JP3972634B2 - Tunnel construction method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
This invention relates to construction method of the tunnel, in particular, to a construction method of a tunnel connecting a plurality of shield tunneling in the lateral direction.
[0002]
[Prior art]
Conventionally, tunnels constructed by the shield method have been mainly tunnels with a structurally stable circular cross section. However, recently, from the viewpoint of diversifying use of underground space, congestion of underground structures, and efforts to reduce costs, a tunnel with a cross-sectional shape in which circular cross-sections are polymerized in two or three in a horizontal direction. Has been built.
[0003]
7 to 8 show an example of such a tunnel. The shield tunnel shown in the figure has first and second shield tunnels 1 and 2 having a circular cross section and the same diameter.
[0004]
The shield tunnels 1 and 2 form the excavation surface having the cross-sectional shape shown in FIG. 4 is assembled.
[0005]
As shown in FIG. 8, the first and second shield tunnels 1 and 2 are formed by directly connecting the ends of the circular cross-sections in the lateral direction so that they overlap each other. The upper and lower connecting segment pieces 6 and 7 are arranged at the joint 5 between the segments 4 of the adjacent shield tunnels 1 and 2 by cutting.
[0006]
These connecting segment pieces 6 and 7 are joined to the segment 4 at both end surfaces, and are opposed to each other at a predetermined interval in the vertical direction, and a middle pillar 8 is installed between the upper and lower connecting segment pieces 6 and 7. ing.
[0007]
In the tunnel having such a shape, in order to structurally stabilize the tunnel, the middle pillar 8 is arranged for each ring of the segment 4 as shown in FIG.
[0008]
In addition to the structure in which the shield tunnels 1 and 2 are directly connected as described above, as a structure for connecting a plurality of shield tunnels in the horizontal direction, for example, as shown in FIG. There is also a structure in which the tunnels 1a and 2a are arranged adjacently in parallel so as to be adjacent to each other, and a coupling portion 5a is formed between the two to indirectly connect the shield tunnels 1a and 2a.
[0009]
Even in such a tunnel, the middle pillar 8a is provided between the upper and lower coupling portions 5a in order to ensure the stability of the shape.
[0010]
However, all the tunnels having the above-described structures have technical problems described below.
[0011]
[Problems to be solved by the invention]
That is, the former tunnel that directly connects the shield tunnels 1 and 2 shown in FIG. 7 and the latter tunnel that indirectly connects the shield tunnels 1a and 2a shown in FIG. It is often used, and it is also considered to be used for a crossover part of a subway or a branch and junction part of a road tunnel.
[0012]
However, because these shield tunnels are provided with the middle pillars 8 and 8a so as to partition the inside of the tunnel, it is difficult to secure a wide space, and in particular, the junction part of the road tunnel and the crossover line of the subway In the case of adopting it in the section, there is a problem that the lanes of the vehicle and the subway cannot be changed between the shield tunnels by the middle columns 8 and 8a.
[0013]
The present invention has been made in view of such conventional problems, and the object of the present invention is to eliminate a central pillar, thereby making it possible to secure a wide space and to divide a lane, a junction The purpose is to provide a tunnel construction method that allows lane change when used in the crossover section.
[0014]
[Means for Solving the Problems]
In order to achieve the above object, the present invention includes a plurality of shield tunnels constructed adjacently in a lateral direction, and a coupling portion that directly or indirectly couples between the shield tunnels. A tunnel construction method in which an underground beam is provided immediately above and a suspension anchor is provided to fix both ends of the coupling portion and the underground beam, and the underground beam is provided between a starting portion and a reaching portion. An arch portion provided, forming a ground improvement area from the inside of the shield tunnel to the upper outside, removing a segment of the shield tunnel adjacent to the ground improvement area, and excavating the ground improvement area; The starting portion and the reaching portion are formed, and the arm that extends in parallel with the axial direction of the shield tunnel and reaches the reaching portion by propulsion of the tubular body from the starting portion or shield excavation. After that, the one end side is composed of a plurality of pieces arranged along the longitudinal direction of the arch portion, and is extended so as to be parallel to each other on the same plane, and the other end side is The suspension anchor for fixing and fixing to the coupling portion is installed, and between the starting portion and the reaching portion, a prestressed steel material having both ends fixed thereto is provided, and a lower portion is provided from the coupling portion to the lower ground. An anchor was installed .
