JPH0957727A - Formwork for precast members - Google Patents

Abstract

(57) Abstract: A stress-dispersing concave portion that is recessed in an arc shape and extends in the longitudinal direction of the joint surface on one side of a curved joint surface, and the other portion that protrudes in an arc shape and is curved in the longitudinal direction in the same manner. It facilitates the production of a mold for molding a precast member provided with a stress-dispersing convex portion extending in a vertical direction. SOLUTION: A mold plate 22 for molding a joint surface is provided with a concave groove 27 that curves and extends in the longitudinal direction, and a molding convex portion 30 or a molding portion having an arc cross section corresponding to the stress dispersion concave portion or convex portion of the precast member. The elastic joint molding material 28 in which the recess for use is formed is curved by using the elasticity and fitted into the groove 27.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mold for molding a precast member having a concavo-convex joint, for example, a shield segment.

[0002]

2. Description of the Related Art Conventional general shield segments are
The segments are tightened with bolts to apply an axial force to each joint surface, and the shear force generated by the tunnel design load (positional pressure, water pressure, etc.) is countered by the friction force of the joint surface. That is, the joint surfaces and the bolts and nuts have strength and tightening force that maintain the design yield strength against the shear load expected after completion.

However, the joint structure using the bolt joints opposes the work load acting in the tail of the shield machine at the time of constructing the shield by the frictional force of the joint surface based on the bolt tightening force. Since the design value corresponds to the expected shear load later, it resists the excessive shearing force during construction caused by the jack thrust when the shield machine is propelled or the competition of each member in the tail. It is not possible, and slip occurs on the joint surface of each other. However, in the case of bolted joints, the actual condition is that the shear load generated during construction must depend on the shear strength of the bolt.
Therefore, a shear load is concentrated on the bolt, and a large stress is concentrated on the segment portion around the bolt, and there is a problem that the segment main body and the attached member under construction are damaged (cracking, peeling of concrete, etc.) from the portion.

Further, in curved construction, a large lateral force (shearing force of the ring joint) acts on the curved portion of the completed tunnel along with the propulsion of the shield machine, and this force is sheared by the bolt tightening force. When it becomes larger than the proof stress,
There has been a problem that slippage occurs between the joints of the segments after the construction and excessive stress is generated around the bolts in the same manner as described above, and the segment body and the attached members after the construction are damaged.

Therefore, the present inventor has previously proposed a shield segment (hereinafter referred to as "segment") having a structure as shown in FIGS. 1 and 2 which solves such a problem. According to this segment, stress concentration on tightening members such as bolts is reduced to prevent damage to the segments and accessory members during earthquakes and construction, and enhance the safety of tunnels, etc. Economical efficiency and workability can be improved by simplifying the joints.

A segment 1 shown in FIGS. 1 and 2 has an RC structure in which a rectangle is curved, and its long side end faces are ring joint faces 2 and both short side end faces are segment joint faces 3 respectively. Since the segments are joined together by means of bolt joints, a plurality of bolt insertion holes 4 are provided in each joint surface 2 and 3. In this example, as shown in FIG.
Since the bolt-shaped bolt joint 5 is used, the bolt insertion hole 4
Is the curved inner surface 1 of the segment 1 as shown in FIG.
The bolt insertion hole 4 has a diameter that allows the C-shaped bolt joint 5 to pass therethrough with a slight allowance, while penetrating curvedly between a and the joint surface 2 or 3. A bolt box 6 is provided on the inner surface of the segment 1 for each bolt insertion hole 4.

The joint surface 2 between both rings of each segment 1 is
As a whole, it is curved in the longitudinal direction (tunnel circumferential direction), and in this curved inter-ring joint surface 2, there is formed a stress-dispersing concave portion 7 that is recessed in an arc shape and extends while curving in the longitudinal direction.
A stress-dispersing convex portion 8 that protrudes in an arc shape and extends while curving in the longitudinal direction is provided respectively, and a stress-dispersing concave portion 7 that is recessed in an arc shape and extends straight in the inter-segment joint surface 3 and an arc-shaped protruding portion. The stress-dispersing convex portions 8 extending straight are respectively provided.

