JP2009174185A - Method of constructing wide section of tunnel - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To minimize the effect of a construction method on a ground surface by adopting a method of constructing a plurality of horizontal tunnels serving as minimum small openings at intervals in the longitudinal direction of a shield tunnel when a diverging/converging wide section is constructed. <P>SOLUTION: In this method of constructing a wide section of a tunnel, the section space of the diverging/converging wide part serving as a diverging section or a converging section from a tunnel main line is constructed. The method comprises a horizontal tunnel excavating step of excavating horizontal tunnels 1, 2 from the tunnel main line T side in the diverging/converging wide section, and a skeleton construction step of constructing covering skeletons 4, 5 in the excavated horizontal tunnels. The horizontal tunnel excavating step comprises a preceding tunnel excavation step of excavating a plurality of preceding tunnels 1, 2 at intervals in the longitudinal direction of the tunnel main line and a following tunnel excavating step of excavating following tunnels 3 between these preceding tunnels. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a method for constructing a widened portion of a tunnel suitable as a technique for constructing a cross-sectional space of a split and widened portion that becomes a branching portion or a joining portion from a main tunnel.

  In recent years, along with the progress of underground use, road tunnels, sewer tunnels, etc. have been constructed in a deep underground space of about 50 m underground. In particular, when constructing a tunnel in an underground space in an urban area where underground use is progressing, a shield method that can handle soft ground is advantageous.

  For example, when a road tunnel is constructed, it is necessary to integrally connect two shield tunnels close to each other at the junction of the main tunnel and the ramp tunnel. In this case, a method of connecting a shield tunnel to a converging part excavated from the road can be considered, but the exclusive area on the ground is wide in both width and length, and this is a serious problem. When the ground is strong, it is conceivable to dig a shield tunnel having a predetermined cross section and then remove the segment and construct a junction by the NATM method or the like.

Moreover, as a technique for constructing a junction between a main tunnel and a lamp tunnel exclusively in an underground space, for example, there are techniques described in Patent Document 1 and Patent Document 2.
JP 2003-148086 A Japanese Patent No. 3765048

  In the technique described in Patent Document 1, when constructing a junction between the main tunnel and the ramp tunnel, the cut-off section can be suppressed to a small scale. However, this construction method requires an open section even though it is a small scale, so that it still has a significant impact on the ground surface, and there is a problem that construction cannot be carried out depending on circumstances. Moreover, in order to connect shield tunnels having a circular cross section in the ground in the horizontal direction, there is a problem that it is necessary to construct a large-scale connection structure.

  In the technique described in Patent Document 2, when the first shield tunnel that becomes the main line is covered by the ECL method using steel fiber reinforced concrete, the second shield tunnel that becomes the branch line or the merge line is contacted. Cover the wall with a thick wall. Then, a ground is dug so as to gradually approach the first shield tunnel from a position away from the first shield tunnel, and the second shield tunnel is formed in parallel with the first shield tunnel to become a branch line or a merge line. The shield tunnel is constructed, and the wall portion between the first and second shield tunnels arranged in parallel is removed to connect the two. As a result, it is possible to provide a tunnel construction method with low construction cost and little influence on the surrounding ground.

  However, in the technology of this Patent Document 2, since the first shield tunnel and the second shield tunnel can be directly connected in the soft ground without using an open-cut method, the influence on the ground surface is reduced. Although it can be made relatively small, there are the following problems.

  In the technique of this Patent Document 2, there is a problem that a joining portion between the shield tunnels cannot be constructed unless a second shield tunnel that joins the first shield tunnel is constructed. That is, it is not possible to adopt a construction method that shortens the work period by forming the split and widened portion in advance and then joining the second shield tunnel to the split and widened portion later.

  Further, from the viewpoint of reducing the influence on the ground surface, it is desirable to make the opening small enough to minimize the removal range of the wall portion between the shield tunnels. However, with the conventional tunnel construction technology, the “split and widened part”, which is the connecting part between the shield tunnels, was constructed along the longitudinal direction of the shield tunnel. There was a problem.

