JP7802284B2 - Tunnel lining method and tunnel lining structure - Google Patents

Description

The present invention relates to a tunnel lining method and tunnel lining structure used to construct lining plates for tunnels that have construction joints at predetermined locations in the tunnel axial direction.

Typically, tunnel construction involves forming a primary lining on the inner surface of the excavated tunnel using shotcrete, then installing formwork along the primary lining and pouring concrete into the formwork to construct a secondary lining. However, this method requires a lot of man-hours for installing and removing the formwork.

Another known lining method is to construct a lining using curved precast slabs fabricated in advance in a factory or similar facility (see, for example, Patent Document 1). With this method, the lining can be constructed by transporting precast slabs to the site and then lining them up in the circumferential and axial directions of the tunnel using erection equipment such as a forklift or an erector. This eliminates the need to pour the lining concrete on-site, allowing for efficient construction.

Furthermore, when constructing a lining using the above-mentioned precast slabs, a lining structure using a staggered arrangement may be used, in which precast slabs are placed on both sides of the tunnel width, offset by half their length in the tunnel axis direction and installed alternately on both sides of the tunnel width with their upper ends butting against each other. This allows a new precast slab to be installed on the other side of the tunnel width without having to temporarily support the previously installed precast slab on one side of the tunnel width with a forklift or other device.

Japanese Patent Application Laid-Open No. 2002-89200

Incidentally, tunnel lining slabs may have construction joints (sections where the lining slab is not structurally connected) at predetermined sections along the tunnel axis or at each curve. Because precast slabs cannot be staggered at construction joints, precast slabs (half panels) half the length of the slab in the direction of the tunnel axis are placed on one side of the tunnel width to ensure that the end surfaces of the lining slab are smooth. For this reason, construction after the construction joints begins with the installation of a new half panel. However, since there is no precast slab on the other side of the tunnel width to support the half panel, the new precast slab must be installed on the other side of the tunnel width while the half panel is temporarily supported by a forklift or similar device. Therefore, temporary support of the half panel by a forklift or similar device is required for each construction joint, which poses a problem of inefficient construction of the entire tunnel.

The present invention was made in consideration of the above-mentioned problems, and its purpose is to provide a tunnel lining method and tunnel lining structure that allows for efficient installation of precast slabs without the need to temporarily support precast slabs that are half the length of the tunnel axial direction at the construction joints.

To achieve the above-mentioned objectives, the present invention provides a tunnel lining method in which curved precast slabs are alternately installed on both sides of the tunnel width direction, offset in the tunnel axis direction and with their upper ends abutting against each other, to form lining slabs. In this method, a first precast slab of a predetermined length in the tunnel axis direction is installed on one side of the tunnel width direction, with its end face positioned in a construction joint at a predetermined location in the tunnel axis direction. A pair of second precast slabs, each formed to half the length in the tunnel axis direction, are temporarily joined in the tunnel axis direction to the first precast slab, and the second precast slab on one side of the tunnel axis direction is installed on the other side of the tunnel width direction so that it abuts against the first precast slab on one side of the tunnel width direction. A new first precast slab is installed on one side of the tunnel width direction so that it abuts against the other second precast slab, and the temporary joint between the second precast slabs is then released to form a construction joint between the second precast slabs.

In order to achieve the above-mentioned objective, the present invention provides a tunnel lining structure in which curved precast slabs are placed alternately on both sides of the tunnel width direction, offset in the tunnel axis direction and with their upper ends abutting each other. The structure includes: a first precast slab of a predetermined length in the tunnel axis direction that is placed on one side of the tunnel width direction so that its end face is positioned at a construction joint at a predetermined location in the tunnel axis direction; and a pair of second precast slabs that are formed so that they can be temporarily joined to each other in the tunnel axis direction and are each formed to half the length of the first precast slab in the tunnel axis direction; the second precast slab on one side of the tunnel axis direction is placed on the other side of the tunnel width direction so that it abuts against the first precast slab on one side of the tunnel width direction, and the second precast slab on the other side of the tunnel axis direction is placed on the other side of the tunnel width direction so that it abuts against the other first precast slab on one side of the tunnel width direction, so that a construction joint is formed between each of the second precast slabs.

