JP2818725B2 - Construction method of tunnel invert part - Google Patents

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 invert section for constructing an invert section which is a floor slab of a tunnel.

[0002]

2. Description of the Related Art Generally, tunnel lining is divided into an arch portion serving as a ceiling, side walls, and an invert portion serving as a floor slab. In the case of ordinary geology, only the arch and side walls are used as lining.However, when the geology is very bad and the construction base surface rises, or when lateral pressure is strong, the invert section is used to connect the lower end of the side wall. To construct. Conventionally, as an example of constructing an invert portion, a method of arranging a reinforcing bar in a portion to be an invert portion and placing concrete is known.However, when a tunnel has a large cross section, the concrete placing area and Because the volume is large and it is difficult to cast concrete, we create a dam to stop the flow of concrete appropriately on site, thereby partitioning the concrete placement place, dividing it into multiple blocks and placing concrete Was.

[0003]

However, the invert portion is often formed in a downwardly convex arc shape in order to support the earth pressure acting on the invert portion. In this case, the surface on which the weir plate is installed is inclined downward. Therefore, in the above-described ordinary weir plate, it takes time and effort to install it in a predetermined position, and when the concrete is poured into the invert portion, the concrete faces the bottom of the invert portion. In this case, pressure may be applied from the concrete to the weir plate, and the weir plate may be destroyed. Therefore, it is difficult to construct an invert portion in a tunnel having a large cross section.

The present invention has been made in view of the above circumstances, and has as its object to provide a method of constructing a tunnel invert portion which can easily and surely construct an invert portion even if the tunnel has a large cross section. The purpose is.

[0005]

In order to achieve the above object, a method for constructing a tunnel inverting part according to the present invention is to provide a method for constructing a tunnel inverting part, comprising: Along with disposing along the circumferential direction of the part, a stopper streak for preventing the flow of concrete to be poured is disposed at a predetermined interval in the circumferential direction of the invert part, and then concrete is poured, A number of vertical reinforcing bars having a mountain shape are arranged side by side at predetermined intervals in the longitudinal direction of the tunnel, and both sides except for the top of the mountain are welded and fixed with a number of linear horizontal reinforcing bars to form a reinforcing bar support. A metal mesh having a small opening degree capable of preventing concrete from flowing out is fixed to the entire surface of one side of the reinforcing bar support except the top.

[0006]

In the method for constructing a tunnel invert portion according to the present invention, since the stopper bar is constituted by a vertical bar, a horizontal bar and a wire mesh and has a sufficient strength, the pressure of the concrete poured into the invert portion is reduced. Can prevent the breakage of the stopper streaks, and can prevent the flow of the concrete by the wire mesh, thereby preventing the flow of the cast concrete to the bottom of the invert portion. In addition, since the stopper streaks are formed in a chevron, they can be easily installed simply by placing them.

[0007]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a sectional view of a tunnel inverting method according to an embodiment of the present invention; First, FIG.
As shown in FIG. 2 and FIG. 2, after the concrete 2 is sprayed on the inner wall surface of the ground at the portion to be the invert portion 1 in the excavated tunnel, a sheet 3 for waterproofing is applied to the concrete surface, and 3 is sprayed with a protective mortar 4 for stopping water.

Next, on the protective mortar 4, a grid-shaped reinforcing bar 5 in which reinforcing bars are assembled in a grid shape is installed along the circumferential direction of the inverting section 1. In this case, the lattice-shaped reinforcing bars 5 that are adjacent to each other in the circumferential direction are wrapped to each other to some extent so that the joining is more reliable. Further, the lattice-shaped reinforcing bars 5 are vertically arranged at predetermined intervals, and a plurality of stopper bars 6 are arranged between the lattice-shaped reinforcing bars at a predetermined interval in the circumferential direction of the inverting portion 1.

The stopper bar 6 is configured as follows. That is, as shown in FIGS. 3 and 4, the stopper bar 6 includes a number of vertical reinforcing bars 7 that are bent in a V shape.
And a large number of straight horizontal reinforcing bars 8 joining the vertical reinforcing bars;
It is mainly composed of a metal lath (including rib lath) 9 which is an example of a wire net attached to one surface.

The vertical reinforcing bar 7 and the horizontal reinforcing bar 8 have a diameter of 4 to 4 mm.
A round bar or deformed bar of about 19 mm is used. The vertical bar 7 is bent at an apex angle of 20 to 90 degrees, and the length of the horizontal bar 8 is about 3 to 5 m. The vertical reinforcing bar 7 and the horizontal reinforcing bar 8 are used to support the reinforcing bar 1.
0 is configured. The metal lath 9 has an opening degree so that concrete does not flow out, and is fitted to the horizontal reinforcing bar 8 or the vertical reinforcing bar 7 using an appropriate number of C-rings on one side inside except the top of the vertical reinforcing bar 7. The metal lath 9 and the vertical reinforcing bar 7 (horizontal reinforcing bar 8) may be joined by welding.

The vertical reinforcing bars 7 and the horizontal reinforcing bars 8 are joined by electric resistance welding. After the horizontal reinforcing bars 8 are arranged in a plane at predetermined intervals, the vertical reinforcing bars 7 are arranged in a cross at predetermined intervals. After performing electric resistance welding from the upper part, the metal lath 9 is placed on a portion corresponding to one side surface, and the metal lath 9 is fixed to a vertical reinforcing bar or a horizontal reinforcing bar.
The stopper bar 6 as shown in FIG. 3 is manufactured by pressing and bending to 90 degrees.