  Therefore, the object of the present invention is to adopt a construction method of constructing a plurality of horizontal shafts that are the minimum necessary small openings at intervals in the longitudinal direction of the shield tunnel when constructing the split and widened portion. It is possible to provide a technique that can reduce the influence on the shield tunnel as much as possible, and can shorten the work period of the shield tunnel to be joined by forming the split and widening portion in advance. .

In order to solve the above problems, the invention described in claim 1
A tunnel widening part construction method for constructing a cross-sectional space of a split and widened part that becomes a branching part or a joining part from a tunnel main line,
A side pit excavation step of excavating a side pit from the tunnel main line side in the merging and widening portion;
A housing construction process for constructing a lining housing in the excavated horizontal shaft,
In the horizontal pit excavation process, a preceding mine excavation process for excavating a plurality of preceding mines at intervals in the longitudinal direction of the tunnel main line, and a subsequent mine excavation process for excavating a subsequent mine between each of the preceding mine shafts. It is characterized by performing.

  According to the first aspect of the present invention, in the horizontal pit excavation process, the preceding mine excavation process for excavating a plurality of preceding mines at intervals in the longitudinal direction of the tunnel main line, and the succeeding mine between each of the preceding mine, respectively. Since the excavation process will be carried out in the subsequent mine excavation, a construction method will be adopted in which multiple horizontal pits with the minimum necessary opening are installed at intervals in the longitudinal direction of the shield tunnel when constructing the split and merged widening section. Can do. Thereby, the influence on the ground surface can be made as small as possible. Furthermore, by forming the split and widened portion in advance, the tunnel to be merged or branched can be constructed at any time as needed, and it is not necessary to construct the split and widened portion when constructing the tunnel to be merged or branched. Therefore, the construction period can be shortened.

  The invention according to claim 2 is the tunnel widening portion construction method according to claim 1, wherein in the frame building step, a preceding frame building step of building a frame following the preceding mine excavation step; And a subsequent frame construction step of constructing a frame following the mine excavation step.

  According to the invention described in claim 2, in the building construction step, a preceding building construction step for building a building following the preceding mine excavation step, and a trailing building construction step for building a building following the following mine excavation step, Therefore, after the building construction of the preceding mine is completed at intervals in the longitudinal direction of the tunnel, the building construction of the succeeding mine can be completed. Thereby, it is possible to connect the small opening housings in the form divided in the longitudinal direction of the tunnel while sequentially constructing them. Therefore, construction can be performed with a minimum necessary small opening.

  According to a third aspect of the present invention, in the tunnel widening portion construction method according to the first or second aspect, in the preceding mine excavation step, at least one horizontal pit is spaced in the longitudinal direction of the main tunnel. It is characterized by excavation.

  According to the invention described in claim 3, in the preceding mine excavation step, the preceding mine is excavated at a sufficient interval by excavating at least one horizontal pit in the longitudinal direction of the main tunnel. Can do. As a result, excavation can be performed while leaving the natural ground (improved ground) thick, so that safety and workability can be improved.

  According to the present invention, in the construction of the merging and widening portion, by adopting a construction method of constructing a plurality of horizontal shafts that are the minimum necessary small openings at intervals in the longitudinal direction of the tunnel, the influence on the ground surface Can be made as small as possible. Moreover, by forming the split and widened portion in advance, it is possible to shorten the construction period of the tunnel to be joined.

(Embodiment)
Hereinafter, the best embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a perspective view showing a schematic structure of a split and merge widened portion K that becomes a branching part or a joining part from the tunnel main line T. FIG. FIG. 2A to FIG. 3F are schematic perspective views (process drawings) showing a construction procedure of the split and merge widened portion K shown in FIG. 4-15 is process drawing which shows the specific construction procedure of the division | segmentation merge widening part K. FIG.

