JPH0258440B2 - - Google Patents

Description

[Detailed Description of the Invention] When constructing a tunnel using the NATM construction method, the present invention provides a method for sequentially lining the tunnel with thin plate precast members manufactured in a factory, without performing secondary lining work using cast-in-place concrete. The purpose of this project is to improve efficiency, save labor, and make tunnel construction more economical.

When constructing a tunnel using the commonly used NATM construction method, the construction sequence can be roughly divided into three steps: excavation of the ground, primary lining, and secondary lining. In other words, after excavating the ground, a primary lining is performed using shotcrete, rock bolts, steel shoring, etc. to reinforce the ground and hold the excavated cavity. After the tunnel is stabilized, a secondary lining is constructed using cast-in-place concrete in a predetermined cross-section.

In this case, the secondary lining is similar to ordinary tunnel construction methods, consisting of one cycle of work: assembling the formwork, pouring the lining concrete, and removing the formwork after curing and cleaning. Because I'm getting used to it,
It requires a lot of time and effort, and there are also difficulties in construction management and quality control to deal with the unique cracks that occur in the secondary lining of NATM tunnels. In addition, this secondary lining is generally installed in a thick layer of about 30 cm above the construction site, even if the ground bedrock is solid and there is no risk of long-term weathering.

In view of these circumstances, the present invention provides a stable inner surface of the tunnel by the primary lining (supporting with shotcrete, rock bolts, etc.) when constructing the secondary lining of a tunnel constructed using the NATM construction method. This invention relates to a construction method characterized by quickly and easily performing secondary lining work for tunnels by setting large, thin-walled precast plates prefabricated in a factory using anchor bolts. The construction method will be explained with reference to one embodiment of the drawings.The cross-sectional form of the tunnel after lining is constructed as shown in FIG. In other words, the primary lining of the tunnel using the NATM construction method (rock bolts a cast into the ground X, shotcrete b), the precast plates A and B that will serve as the secondary lining, and the anchor bolts C that fix this to the ground, and then on both sides. It is made up of side wall concrete d that serves as the fixed leg of the precast plate at the lower end. As shown in Fig. 2, the precast board A constituting this secondary lining has a main body made of reinforced concrete, fiber reinforced concrete, metal, high-strength plastic resin, etc.
The planar shape is rectangular with short sides 2, and the end faces are formed into, for example, a chevron shape as shown in FIGS.
1' is also provided with a convex edge 2' on the upper surface opposite to the short side 2,
2' to form a series of peripheral edges, and a suitable number of ribs 3-- extending between opposing convex edges 1', 1' on the long side 1.
This is reinforced by adding -. Note that the convex edges and reinforcing ribs may be provided inside the main body. Further, at both ends of the long sides 1, 1, a convex edge 4 is provided at the upper part of one edge for joining with the precast plate A adjacent in the circumferential direction, and a concave groove 5 and a waterproof groove are provided at the lower surface of the edge. A caulking groove 5' is provided, a convex strip 6 corresponding to the concave groove 5 is provided at the lower part of the other edge, a concave groove 7 is formed in the longitudinal direction on the upper surface thereof, and one end surface of the short sides 2, 2 is provided. A pin hole 8 is provided for joining the rings together, and a pin 9 is provided protruding from the other end surface. In addition, as shown in Fig. 4, the rib 3 is appropriately provided with a mounting hole 10 that communicates with the upper and lower surfaces so that bolt fittings for transportation and assembly can be attached and removed. It can also be used for pouring and placing materials. Further, in order to fasten this precast plate to the ground, an appropriate number of anchor attachment holes 11 are provided on the upper surface of the precast plate. Furthermore, if necessary, a ready-made interior material may be attached to the inner surface of this precast board, or the inner surface itself may be surface-treated to provide a function as an interior material.

