JP2010077605A - Construction method for widening tunnel - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reasonably construct a laterally enlarged tunnel with a laterally elongated cross section by enlarging a tunnel sideways. <P>SOLUTION: A pilot tunnel 2 (a second tunnel 2a) is constructed at least on the side of a circular tunnel 1 (first tunnel) to be laterally enlarged, and an underground wall 4 positioned on the side of the circular tunnel is constructed from the inside of the pilot tunnel. An arch-shaped forepole 5 is installed between the upper parts of the pilot tunnel and the circular tunnel, and the area surrounded by the pilot tunnel, underground wall, and the forepole is excavated to laterally enlarge the circular tunnel sideways for constructing the laterally enlarged tunnel 3. A second tunnel 2a and a third tunnel 2b are constructed as pilot tunnels 2 in two upper and lower stages, and an underground wall is constructed therebetween. The underground wall is constructed in the form of a column-arranged wall formed by densely arranging columns. A forepole is formed of a pipe roof, and the front end thereof is joined to the upper part of the circular tunnel, a secondary forepole formed of a steel pipe forepole is provided to the lower part of a curved pipe roof, or a steel pipe forepole is constructed, as a forepole, in place of the curved pipe roof. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a construction method for constructing a widened tunnel having a horizontally long cross section by widening a previously constructed tunnel to the side.

As this type of construction method, those shown in Patent Documents 1 and 2 are well known. These are all constructed by excavating between two circular tunnels provided in two horizontal rows so that both circular tunnels communicate with each other and a tunnel having a horizontally long cross section is constructed.
JP 2006-183280 A JP 2007-9430 A

  The conventional method described above is a method that can be suitably used when widening the entire length of the tunnel, that is, when constructing a horizontally large cross-section tunnel over the entire length. In the case where only a small part of it is required to be widened, the construction is too large and not necessarily rational, and the development of an effective and appropriate construction method that can be suitably used in such a case is desired. It's real.

  In view of the above circumstances, the present invention is a tunnel widening method for widening a first tunnel laterally to construct a widened tunnel having a laterally long cross section, and the second tunnel is formed at least laterally of the first tunnel to be widened. And an underground wall located on the side of the first tunnel from within the second tunnel, and an arch between the upper part of the second tunnel and the first tunnel. A wide-width tunnel is constructed by excavating a region surrounded by the first tunnel, the first-hand construction, the second tunnel, and the underground wall, and then widening the first tunnel to the side. It is characterized by constructing.

In the present invention, a third tunnel is provided at an interval below the second tunnel, the pre-construction is performed from the second tunnel, and the second tunnel and the third tunnel It is conceivable to construct underground walls.
Moreover, it is preferable to construct the underground wall as a columnar wall formed by densely arranging columns.

In the present invention, the receiving work is formed by a curved pipe roof that reaches the upper part of the first tunnel from the second tunnel, and the tip of the curved pipe roof is joined to the upper part of the first tunnel. It is preferable to excavate below the curved pipe roof.
Alternatively, the first construction is formed by a curved pipe roof reaching from above the second tunnel to the upper side of the first tunnel, and between the second tunnel and the first tunnel below the curved pipe roof. You may excavate the lower part of the secondary receiving work while forming a secondary receiving work made of a steel pipe receiving work in the axial direction of the first tunnel.
Alternatively, a steel pipe tip receiver is formed between the second tunnel and the first tunnel as the tip receiver, and the steel pipe tip receiver is being constructed in the axial direction of the first tunnel. It is also conceivable to excavate below the steel pipe tip receiving work.

According to the present invention, since the widened area is surrounded by the first tunnel, the first receiver, the second tunnel, and the underground wall, and the widened portion is constructed by excavating the inner side, The ground stability can be ensured. Especially, the stress applied to the upper half arch part can be stably maintained in the entire receiving work, the second tunnel and the underground wall, and the settlement can be sufficiently suppressed. In addition, lateral displacement can be reliably suppressed by the underground wall.
Moreover, it is only necessary to provide a second tunnel with a small cross-section for constructing the underground wall and the receiving work at the planned widening position, so two circular tunnels with a large cross-section at the planned widening position as in the conventional construction method. Compared to the case where it is installed side by side, the overall work can be streamlined, and the construction cost and the construction period can be shortened.