As a result, a pair of second precast slabs, each half the length of the tunnel axial direction, installed at the construction joint location are temporarily joined in the tunnel axial direction, eliminating the need to temporarily support the second precast slabs with a forklift or similar device.

According to the present invention, there is no need to temporarily support the second precast slab, which is half the length of the tunnel axial direction, at the construction joint. This allows the precast slab to be installed efficiently, and construction of the entire tunnel can be carried out efficiently. Furthermore, because there is no need to temporarily support the second precast slab with a forklift or similar, even if traffic is restricted on one side of the tunnel width for construction equipment work, the other lane on the other side of the tunnel width can be opened to traffic, which has the advantage that construction can be carried out without a full road closure.

FIG. 1 is a partial perspective view of a covering plate showing one embodiment of the present invention. Partial plan view of the lining A perspective view of the first precast plate Perspective view of the second precast plate A perspective view of the second precast slab showing the temporary joint state Perspective view of the spacer Side cross-sectional view of the main part of the second precast slab A cross-sectional side view of the main part of the second precast slab showing the temporary joint state A partial plan view of the lining plate showing the precast plate installation process A partial plan view of the lining plate showing the precast plate installation process A partial plan view of the lining plate showing the precast plate installation process A partial plan view of the lining plate showing the precast plate installation process A partial perspective view of the covering plate showing the installation process of the second precast plate FIG. 10 is a partial perspective view of the covering plate showing the installation state of the second precast plate. A cross-sectional side view of the main part of the second precast slab showing the temporary joint release state FIG. 10 is a partial plan view of a lining plate showing another embodiment of the present invention.

Figures 1 to 15 show one embodiment of the present invention, illustrating a tunnel lining method and tunnel lining structure used to construct a lining plate in which construction joints are provided at predetermined locations in the tunnel axial direction.

The lining plate 1 of this embodiment is constructed as a secondary lining for tunnels, for example, roads, railways, or waterways in mountainous areas, and is formed in an arch shape by alternately installing curved precast plates on both sides of the tunnel width, offset in the tunnel axis direction and with their upper ends butting together.

The construction of the lining slab 1 uses a first precast slab 10 placed on one side or the other of the tunnel width, and a second precast slab 20 formed to half the length of the first precast slab 10 in the tunnel axial direction. Each precast slab 10, 20 is made of panel-shaped concrete manufactured in a factory, etc.

The first precast slabs 10 have a trapezoidal convex portion 11 at the top end, toward the center in the tunnel axial direction. When they are lined up in the tunnel axial direction, continuous irregularities are formed in the tunnel axial direction at the top of the lining slab 1. The first precast slabs 10 arranged on one side of the tunnel width and the first precast slabs 10 arranged on the other side of the tunnel width are offset from each other by half the length in the tunnel axial direction, and the irregularities fit together without any gaps.

The second precast slab 20 is formed in a shape obtained by dividing the first precast slab 10 in half in the tunnel axis direction. When one second precast slab 20A has a half-shaped convex portion 21 at one end of its upper end in the tunnel axis direction, and the other second precast slab 20B has a half-shaped convex portion 21 at the other end of its upper end in the tunnel axis direction, a precast slab 10 having the same shape as the first precast slab 10 is formed by the pair of second precast slabs 20A, 20B.

The second precast slabs 20A and 20B are temporarily joined together by connecting them with bolts 22. Specifically, as shown in FIG. 7, inserts 23 are embedded in multiple locations around the tunnel circumferentially on the end face of one of the second precast slabs 20A in the tunnel axial direction, and bolt insertion holes 24 are provided in multiple locations around the tunnel circumferentially on the end face of the other second precast slab 20B. As shown in FIG. 8, the second precast slabs 20A and 20B are connected to each other by threading bolts 22 inserted into the bolt insertion holes 23 of the other second precast slab 20B into the inserts 23 of the one second precast slab 20A. In this case, a spacer 25 is interposed between the end faces of the second precast slabs 20A and 20B to form a gap between the end faces of the second precast slabs 20A and 20B. The spacer 25 is a cylindrical member made of an elastic material such as rubber, and has holes 25a through which the bolts 22 are inserted. A tapered recess 26 is provided in the bolt insertion portion of the end face of each second precast slab 20A, 20B, and a spacer 25 is designed to engage with each recess 26.