[0015]
According to the construction method of the tunnel constructed as described above, the underground beam is provided immediately above the coupling portion, and the suspension anchors fixed to the coupling portion and the underground beam are provided at both ends. The load applied to the shield tunnel can be received by the suspension anchor.
[0016]
For this reason, when a wide space is secured and it is adopted as a lane junction, it is possible to easily change the lane of the subway or the traveling vehicle.
[0017]
The underground beam can be provided such that its longitudinal axis extends in the same direction as the axis of the shield tunnel.
[0018]
The underground beam can be formed in an arch shape so as to bulge upward along the axial direction of the shield tunnel.
[0019]
The underground beam may be provided between a starting portion and a reaching portion provided above the shield tunnel, and an arch portion having a central portion bulging upward and curved may be provided.
[0024]
DETAILED DESCRIPTION OF THE INVENTION
DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments of the invention will be described in detail with reference to the accompanying drawings. 1 to 6 show an embodiment of a tunnel construction method according to the present invention.
[0025]
The tunnel shown in the figure includes a first shield tunnel 10 and a second shield tunnel 12 having a circular cross section of the same diameter, and these are connected so that their ends overlap each other. This is applied when building a part (which may be a merging / merging part of a road tunnel).
[0026]
The shield tunnels 10 and 12 are arranged adjacent to each other so that the tunnel axes are parallel to each other, and the shield tunnels 10 and 12 are directly connected to each other via the coupling portion 14. Are formed in a two-way subway tunnel that communicates with each other.
[0027]
The shape of each shield tunnel 10, 12 is maintained by assembling a plurality of segments 10a, 12a obtained by dividing a cylindrical body in the circumferential and axial directions along the excavation surface.
[0028]
The coupling portion 14 includes an upper coupling segment 14a and a lower coupling segment 14b arranged in parallel in the vertical direction, and a shield machine that excavates the same shape as the shield tunnel whose cross section is shown in FIG. Has been.
[0029]
The upper and lower coupling segments 14a and 14b of the coupling portion 14 are integrally fixed to portions where the segments 10a and 12a of the shield tunnels 10 and 12 are removed at both ends in the lateral direction.
[0030]
An underground beam 16 is provided immediately above the coupling portion 14. The underground beam 16 of the present embodiment is provided so that the tunnel axes of the shield tunnels 10 and 12 are substantially parallel to the longitudinal axis.
[0031]
The underground beam 16 includes a starting portion 18, a reaching portion 20, and an arch portion 22 provided therebetween. The starting portion 18 has a hollow rectangular tube shape whose upper and lower ends are closed, and is arranged close to the coupling portion 14 so that its axis is parallel to the cross section of the first shield tunnel 10. ing.
[0032]
The reaching part 20 is formed in a hollow rectangular tube shape that is substantially the same as the starting part 18, and is opposed to the starting part 18 so that its axis is located immediately above the coupling part 14 with a predetermined distance from the starting part 18. Has been placed. The shape of the start part 18 and the reach | attainment part 20 is not restricted to a square tube, For example, a cylindrical shape may be sufficient.
[0033]
The arch portion 22 has a hollow cylindrical shape, the longitudinal axis extends in the same direction as the tunnel axis of the first and second shield tunnels 10 and 12, and both ends are integrated with the start and reach portions 18 and 20. Has been.
[0034]
This arch part 22 connects both ends of a plurality of hollow tube bodies 22a to each other, and the hollow tube body 22a is sequentially pushed into the upper ground from the center of the side surface of the starting part 18 by the propulsion method. Thus, by causing the tip to reach the center of the side surface of the reaching portion 20, the central portion is formed in a shape that is curved to release upward.
[0035]
The means for forming the arch portion 22 is not limited to the propulsion method, and may be formed by a shield method using a shield machine and a segment when the diameter is relatively large, for example.
[0036]
In the case of the present embodiment, a plurality of suspension anchors 24 are installed between the coupling portion 14 and the underground beam 16. The suspension anchor 24 is composed of a rod-shaped body such as a steel rod, and is driven from the inside of the arch portion 22 of the underground beam 16 toward the coupling portion 14 so as to penetrate the arch portion 22. The hanging anchor 24 may be driven from the shield tunnel side upward.
[0037]
Each suspension anchor 24 is fixed and fixed at the lower end side to the coupling portion 14, and the upper end side of each suspension anchor 24 is fixed and fixed to the side wall of the hollow tube body 22 a of the arch portion 22.
