JP2017172135A - Connection structure between insert and PCT plate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce labor in burial work for a bolt box and suppress damaging of concrete.SOLUTION: A precast arch tunnel has PCT plates 3 provided on right and left and connected at an upper center, and the PCT plates 3 are lined up in a tunnel axial direction and connected to each other at respective edge surface 3b. For connecting the PCT plates 3 in the axial direction, a bolt box 8 is formed on the edge surface 3b of the PCT plate 3 on a side, and a bearing plate 11 having a bolt hole 11a is provided. On the edge surface 3b of the PCT plate 3 on the other side, an insert 9 is buried in concrete. The insert 9 has a female screw part 15 for screwing a fastening bolt 12 inside an insert body 16, through the bolt hole 11a. A steel pipe 18 is fitted on an entrance side of the female screw part 15 of the insert body 16 through a tapered pipe 17, and an outer peripheral surface of the steel pipe 18 and the tapered pipe 17 is covered with a cushioning pipe 19 made of styrene foam or the like, for protecting concrete.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a PCT plate insert for connecting substantially arc-shaped PCT plates to each other, and a PCT plate connecting structure formed by connecting the PCT plates in the circumferential direction or the axial direction.

  In recent years, tunnels constructed with open cuts are required to be omitted in order to cope with a decrease in the number of workers and an aging population, to improve the quality of factory production, and to shorten the construction period. PC-ATM (Pre-Cast Arch Tunnel Method) is known as one of tunnel construction methods that meet such needs. PC-ATM is a method of building a tunnel by assembling a precast concrete member called a PCT plate divided into two in the tunnel cross-section direction into an arch shape on the foundation, and connecting them with bolts in order to assemble in the tunnel axial direction. .

  For example, in the arch tunnel described in Patent Document 1, the substantially arc-shaped PCT plates adjacent to each other in the axial direction of the arch tunnel are connected by a joint portion. This joint portion is fixed by connecting a bolt and a nut between the bearing plates of the bolt boxes that are the recesses of each PCT plate. And each bolt box provided with this joint part is embed | buried with the cast-in-place concrete in a next process.

JP 2002-88789 A

However, in the precast arch tunnel described in the above-mentioned Patent Document 1, after the substantially arc-shaped PCT plate forming the arch portion is joined in the axial direction, the bolt boxes on both sides of the bearing plate are embedded with concrete respectively. There is a drawback that it is complicated and time-consuming.
In addition, if an insert is embedded instead of the bolt box of one PCT plate, a positioning jig such as Shino is inserted from the bolt box of the other PCT plate to adjust the positions of the PCT plates. There was a risk of cracking or chipping in the concrete on the outer surface side of the insert due to the load of the jig. In addition, there is a drawback that the thread of the female thread portion formed on the insert is pressed by the positioning jig and crushed.

  The present invention has been made in view of such problems, and it is an object of the present invention to provide a connecting structure between an insert and a PCT plate that can reduce the labor of embedding a bolt box and can suppress breakage of concrete. And

That is, the insert according to the present invention is provided on the inlet side of the insert main body embedded in the end face side of the PCT plate, the internal thread portion provided inside the insert main body to which the fastening bolt is screwed, and the internal thread portion of the insert main body. And a guide ring.
According to the present invention, when the position of the insert embedded in the PCT plate is adjusted with another PCT plate, the load of the alignment jig is adjusted even if the tip of the alignment jig pushes the guide ring to adjust the position. Since the guide ring receives the screw, the position of the PCT plate with the insert can be adjusted safely without damaging the thread of the female thread provided on the insert or causing cracks or damage to the concrete surrounding the insert. It can be fixed to other PCT plates with fastening bolts.

Moreover, it is preferable that a guide ring is a buffer pipe which consists of a cylindrical steel pipe and the buffer material provided in the outer peripheral surface.
As the guide ring, a cylindrical steel pipe and a buffer pipe of buffer material provided on its outer peripheral surface are provided, so even if the steel pipe is pushed when the positioning jig is moved, the buffer pipe absorbs the load of the positioning jig. Or, since it can be dispersed, the surrounding concrete is not cracked or damaged.

The guide ring may be a cylindrical steel pipe or a buffer pipe made of a buffer material.
Since a cylindrical steel pipe or buffer pipe is provided as a guide ring, even if the steel pipe or buffer pipe is pushed when the alignment jig is moved, the load on the alignment jig is reduced or absorbed by the steel pipe or buffer pipe. So that the surrounding concrete is not cracked or damaged.

Moreover, you may provide the taper-shaped spot digging gradually diameter-reduced toward the front-end | tip side of the internal thread part of an insert main body toward the internal thread part side.
Since a countersink is provided between the steel pipe and the female thread part, the alignment jig is not inserted into the female thread part of the insert, and when the fastening bolt is inserted into the female thread part of the insert after position adjustment, Can guide the insertion.

The PCT plate connecting structure according to the present invention is a PCT plate connecting structure formed by connecting a plurality of arc-shaped PCT plates, and a bolt box is provided on one end surface of one PCT plate and the other PCT plate connecting portion. , And an insert having a female threaded portion inside is installed on the other end face, and the insert is provided with a guide ring on the end face side in contact with the bolt box of the other PCT plate.
In the present invention, in order to connect a plurality of PCT plates in the circumferential direction or the axial direction, when aligning the PCT plates using a machine such as a crane, the alignment jig such as Shino is used as the other PCT plate. The guide ring is inserted through the bolt hole on the bolt box side and provided at the tip of the insert of one PCT plate, and can be aligned by relatively moving the guide ring. At that time, even if the guide ring is pushed with the alignment jig, the thread of the female thread part is not damaged, and the insert is pushed directly with the alignment jig, causing cracks or damage to the concrete around the insert. The positions of the PCT plates can be adjusted safely by making the insert and the bolt hole of the bolt box face each other safely. Moreover, since the bolt box is provided only in one joint portion of the opposing PCT plate, the labor of burying the bolt box with concrete after tunnel construction can be reduced.

According to the insert of the present invention, when the position of the insert embedded in the PCT plate is adjusted, the load of the alignment jig is received by the guide ring even if the tip of the alignment jig adjusts the position of the guide ring. The position of the PCT plate provided with the insert can be adjusted safely without damaging the thread of the female thread portion provided in the insert or causing cracks or damage to the concrete around the insert.
Further, according to the connecting structure of the PCT plate according to the present invention, one PCT plate and the other PCT plate are opposed to each other, and an alignment jig is inserted from the bolt box of the one PCT plate, and the other PCT plate is inserted. The plate can be aligned through the insert. At that time, even if the tip of the alignment jig pushes the guide ring, the screw thread of the female thread part is not damaged, and the concrete around the insert is not cracked or damaged. The positions of the PCT plates can be adjusted so as to face each other.

It is a perspective view which shows the attachment state of the PCT plate in the construction process of the precast arch tunnel by embodiment of this invention. It is a principal part perspective view which shows the state which PCT plates adjacent to the axial direction were made to oppose. FIG. 3 shows the insert shown in FIG. 2, (a) is a side view, and (b) is a front view. It is principal part explanatory drawing which shows the connection part of the joint in the connection state of a PCT plate.

Hereinafter, a precast arch tunnel and an insert according to an embodiment of the present invention will be described with reference to FIGS.
FIG. 1 shows a construction state of a precast arch tunnel 1 according to the embodiment, and a PCT plate 3 made of concrete and having a substantially arc-shaped cross section is installed on a foundation portion 2 made of on-site concrete. The precast arch tunnel 1 has a substantially semicircular arch portion 4 formed by combining a plurality of, for example, two, PCT plates 3 having a substantially arcuate cross section in the circumferential direction to form a cylindrical wall body. ing.
The base portion 2 has a substantially recessed shape in cross section, and the both end leg portions 3a of each PCT plate 3 constituting the arch portion 4 are received by the recessed portions 2a and extend in the axial direction of the precast arch tunnel 1, respectively. After both end legs 3a of the PCT plate 3 are installed in the recess 2a, they are fixed to the base 2 by extrusion bolts or the like from both the front and back surfaces.

A embankment is made between the pair of base portions 2, and a temporary support column 6 whose upper end abuts on the inner surface of the connecting portion of the PCT plate 3 on both sides is arranged at one place where the construction is started. It will be removed after the planned PCT 3 installation.
The arc-shaped PCT plate 3 is installed on the left and right sides along the axial direction, and the left and right PCT plates 3 except for both end portions in the axial direction are positioned in the middle of the length in the width direction of the mating PCT plate 3 in the axial direction. The end portions are installed so as to be offset from each other. As a result, the left and right PCT plates 3 can lean against each other when viewed in the tunnel axis direction, and only one erection machine is required. Further, recesses (bolt boxes) 5a and 5a are formed in the upper joint portions 5 of the PCT plates 3 of the arch portion 4 and are fastened to each other by fastening bolts 5c and nuts 5d via supporting plates 5b and 5b. Has been. These recesses 5a and 5a are buried with cast-in-place concrete in a later process.