  First, with reference to FIGS. 1 to 3, a tunnel widening portion construction method for constructing a cross-sectional space of a split and widened portion K that becomes a branching portion or a merging portion from the tunnel main line T will be described. In this embodiment, as shown in FIG. 2 (a), a ground improvement process for constructing an improved ground G1 by a ground improvement method for a ground mountain G including a split and widened portion K to be constructed, and FIG. As shown in b) and (c), the side shaft excavation process for excavating side shafts 1, 2, and 3 (leading shafts 1, 2, and subsequent shafts 3) from the tunnel main line T side in the region of the split and widened portion K Then, as shown in FIG. 3, a skeleton construction process for constructing the lining housing 4 in the preceding pits 1 and 2 and the lining housing 5 in the succeeding mine 3 is performed.

  In the horizontal excavation process, as shown in FIGS. 2B and 2C, the preceding mine excavating a plurality of preceding mines 1 and 2 at intervals in the longitudinal direction of the tunnel main line T (tunnel axis direction). As shown in FIG. 3 (e), the excavation process and the subsequent mine excavation process for excavating the subsequent mine 3 between each preceding mine are performed.

  In addition, in the case construction process, as shown in FIG. 3 (d), a preceding case construction process in which the lining case 4 is constructed following the preceding mine excavation process, and as shown in FIG. Following the mine excavation process, a follow-up chassis construction process for constructing the lining chassis 5 is performed. The above-described process is repeated to construct the merging and widening portion K shown in FIG. Here, in the preceding mine excavation process, it is desirable to excavate at least one horizontal pit in the longitudinal direction of the tunnel main line T. Of course, it is also possible to excavate at intervals of two horizontal shafts.

The construction (overall outline) of the merging and widening portion in this embodiment is preferably performed by the following procedure. In addition, a numerical value etc. are an example.
(1) Water stop injection: Zone water stop injection with organic long gel time material.
(2) 1 block excavation in the leading part: Horizontal excavation by the NATM method with a width of 4.5 m.
(3) 2 block excavation in the leading part ... Horizontal excavation by the NATM method in the adjacent section with a width of 4.5 m.
(4) Predecessor structure construction ... The structure of the horizontal shaft excavation part (width 9.0m) is 6.0m wide.
(5) Trailing part excavation: After the construction of the leading part frame is completed, the leading part excavation interval of 4.5 m is excavated.
(6) Consecutive body building construction ... Building the preceding body building construction section 7.5m.
(7) Completed housing

  Next, each step will be described more specifically with reference to FIGS. 4 to 15 are process diagrams showing the construction procedure of the split and widened portion. In each figure, (a) is a schematic cross-sectional view of the split and widened portion, and (b) is a schematic vertical cross-sectional view thereof. Show.

(A) Water stop injection construction When the improved ground G1 shown in FIG. 1 (a) is constructed, as shown in FIGS. 4 (a) and 4 (b), construction is performed from the tunnel main line T by the existing water stop injection construction method. . In this water stop pouring method, the ground G outside the tunnel main line T is drilled by the boring machine 16 for the high place and the boring machine 17 for the low place placed on the high work vehicle 15 in the main line T of the tunnel. The water-stopping material (ground improvement material) is injected while forming the injection hole 18. As this ground improvement material, for example, organic long gel time is preferably used, but other known ground improvement materials can also be used.

(B) The first half construction of the preceding mine 1 After the ground improvement process shown in FIG. 4 is completed, the first half construction of the preceding mine 1 is performed as shown in FIGS. In this upper half construction, excavation equipment 19 such as a 0.4 m3 class breaker and an erector carriage 20 are used to excavate and construct the support work 21 while building the support work 21 by the NATM construction method. Here, for example, as a construction cycle per 1 m, excavation / extrusion, support construction, and concrete spraying are performed. In this embodiment, as shown in FIG. 5B, construction is performed with A1 = 9.0 m and A2 = 4.5 m.