[0038]
In the case of the present embodiment, a plurality of suspension anchors 24 are arranged on the one end side along the longitudinal direction of the arch portion 22 at a predetermined interval, and each suspension anchor 24 is on the same plane, that is, the shield tunnel 10. , 12 are provided so as to be parallel to each other on a cross section substantially parallel to the tunnel axis.
[0039]
Further, the suspension anchors 24 are arranged in two rows so that the cross sections arranged in parallel to each other are in two rows so that the pairs are opposed to each other at a predetermined interval. 24, and the lower end side of each suspension anchor 24 is fixedly fixed to this portion so as to penetrate the upper coupling segment 14a.
[0040]
When the suspension anchor 24 is arranged in such a state, the load of the shield tunnels 10 and 12 can be supported uniformly over the entire length of the arch portion 22.
[0041]
Further, in the case of the present embodiment, the underground beam 16 is provided with prestressed steel material 28 whose both ends are fixed and fixed by introducing tension between the starting portion 18 and the reaching portion 20. Yes.
[0042]
The prestressed steel material 28 has a space between the starting portion 18 and the reaching portion 20 provided at both ends of the arch portion 22 when the earth pressure is applied to the arch portion 22 of the underground beam 16. It is provided in order to regulate the enlargement by the action.
[0043]
In the case of the present embodiment, a plurality of lower anchors 30 that are driven from the coupling portion 14 toward the lower ground are provided. Each lower anchor 30 includes an anchor main body 30a and a lower fixing portion 30b installed at the lower end of the anchor main body 30a.
[0044]
The lower anchors 30 are arranged so that one pair at a time expands in a substantially C shape on the same plane, the upper end side is fixedly fixed to the lower coupling segment 14b of the coupling portion 14, and the underground beam 16 is connected to the shield tunnel 10 , 12 is provided to balance the acting force in the vertical direction when the load of 12 is supported. The arrangement position of the lower anchor 30 that expands in a substantially C shape is on the same plane as the position where the suspension anchor 24 is arranged.
[0045]
Next, the construction method of the shield tunnel having the above configuration will be described with reference to FIGS. When constructing the shield tunnel having the structure shown in FIGS. 1 and 2, first, the first and second shield tunnels 10 and 12 reach the position near the planned construction site of the station building as shown in FIG. Then, first, the ground improvement area A is formed from the inside of the first and second shield tunnels 10 and 12 by a freezing method or the like.
[0046]
The ground improvement area A is located directly above and outside the coupling portion 14 of the first and second shield tunnels 10 and 12 and corresponds to a place where the starting portion 18 and the reaching portion 20 of the underground beam 16 are formed. When the ground improvement area A is formed, the segments 10a and 12a in these portions are removed, and after excavating the ground improvement area A, as shown in FIGS. The starting portion 18 and the reaching portion 20 are formed at positions facing each other.
[0047]
When the starting portion 18 and the reaching portion 20 are formed, as shown in FIGS. 5 and 6, the cylindrical hollow tube body 22 a is sequentially pushed out from the central portion of the side surface of the starting portion 18 toward the ground by a propulsion method. The hollow cylindrical arch portion 22 is formed so that the tip reaches the central portion of the side portion of the reaching portion 20.
[0048]
In this case, the hollow tube body 22a disposed at the forefront of the arch portion 22 has a closed tip.
[0049]
The arch portion 22 is formed in a shape in which both ends are integrated with the start portion 18 and the reaching portion 20, and a central portion is bulged and curved upward.
[0050]
In this embodiment, the arch portion 22 is formed after the start portion 18 and the arrival portion 20 are formed. However, the formation method of the underground beam 16 is not limited to this. The reaching portion 20 may be constructed in the middle of forming the arch portion 22 from the starting portion 18.
[0051]
Next, as shown in FIGS. 1 and 2, a suspension anchor 24 extends from the inside of the arch portion 22 of the underground beam 16 through the tubular body 22 a toward the coupling portion 14, and its lower end is The fixing portion 14 is fixed and fixed to the upper connecting segment 14a. In this case, the suspension anchor 24 may be driven upward from the shield tunnels 10 and 12 side.
[0052]
In this case, the suspension anchors 24 are projected in a plurality along the shape of the arch portion 22 so as to be parallel to each other at a predetermined interval, and the plurality of suspension anchors 24 are positioned on the same cross section. The upper ends of the suspension anchors 24 are fixed to the wall surface of the tubular body 22a of the arch portion 22.
[0053]
When the installation of the suspension anchor 24 is completed, the pre-stressed steel material 28 is passed between the start portion 18 and the reaching portion 20, and both ends of the start portion 18 and the reach portion 20 are in a state where tension is introduced. And fixed respectively.
