Water stop device for tubular body

Abstract

To maintain a water cut-off function even when a pipe body is largely separated in the axial direction by an earthquake or the like, and to suppress swelling of a water cut-off member without using an exclusive protective cover.SOLUTION: The water cut-off device 100 includes a water cut-off member 3 made of an elastic body, a first pressing plate 4 and a second pressing plate 5 for pressing the water cut-off member 3 toward the inner peripheral surface 11 of the pipe body 1, and a bottom board 6 interposed between the water cut-off member 3 and the pressing plates 4, 5. The water cut-off member 3 has a first base part 32 arranged on one side in the axial direction X of the pipe body 1, a second base part 35 arranged on the other side in the axial direction X, and an extension part 31 arranged between these base parts 32 and 35 and extendable in the axial direction X. The first pressing plate 4 is provided across the first base portion 32 and a portion of the extension portion 31 close to the first base portion, and the second pressing plate 5 is provided across the second base portion 35 and a portion of the extension portion 31 close to the second base portion. Sole plate 6 is interposed between water cut-off member 3 and presser plates 4 and 5 so as to cover extension portion 31.SELECTED DRAWING: Figure 6

Description

[Technical Field]

[0001] The present invention relates to a device for preventing groundwater or the like from infiltrating into a pipe such as a water supply or sewerage pipe laid underground. [Background technology]

[0002] In pipes laid underground, such as water supply and sewerage pipes and drainage pipes, if cracks or breakage occur at the joints between the pipes due to earthquakes, land subsidence, etc., the watertight function of the joints is impaired, allowing groundwater to seep into the inside of the pipes. For this reason, it has been conventional to provide a watertight device on the inner surface of the pipe joints to prevent groundwater from seeping into the pipes. Patent Document 1 shows an example of such a watertight device.

[0003] The watertight device in Patent Document 1 includes a watertight rubber ring attached to cover the entire inner periphery of the joint of the pipe, and a clamping ring that presses and crimps the rubber ring against the inner surface of the joint. The clamping ring includes a thin iron ring body and ribs that protrude inward from both edges of the ring body, allowing it to expand radially.

[0004] In pipes, watertight devices are not limited to joints. For example, in the case of a sewer pipe connected to a manhole underground, if a large earthquake causes liquefaction, excessive force due to buoyancy will be exerted on the manhole, causing it to lift upward. This will result in large bending moments and shear stresses acting on the sewer pipe connected to the manhole, causing cracks in the pipe. To prevent the damage caused by these cracks from spreading, guide joints have traditionally been installed in the pipe. Guide joints are grooves that guide cracks so that they occur only near the connection between the pipe and the manhole, and are installed circumferentially on the inner surface of the pipe near the connection.

[0005] Patent Document 2 shows an example of a lead joint. This lead joint limits the location of cracks to the vicinity of the connection between the pipe body and the manhole, preventing multiple cracks from occurring in other parts of the pipe body and causing widespread damage. However, if a crack occurs in the lead joint, groundwater will seep into the pipe through that location, so watertight measures are also required for the lead joint. In Patent Document 2, a watertight measure is taken by covering the lead joint with an annular sheet member made of a flexible material such as rubber. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Laid-Open No. 2004-232849 [Patent Document 2] Patent No. 4695381 Summary of the Invention [Problem to be solved by the invention]

[0007] In the watertight device of Patent Document 1, even if a crack or break occurs in the joint of the pipe, the affected area is covered with a watertight rubber ring, preventing groundwater from seeping in. However, because this rubber ring barely stretches in the axial direction of the pipe, if a major earthquake occurs and the pipes on both sides of the joint are significantly separated in the axial direction, the rubber ring loses its watertight function, allowing groundwater to seep into the pipe.

[0008] Also in Patent Document 2, the sheet material covering the guide joint hardly stretches in the axial direction of the pipe body, so if a crack occurs in the guide joint due to a large earthquake and causes the pipe bodies on both sides of the guide joint to separate significantly in the axial direction, the water-stopping function of the sheet material is lost, and groundwater will seep into the pipe, just as in Patent Document 1.

[0009] One possible solution to this problem is to provide water-stopping components such as rubber rings or sheet members with extensions (such as bellows sections) that can stretch in the axial direction of the pipe, and use these extensions to cover the joints and guide joints of the pipe. In this way, even if the pipe separates significantly in the axial direction during an earthquake, the extensions will follow suit and expand in the axial direction, covering the separated area of ​​the pipe, preventing groundwater from seeping into the pipe.

[0010] However, the extension of the water-stopping member swells under the pressure of groundwater in the separation area of ​​the pipe, protruding into the flow path inside the pipe, which increases water resistance. One way to avoid this is to cover the entire water-stopping member with a protective cover to prevent the extension from expanding, but this requires a special cover, which increases costs.