(C) The upper half of the preceding mine 1 The upper half of the preceding mine 1 is constructed by the NATM method as shown in FIGS. Here, the excavator 19 is used to excavate the upper half of the leading mine 1, the concrete spraying process to the excavation wall surface using the spraying robot 22, the process of placing the lock bolt 24 (see FIG. 7) using the crawler drill 23, and the like. I do. In this upper half upper construction, excavation / push-out, support construction, concrete spraying, and rock bolting are performed as a construction cycle per 1 m.

(D) Leading pit 1 girder installation work After the upper half upper construction of the preceding mine 1 is finished, as shown in FIG. Here, for example, a 1t electric chain block (electric CB) 25 is used, and the receiving girder 26 is installed or installed in a rearranged manner. At that time, a temporary H steel 27 for supporting the receiving beam 26 is also installed and removed at the time of replacement.

  In addition, the construction of the preceding mine 2 can be performed by performing the same work as the processes (b) to (d) above.

(E) Lower half construction of preceding mine 1, 2 In the lower half construction of preceding mine 1, 2, excavation work is performed using backhoe 28 as shown in FIG. It can be constructed by repeating the process of).

(F) Construction of preceding mine body At the time of construction of the preceding mine body, in the construction of the bottom plate, as shown in FIG. 9, the leveling concrete 31 and the bottom plate waterproofing work 32 are constructed, and then the bottom printing work 33 is constructed. In the construction of the side wall, a side wall waterproofing work 35 is constructed inside the temporary side wall 34, and a side wall construction 36 is constructed inside thereof. In the floor slab worker 37, a cavity filling worker 39 is constructed outside the floor slab waterproofer 38.

  In addition, as construction procedure in one place of the frame, 1. Leveled concrete, 2. 2. Temporary side wall, waterproof work Bottom platemaker, 4. Side wall pits, 5. Floor slab, waterproofing, 6. From the viewpoint of process control, it is desirable to adopt the order of cavity filling.

(G) The upper half construction of the following mine The upper half construction of the following mine 3 is the repetition of the steps (b) to (c) except for the point of construction between the preceding mine as shown in FIG. Therefore, the description is simplified here by showing the reference numerals.

(H) The upper half upper construction of the succeeding mine The upper half upper construction of the following mine 3, as shown in FIG. Therefore, the description is simplified by showing the reference numerals.

(L) Installation of trailing girder girder (replacement beam installation)
As shown in FIG. 12, the girder installation work for the trailing mine 3 is performed. Also here, as shown in (d) above, using the electric chain block (electric CB) 25, the receiving girder 26 is installed or installed in a rearranged manner. At that time, a temporary H steel 27 for supporting the receiving beam 26 is also installed.

(Nu) Subsequent mine half construction As shown in FIG. 13, this mine below half construction is repeated by repeating the steps (b) to (b) except for the construction between the preceding mine. Since this is possible, the reference numeral is shown here to simplify the description.

Subsequent mine body construction At the time of construction of the following mine body, in the construction of the bottom plate, as shown in FIGS. 14 and 15, the leveling concrete 31 and the bottom plate waterproofing work 32 are constructed, and then the bottom printing work 33 is constructed. In the construction of the side wall, a side wall waterproofing work 35 is constructed inside the temporary side wall 34, and a side wall construction 36 is constructed inside thereof. In the floor slab worker 37, a cavity filling worker 39 is constructed outside the floor slab waterproofer 38. In addition, as a construction procedure at this one place, as in the case of the construction of the preceding pits 1 and 2, 1. Leveled concrete, 2. 2. Temporary side wall, waterproof work Bottom platemaker, 4. Side wall pits, 5. Floor slab, waterproofing, 6. It is desirable that the order of the cavity filling work.

  According to this embodiment, when constructing the merging and widening portion K, a construction method is employed in which a plurality of horizontal shafts 1, 2, and 3 that are the minimum necessary openings are spaced apart in the longitudinal direction of the main tunnel T. By doing so, the influence on the ground surface can be reduced as much as possible, and the construction time of the ramp tunnel to be merged or branched can be shortened by forming the split and widening portion K in advance. Can do.