2 by the precast board configured as above
To explain the next lining work, first, the ground is excavated, and the first lining of rock bolt a and shotcrete b is applied to the ground Pour concrete d and d on both sides. This side wall concrete d will serve as the foundation for assembling precast plates A and B, and is set at an appropriate height.
Or it is something that fixes the legs of B.

After the ground has been stabilized by the primary lining in this way, the hanging anchor bolts c-- for attaching the secondary lining material are attached, and the precast plates A and B are assembled. As shown in Figure 1, this is carried out using an assembly device consisting of an erector device C, a workbench D, and a support device E. That is, first, the precast plate A is supported by the erector C and moved to the set position, and as shown in Fig. 1, the first plate is installed by fastening it to the anchor bolt c previously attached to the rock mass. . Next, the same assembly work is sequentially performed in the circumferential direction from the bottom to the top as shown in Fig. 6.Finally, the key precast plate B (half size) in the axial direction and close it. In this way, one ring is assembled in the circumferential direction, and when assembling the precast plates A and B of the next ring, insert the precast plates A and B of the next ring into the pinholes 8 made at the ends of the rings installed before. The plate A is shifted in the axial direction and a pin 9 provided on the edge thereof is inserted and set, and the edges on both sides in the circumferential direction are joined by interlocking grooves 5 and protrusions 6 provided in the longitudinal direction.
The next ring is constructed by engaging the two rings. Therefore, this ring is not directly connected to the ground with anchor bolts, but is supported by supporting device E etc. until the next ring is assembled, and the adjacent ring to be set after this ring is set in the same manner as above. After assembling and connecting to the ground with anchor bolts, the former supporting device E is removed. In other words, every other ring is connected to the ground. Further, when assembling these adjacent rings, the precast plates B, which serve as keys inserted at the end of the ring configuration, are arranged in a staggered manner so as not to be located in the same phase, as shown in FIG. After performing the secondary lining as described above, if necessary, insert holes into the space between the secondary lining material A and the ground X through the mounting holes 10 for transportation and assembly bolts provided in each lining material. Sometimes backfilling material is injected and filled.

As mentioned above, in the construction method of the present invention, NATM
When constructing a tunnel using this construction method, instead of using the conventional secondary lining using cast concrete on-site, we constructed a thin-walled, flat plate with a chevron-shaped or curved cross-section to the extent that it does not hinder transportation, assembly work, etc. in the tunnel. By using a large-sized precast board that also serves as interior material, it not only simplifies the installation work inside the tunnel, but also has remarkable effects and features such as being able to start its combined use earlier.

[Brief explanation of the drawing]

Fig. 1 is a front view showing the tunnel set up by the construction method of the present invention and the assembly mode, Fig. 2 is a plan view showing an example of a precast board, and Fig. 3 is the X of Fig. 2.
-X' sectional view, Figure 4 is the Y-Y' sectional view of Figure 1,
FIG. 5 is a perspective view, and FIG. 6 is an explanatory diagram showing the manner in which the precast plates are arranged. A... Precast board, B... Precast board serving as a key, 1... Long side of the precast board, 2...
...same short side, 1', 2'...convex edge, 3...rib, 4...
...Convex edge, 5...Concave line, 5'...Caulking groove, 6
...Convex strip, 7...Concave strip, 8...Pinhole, 9...
...Pin, 10...Back filling injection and bolt mounting hole, 11
...Anchor mounting hole, a... Lock bolt, b...
...Shotcrete, c...Anchor bolt, d
...Side wall concrete, x...ground.

Claims (1)

[Claims] 1 For the inner surface of the primary lining in a stable tunnel, such as a tunnel excavated using the NATM construction method or for repairing an old tunnel, a thin flat plate with reinforcing ribs on the periphery and inside can also be used as an interior material. Precast folded plate members or curved surface members are sequentially arranged in the circumferential direction using anchor bolts.
While forming a ring, for this ring,
A method for constructing a secondary tunnel lining in the NATM construction method using precast members, characterized by assembling and constructing a ring made of the next precast folded plate or curved member using pinholes and pins on the end face.