Next, the lining method of this embodiment will be explained with reference to Figures 9 to 12. Note that the numbers written on the precast slabs in the figures indicate the installation order.

As shown in Figure 9, the second precast slab 20 is first temporarily supported as the first precast slab on one side of the tunnel width direction by a forklift or similar device (not shown), and the first precast slab 10, as the second precast slab, is then installed on the other side of the tunnel width direction by an erection machine (not shown). At this time, the upper end of the second precast slab 20 is butted against the tunnel axial half of the upper end of the first precast slab 10. Next, when the temporary support of the second precast slab 20 by the forklift or similar device is released, the first precast slab 10 and the second precast slab 20 are held in an arch shape so that they support each other.

Next, the third first precast slab 10 is installed by an erection machine on one side of the tunnel width so that it is offset from the second first precast slab 10 by half the distance in the tunnel axial direction. In this case, the second first precast slab 10 and the third first precast slab 10 are held in an arch shape so that they support each other. In this way, the fourth and subsequent first precast slabs 10 are installed alternately on both sides of the tunnel width.

When the construction joints 2, which are provided at predetermined intervals in the tunnel axis direction, are reached, a pair of second precast slabs 20A, 20B, which are temporarily joined together, are installed in the other direction of the tunnel axis in place of the first precast slab 10. At this time, one second precast slab 20A is connected to the other second precast slab 20B in a temporarily joined state with bolts 22, so there is no need to temporarily support the other second precast slab 20B with a forklift or the like.

Next, as shown in Figure 10, a new first precast slab 10 is installed on one side of the tunnel width, and the tunnel axial half of its upper end is butted against the upper end of one of the second precast slabs 20A.

After this, as shown in Figure 11, the bolts 22 are removed from each of the second precast slabs 20A, 20B, releasing the temporary connection between each of the second precast slabs 20A, 20B. This leaves the second precast slabs 20A, 20B structurally unconnected to each other, and a continuous construction joint 2 is formed around the tunnel between the end faces of each of the second precast slabs 20A, 20B and between the end faces of the adjacent first precast slabs 10 on one side of the tunnel width. At this time, spacers 25 are left between the end faces of each of the second precast slabs 20A, 20B, as shown in Figure 13.

Then, in the same manner as the second and subsequent first precast slabs 10, new first precast slabs 10 are installed alternately on both sides of the tunnel width direction as shown in Figure 12, and when the position of the next construction joint section 2 is reached, a pair of second precast slabs 20A, 20B temporarily joined to each other is used, as described above, to construct a lining slab 1 extending in the tunnel axial direction.

In this way, according to this embodiment, a first precast slab 10 with its end face located at the construction joint portion 2 of the lining slab 1 is installed on one side of the tunnel width direction, and two second precast slabs 20A, 20B, each half the length in the tunnel axial direction, are temporarily joined in the tunnel axial direction. One of the second precast slabs 20A is then installed on the other side of the tunnel width direction so that it abuts against the first precast slab 10 on one side of the tunnel width direction. A new first precast slab 10 is then installed on one side of the tunnel width direction so that it abuts against the other second precast slab 20B. After that, the temporary joining of the second precast slabs 20A, 20B is released, thereby forming the construction joint portion 2 between the second precast slabs 20A, 20B. Therefore, when installing each second precast slab 20A, 20B at the construction joint portion 2, there is no need to temporarily support the other second precast slab 20B with a forklift or the like, and the precast slabs 10, 20 can be installed efficiently. Furthermore, because there is no need to temporarily support the second precast slab 20B on the other side of the tunnel width with a forklift or similar, even if traffic is restricted on one side of the tunnel width for construction work, the other lane on the other side of the tunnel width can be opened to traffic, which has the advantage that construction can be carried out without a full road closure.