“First Embodiment”
FIG. 1 shows a first embodiment of the present invention. When constructing the widening tunnel 3 having a laterally long cross-sectional shape (falling dharma shape) as shown in (f), the circular tunnel (first tunnel) 1 is first constructed as shown in (a). In addition, two narrow tunnels 2 (upper second tunnel 2a and lower third tunnel 2b) are provided in the upper and lower two stages, and the widening tunnel is excavated between them. 3 is constructed.

  Specifically, the circular tunnel 1 is constructed by a normal shield method, and a two-stage guide shaft 2 is provided on the side of the circular tunnel 1 with a vertical interval. The order of construction of the circular tunnel 1 and the guide tunnel 2 may be appropriate, and the guide tunnel 2 may be installed prior to the circular tunnel 1 as an advanced guide tunnel, or they may be installed by simultaneous parallel work. .

And as shown in (b), while constructing the underground wall 4 between the upper and lower guide shafts 2, an arched receiving work 5 is installed between the upper guide shaft 2 and the circular tunnel 1.
The underground wall 4 is preferably constructed as a columnar wall having a structure in which columns such as steel pipe columns are densely arranged. However, if possible, the underground wall 4 may have a structure such as an underground continuous wall. In any case, the underground wall 4 can function as a mountain stop in a subsequent excavation process (a side opening process of the circular tunnel 1), and at that time, the upper half along with the upper and lower guide shafts 2 and the first receiving work 5. It is constructed with a function capable of supporting the stress applied to the arch.
As the arch-shaped receiving work 5, a curved pipe roof is used, in particular, a steel pipe curved in an arc shape is driven from the guide shaft 2 toward the upper part of the circular tunnel 1, and a core material such as H-shaped steel is placed inside the steel pipe. A structure that is inserted and filled with concrete can be suitably employed. In any case, in the present embodiment, the leading end of the receiving work 5 reaches the upper part of the circular tunnel 1 and is joined thereto, so that the guiding work 2 and the circular tunnel 1 are structurally formed by the receiving work 5. They are connected together to form a solid support structure as a whole.

As described above, after the area to be widened on the side of the circular tunnel 1 is surrounded by the circular tunnel 1, the upper and lower guide shafts 2, the underground wall 4, and the receiving work 5 except for the lower part thereof, the inside thereof is excavated. I will do it.
Specifically, first, as shown in (c), the upper half arch part (the hatched part) just below the receiving work 5 is excavated, and then the side of the underground wall 4 as shown in (d). Then, the lower half arch part (same as above) is excavated as shown in (e).
The above excavation can be performed by dismantling and removing the main tunnel 2 or the circular tunnel 1 or the segments of both of them, and passing through the inside of them. The work 6 may be installed, and an appropriate support 7 may be installed between the circular tunnel 1 and the guide pit 2 along with the excavation.

  After completion of excavation for the area to be widened, as shown in (f), the segment of the circular tunnel facing the widened part is dismantled and a series of lining walls 8 are constructed on the entire inner surface of the widened part to complete the widened tunnel 3 Let

“Second Embodiment”
FIG. 2 shows a second embodiment of the present invention. In addition, the same code | symbol is attached | subjected to the same element as said 1st Embodiment, and description is simplified.
In this 2nd Embodiment, as shown to (a), one guide shaft 2 is constructed to the side of the circular tunnel 1, and the underground wall 4 is constructed below as shown to (b).
In addition, the front receiving work 5 is formed by a curved pipe roof as in the first embodiment, but the tip is constructed so as to cover the upper part of the circular tunnel 1 without joining it, as shown in FIG. Under the curved pipe roof, a steel pipe tip receiver as a secondary tip receiver 9 is further constructed.
The steel pipe tip receiving work as the secondary receiving work 9 can be suitably adopted by the so-called AGF method, and it is constructed by a predetermined length in the axial direction of the circular tunnel 1 between the guide tunnel 2 and the circular tunnel 1. While drilling, drill below.

  Thereafter, as in the first embodiment, as shown in (c) to (e), it is surrounded by the circular tunnel 1, the secondary tip receiving (steel pipe tip receiving) 9, the guide tunnel 2, and the underground wall 4. The area is excavated, and the lining wall 8 is constructed in the widened portion to complete the widened tunnel 3.

“Third Embodiment”
FIG. 3 shows a third embodiment of the present invention. In this, the guiding mine 2 has a horseshoe-shaped cross section, and a receiving work 10 composed of a steel pipe receiving work is constructed between the guiding mine 2 and the circular tunnel 1. That is, in the third embodiment, the steel pipe tip receiver itself that is the secondary tip receiver 9 in the second embodiment is constructed as an original tip receiver 10 that replaces the curved pipe roof. While a receiving work 10 made of a work is being constructed between the guide tunnel 2 and the circular tunnel 1, the lower part is excavated, and the other steps are the same as in the above embodiment.

