JP2012251360A - Sheath junction structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sheath junction structure capable of surely joining sheath pipes through which a tendon is inserted, shortening a construction period of mutual segment joining, and improving economical efficiency.SOLUTION: A sheath junction structure 1 for joining sheath pipes 21 of adjoining segments 2 to each other includes: an outer cylindrical pipe 11 attached to an end of a sheath pipe 21 provided in one segment 2; a rotary seal pipe 12 attached to the outer cylindrical pipe 11; and a pressing plate 13 provided on an end of the other segment 2 side of the rotary seal pipe 12. An outer surface of the outer cylindrical pipe 11 is externally threaded while an inner surface of the rotary seal pipe 12 is internally threaded so that the female thread of the rotary seal pipe 12 is engaged with the male thread of the outer cylindrical pipe 11. The rotary seal pipe 12 moves along the axial direction of the sheath pipe 21 as the rotary seal pipe 12 is rotated, and the pressing plate 13 moves toward an end face of the other segment 2 along with the rotary seal pipe 12.

Description

  The present invention relates to a sheath joining structure for joining sheath tubes of adjacent segments.

  In the case of constructing a structure using precast segments, there is a case where a tension material is inserted into adjacent segments and the segments are joined to each other by a post tension introduced into the tension material.

  For example, in Patent Document 1, a bridge girder is formed by arranging segments embedded with a sheath tube side by side in the beam axis direction, inserting a tension material into the sheath tube, and introducing a tension force into the tension material. Yes.

  As a joining method between segments, two types, a dry joint method and a wet joint method, are employed.

The dry joint method is a method in which the segments are brought into close contact with each other in a state where an adhesive is applied to the contact surfaces between the segments and joined by introducing prestress.
On the other hand, in the wet joint method, a segment is set in a state where there is a gap with other adjacent segments, and a filler is filled in the gap, and after a predetermined strength is developed in the filler, a prestress is introduced. This is a method of joining segments together.

  In the dry joint method, it is necessary to closely contact the contact surfaces of the segments. For this reason, it is desirable to employ a match cast that uses the end face of another segment manufactured in advance as a mold when manufacturing the segment.

However, in the match cast, it is necessary to manufacture the segments one by one in order from one end, and therefore it is impossible to manufacture a plurality of segments at the same time, and it is difficult to shorten the manufacturing process.
In addition, since large installation facilities are required for joining segments and producing segments, the application of the dry joint method is generally limited to long span bridges.

  On the other hand, since the wet joint method can simultaneously produce a plurality of segments, the production process can be shortened. In addition, since no special installation facility or the like is required when joining the segments, even a relatively small bridge can be employed.

JP 2009-41271 A

  In the wet joint method, it is necessary to join the sheath tubes of adjacent segments in advance so that the filler does not enter the sheath tube when the filler is filled in the gap between the segments.

Conventionally, the sheath tubes are joined by projecting the sheath tube from the joining end surface of the segment, setting the segment, and then winding the cover sheet and the adhesive tape so as to cover the butted portion of the sheath tubes. It was done by.
Also, depending on the manufacturing accuracy of the segments, the butted portions of the sheath tubes may be slightly shifted. In that case, since a gap is formed between the cover sheet and the sheath tube, it is difficult to completely avoid the leakage of the filler.

  The gap between the segments needs to ensure a width (at least 20 to 30 cm) at which an operator can work by putting hands. However, if the gap between the segments becomes large, the amount of the filler is inevitably large. Therefore, filling work and curing hinder the shortening of the construction period.

As a method of joining sheath tubes without manual work, a flexible ring seal is pasted around the sheath tube at the end face of one segment, and the segments are pressed against each other, so that the ring is pressed by pressing force. The seal may be crushed to join the sheath tubes together.
According to this method, the gap between the segments can be reduced, the amount of filler can be reduced, and the construction period can be shortened.

However, when the manufacturing accuracy of the segment is not high, or when the contact pressure to the joint surface of the ring seal is insufficient, the degree of adhesion of the ring seal to the end surface of the segment becomes insufficient, and the filler is contained in the sheath tube. There was a risk of getting in.
Further, the flexible ring seal may be deformed by the pressure when the filler is filled.

  The present invention solves the above-mentioned problem, and in a state in which the gap between the segments is minimized, the sheath pipes through which the tension material is inserted are reliably joined, and thus the work period for joining the segments is shortened. It is an object of the present invention to propose a sheath joint structure that can improve economy.

  In order to solve the above-described problem, the joining structure according to the first invention is a sheath joining structure that joins the sheath tubes of adjacent segments, and is attached to the end portion of the sheath tube provided in one segment. An outer cylinder pipe, a rotary seal pipe mounted on the outer cylinder pipe, and a pressing plate provided at an end portion on the other segment side of the rotary seal pipe, on the outer surface of the outer cylinder pipe Male thread processing is performed, and the inner surface of the rotary seal tube is female threaded to be engaged with the external thread of the outer tube, and the rotary seal tube rotates to rotate the sheath tube The pressing plate moves together with the rotary seal tube toward the end surface of the other segment.

  Further, the sheath joining structure of the second invention is a sheath joining structure for joining the sheath tubes of adjacent segments, and a rotary seal tube attached to an end of the sheath tube provided in one segment; A pressing plate provided at an end portion on the other segment side of the rotary seal tube, and spiral irregularities are formed on the outer surface of the sheath tube, and the sheath tube is formed on the inner surface of the rotary seal tube Concavities and convexities that conform to the concavities and convexities formed on the outer surface of the sheath tube are formed, and the rotating seal tube moves along the axial direction of the sheath tube by rotating, and the pressing plate together with the rotating seal tube It is characterized by moving toward the end face of the other segment.

According to such a sheath bonding structure, the rotating seal tube is rotated and moved toward the other segment, and the joining portion of the sheath tubes is covered with the rotating seal tube simply by bringing the pressing plate into contact with the other segment. Can do.
The gap between the segments may be any width as long as a jig for rotating the rotary seal tube can be inserted, and can be made smaller than the conventional one. Therefore, it is possible to reduce the amount of the filler, and as a result, it is possible to reduce the labor required for filling work and the time required for curing.

You may provide the sealing member installed in the end surface of the said press plate, and you may provide the seal member installed in the contact surface with the said press plate of said other segment.
At this time, it is preferable that the seal member is provided so as to surround an end portion of a sheath tube provided in the other segment.

  According to such a sheath bonding structure, the pressing plate can be brought into close contact with the other segment via the seal member regardless of the manufacturing quality of the end face of the segment. For this reason, the sheath tubes can be more reliably joined to each other.

  If the pressing plate is a polygonal member or a member having a plurality of irregularities on the outer peripheral surface, it is possible to use a thin plate-like wrench or ring tightening jig, so even if the gap is small The rotary seal tube can be easily rotated.

  According to the sheath joining structure of the present invention, it is possible to reliably join the sheath pipes through which the tendon material is inserted, thereby shortening the work period of joining the segments and improving the economy.

It is a perspective view which shows the bridge girder which concerns on embodiment of this invention. It is a figure which shows the segment which comprises the bridge girder shown in FIG. 1, Comprising: (a) is a cross-sectional view, (b) is AA sectional drawing of (a). It is sectional drawing which shows the sheath junction structure which concerns on 1st embodiment. (A) And (b) is a perspective view which shows a part of sheath joining structure. (A) And (b) is sectional drawing which shows the operation | movement by the sheath joining structure of 1st embodiment. It is sectional drawing which shows the sheath joining structure which concerns on 2nd embodiment. It is sectional drawing which shows the joining condition of the sheath pipe | tube by the sheath joining structure of 2nd embodiment. (A)-(c) is sectional drawing which shows the other form of a sheath joining structure.

<First embodiment>
A first embodiment according to the present invention will be described with reference to the drawings.
In the present embodiment, as shown in FIG. 1, a case where a prestressed concrete bridge is constructed using a plurality of concrete precast segments (hereinafter simply referred to as “segment 2”) is illustrated.

A plurality of segments 2 are arranged side by side in the beam axis direction, and are connected by introducing a tension force to the tension members 3 penetrating each segment 2.
In the present embodiment, a so-called box-shaped cross section is used as the segment 2, but the shape and the like of the segment are not limited and may be, for example, an I-shaped cross section.

  As shown in FIGS. 2A and 2B, the segment 2 is provided with a plurality of sheath tubes 21, 21,.

  The sheath tube 21 is a tube material for inserting the tendon 3 and is disposed along the beam axis direction of the bridge beam.

The sheath tube 21 has an inner diameter equal to or greater than the outer diameter of the tendon 3 so that the tendon 3 can be inserted.
The material and shape of the sheath tube 21 are not limited. For example, a spiral sheath obtained by spirally winding a thin strip steel or a spiral sheath made of polyethylene may be used.