Furthermore, the second precast slabs 20A, 20B are temporarily joined together by connecting them with bolts 22, with elastically deformable spacers 25 interposed between the end faces in the tunnel axis direction. The temporary joining of the second precast slabs 20A, 20B is released by removing the bolts 22, with the spacers 25 remaining between the end faces of the second precast slabs 20A, 20B. Therefore, even after the temporary joining of the second precast slabs 20A, 20B is released, the spacers 25 can still form gaps for the construction joints 2 between the end faces of the second precast slabs 20A, 20B.

In this case, the spacer 25 is made of a cylindrical member through which the bolt 22 can be inserted. Therefore, when the bolt 22 is inserted into the spacer 25 during temporary joining, the rigidity of the bolt 22 prevents the spacer 25 from misaligning the second precast slabs 20A, 20B relative to each other. After the temporary joining is released, the elasticity of the spacer 25 alone allows the second precast slabs 20A, 20B to move relative to each other, ensuring their function as a construction joint portion 2.

In the above embodiment, a lining plate 1 for a straight section was shown, but the present invention can also be applied to a lining plate 1 for a curved section, as shown in another embodiment in Figure 16.

Furthermore, each of the above embodiments is merely an example of the present invention, and the present invention is not limited to what is described in each of the above embodiments.

1...Covering plate, 2...Construction joint, 10...First precast plate, 20, 20A, 20B...Second precast plate, 22...Bolt, 25...Spacer.

Claims (6)

In this tunnel lining method, curved precast slabs are placed on both sides of the tunnel width direction, and are alternately installed on both sides of the tunnel width direction so that their upper ends are butted against each other in the tunnel axial direction,
A first precast slab having a predetermined length in the tunnel axial direction and having an end face located in a construction joint portion at a predetermined location in the tunnel axial direction is installed on one side in the tunnel width direction,
A pair of second precast slabs, each formed to be half the length in the tunnel axial direction, are temporarily joined to the first precast slab in the tunnel axial direction, and are installed on the other side of the tunnel width direction so that the second precast slab on one side in the tunnel axial direction is abutted against the first precast slab on one side in the tunnel width direction;
After installing a new first precast slab on one side of the tunnel width so that it is abutted against the other second precast slab,
A tunnel lining method, characterized by forming a construction joint between each of the second precast slabs by releasing the temporary joints between the second precast slabs. The second precast slabs are temporarily joined together by connecting them with bolts with elastically deformable spacers interposed between the end faces in the tunnel axial direction,
2. A tunnel lining method according to claim 1, characterized in that the temporary joints between the second precast slabs are released by removing the bolts while leaving spacers between the end faces of the second precast slabs. 3. The tunnel lining method according to claim 2, wherein the spacer is a cylindrical member through which the bolt can be inserted. In a tunnel lining structure in which curved precast slabs are placed on both sides of the tunnel width direction, and are alternately installed on both sides of the tunnel width direction so that their upper ends are butted against each other in the tunnel axial direction,
a first precast slab having a predetermined length in the tunnel axial direction and installed on one side in the tunnel width direction so that its end face is located in a construction joint portion at a predetermined location in the tunnel axial direction;
a pair of second precast slabs formed so as to be temporarily joinable to each other in the tunnel axial direction, and each formed to have a length half the length of the first precast slab in the tunnel axial direction;
The second precast slab on one side of the tunnel axial direction is arranged on the other side of the tunnel width direction so as to abut against the first precast slab on one side of the tunnel width direction,
The second precast slab on the other side of the tunnel axial direction is arranged on the other side of the tunnel width direction so as to abut against the other first precast slab on the one side of the tunnel width direction;
A tunnel lining structure characterized in that construction joints are formed between each of the second precast slabs. The tunnel lining structure according to claim 4, characterized in that each of the second precast slabs is formed so as to be temporarily joined by interposing an elastically deformable spacer between the end faces in the tunnel axial direction and connecting them with bolts. The tunnel lining structure according to claim 5, wherein the spacer is a cylindrical member through which the bolt can be inserted.