  Moreover, in the skeleton construction process, the preceding skeleton construction process that performs the skeleton construction following the preceding mine excavation process and the subsequent skeleton construction process that performs the skeleton construction following the subsequent mine excavation process are performed. After completing the construction of the chassis 4 of the preceding mine 1 and 2 with an interval in the longitudinal direction, the construction of the chassis 5 of the succeeding mine 3 can be completed. Thereby, the frame | skeleton of the small opening h of the form divided | segmented into the vertical direction of the tunnel can be connected, constructing sequentially. Therefore, it can be constructed with the minimum necessary small opening h.

  Further, in the preceding mine excavation step, the preceding mine can be excavated with a sufficient interval by excavating at least one horizontal pit in the longitudinal direction of the main tunnel. As a result, excavation can be performed while leaving the natural ground (improved ground) thick, so that safety and workability can be improved.

The perspective view which shows schematic structure of the division | segmentation merge widening part which concerns on embodiment of this invention. The schematic perspective view which shows the construction procedure of the division | segmentation merge widening part which concerns on embodiment of this invention. The schematic perspective view which shows the construction procedure of the division | segmentation merge widening part which concerns on embodiment of this invention. Process drawing which shows the concrete construction procedure of the division | segmentation merge widening part which concerns on embodiment of this invention. Process drawing which shows the concrete construction procedure of the division | segmentation merge widening part which concerns on embodiment of this invention. Process drawing which shows the concrete construction procedure of the division | segmentation merge widening part which concerns on embodiment of this invention. Process drawing which shows the concrete construction procedure of the division | segmentation merge widening part which concerns on embodiment of this invention. Process drawing which shows the concrete construction procedure of the division | segmentation merge widening part which concerns on embodiment of this invention. Process drawing which shows the concrete construction procedure of the division | segmentation merge widening part which concerns on embodiment of this invention. Process drawing which shows the concrete construction procedure of the division | segmentation merge widening part which concerns on embodiment of this invention. Process drawing which shows the concrete construction procedure of the division | segmentation merge widening part which concerns on embodiment of this invention. Process drawing which shows the concrete construction procedure of the division | segmentation merge widening part which concerns on embodiment of this invention. Process drawing which shows the concrete construction procedure of the division | segmentation merge widening part which concerns on embodiment of this invention. Process drawing which shows the concrete construction procedure of the division | segmentation merge widening part which concerns on embodiment of this invention. Process drawing which shows the concrete construction procedure of the division | segmentation merge widening part which concerns on embodiment of this invention.

Explanation of symbols

1 Leading mine (horizontal mine)
2 Leading mine (horizontal mine)
3 Back pit (horizontal mine)
4 Lining enclosure 5 Lining enclosure T Tunnel main line K Split junction widening part G Ground G1 Improved ground h Small opening

Claims (3)

A tunnel widening part construction method for constructing a cross-sectional space of a split and widened part that becomes a branching part or a joining part from a tunnel main line,
A side pit excavation step of excavating a side pit from the tunnel main line side in the merging and widening portion;
A housing construction process for constructing a lining housing in the excavated horizontal shaft,
In the horizontal pit excavation process, a preceding mine excavation process for excavating a plurality of preceding mines at intervals in the longitudinal direction of the tunnel main line, and a subsequent mine excavation process for excavating a subsequent mine between each of the preceding mine shafts. A method for constructing a widened portion of a tunnel, characterized in that it is performed.   The skeleton construction step includes a preceding skeleton construction step for constructing a skeleton following the preceding mine excavation step, and a subsequent skeleton construction step for constructing a skeleton following the subsequent mine excavation step. The tunnel widening part construction method according to claim 1.   The method for constructing a widened portion of a tunnel according to claim 1 or 2, wherein, in the preceding mine excavation step, excavation is performed at an interval of at least one horizontal pit in the longitudinal direction of the tunnel main line.

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