  1 and 2, a joint portion 10, which is a connecting portion between adjacent end faces 3 b of a plurality of PCT plates 3 arranged on the right side, has bolt boxes 8 formed at a predetermined interval on the front side, and a bolt box on the far side. An insert 9 is embedded facing 8. The bolt box 8 and the insert 9 are installed at positions facing each other by adjusting the position of one PCT plate 3. Further, the joint portion 10, which is a connecting portion between the adjacent end faces 3 b of the plurality of PCT plates 3 arranged on the left side, has the inserts 9 embedded at a predetermined interval on the front side and the bolt box 8 on the far side. Has been. The bolt box 8 and the insert 9 are installed and connected at predetermined intervals along the circumferential direction of the PCT plate 3.

  2 to 4 show the joint portion 10 between the PCT plates 3 connected in the axial direction. A bolt box 8 for forming a recess is provided on the circumferential end surface of one PCT plate 3. The bolt box 8 is provided with a support plate 11 for partitioning the recess of the bolt box 8 on the end surface 3b of the PCT plate 3, and a bolt hole 11a for inserting the fastening bolt 12 is formed at the center thereof. For example, two anchor bars 13 are connected to both ends in the horizontal direction of the support plate 11 in the vertical direction, and these anchor bars 13 are embedded in the concrete c.

An insert 9 is embedded in the concrete c on the end face 3 b of the other PCT plate 3. As shown in FIG. 3, the insert 9 is formed in a substantially cylindrical shape, and an insert body 16 having an internal thread portion 15 inside the end surface 3b is embedded in the concrete c. The insert body 16 is divided into two at the rear end side, and anchor portions 16a and 16b that are bent in the vertical direction or the horizontal direction are formed. A steel taper pipe 17 having a substantially tapered tube is formed as a countersink on the inlet side of the female thread portion 15, and a substantially cylindrical steel pipe whose front end surface is exposed to the end face 3 b of the PCT plate 3 is formed in front of the taper pipe 17. 18 is fixed.
The inner diameter 18a of the steel pipe 18 is formed larger than the inner diameter of the female threaded portion 15, and the tapered pipe 17 has a tapered inner surface 17a that gradually decreases in diameter from the inner surface 18a of the steel pipe 18 to the inner surface of the female threaded portion 15. . The steel pipe 18, the taper pipe 17, and the female thread portion 15 are preferably coaxial. The taper pipe 17 and the steel pipe 18 may be integrally formed of the same material or connected by welding or the like.

A buffer pipe 19 made of a cushioning material such as foamed polystyrene is provided on the outer peripheral surfaces of the steel pipe 18 and the tapered pipe 17 with a predetermined thickness. The front end surface of the buffer tube 19 may be exposed to the end surface 3b of the PCT plate 3 flush with the front end surface of the steel tube 18, or may be recessed from the steel tube 18 and embedded in the concrete c.
Therefore, when the tip of the positioning jig 21 such as Shino is inserted from the bolt hole 11a on the bolt box 8 side of one PCT plate 3 to align the insert 9 with the bolt hole 11a, the steel pipe 18 is connected to the PCT plate. Even if it is pushed together with 3 and moved slightly, the buffer tube 19 can prevent cracks, breakage, etc. from occurring in the concrete c of the PCT plate 3 due to the load. Further, since the female screw portion 15 is disposed from the end surface 3b of the PCT plate 3 via the steel pipe 18 and the taper tube 17, the alignment jig 21 is difficult to reach the female screw portion 15 and prevents damage to the thread of the female screw portion 15. it can.

