JPH047498A - Joint construction of shield segment - 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 Industrial Application] The present invention relates to a joint structure for concrete shield segments used in shield tunnels.

[Prior Art] Concrete shield segments in the form of rectangular arc plates are used in shield tunnels, and a plurality of shield segments are arranged in a staggered manner and mutually arranged in the curved direction and in the width direction perpendicular to this. They are connected to form a cylindrical segment ring.

The conventional shield segment is shown in Figure 3.
Recesses 5L52 called box cutouts are formed in the curved end faces and width end faces of the concrete shield segment 50, and bolt holes 5 are formed in the respective end faces of these recesses.
Plate-shaped face plate fittings 53 and 54 having 3A and 54A are fixed. Thus, the shield segments adjacent in the curved direction and the width direction are fastened by nuts (not shown) within the recesses 51, 52 by passing straight bolts (not shown) through the bolt holes 53A, 54A.

It is desirable that the joint made of the metal fittings and bolts/nuts have the same strength and rigidity as the concrete segment body, but it is difficult to satisfy this with the above-mentioned types. Therefore, as mentioned above, the actual situation is to arrange them in a staggered manner and compensate for this by the effect of adhesion with adjacent segments.

[Problem to be solved by the invention]

However, the conventional shield segment joint structure described above has the following problems.

(2) Since the recess is formed by opening at the periphery of the segment body, the strength at the periphery is reduced.

■ The face plate fittings of the joint are easily deformed, reducing the bending rigidity of the joint. Therefore, due to the structure of the segment ring, the joint portion tends to be a weak point, and the rigidity of the entire segment ring is reduced. Since the rigidity and strength of the joint are smaller than that of the segment main body, the shield segments are arranged in a staggered manner to compensate for the joint effect, but it is necessary to increase the strength of the segment main body accordingly.

■ In the cross section of the joint, the bolt is placed biased toward the inside of the tunnel with respect to the center of thickness of the shield segment.
The cross-sectional rigidity and strength are different for the direction of bending, that is, positive bending and negative bending. For example, a bolt functions effectively as a tensile member for positive bending, but does not function effectively for negative bending and lacks resistance strength.

- When bolts are fastened, axial force acts on the inner side of the thickness center of the shield segment, which tends to cause openings on the joint surface. Also, at that time, stress concentration may cause a crank in the segment.

■ In large-section shield segments, as the segment thickness increases, it becomes relatively difficult to ensure rigidity and strength at the joint compared to the segment body.

SUMMARY OF THE INVENTION An object of the present invention is to provide a shield segment joint structure that can solve the above-mentioned problems, reduce cross-sectional defects in the segment body, and increase the rigidity and strength of the joint.

[Means to solve the problem]

According to the present invention, the above object is to form recesses at a plurality of symmetrical positions separated by a predetermined distance from the peripheral end face on the inner surface of the shield segment which is an arcuate plate having a quadrangular unfolded shape, and to connect the recesses and the curved end face. , which are respectively opened in the recess and the end face in the width direction, and form a curved hollow hole that curves toward the outer surface beyond the center of thickness of the shield segment and a curved hollow hole that curves toward the inner surface, and are arranged adjacent to each other. A connecting member is passed through each of the hollow holes in the curved direction and the width direction of the shield segments that are connected to each other by the shield segments.
This is achieved by connecting the adjacent shield segments by tensioning the connecting member at both ends of the connecting member.

[Effect]

In the present invention, the shield segments are arranged adjacent to each other in the curved direction and width direction of the tunnel inner wall surface, that is, in both the circumferential direction and the longitudinal direction of the tunnel inner wall surface, and the hollow holes of the adjacent shield segments are recessed so that they can communicate with each other. The connecting means is inserted in both directions from above, and then both ends of the connecting means are tightened within the recess to tension the connecting means. Adjacent shield segments are thus connected. This connection is made in the curvature direction and width direction of the shield segment.

Because the connecting members are arranged symmetrically about the thickness center of the shield segments, two adjacent shield segments have strength against hemostasis and negative bending. Note that the force for tensioning the connecting means is received on the inner surface of the recess.

〔Example〕

Hereinafter, the present invention will be described in detail with reference to FIGS. 1(A), 2(B), and 2 of the accompanying drawings.

FIG. 1(A) is a sectional view of the shield segment of this embodiment, and FIG. 1(B) is a bottom view of the shield segment of FIG. 1(8).

As seen in FIG. 1(B), the shield segment 1 of this embodiment is an arcuate plate having a rectangular shape in a bottom view.

The shield segment 1 is provided with recesses 4 on its curved inner surface at a plurality of positions symmetrical with respect to center lines 2 and 3 extending in the curve direction and width direction. The recess 4 is formed at a predetermined distance from the peripheral end faces, that is, the curved end face 5 and the width end face 6. This predetermined interval is appropriately determined within a range that does not reduce the strength of the peripheral edge of the shield segment 1 by providing the recess.

As can be seen, the hollow hole 7 is in the shape of a truncated quadrangular pyramid with an opening on the curved inner surface, and the hollow hole 7 communicates from the slope to the curved end surface 5 and the width direction end surface 6.
．． 8 is extended. In the case of this embodiment, two hollow holes 7 that open to the end surface 5 in the curved direction among the hollow holes are as follows.
Two are provided at intervals in the thickness direction of the shield segment 1, and at least one of them is curved toward the outer surface beyond the center of the thickness (see FIG. 1(A)).

When using the shield segment 1 of this embodiment, the shield segments 1.1'' are positioned adjacent to each other on the inner wall surface of the tunnel (see FIG. 1 (A)), and the end surfaces 5 in the curved direction and the width direction The end surfaces 6 are brought into contact with each other,
The hollow holes 7 and the hollow holes 8 are made to communicate with each other.

Next, from the recess 4 in one shield segment, the hollow hole 7 is
Then, curved long bolts 9 are inserted into each of the bolts 8 so that the ends thereof face the recesses 4 of adjacent shield segments in the curved direction and the width direction. Thereafter, both ends of the long bolt 9 are tightened with nuts 10 within the recess 4. Adjacent shield segments are thus connected in the curvature and width direction (see FIG. 2).

In this embodiment, the hollow holes for the long bolts in the curve direction and the width direction are opened in the same recess, but they may be opened in different recesses. In that case, the number of recesses increases, but their dimensions become smaller.

Furthermore, although a long curved bolt was used as the connecting means in this embodiment, the connecting means is not limited to this, and for example,
It may also be a cable. It takes some effort to manufacture long bolts so that they match the curved curve of the hollow hole, but the advantage of using cables is that this is not necessary. It is also advantageous in that the length can be easily adjusted to an arbitrary value on site.

〔Effect of the invention〕

As described above, according to the present invention, the following effects can be obtained.

■ The joint, which has a long and curved connection means, is arranged symmetrically within the segment cross section, resulting in a joint structure with high rigidity and strength.
A segment ring with high ring rigidity, that is, strong against bending, can be obtained.

■ Since the axial force at the time of fastening acts evenly on the joint surfaces (end faces), cracks are less likely to occur at the corners of the concrete segment, and the opening of the joints is small, increasing the water-stopping effect of the segments. Further, since no recess exists in the end face, a decrease in strength of the end face is prevented.

(2) If the arrangement is such that the recesses for connection in the curved direction and the width direction are shared, the cross-sectional defects of the segment body will be reduced, resulting in a high-strength segment structure.

[Brief explanation of drawings]

FIG. 1(A) is a sectional view of a shield segment used in an embodiment of the present invention, FIG. 1(B) is a bottom view of the shield segment shown in FIG. 1(8), and FIG. 2 is a bottom view of the shield segment shown in FIG. FIG. 3 is a partial perspective view of a conventional shield segment. 1......Shield segment 4...
・・・・・・・・・Recess 7.8・・・・・・Hollow hole 9.10・・・Connection member (9・・・Long bolt 10...Nara

Claims (3)

[Claims] (1) Recesses are formed at multiple symmetrical positions spaced a predetermined distance from the peripheral end face on the inner surface of the shield segment, which is an arcuate plate with a rectangular expanded shape, and the recesses and the end face in the curved direction, and the recess and the width direction. forming a curved hollow hole that curves toward the outer surface beyond the center of thickness of the shield segment and a curved hollow hole that curves toward the inner surface, opening at each end surface, and communicating with each other through adjacently arranged shield segments; A connecting member is passed through each of the hollow holes in the curved direction and the width direction of each shield segment, and the connecting member is tensioned at both ends of the connecting member facing into the recess to connect the adjacent shield segments. This is the joint structure of the shield segment. (2) The shield segment joint structure according to claim 1, wherein the hollow hole opening in the end face in the curve direction and the hollow hole opening in the end face in the width direction open in the same recess. (3) The shield segment joint structure according to claim 1, wherein the hollow hole opening in the end face in the curve direction and the hollow hole opening in the end face in the width direction open in mutually different recesses.