[0054]
In this case, the prestressed steel material 28 is provided at a position where it does not interfere with the suspension anchor 24, for example, at the center arranged in two rows. Further, the prestressed steel material 28 may be installed between the starting portion 18 and the reaching portion 20 before the suspension anchor 24 is installed.
[0055]
Next, the anchor main body 30a of the lower anchor 30 is driven into the lower ground of the coupling portion 14, and the tip thereof is fixed by the lower fixing portion 30b, and the upper end side of the anchor main body 30a is fixed and fixed to the lower coupling segment 14b. .
[0056]
At this time, in the present embodiment, a plurality of lower anchors 30 are installed at predetermined intervals along the tunnel axis direction in an expanded state so that each pair of the lower anchors 30 is substantially C-shaped. When the lower anchor 30 is installed, the construction of the shield tunnel is completed.
[0057]
Now, according to the tunnel construction method constructed as described above, the underground beam 16 is provided immediately above the coupling portion 14, and the suspension anchor 24 having both ends fixed to the coupling portion 14 and the underground beam 16 is provided. Therefore, the load applied to the shield tunnels 10 and 12 can be received by the suspension anchor 24 without providing the middle pillar.
[0058]
For this reason, a wide space is ensured, and when it is adopted as a junction / crossover part, it is possible to easily change the lane of the traveling vehicle or the subway.
[0059]
In the above embodiment, the case where the first and second shield tunnels 10 and 12 are directly connected in advance by the coupling portion 14 is exemplified. However, the embodiment of the present invention is not limited to this, for example, As shown in FIG. 9, the present invention can also be applied to a case where shield tunnels are formed adjacent to each other in parallel and are indirectly connected to each other through a coupling portion.
[0060]
In the above embodiment, the case where the present invention is applied to a double shield tunnel having a circular cross section is illustrated. However, the implementation of the present invention is not limited to this structure. It can also be applied to tunnels with other cross-sectional shapes such as a structure, a triple structure with a circular cross-section, and a square shape.
[0061]
【The invention's effect】
As described above in detail, according to the tunnel construction method according to the present invention, it is possible to secure a wide space by eliminating the central pillar, and it is adopted for the lane, merge part and crossover part. In some cases, lane changes are possible.
[Brief description of the drawings]
FIG. 1 is a longitudinal cross-sectional explanatory view showing an embodiment of a tunnel according to the present invention.
FIG. 2 is a cross-sectional view of the main part of FIG.
FIG. 3 is a longitudinal sectional explanatory view of an initial step showing a construction method of the tunnel shown in FIG. 1;
4 is a cross-sectional view of the main part of FIG. 3;
FIG. 5 is a longitudinal cross-sectional explanatory diagram of a process performed subsequent to FIG. 3;
6 is a cross-sectional view of the main part of FIG.
FIG. 7 is a cross-sectional view showing an example of a conventional tunnel.
FIG. 8 is an enlarged view taken along line AA in FIG.
FIG. 9 is a cross-sectional view showing another example of a conventional tunnel.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 1st shield tunnel 12 2nd shield tunnel 14 Joint part 14a Upper joint segment 14b Lower joint segment 16 Underground beam 18 Starting part 20 Reaching part 22 Arch part 24 Hanging anchor 28 Prestressed steel 30 Lower anchor

Claims (1)

A plurality of shield tunnels constructed adjacent to each other in a lateral direction, and a coupling portion that directly or indirectly couples between the shield tunnels, and an underground beam is provided immediately above the coupling portion; and A construction method of a tunnel in which a suspension anchor that fixes both ends to the underground beam is provided,
The underground beam includes an arch portion provided between the start portion and the arrival portion, and forms a ground improvement area from the inside of the shield tunnel to the upper outside, and the shield tunnel adjacent to the ground improvement area. The segment is removed and the ground improvement area is excavated to form the starting portion and the reaching portion, and the tube is extended from the starting portion in parallel with the axial direction of the shield tunnel by propelling the pipe or shield. And forming the arch part reaching the reaching part,
After this, one end side is composed of a plurality of pieces arranged along the longitudinal direction of the arch portion, and is extended so as to be parallel to each other on the same surface, and the other end side is fixed to the coupling portion. Installing the hanging anchor
Between the starting part and the reaching part, a pre-stressed steel material having both ends fixed thereto is provided, and a lower anchor is installed in the lower ground from the joint part. Tunnel construction method.

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