According to the tunnel widening method of the first to third embodiments described above, the circular tunnel (first tunnel) 1 and the guide tunnel 2 (second tunnel 2a and third tunnel) are provided around the widened portion. Since the tunnel 2b), the front receiving work 5 (curved pipe roof) or the front receiving work 10 (steel pipe front receiving work), and the underground wall 4 are excavated to construct the widened part, The ground stability during excavation can be ensured. In particular, the stress applied to the upper half arch can be stably held by the first and second receiving works 5 and 10, the guide shaft 2 and the underground wall 4 to sufficiently suppress subsidence. The lateral displacement can be reliably suppressed by the underground wall 4.
In addition, since the underground tunnel 4 and the downholes 2 (second tunnel 2a and third tunnel 2b) for constructing the receiving works 5 and 10 may be provided at the planned widening position, the prior art Thus, compared with the case where two large-section circular tunnels are additionally provided at the position to be widened, the overall work can be streamlined, and the construction cost and the construction period can be shortened.

Of course, the present invention is not limited to the above embodiments, and may be appropriately selected within a range not departing from the gist of the present invention, depending on the scale, cross-sectional shape, ground condition, and other conditions of the widening tunnel to be constructed. Needless to say, the design can be changed.
For example, providing an underground wall between the upper and lower two-stage shafts (second tunnel and third tunnel) adopted in the first embodiment can also be adopted in other embodiments, and the third embodiment The horseshoe-shaped cross-section shaft (second tunnel) employed in the embodiment can be employed in other embodiments.

It is a figure which shows the schematic process of the tunnel widening method which is 1st Embodiment of this invention. It is a figure which shows the schematic process of the tunnel widening method which is 2nd Embodiment of this invention. It is a figure which shows the schematic process of the tunnel widening method which is 3rd Embodiment of this invention.

Explanation of symbols

1 Circular tunnel (first tunnel)
2 tunnel 2a 2nd tunnel 2b 3rd tunnel 3 widening tunnel 4 underground wall (column wall)
5 Prior construction (curved pipe roof)
6, 7 Supporting work 8 Lining wall 9 Secondary receiving work (steel pipe receiving work)
10 Prior construction (steel pipe prior construction)

Claims (6)

A tunnel widening method for widening a first tunnel to the side and constructing a wide tunnel with a transverse section,
A second tunnel is constructed at least on the side of the first tunnel to be widened, an underground wall located on the side of the first tunnel is constructed from within the second tunnel, and the second tunnel is constructed. An arch-shaped receiving work is constructed between the upper part of the tunnel and the upper part of the first tunnel,
A tunnel characterized in that a widening tunnel is constructed by widening the first tunnel laterally by excavating a region surrounded by the first tunnel, the first receiving work, the second tunnel, and the underground wall. Widening method. The tunnel widening method according to claim 1,
A third tunnel is provided at an interval below the second tunnel, the pre-construction is constructed from the second tunnel, and the underground wall is constructed between the second tunnel and the third tunnel. A tunnel widening method characterized by: The tunnel widening method according to claim 1 or 2,
A tunnel widening method characterized in that the underground wall is constructed as a columnar wall formed by densely arranging columns. The tunnel widening method according to claim 1, 2 or 3,
The leading construction is formed by a curved pipe roof extending from the second tunnel to the upper part of the first tunnel, and a tip end portion of the curved pipe roof is joined to the upper part of the first tunnel. A tunnel widening method characterized by excavating the lower part of the tunnel. The tunnel widening method according to claim 1, 2 or 3,
The receiving work is formed by a curved pipe roof that extends from the second tunnel to the upper side of the first tunnel, and a steel pipe tip is provided between the second tunnel and the first tunnel below the curved pipe roof. A tunnel widening method characterized by excavating a lower side of the secondary front receiving work while forming a secondary front receiving work made of the receiving work in the axial direction of the first tunnel. The tunnel widening method according to claim 1, 2 or 3,
A steel pipe tip receiving work is formed between the second tunnel and the first tunnel as the prior receiving work, and the steel pipe tip receiving work is carried out in the axial direction of the first tunnel. Tunnel widening method, characterized by excavating under the receiving work.

Images