel 1 for constructing the underground station 2, the main line shield machine 17 and the branch shield machine 18 are installed inside the outer shell 12. Even if the diameter is expanded, the height does not increase and the rotation center position does not move. Therefore, when constructing the egg-shaped tunnel 1 for constructing the underground station 2, the extension of the shield 9 of the egg-shaped tunnel 1 in the horizontal direction and the height direction can be suppressed, the soil load resistance is high, the strength is high, and the construction cost is low. It can suppress the rise. In addition, a large space can be formed in the egg-shaped tunnel 1 at the junction.
Moreover, since the main line shield machine 17 and the branch shield machine 18, which are child machines, can excavate the parent shield machine 16, the machine cost can be reduced.

Although the egg-shaped tunnel 1 according to the embodiment of the present invention and the construction method thereof have been described in detail above, the present invention is not limited to the above-described embodiment, and can be modified as appropriate without departing from the scope of the present invention. , substitution, etc. are possible, and all of these are included in the present invention. Modifications and the like of the present invention will be described below, but the same reference numerals will be used for the same or similar parts and members as in the above-described embodiment, and the description will be omitted.

In the above-described embodiment, when excavating the confluence and branching sections in the egg-shaped tunnel 1, the main cutter heads 21 of both the main line shield machine 17 and the branching shield machine 18 are cut in the area of the confluence (underground station 2). and the telescopic cutters 20 and 22 of the sub-cutter head 23 are expanded in diameter, but the present invention is not limited to such a configuration. Even if the diameter of the auxiliary cutter head 23 is not expanded, at least the diameter of the main cutter head 21 is expanded so that the diameter-expanded main tunnel 3 and the subsidiary tunnel 4 can be communicated and integrated.

In the above-described embodiment, the main line shield machine 17 and the branch shield machine 18 are provided with the telescopic cutters 20 and 22, and the fixed auger screw 25 is provided. 6, cutters 24 and 26 may be fixed to the main cutter head 21 and the sub-cutter head 23 in diameter-reduced positions, respectively. In this case, a main sub-cutter 27 and a sub-sub-cutter 28 that can protrude from the outer peripheral surface of each fixed cutter may be provided in the expanded area that cannot be excavated by the main line shield machine 17 and the branch shield machine 18 .

The main sub-cutter 27 and the sub-sub-cutter 28 are provided with extendable hydraulic jacks 30 fixed to the main cutter head 21 and the sub-cutter head 23, respectively, and substantially ax-shaped cutter parts 31 pivotally supported at the tips thereof. . The main sub-cutter 27 is configured to be able to protrude outward from the outer peripheral portion of the main cutter head 21 and to contract by extension and contraction of the hydraulic jack 30 . The sub-sub-cutter 28 is also configured to be able to protrude and contract outward from the outer peripheral portion of the sub-cutter head 23 by extension and contraction of the hydraulic jack 30 .
The amount of protrusion of the main sub-cutter 27 and sub-sub-cutter 28 can be adjusted by computer control. As a result, the enlarged diameter portion that cannot be excavated by the main cutter head 21 and the sub cutter head 23 may be excavated. Furthermore, the uncut areas P1 and P2 may also be excavated by the main sub-cutter 27 and sub-sub-cutter 28 in the same manner.

In the above-described embodiment, the egg-shaped tunnel 1 is installed in a railway tunnel, but instead of this, it may be installed in a road tunnel 35 as shown in FIG. In the road tunnel 35, a main tunnel 37 with a main road 36 and a sub-tunnel 39 with a branch road 38 are constructed, and an egg-shaped tunnel 40 is constructed at the junction and junction of the main road 36 and the branch road 38. ing.
Alternatively, even if only the main sub-cutter 27 is provided without installing the sub-sub-cutter 28, the main tunnel 3 and the sub-tunnel 4 having enlarged diameters can be communicated with each other and integrally formed.

1, 40 Egg-shaped tunnel 1a Egg-shaped segment ring 2 Underground station 3, 37 Main tunnel 4, 39 Sub tunnel 9 Shield 12 Outer shell 17 Main line shield machine 18 Branching shield machine 20, 22 Telescopic cutter 21 Main cutter head 23 Sub cutter head
25 Auger screw 27 Main sub cutter 28 Sub sub cutter 35 Road tunnel

Claims (4)

An egg-shaped tunnel comprising a shield with an egg-shaped cross section and a branch structure of a relatively large-diameter main tunnel and a relatively small-diameter sub-tunnel,
a branching portion, which is an area in the shield where the main tunnel and the sub-tunnel are arranged close to each other in parallel;
Within the shield, without changing the center position of the main tunnel with respect to the sub-tunnel, at least the main tunnel is expanded to a position close to the top and bottom of the shield and communicates with the sub-tunnel. a confluence portion, which is an integrally formed region;
An egg-shaped tunnel with a branch structure having a A construction method for an egg-shaped tunnel comprising a shield having an egg-shaped cross section and a branch structure of a relatively large-diameter main tunnel and a relatively small-diameter sub-tunnel, comprising:
In the branching portion, which is a region in which the main tunnel and the sub-tunnel are arranged close to each other in parallel within the shield, the diameter of the main cutter of the shield machine for the main line is reduced to excavate the main tunnel, excavating the sub-tunnel at a position close to the main cutter by a sub-cutter of a shield machine for branching;
Within the shield, without changing the center position of the main tunnel with respect to the sub-tunnel, at least the main tunnel is expanded to a position close to the top and bottom of the shield and communicates with the sub-tunnel. In the confluence portion, which is an integrally formed region, at least the main cutter is enlarged in diameter and excavated so that it overlaps with the sub-cutter at a position shifted in the front-rear direction, and the main tunnel and the sub-tunnel are integrated. Form,
A construction method for an egg-shaped tunnel with a branch structure. 3. The bifurcation according to claim 2, wherein the sub-cutter of the branching shield machine is extendable, and excavates by reducing the diameter of the sub-cutter at the branching portion and by extending the sub-cutter at the junction portion. Construction method of egg-shaped tunnel with structure. A construction method for an egg-shaped tunnel comprising a shield having an egg-shaped cross section and a branch structure of a relatively large-diameter main tunnel and a relatively small-diameter sub-tunnel, comprising:
In the branching portion, which is a region in which the main tunnel and the sub-tunnel are arranged in parallel and close to each other in the shield, the main tunnel is excavated by the main cutter of the main line shield machine, and the branch shield machine excavating the sub tunnel at a position close to the main cutter by the sub cutter of
Within the shield, without changing the center position of the main tunnel with respect to the sub-tunnel, at least the main tunnel is expanded to a position close to the top and bottom of the shield and communicates with the sub-tunnel. In the confluence portion, which is an integrally formed region, the main tunnel and the sub tunnel are formed by extending at least the expandable main sub-cutter provided in the main cutter to excavate the portion outside the outer peripheral surface of the main cutter. integrally form the
A construction method for an egg-shaped tunnel with a branch structure.

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