When the segments 1 are joined together, the inter-ring joint surface 2 and the inter-segment joint surface 3 are joined together.
Are contacted with each other to fit the stress-dispersing concave portion 7 and the stress-dispersing convex portion 8 to each other, and the curvature of the curved surface of the concave portion 7 is adjusted so that a gap is formed between the concave portion 7 and the convex portion 8 in the fitted state. Is slightly larger than the curvature of the curved surface of the convex portion 8. That is, when the curved surface is an arc surface, the radius of the curved surface of the concave portion 7 is larger than the radius of the curved surface of the convex portion 8 as shown in FIG.
However, the depth of the concave portion 7 and the height of the convex portion 8 are equal to each other, and when the inter-ring joint surface 2 is in contact with each other and the inter-segment joint surface 3 is in contact with each other,
The curved surface valley portion 7a of the concave portion 7 and the curved surface top portion 8a of the convex portion 8 are in contact with each other, and usually a slight gap is provided on both sides of the contact portion (the width direction of the joint surfaces 2 and 3) as shown in FIGS. 9 is formed.

Therefore, since the concave portions 7 and the convex portions 8 have different curvatures, there is a loose fitting state, and there is a margin for sliding in the width direction of the joint surfaces 2 and 3 by the gap 9.
However, since the gap 9 is smaller than the gap 10 formed between the bolt of the bolt joint 5 and the bolt insertion hole 4, the ring-to-ring joint surface 2 of each of the segments 1 is formed.
Or, even if the inter-segment joint surface 3 is displaced in the width direction and the concave portion 7 and the convex portion 8 reach the sliding limit as shown in FIG. 7, a gap between the bolt of the bolt joint 5 and the bolt insertion hole 4 is formed. 10 remains slightly.

A segment 1 as described above in FIGS.
The state which joined each other is shown. In the axial direction of the tunnel, the joint surfaces 2 between the rings are brought into contact with each other and the recesses 7
And the convex portion 8 are fitted together, and in the tunnel cross-sectional direction, the inter-segment joint surfaces 3 are brought into contact with each other and the concave portion 7 and the convex portion 8 are fitted together, and for example, the C-shaped bolt joint 5 is inserted through the bolt. The holes 4 are inserted and tightened, and the tightening force causes the joint surfaces to be joined so that the design proof strength is maintained.
At this time, even if the centers of the concave portion 7 and the convex portion 8 are eccentric, the curved top portion 8a of the convex portion 8 slides toward the deepest curved valley portion 7a of the concave portion 7 due to the tightening force of the bolt joint 5. As a result of the centering action of trying to align the center of the concave portion 6 with the center of the convex portion 8, the positions of the segments 1 are automatically corrected. This occurs even after construction.

After joining the segments 1 together in this manner, when a shear load exceeding the design proof strength due to the tightening force of the bolt joint 5 acts on their joint surfaces, the recess 7 is formed.
Since a gap 9 is formed between the bolt 8 and the convex portion 8 and a gap 10 is formed between the bolt of the bolt joint 5 and the bolt insertion hole 4, their joint surfaces slide. In this case, since the curved surface of the concave portion 7 and the curved surface of the convex portion 8 are arcuate surfaces, as the curved surface of the convex portion 8 slides along the curved surface of the concave portion 7, the stress is absorbed so as to be radially dispersed. To be done. Further, the gap 9 between the concave portion 7 and the convex portion 8 is the gap 10 between the bolt and the bolt insertion hole 4.
Since it is smaller, the sliding limit is reached between the concave portion 7 and the convex portion 8 before the bolt contacts the wall surface of the bolt insertion hole 4. Then, after that, the shear load is transmitted even in the fitting portion between the concave portion 7 and the convex portion 8 in the state where the gap 10 between the bolt and the bolt insertion hole 4 slightly remains, so that the stress concentration on the bolt can be prevented. . In addition, in FIG. 3, FIG. 4, and FIG. 5, reference numeral 11 is a seal member.

[0012]

However, although this segment 1 has many excellent aspects as described above, the problem is that it is difficult to form due to the shape of the joint portion. That is, since the concave portions 7 and the convex portions 8 of the joint surface 3 between the segments extend straight as a whole even if the cross section has an arc shape, the mold plate for molding the same is not so much processed. Since the concave portion 7 and the convex portion 8 of the inter-ring joint surface 2 are arcuate in cross section and are curved as a whole, the form plate for molding the same has the curvature of the inter-ring joint surface 2 as a whole. After the combined curved shape, the curved curvature of the arcuate cross section of the mold plate for forming the recess 7 and the arcuate cross section of the concave plate for forming the projection 8 are adjusted to the curvature of the inter-ring joint surface 2. Moreover, the curvature of curvature and the curvature of arcuate cross section must be constant over the entire length. It is very difficult to directly perform such processing on the form plate, which is a steel plate, because the form plate has a large length and a large width. It will be very expensive.

Therefore, the present invention is intended to facilitate the processing of such a mold and to provide it at low cost as a mold for molding the above-mentioned shield segment and the like.

[0014]

According to the mold of the present invention, a groove extending in the longitudinal direction is provided in a mold plate for molding a joint surface of a precast member, and the groove has an arc-shaped cross-sectional stress distribution of the precast member. The fitting molding material is formed by fitting a molding convex portion or a molding concave portion having an arcuate cross section corresponding to the concave portion for stress or the convex portion for stress dispersion.

When the joint surface of the precast member is curved as a whole, the form plate is provided with a concave groove that curves and extends in the longitudinal direction, and a molding convex portion having an arc cross section or a molding concave portion having an arc cross section is formed. It is advisable to bend the formed joint molding material having elasticity and fit it into the groove.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, embodiments of the present invention will be described in detail with reference to the drawings. The form A of this embodiment shown in FIGS. 7 to 9 is for forming the shield segment 1 described above, and is a curved form plate 21 for forming the inner surface (tunnel inner surface) of the shield segment 1. And the front and rear formwork plates 22 and 23 for molding the front and rear ring joint surface 2
And the left and right mold plates 24 and 25 for molding the left and right inter-segment joint surfaces 3 are assembled to form a curved molding space 26 having the mold plate 21 as a bottom mold. The shield segment 1 having the above-described shape is molded by arranging reinforcing bars in the molding space 26 and filling concrete. Each of these form plates 21, 22, 23, 24, 25 is a steel plate reinforced with ribs.

The upper edge 22a of the front and rear mold plates 22 and 23
23 a is curved with a curvature corresponding to the curvature of the inter-ring joint surface 2 of the shield segment 1.
Substantially 2 and 23, the front and rear ring joint surfaces 2 are formed only at a portion above the upper surface of the mold plate 21, which is the bottom surface of the molding space 26. The sectional structure of this part of the front mold plate 22 is shown in FIG. 10, and the shape of its inner surface is shown in FIG.
On the inner surface of this portion, a concave groove 27 having a U-shaped cross section is formed, which is curved with a curvature corresponding to the curvature of the inter-ring joint surface 2 and extends in the longitudinal direction. A joint molding material 28 as shown in FIG. 11 is fitted and fixed in the groove 27. Further, a similar concave groove 27 is provided on the inner surface of the rear mold plate 22 as shown in FIG. 12, and a joint molding material 29 as shown in FIG. 13 is fitted and fixed in the concave groove 27. ing.

In the front joint molding material 28, a molding convex portion 30 having an arc-shaped cross section is integrally formed so as to mold the stress dispersion concave portion 7 having an arc-shaped cross section of the inter-ring joint surface 2. In the joint molding material 29 on the rear side, a molding concave portion 31 having an arc cross section is formed in order to mold the stress dispersion convex portion 7 having an arc cross section of the inter-ring joint surface 2. These joint molding materials 2
8.29 itself is straight as a whole,
Each of them is made of a hard synthetic resin having a slight elasticity, or an elastic metal such as aluminum or copper so as to bend along the concave grooves 27 when fitted into each groove 27. That is, the joint members 28 and 29 are fitted in the recessed groove 27 by processing themselves and the molding convex portion 30 or the molding concave portion 31 in a straight state, and then curving by utilizing their elasticity. , The molding convex portion 30 or the molding concave portion 31
Also, it is curved with such fitting, and is deformed to have a curvature curvature corresponding to the curvature curvature of the stress dispersion concave portion 7 and the stress dispersion convex portion 8.

The inter-segment joint surface 3 of the shield segment 1 is formed on the inner surface of one of the left and right mold plates 24 and 25.
Forming recess 32 for forming the stress-dispersing convex portion 8 and the molding convex portion 33 for forming the stress-dispersing concave portion 7 of the inter-segment joint surface 3 on the other inner surface, similarly to the above. It is formed by fitting the material into the concave grooves of the form plates 24 and 25. However, in this case, since the stress-dispersing concave portions 7 and the convex portions 8 of the inter-segment joint surface 3 are straight, the concave grooves of the mold plates 24 and 25 are also formed straight, and the molding concave portions 32 are formed in the concave grooves. Alternatively, the joint molding material having the molding convex portion 33 is fitted in a straight state. Since the left and right molding recesses and projections may be straight, it is not so difficult in manufacturing if they are directly formed on the left and right mold plates 24 and 25 without using a joint molding material.