The connecting structure of the PCT plate 3 of the precast arch tunnel 1 according to the present embodiment and the insert 9 have the above-described configuration. Next, a method for assembling the precast arch tunnel 1 will be described.
In the case of the precast arch tunnel 1 shown in FIG. 1, when the next PCT plate 3 is lifted with a crane or the like in the row of the PCT plate 3 on the left side, a new PCT plate 3 is installed. It mounts on the ground of the position which the existing PCT plate 3 adjoins, and the end surfaces 3b of the PCT plate 3 are contacted. At this time, the new PCT plate 3 is not positioned. For example, the bolt hole 11a of the bolt box 8 of the new PCT plate 3 is slightly displaced from the position of the insert 9 of the existing PCT plate 3.
In this state, the tip of the alignment jig 21 such as Shino is passed through the bolt hole 11 a of the bearing plate 11 in the bolt box 8 and inserted into the steel pipe 18 provided at the tip of the insert 9 of the other PCT plate 3. . Then, the position of the new PCT plate 3 provided with the bolt hole 11a is finely adjusted by pushing the steel pipe 18 with the positioning jig 21 and relatively moving the bolt hole 11a by a small amount. Adjust to match the steel pipe 18.

  At this time, even if the tip of the alignment jig 21 hits the inner surface 18 a of the steel pipe 18 and a load is applied to the steel pipe 18, the shock or load is applied because the buffer pipe 19 made of foamed polystyrene or the like is installed outside the steel pipe 18. It is possible to prevent the concrete c surrounding the insert 9 from being cracked or broken. Moreover, since the internal thread part 15 is installed in the inner surface of the insert 9 via the steel pipe 18 and the taper pipe 17, it can suppress that a front-end | tip contacts the internal thread part 15 when adjusting the position with the jig | tool 21 for alignment, It is possible to prevent the screw thread of the female screw portion 15 from being crushed.

  Then, the fastening bolt 12 is provided in the bolt box 8 directly or via the washer 23 or the like in a state where the end surface 3b of the new PCT plate 3 is brought into contact with the end surface 3b of the existing PCT plate 3 and positioned. It inserts in the steel pipe 18 exposed to the end surface 3b of the PCT plate 3 which opposes through the bolt hole 11a of the bearing plate 11. The front end of the fastening bolt 12 is guided by the taper tube 17 and inserted into the female screw portion 15 to be screwed together. As a result, as shown in FIG. 4, the PCT plates 3 are firmly fixed to each other by the fastening bolt 12 and the female screw portion 15 of the insert 9.

In FIG. 1, similarly, in the row of the PCT plate 3 on the right side of the precast arch tunnel 1, a new PCT plate 3 is lifted with a crane or the like from the existing PCT plate 3 provided with the bolt box 8. Abut. The insert 9 of the new PCT plate 3 is slightly displaced from the bolt hole 11 a of the bolt box 8 of the existing PCT plate 3.
In this state, the tip of the alignment jig 21 such as Shino is passed through the bolt hole 11a of the bearing plate 11 in the bolt box 8 and inserted into the steel pipe 18 provided at the tip of the insert 9 of the new PCT plate 3. . Then, by operating the positioning jig 21, the new PCT plate 3 is slightly moved and adjusted so as to coincide with the bolt hole 11 a of the existing PCT plate 3. Also in this case, since the buffer pipe 19 is provided on the outer peripheral surface of the steel pipe 18, the concrete c of the new PCT plate 3 is protected even when a load of the alignment jig 21 is applied. It is possible to prevent damage to the screw thread of the female screw portion 15 provided via 17.

Such operations are sequentially performed, and the PCT plates 3 are sequentially connected by the joint portion 10 in the axial direction of the precast arch tunnel 1. Further, the recesses 5a of the upper joint portions 5 of the PCT plates 3 constituting the arch portion 4 are fastened to each other by the fastening bolts 5c and the nuts 5d via the support plates 5b and 5b.
Then, after assembling the precast arch tunnel 1 between the left and right PCT plates 3, the interior of the bolt box 8 is filled with cast-in-place concrete. Similarly, the precast arch tunnel 1 is completed by filling the recess 5a of the upper joint 5 of the PCT plate 3 with cast-in-place concrete. Thereafter, the temporary support 6 is removed.

As described above, according to the connection structure of the PCT plate 3 of the precast arch tunnel 1 according to the present embodiment and the insert 9 used for the PCT plate 3, the insert 9 is provided on the end surface 3b of one PCT plate 3, and the other PCT plate 3 is provided. A bolt box 8 is provided on the end surface 3b of the bolt box 8 and a positioning jig 21 such as Shino is inserted into the steel pipe 18 from the bolt hole 11a of the bolt box 8 to align the bolt hole 11a of the bolt box 8 with the insert 9. The position of the PCT plate 3 can be adjusted.
In addition, since the bolt box 8 that is filled with the concrete c after the precast arch tunnel 1 is constructed is provided only on one side of the two PCT plates 3 that are connected to each other, it is possible to reduce manufacturing effort and cost.