Both ends of the sheath tube 21 are open at the end of the segment 2 (surface facing the other segment 2). The tension member 3 inserted through the sheath tube 21 of another adjacent segment 2 is inserted into the sheath tube 21.
Although the installation method of the sheath tube 21 to the segment 2 is not limited, for example, it may be fixed to a formwork or a reinforcing bar so as not to be displaced by placing concrete or compacting.

  The sheath tube 21 may be inclined with respect to the horizontal. Moreover, in the segment 2 arrange | positioned in the location where bending stress concentrates on the lower surface side of a bridge, the sheath pipe | tube 21 may be concentrated and arrange | positioned at the lower surface side of a segment.

  As shown in FIG. 3, the sheath joining structure 1 of the present embodiment joins the sheath tubes 21 of the adjacent segments 2, and includes an outer tube 11, a rotary seal tube 12, a pressing plate 13, And a seal member 14.

  The outer tube 11 is a tubular member attached to the end of the sheath tube 21 provided in one segment 2.

  The outer tube 11 is fixed to the outer peripheral surface of the end portion of the sheath tube 21 with an epoxy adhesive, a silicon seal material, or the like. Male threads are provided on the outer surface of the outer tube 11.

The material which comprises the outer cylinder pipe 11 is not limited, A metal, resin, such as a vinyl chloride and an acrylic resin, wood, etc. can be used.
Further, by forming irregularities corresponding to the helical irregularities of the sheath tube 21 made of a spiral tube on the inner surface of the outer tube 11 and screwing the outer tube 11 to the sheath tube 21, the outer tube The degree of fixation between the sheath 11 and the sheath tube 21 may be increased.

  The rotary seal tube 12 is a cylindrical member attached to the outer tube 11.

The rotary seal tube 12 has a length longer than the gap 4, and a part of the rotary seal tube 12 enters one segment 2. The inner surface of the rotary seal tube 12 is processed with a female screw that is screwed into the male screw of the outer tube 11.
The rotary seal tube 12 moves along the axial direction of the sheath tube 21 by being rotated by a jig 5 (see FIG. 4A) inserted from the outside of the gap 4.

  The material which comprises the rotation seal pipe | tube 12 is not limited, A metal, resin, such as a vinyl chloride and an acrylic resin, wood, etc. can be used.

  The pressing plate 13 is a bowl-shaped plate provided at the end of the rotary seal tube 12 on the other segment 2 side. The thickness of the pressing plate 13 is determined in consideration of the size of the gap 4 and is preferably as thin as possible within a range where necessary rigidity can be ensured. In addition, the material which comprises the press plate 13 is not limited, For example, metals, resin, such as a vinyl chloride and an acrylic resin, wood, etc. can be used.

As shown in FIG. 4A, the pressing plate 13 is formed of a hexagonal flat plate. A through hole 13 a is formed at the center of the pressing plate 13. A tendon is inserted through the through hole 13a.
In the present embodiment, a flat plate member is fixed to the end of the rotary seal tube 12 as the pressing plate 13, but the method of forming the pressing plate 13 is not limited. For example, the rotary seal tube 12 and the pressing plate 13 may be integrally formed in advance by casting.

  The shape of the pressing plate 13 is not limited, and may be formed in other polygonal shapes. As shown in FIG. 4B, a plurality of irregularities are formed in a gear shape on the outer peripheral surface. It may be a plate material.

  When the pressing plate 13 is rotated through the jig 5 inserted from the gap 4, the rotary seal tube 12 is also rotated integrally. Since the rotary seal tube 12 rotates and moves along the axial direction of the sheath tube 21, the pressing plate 13 also moves accordingly. The pressing plate 13 moves toward the end surface of the other segment 2 together with the rotary seal tube 12, thereby closely contacting the sealing member 14 installed on the end surface of the other segment 2 (see FIG. 5B).

  In the present embodiment, a hexagon wrench is used as the jig 5, but the jig 5 is not limited and may be appropriately adopted according to the pressing plate 13. For example, as shown in FIG. 4B, when the pressing plate 13 is a plate material having gear-like irregularities formed on the outer peripheral surface, an Ω-shaped jig having gear-like irregularities formed on the inner surface. (Ring tightening jig) 5 is used. The jig 5 can grip the pressing plate 13 and rotate the rotary seal tube 12 by narrowing the grips 5a and 5a. In addition, the material which comprises a jig | tool is not limited, For example, what is necessary is just to comprise with steel materials, a synthetic resin, etc.