The stopper bar 6 having the above-described structure is connected to the inverting section 1.
In the case of disposing on the protective mortar 4 in the above, a large number of stopper streaks 6 are prepared, and these stopper streaks 6 are arranged at predetermined intervals along the circumferential direction of the invert portion 1 and the tops of the stopper streaks 6 are connected to the tunnel. Arrange inward. In this case, since the stopper streaks 6 are formed in the shape of a chevron, they need only be placed on the protective mortar 4 without any trouble. Further, the length of the tunnel in the longitudinal direction can be easily adjusted by partially wrapping the stopper streaks 6 and 6 together.

When the reinforcement of the grid-like reinforcing bars 5 and the stopper bars 6 has been completed, concrete C is poured into the portion to be the inverting section 1. In this case, since the stopper bar 6 is mainly composed of a reinforcing bar and a wire mesh, the stopper bar 6 has sufficient strength. Therefore, even if a pressure acts on the stopper bar 6 from the concrete C, the stopper bar 6 is broken. There is no. Also. Since the flow of concrete can be prevented by the metal lath 9, the concrete C can be prevented from flowing to the bottom of the invert portion 1. Further, a metal lath 9 is provided on the other side of the stopper streaks 6.
Is not provided, and the concrete C
Can sufficiently spread inside the stopper streaks 6, the reinforcement C can be reinforced by the stopper streaks 6, and the invert portion 1 can be made stronger. Therefore, even in a tunnel having a large cross section, the invert portion 1 can be easily and reliably constructed.

When the concrete C is poured into the invert portion 1, an H-shaped steel which is a part of a support for assembling a reinforcing bar for lining the inner wall of the tunnel (side wall and arch portion) before the concrete C is cast. The support pieces 12 are disposed at both ends of the invert portion 1 and the support pieces 12 are fixed by placing concrete C into the invert portion 1. Then, by connecting the support pieces 12 to the support pieces 12 sequentially along the inner wall of the tunnel and assembling the support, the reinforcing steel for lining the inner wall of the tunnel can be easily assembled. Further, since the stopper streaks 6 are formed in a chevron, and as described above, their installation and adjustment of the length are easy, they can be manufactured at a factory or the like, and the construction period and construction cost of the invert portion construction are reduced. Savings can be achieved, and storage and transportation can be easily performed by stacking.

[0015]

As described above, according to the method for constructing a tunnel invert portion of the present invention, a lattice reinforcing bar is disposed at a portion to be an invert portion, and a stopper for preventing the flow of concrete to be poured is provided. The reinforcing bars are arranged at predetermined intervals in the circumferential direction of the inverting section, and then concrete is cast.The stopper bars are provided with a number of vertical reinforcing bars in the form of a mountain, and both sides excluding the top of the chevron. The part is welded and fixed with a number of linear transverse reinforcing bars to form a reinforcing bar support, and a wire mesh with a small opening that can prevent concrete from flowing out is fixed to the entire surface of one side of the reinforcing bar support except the top. Since the stopper bar has sufficient strength, even if pressure is applied to the stopper bar from concrete, the stopper bar does not break, and furthermore, the stopper bar does not break. It is possible to prevent the flow of Nkurito, concrete can be prevented from flowing to the bottom of the inverter unit, moreover it can be easily performed by simply placing also the installation of the stopper muscle.

Further, since no metal lath is provided on the other surface side of the stopper streaks, the poured concrete sufficiently spreads inside the stopper streaks, and the concrete can be reinforced by the stopper streaks. The invert portion can be made stronger.

Accordingly, even in a tunnel having a large cross section, the invert portion can be easily and reliably constructed.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a tunnel including an inverting section for explaining one embodiment of a method of constructing a tunnel inverting section of the present invention.

FIG. 2 is an enlarged view of a main part of an invert unit in FIG.

FIG. 3 is a perspective view of a stopper streak used in the tunnel construction method of the present invention.

FIG. 4 is a cross-sectional view of a main part of an invert portion showing a state where concrete has been cast.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Invert part 5 Lattice reinforcing bar 6 Stopper bar 7 Vertical reinforcing bar 8 Horizontal reinforcing bar 9 Metal lath (wire mesh) 10 Reinforcing bar support C Casting concrete

──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Shuji Maekawa 2-10-26 Fujimi, Chiyoda-ku, Tokyo Inside Maeda Construction Industry Co., Ltd. (72) Inventor Yukihisa Inagawa 144, 14-14, Masamasa, Motosu-gun, Gifu Prefecture Inside Gifu Industries Co., Ltd. No. Sumikura Steel Co., Ltd. (72) Inventor Kunio Ichino 2-1-1, Higashiko, Kokurakita-ku, Kitakyushu-shi, Fukuoka Prefecture Sumikura Steel Co., Ltd. (56) References JP-A-7-102767 (JP, A) JP Hei 7-127255 (JP, A) (58) Field surveyed (Int. Cl. ⁶ , DB name) E21D 11/10 E04B 5/32

Claims (1)

(57) [Claims] 1. A method for constructing a tunnel invert portion for constructing an invert portion serving as a floor slab of a tunnel inner wall,
In the portion to be the invert portion, a grid-like reinforcing bar in which reinforcing bars are assembled in a grid shape is arranged along the circumferential direction of the invert portion, and a stopper bar for preventing the flow of the concrete to be poured is provided in the circumferential direction of the invert portion. At a predetermined interval, and then cast concrete.The stopper bars are provided with a large number of mountain-shaped vertical reinforcing bars arranged at predetermined intervals in the longitudinal direction of the tunnel, and excluding the mountain-top portions. Both sides are fixed by welding with a number of straight horizontal reinforcing bars to form a reinforcing bar support, and a wire mesh with a small opening that can prevent concrete from flowing out is fixed to the entire surface of one side except the top of this reinforcing bar support. A method for constructing a tunnel inverting section, characterized by comprising: