JPS6131599A - Tunnel covering construction method - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention mainly relates to a method for lining tunnels with relatively stable ground, such as mountain tunnels.

``Conventional technology'' In recent years, as a lining method for mountain tunnels, etc., spraying is a NATM method in which the load of the ground is supported by a primary lining such as concrete and rock bolts, and then the secondary lining is cast-in-place concrete. is being actively implemented.

[Problems to be solved by the invention] By the way, the secondary lining in the NATM construction method is constructed using cast-in-place concrete, which requires complex and large formwork such as movable formwork, as well as the need for decorative mortar for the interior. Not only does it require a lot of man-hours and is complicated, but it also increases the amount of concrete poured due to over-drilling during tunnel excavation.
Many problems have been pointed out that need to be solved, including cracks in the concrete due to drying shrinkage and a decrease in strength due to breathing in the crown concrete.

"Means for Solving the Problems" This invention involves assembling four arc-shaped PC boards in an arch shape along the ground between the upper ends of the left and right side wall concrete fixed to the tunnel side walls, and PC located on the side wall
By fixing the lower end of the board to the side wall concrete and the upper end to the ground via an anchor, and joining the PC board of the crown part of the arch between the side wall PC boards via a pin joint, By constructing cast-in-place concrete as a secondary lining, it is possible to build a safe and stable tunnel by solving problems such as imperfections in the formwork and poured concrete, while also expanding the tunnel internal cross section and reducing the excavation cross section. Moreover, it is easy to make up the inner surface of the tunnel.
This project proposes a highly reliable tunnel lining method that is easy to construct and economical.

"Embodiments" Below, embodiments of this invention will be described with reference to the drawings.
Figures 3 to 7 show an example of a PC board used in the construction method of this invention, which is formed into a rectangular arc shape with the required curvature, the concave inner surface 2 is smooth, and the convex outer surface is 3 is formed in an uneven shape having a concave portion 4 that is long in the arc direction.

Knuckle joints 5, 5, one of which is convex and the other concave, are formed on the left and right side surfaces of the PCC 10 in the arc direction, and a sealing material fitting groove 6 and a joint 7 are formed in series in the circumferential direction on the left and right side surfaces and the front and rear surfaces, respectively. It is formed.

In addition, inside the PC@l, as shown in Fig. 6, a mesh 8 made of hard steel wire is buried on the inner surface side, and reinforcing bars 9 are arranged in required parts. 100mm thick to withstand loads and backfill injection pressure
It can be formed into a strong plate with a thickness of less than 2 mm, yet has high toughness and composition.In particular, since the mesh 8 is placed on the tension side of the plate, it has high bending strength and toughness, has a crack dispersion effect, and is highly durable. Even in the event of a single breakage, there is no risk of broken pieces collapsing and falling, making it possible to construct an extremely safe lining plate. In this case, when forming with PCC10 fiber concrete, the reinforcing bars 9 can be omitted or reduced, strengthening the strength even in details such as the knuckle joint 5.5", which is difficult to arrange, and preventing concrete from missing. can.

Note that a decorative material such as tiles may be applied to the inner surface of the PCC 10 in advance during molding, if necessary. Also,
Anchor bolt fixing holes 10 and through holes 11 for internal inspection and backfill injection as required for PCC 10.
will be established.

Fig. 1.2 shows a state in which a tunnel is constructed using the PCC 10 having the above configuration. First, side wall concrete 12 made of cast-in-place concrete or hardened PC board is fixed to the side wall of the excavated tunnel. A fixed hardware 13 is fixed to its upper end, and four PC boards 1a, la are placed on top of this.

Assemble lb and lb in an arch shape along the surrounding wall of the ground.

When assembling this, first, the PC board 1a of the arch side wall
An earth anchor or rock bolt is placed on the fixed hardware 13 and the lower end is fastened using a jack bolt or the like. Alternatively, an anchor 14 such as a joint bolt connected to these is connected and fixed.

Next, the two PC boards 1b of the arch crown part are supported on a movable temporary stand or the like and carried between the upper ends of the left and right fixed side wall PC boards 1a, la, and joined with pins using each knuckle joint 5.5. It is made to stably stand on its own using mutual axial force, and is constructed as a statically fixed arch structure with three-point pin hinges. In this case, there is some space between the installation part of the PC board 1a and the ground, so using this space, the PCCl2Ola is brought in with its upper end slightly lifted to leave a space between them. After joining the lower ends of left and right PCCl2O to the upper ends of PCCl2O via knuckle joints 5 and 5', PCCl2Ola
They can be joined by lowering their upper ends and engaging the knuckle joints 5, 5'.

Then, such construction is performed successively in the tunnel direction, and PCCl2Olb is also connected and integrated in the front and rear directions.

Note that the front, rear, left, and right joints of each PC board 1a, lb are connected to the seventh
As shown in the figure, the sealing material 15 loaded in the sealing material fitting groove 6 and the joint material 16 filled in the joint 7 are used to seal water, and each joint is tightened with bolts or one side as necessary to enhance safety. By inserting the protruding bolt into the hole of the other receiver and solidifying them with adhesive, the adjacent PCCl2Olbs in the front, rear, left, and right directions are interconnected and integrated. In addition, since most of the leakage water from the ground flows into the recesses 4 on the outer surface of each PC board 1a and lb and flows downward, the PCCl
The amount of water that seeps into the joints around the 2Olb is extremely reduced, which is extremely advantageous in terms of water stoppage.

Furthermore, if there is a danger of the ground collapsing or loosening, etc., a backfilling solidifying material 17 such as air mortar is injected into the gap between the PCCl2Olb and the ground through the through hole 11 as necessary, and each PC By integrating it with the plates 1a and 1b, it is possible to maintain sufficient resistance against external forces due to the arch action effect thereof. In this case, the irregularities on the outer surface of PCCl2Olb enhance its adhesion to the backfilling material 15.

This will further strengthen unity.

Moreover, a PC board whose surface is covered with tiles during molding can be attached to the inner surface of the side wall concrete 12 for decorative purposes.

The tunnel constructed in this way has an extremely smooth inner surface with no irregularities, so it can be easily and neatly finished by directly spraying or painting without the need for interior construction such as decorative mortar. Moreover, by applying decoration such as tiles to the inner surfaces of the PC boards Ia and lb in advance, the inner decoration can be completed at the same time as the lining, and the construction can be streamlined and made more efficient.

Furthermore, since the PC board 1 is thin, it is economical and easy to construct, and it is possible to enlarge the tunnel internal cross section and reduce the excavation cross section.

``Effects of the Invention'' As described above, according to the present invention, a statically fixed arch structure with a three-point pin hinge that stably stands on its own due to the axial force of a PC board formed as a uniform product is constructed, so it is resistant to external forces. It is possible to construct tunnels that are safe and stable in terms of strength, and the thickness of the PC board can be made thinner because it only needs to maintain enough strength to withstand the backfill injection pressure, which allows for enlargement of the tunnel internal cross section and reduction of the excavation cross section. It is especially suitable for repairing aging tunnels.

Since the lining is made of a PC board with a smooth surface, the inner surface is finished with no irregularities without the need for decorative mortar, and the inner surface of the tunnel can be easily decorated by spraying, painting, or tiling. Can be done, workability,
It is possible to construct highly economical and reliable tunnels.

Furthermore, by injecting and hardening a backfilling material between the PC board and the ground as necessary, it is possible to create a stronger tunnel that is integrated with the ground.

[Brief explanation of the drawing]

Fig. 1 is a longitudinal sectional front view of a tunnel constructed according to the present invention, Fig. 2 is an enlarged side view of the same part, Fig. 3 is a plan view of a PC board used in this invention, Fig. 4 is a bottom view of the same, and Fig. 4 is a bottom view of the same. FIG. 5 is a front view of the same, FIG. 6 is an enlarged longitudinal sectional front view of the same, and FIG. 7 is a partial front view showing the joined state. 1, la, 1b @PC board, 2...inner surface, 3... outer surface,
4. Recess, 5,5◆Φ knuckle joint, 8. Mesh, 12. Side wall concrete, 13. Life-fixing hardware, 14. Anchor, 17. Backfill material.

Claims (1)

[Claims] 1) Four arc-shaped PC boards are assembled in an arch shape along the ground between the upper ends of the left and right side wall concrete fixed to the tunnel side walls, and the PC boards are located on the left and right side walls of the arch. The lower end of the arch is fixed to the side wall concrete, the upper end is fixed to the ground via an anchor, and the PC board of the crown part of the arch is joined between the side wall PC boards via a pin joint. tunnel lining method. 2) A tunnel lining method characterized in that the PC board has a concave inner surface which is a smooth surface and a convex outer surface which is formed in an uneven shape having concavities long in the arc direction. 3) Claim 1, characterized in that a steel wire mesh is embedded in the concrete on the inner surface of the PC board.
The tunnel lining method described in paragraph 2 or paragraph 2. 4) The tunnel lining method according to claim 1, 2 or 3, characterized in that the inner surface of a PC board is tiled. 5) Inject backfilling material into the gap between the PC board and the ground.
Claim 1 characterized in that it is integrated with the C plate.
2. The tunnel lining method described in Section 2, Section 2, Section 3, or Section 4.