Although the formwork for forming the shield segment has been exemplified above, the present invention is not limited to the shield segment, but other precast members (vertical tunnels or boxes) obtained by dividing a circle or an ellipse into a precast member. It can also be applied to formwork for culverts and piers).

[0021]

According to the mold of the present invention, the stress-dispersing concave portion or the stress-dispersing convex portion having an arcuate cross-section of the precast member is provided.
Since it is molded with a joint molding material fitted in the groove of the form plate,
The concave groove may have a simple cross-sectional shape such as a U-shaped cross section, and its processing does not require particularly high precision, and therefore the processing of the form plate itself is easy. The joint molding material must be processed with a molding convex portion or a molding concave portion having an arcuate cross section.
Since this joint molding material is an elongated one that fits into the groove of the form plate, its processing is easy, and at the time of processing,
After processing the forming convex portion or the forming concave portion having an arc-shaped cross section in a straight state as a whole, and then fitting the molded joint material by bending it along the curved concave groove of the formwork plate, Since the molding convex portion or molding concave portion having an arc-shaped cross section of the joint molding material is also curved along the concave groove, it is not necessary to process these molding convex portion or molding concave portion into a curved shape. Therefore, even if it is a mold for a precast member that is entirely curved and has a joint portion with an arcuate cross section, it can be easily manufactured and provided at low cost, and the unit price of the precast member that is a molded product can be reduced.

[Brief description of drawings]

FIG. 1 is a view showing an inter-ring joint surface of an example of a shield segment molded by a mold of the present invention.

FIG. 2 is an inner surface view of the same segment.

FIG. 3 is a cross-sectional view showing a state before joining the segments.

FIG. 4 is a cross-sectional view of the above joined state.

5 is a cross-sectional view of a portion different from FIG.

FIG. 6 is a diagram showing a size relationship between the curved surface of the stress-dispersing concave portion and the curved surface of the stress-dispersing convex portion in the above-mentioned joined state.

FIG. 7 is a cross-sectional view of a mold of one embodiment of the present invention for molding the above shield segment.

FIG. 8 is a plan view of the same frame.

FIG. 9 is a rear view in which a part of the mold is cut away.

FIG. 10 is a cross-sectional view of a portion of the same frame where a shield segment concave portion for forming a stress is formed.

FIG. 11 is a perspective view of a part of the joint molding material for molding the stress-dispersing convex portion.

FIG. 12 is a cross-sectional view of a portion for forming a stress-dispersion convex portion.

FIG. 13 is a perspective view of a part of a joint molding material for molding the stress-dispersing convex portion.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Shield segment 2 Joint surface between rings 3 Joint surface between segments 7 Recess for stress dispersion 8 Relief for stress dispersion A Formwork 22 ・ 23 ・ 24 ・ 25 Formwork plate 26 Forming space 27 Recessed groove 28 ・ 29 Joint forming material 30 Molding convex part 31 Molding concave part

Claims (2)

[Claims] 1. To join precast members together,
A precast member is provided in which one of the joint surfaces is provided with a concave portion for stress dispersion that is recessed in an arc shape and extends in the longitudinal direction of the joint surface, and the other is provided with a convex portion for stress dispersion that similarly projects in an arc shape and also extends in the longitudinal direction. A mold frame for forming the joint surface, wherein a concave groove extending in the longitudinal direction is provided in the mold plate for molding the joint surface, and the concave convex groove has a cross-section arc-shaped corresponding to the concave portion or convex portion for stress dispersion. Alternatively, a mold for a precast member is characterized in that a joint molding material having a molding recess is fitted therein. 2. A stress-dispersing recess, which is recessed in an arc shape on one of the curved joint surfaces and extends curved in the longitudinal direction of the joint surface, and an arc shape on the other, for joining the curved precast members to each other. A mold for molding a precast member provided with a stress-dispersing convex portion that protrudes and extends in the same manner as it curves in the longitudinal direction, and is curved in the longitudinal direction on a mold plate that molds the joint surface. An elastic joint molding material is provided which is provided with an extending concave groove and which has a molding convex portion or a molding concave portion having an arc-shaped cross section corresponding to the stress dispersing concave portion or the convex portion, and is curved by utilizing the elasticity to form the concave portion. A mold for a precast member, which is fitted in a groove.