  As shown in FIG. 3, the seal member 14 is installed on the contact surface of the other segment 2 with the pressing plate 13.

The seal member 14 is provided along the outer periphery of the sheath tube 21 so as to surround the end portion of the sheath tube 21 provided in the other ring-shaped segment 2.
The seal member 14 is a flexible member, and includes a main body portion 14a and a lip portion 14b projecting from the main body portion 14a.

The main body 14 a is bonded to the outer periphery of the sheath tube 21 and is embedded in the segment 2.
In addition, the installation method of the sealing member 14 is not limited, For example, a part of main body part 14a may protrude from the end surface of the segment 2. FIG.

  The lip portion 14 b protrudes from the end surface of the segment 2. The lip portion 14 b protrudes from the outer edge side of the main body portion 14 a, is inclined so as to increase in diameter as it approaches the tip (pressing plate), and is deformed (tilted) outward by the pressing force of the pressing plate 13.

  Although the material which comprises the sealing member 14 will not be limited if it is the material which has the designed deformation coefficient, The urethane resin which can set a deformation coefficient (hardness) easily is desirable. Examples of other desirable materials for the seal member 14 include natural rubber, neoprene rubber, vulcanized rubber, and foamed rubber.

The segment 2 is formed by placing concrete in a state where a sheath tube 21 having an outer tube 11 at one end and a seal member 14 fixed at the other end is set in a mold.
At this time, the rotary seal tube 12 is screwed into the outer tube 11, and a release material is applied to the outer peripheral surface of the rotary seal tube 12. By doing so, the rotary seal tube 12 is peeled from the concrete by the rotational force applied to the rotary seal tube 12 and can move toward the other segment 2. When the box is removed around the outer tube 11, the rotary seal tube 12 may be set after the segment 2 is completed.

  In the joining between the sheath tubes 21 by the sheath joining structure 1, first, as shown in FIG. 5A, the segment 2 is disposed with a predetermined gap 4 between the other adjacent segments 2. To do.

  Next, a hexagon wrench (jig 5) is inserted from the gap 4, and the rotary seal tube 12 is rotated. When the rotary seal tube 12 rotates, the male screw formed on the inner surface slides on the female screw of the outer tube 11 and moves to the other segment 2 side.

  When the rotary seal tube 12 moves to the other segment 2 side, the pressing plate 13 comes into contact with the seal member 14. When the rotary seal tube 12 is further rotated, as shown in FIG. 5B, the pressing plate 13 presses the sealing member 14, and the lip portion 14b is deformed (tilted) outward, so that the pressing plate 13 and the seal are sealed. The member 14 is in close contact with the gap.

When the pressing plate 13 and the seal member 14 are in close contact with each other, the gap between the sheath tubes 21 is sealed, and the sheath tubes 21 are joined.
This prevents the filler 41 filled in the gap 4 between the segments 2 from entering the sheath tube 21.

  The seal member 14 (lip portion 14b) tends to be deformed inward (center side of the seal member 14) by the pressure of the filler 41. However, the seal member 14 (lip portion 14b) is blocked by the pressing plate 13 that is in close contact with the lip portion 14b, thereby sealing more reliably. Is done.

According to the sheath joining structure 1 of the present embodiment, the rotating seal tube 12 is rotated, and the pressing plate 13 is brought into close contact with the seal member 14 only by moving the pressing plate 13, and the joint portion between the sheath tubes 21 is rotated. It can be covered by the seal tube 12.
Therefore, the sheath tubes 21 can be reliably joined to each other without being limited to the quality of the end surfaces of the segments 2.

  Further, the gap 4 between the segments 2 may be smaller than the conventional one (for example, 2 to 3 cm) because it is sufficient to secure a width in which a jig 5 (hexagon wrench) for rotating the rotary seal tube 12 can be inserted. Degree). Therefore, it is possible to reduce the amount of the filler 41, and consequently, it is possible to reduce time and labor required for filling work and curing. Therefore, the construction period can be shortened and the economy can be improved.

  Further, by reducing the width of the gap 4 between the segments 2, the formation of a structural weak portion is suppressed.

  Even if there is a variation in the width of the gap 4 due to a decrease in segment manufacturing accuracy, the sheath pipes 21 can be reliably joined to each other by adjusting the protruding length of the rotary seal pipe 12 from the end face of the segment 2. .

  If data on how much rotational torque of the rotary seal tube 12 is required with respect to the maximum pressure by the filler 41 is prepared in advance, reliable sealing can be performed.

  As the bridge girder height increases, the pressure of the filler 41 also increases. In this case, the risk of deformation can be suppressed by increasing the rigidity of the rotary seal tube 12. Therefore, deformation and leakage due to the pressure of the filler 41 are prevented.

  Since an off-the-shelf product can be used as the material or the like constituting the sheath joining structure 1, the sheath tubes 21 in the narrow gap 4 can be joined economically.

<Second Embodiment>
A second embodiment according to the present invention will be described with reference to the drawings.
In this embodiment, the case where a prestressed concrete bridge is constructed using the segment 2 is illustrated as in the first embodiment.

In the segment 2 of this embodiment, as shown in FIG. 6, a space 22 is formed by boxing around the rotary seal tube 12. Further, the sheath tube 21 is a spiral tube, and spiral irregularities are formed on the outer surface of the sheath tube 21.
Since the configuration of the other segment 2 is the same as that shown in the first embodiment, detailed description thereof is omitted.

  As shown in FIG. 6, the sheath joining structure 1 of the present embodiment includes a rotary seal tube 12, a pressing plate 13, and a seal member 14.

  The rotary seal tube 12 is a cylindrical member attached to a sheath tube 21 provided in one segment 2. An off-the-shelf sheath joint may be used as the rotating sheath tube 12.

  The rotary seal tube 12 has a length longer than the gap 4 between the segments 2, and irregularities that match the irregularities of the outer surface of the sheath tube 21 are formed on the inner surface thereof. The rotary seal tube 12 moves along the axial direction of the sheath tube 21 by rotating it around the axis.

  The material which comprises the rotation seal pipe | tube 12 is not limited, A metal, resin, such as a vinyl chloride and an acrylic resin, wood, etc. can be used.

The pressing plate 13 is a plate material provided at the end of the rotary seal tube 12 on the other segment 2 side, and is fixed to the end of the rotary seal tube 12. As a method for fixing the pressing plate 13 to the rotary seal tube 12, for example, there is a method using welding or an adhesive.
A through hole 13a is formed in the central portion of the pressing plate 13 so that a tension material can be inserted therethrough.

  Note that the shape of the pressing plate 13 is not limited, and may be, for example, a plate material (see FIG. 4A) formed in a polygonal shape, or a plurality of irregularities in a gear shape on the outer peripheral surface. It may be a formed flat plate (see FIG. 4B).

  The pressing plate 13 moves along with the rotary seal tube 12 along the axial direction of the sheath tube 21. The pressing plate 13 moves toward the end surface of the other segment 2 together with the rotary seal tube 12, thereby closely contacting the end surface of the other segment 2.

  The seal member 14 is installed on a contact surface (end surface) with the other segment 2 of the pressing plate 13.

The seal member 14 is a flexible ring-shaped member, and includes a main body portion 14a and a lip portion 14b protruding from the main body portion 14a.
When the seal member 14 is in contact with the other segment 2, the seal member 14 surrounds the periphery of the sheath tube 21 provided in the other segment 2.

  The main body portion 14 a is bonded to the end surface of the pressing plate 13. The lip portion 14 b protrudes from the outer edge side of the main body portion 14 a, is inclined so as to increase in diameter as it approaches the tip (the other segment 2), and is deformed (tilted) outward by the pressing force of the pressing plate 13. . In addition, the cross-sectional shape of the sealing member 14 is not limited.

  Although the material which comprises the sealing member 14 is not limited, The urethane resin which can set a deformation coefficient (hardness) easily is desirable. Examples of other desirable materials for the seal member 14 include natural rubber, neoprene rubber, vulcanized rubber, and foamed rubber.

The segment 2 is formed by placing concrete with the sheath tube 21 set in the mold.
At this time, a space 22 in which the rotary seal tube 12 is installed is formed by boxing around the one end side of the sheath tube 21. The rotary seal tube 12 may be installed in the sheath tube 21 in advance with a release material applied to the outer peripheral surface.

  In joining the sheath tubes 21 by the sheath joining structure 1, first, the segment 2 is disposed with a predetermined gap 4 between the other adjacent segments 2.

  Next, the jig 5 (see FIG. 4B) is inserted from the gap 4, and the rotary seal tube 12 is rotated. The rotating seal tube 12 slides on the spiral irregularities of the sheath tube 21 by rotating, and moves to the other segment 2 side.