  Further, when the position is adjusted, even if the steel pipe 18 or the taper pipe 17 of the insert 9 is pushed by the tip of the positioning jig 21 through the bolt hole 11a of the bolt box 8 and the position is adjusted, the load is absorbed by the buffer pipe 19 such as polystyrene foam. Therefore, the concrete c around the insert 9 is not cracked or damaged. Moreover, since the alignment jig 21 does not easily reach the female screw portion 15, the screw thread of the female screw portion 15 is not damaged.

  As described above, the precast arch tunnel 1 and the insert 9 of the PCT plate 3 according to the embodiment of the present invention have been described in detail. However, the present invention is not limited to the above-described embodiment, and does not change the gist of the present invention. Appropriate changes and substitutions can be made and these are all included in the present invention. Hereinafter, modifications and the like of the present invention will be described, but the same or similar parts and members as those of the above-described embodiment are denoted by the same reference numerals, and description thereof will be omitted.

For example, in the above-described embodiment, the end surfaces 3b of the PCT plates 3 are joined to each other by the bolt box 8 and the insert 9, and the joint portion at the upper joint portion 5 at the upper center between the left and right PCT plates 3 is the recess 5a. Although it was made to join with the bolt box by 5a, you may make it the structure which connects a joint part with the bolt box 8 and the insert 9 also in the upper junction part 5. FIG.
Further, when joining segments in a shield tunnel or the like, the bolt box 8 and the insert 9 may be used similarly.

Further, in the above-described embodiment, when the insert 9 is embedded in the PCT plate 3, the buffer pipe 19 such as foamed polystyrene is provided on the outer peripheral side of the steel pipe 18 and the tapered pipe 17. Instead, the buffer pipe 19 is provided. Only the steel pipe 18 may be installed on the distal end side of the tapered pipe 17. Even in this case, the movement due to the operation of the positioning jig 21 can be received by the steel pipe 18 to reduce cracks or breakage of the concrete c.
Alternatively, instead of the steel pipe 18, only the buffer pipe 19 may be installed on the distal end side of the tapered pipe 17. Even in this case, a slight movement due to the operation of the alignment jig 21 can be received by the buffer tube 19 such as a polystyrene foam to absorb the load.

Further, the taper pipe 17 may be omitted, and the steel pipe 18 and the buffer pipe 19 may be provided on the distal end side of the female thread portion 15 of the insert main body 16, or only one of the steel pipe 18 and the buffer pipe 19 may be provided. In these cases, the steel pipe 18 and the buffer pipe 19 may be formed in a tapered tubular shape toward the female screw portion 15.
In addition, the steel pipe 18, the taper pipe 17, and the buffer pipe 19 in the insert 9 are included in the guide ring.

DESCRIPTION OF SYMBOLS 1 Precast arch tunnel 2 Base part 3 PCT plate 3b End surface 5 Upper joint part 8 Bolt box 9 Insert 11 Supporting plate 11a Bolt hole 12 Fastening bolt 15 Female thread part 16 Insert main body 17 Taper pipe 18 Steel pipe 19 Buffer pipe 21 Positioning treatment Ingredients

Claims (5)

An insert body embedded in the end face of the PCT plate,
A female thread portion provided inside the insert body and screwed with a fastening bolt;
An insert comprising: a guide ring provided on an inlet side of the female thread portion of the insert body.   The insert according to claim 1, wherein the guide ring is a buffer pipe made of a cylindrical steel pipe and a buffer material provided on an outer peripheral surface thereof.   2. The insert according to claim 1, wherein the guide ring is a cylindrical steel pipe or a buffer pipe made of a buffer material.   The insert according to any one of claims 1 to 3, further comprising a tapered spot digging that gradually decreases in diameter toward the female screw portion side at a distal end side of the female screw portion of the insert body. In the connecting structure of PCT plates formed by connecting a plurality of arc-shaped PCT plates,
A bolt box is installed on one end surface of the connecting portion of one PCT plate and the other PCT plate, and an insert having an internal thread portion is installed on the other end surface,
The PCT plate connection structure according to claim 1, wherein the insert is provided with a guide ring on an end surface side which comes into contact with the bolt box of the other PCT plate.

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