  When the rotary seal tube 12 moves to the other segment 2 side, the seal member 14 fixed to the pressing plate 13 comes into contact with the end surface of the other segment 2. When the rotary seal tube 12 is further rotated, the pressing plate 13 presses the sealing member 14 and the lip portion 14b is deformed, so that the sealing member 14 adheres to the end face of the other segment 2 without a gap as shown in FIG. To do.

When the seal member 14 is in close contact, the gap between the sheath tubes 21 is sealed, and the sheath tubes 21 are joined.
Thereby, the filler 41 filled in the gap 4 between the segments 2 is prevented from entering the sheath tube 21.

  According to the sheath joint structure 1 of the second embodiment, the same effect as the sheath joint structure 1 of the first embodiment can be obtained.

  The preferred embodiments of the present invention have been described above. However, the present invention is not limited to the above-described embodiments, and it goes without saying that the above-described constituent elements can be appropriately changed without departing from the gist of the present invention.

  For example, the sheath joint structure according to the present invention is not limited to a bridge girder, and can be applied to various prestressed concrete structures composed of a plurality of segments.

  The tendon material 3 which penetrates a sheath pipe | tube is not limited, For example, what is necessary is just to use a PC steel rod, a PC steel wire, a PC twisted wire, etc.

  In each of the above embodiments, the case where the pressing plate 13 is a flat plate has been described. However, the pressing plate 13 is not limited to this, and for example, as shown in FIG. It may be provided. According to the pressing plate 13, leakage of the filler 41 (penetration into the sheath tube 21) is prevented by causing the protrusion 13 b to bite into the seal member 14. The protrusion 13b bites into the seal member 14 because the contact pressure locally increases, so that it can be sealed even when the pressure of the filler 41 to leak is large.

  Further, the cross-sectional shape of the seal member 14 is not limited, and may be, for example, a rectangular cross section (see FIG. 8A) or a circular cross section (see FIG. 8B).

As shown in FIG. 8B, when an O-ring is used as the seal member 14, the seal member 14 is fixed in a ring-shaped groove formed on the end surface of the other segment 2. By pressing the pressing plate 13 against the seal member 14, the contact pressure of the contact portion of the O-ring is increased and sealing is performed.
The sealing member 14 made of an O-ring may be fixed to the pressing plate 13 as shown in FIG.

  In each of the above embodiments, the case where the rotary seal tube 12 extends from the one segment 2 side has been described. However, the rotary seal tube 12 may extend from both the segments 2 and 2 that sandwich the gap 4.

DESCRIPTION OF SYMBOLS 1 Sheath joining structure 11 Outer cylinder pipe 12 Rotating seal pipe 13 Pressing plate 14 Seal member 2 Segment 21 Sheath pipe 3 Tension material 4 Crevice 41 Filling material

Claims (5)

A sheath joint structure for joining sheath tubes of adjacent segments,
An outer tube attached to an end of a sheath tube provided in one segment;
A rotary seal tube mounted on the outer tube;
A pressing plate provided at the other segment side end of the rotary seal tube,
The outer surface of the outer tube is subjected to male thread processing,
The inner surface of the rotary seal tube is subjected to a female thread process that is screwed into a male thread of the outer tube,
The rotating seal tube moves along the axial direction of the sheath tube by rotating,
The sheath joining structure according to claim 1, wherein the pressing plate moves together with the rotary seal tube toward an end surface of the other segment. A sheath joint structure for joining sheath tubes of adjacent segments,
A rotary seal tube attached to the end of a sheath tube provided in one segment;
A pressing plate provided at the other segment side end of the rotary seal tube,
Helical irregularities are formed on the outer surface of the sheath tube,
The inner surface of the rotary seal tube is formed with irregularities that match the irregularities formed on the outer surface of the sheath tube,
The rotating seal tube moves along the axial direction of the sheath tube by rotating,
The sheath joining structure according to claim 1, wherein the pressing plate moves together with the rotary seal tube toward an end surface of the other segment.   The sheath joint structure according to claim 1, further comprising a seal member installed on an end surface of the pressing plate. A seal member installed on the contact surface of the other segment with the pressing plate;
The sheath joining structure according to claim 1 or 2, wherein the seal member is provided so as to surround an end portion of a sheath tube provided in the other segment.   The sheath joining structure according to any one of claims 1 to 4, wherein the pressing plate is a polygonal member or a member having a plurality of irregularities formed on an outer peripheral surface thereof.

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