[0011] In view of the above problems, an object of the present invention is to maintain the watertight function even when the pipes on both sides of the pipe joint or guide joint are largely separated due to an earthquake, etc. Another object of the present invention is to suppress the swelling of the watertight member without using a dedicated cover. [Means for solving the problem]

[0012] The waterstop device for a pipe according to the present invention is a waterstop device installed at a predetermined location within a pipe laid underground so as to cover the entire inner circumferential surface of the pipe. The waterstop device includes a waterstop member made of an elastic body, a presser plate that presses the waterstop member toward the inner circumferential surface of the pipe, and a base plate interposed between the waterstop member and the presser plate. The waterstop member has a first base, a second base, and an extension portion. The first base is installed on one axial side of the pipe, and the second base is installed on the other axial side of the pipe. The extension portion is installed between the first and second bases and is elastically deformable and extendable in the axial direction of the pipe. The presser plate is made up of a first presser plate and a second presser plate. The first presser plate is installed across the first base of the waterstop member and a portion of the extension portion of the waterstop member closer to the first base. The second press plate is provided across the second base portion of the water-stopping member and the portion of the extension portion of the water-stopping member closer to the second base portion. The base plate is interposed between the water-stopping member and the first and second press plates so as to cover the extension portion of the water-stopping member.

[0013] In this type of waterstop device, even if a crack caused by a major earthquake or subsidence causes the pipe on both sides of the joint or guide joint to separate and separate significantly in the axial direction, the extension of the waterstop device will expand and cover the crack, preventing groundwater from seeping into the pipe. Furthermore, even if groundwater pressure is applied to the extension of the waterstop member through a crack, the extension will not expand and protrude into the pipe because it is covered by the base plate. This eliminates the need for a dedicated cover to completely cover the waterstop member, reducing costs. [Effects of the Invention]

[0014] According to the present invention, the watertight function is maintained even if the pipe body is severely separated during an earthquake, etc., so it is possible to prevent groundwater from seeping into the pipe body. In addition, it is possible to suppress the expansion of the extension part of the watertight member without using a dedicated cover. [Brief explanation of the drawings]

[0015] [Figure 1] 1 is a cross-sectional view of a pipe provided with a water-stopping device according to the present invention. [Figure 2] FIG. 2 is a cross-sectional view of a water-stopping member. [Figure 3] FIG. 3 is a cross-sectional view showing the detailed structure of the waterproofing device. [Figure 4] FIG. 2 is a cross-sectional view of a portion of a tube body. [Figure 5] FIG. 10 is a cross-sectional view of another part of the tube body. [Figure 6] FIG. 4 is a cross-sectional view illustrating the function of the waterproofing device. [Figure 7] FIG. 10 is a cross-sectional view showing another embodiment of the present invention. [Figure 8] FIG. 10 is a cross-sectional view showing another embodiment of the present invention. [Figure 9] FIG. 10 is a cross-sectional view showing another embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0016] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described with reference to the drawings. Throughout the drawings, identical or corresponding parts are designated by the same reference numerals.

[0017] FIG. 1 shows a cross-sectional view of a pipe 1 equipped with a waterstop device 100 according to the present invention. The pipe 1 is a sewer pipe, such as a concrete Hume pipe, and is connected to a manhole (not shown) located on the left side of the figure. The coordinate axes X, Y, and Z represent the axial, radial, and circumferential directions of the pipe 1, respectively. The interior of the pipe 1 forms a hollow flow path 20 through which sewage flows. The pipe 1 also has induction joints 2 formed in the circumferential direction Z to induce cracks during an earthquake or other such event.

[0018] The watertight device 100 is provided so as to cover the area where the induction joint 2 is formed on the inner peripheral surface 11 of the pipe body 1 and the vicinity thereof over the entire circumference in the circumferential direction Z. The watertight device 100 is provided with a watertight member 3 made of an elastic material such as rubber, pressure plates 4, 5, 7, and 9 made of flexible metal plates such as stainless steel spring steel, and base plates 6, 8, and 10 made of similarly flexible metal plates.

[0019] FIG. 2 shows the detailed structure of the water-stopping member 3. The water-stopping member 3 is made of earthquake-resistant synthetic rubber or the like and has a first base portion 32 provided on one side of the tubular body 1 in the axial direction X (see FIG. 1), a second base portion 35 provided on the other side in the axial direction X, and an extension portion 31 provided therebetween. The first base portion 32 is provided with a first hollow portion 33 and a first tooth portion 34 in the circumferential direction Z of the tubular body 1 (see FIG. 1). The second base portion 35 is provided with a second hollow portion 36 and a second tooth portion 37 also in the circumferential direction Z. The extension portion 31 is thinner than the first base portion 32 and the second base portion 35 and is formed in a bellows shape, so that it can elastically deform and extend in the axial direction X of the tubular body 2, as will be described later.

[0020] FIG. 3 is a cross-sectional view showing the detailed structure of the water-stopping device 100. This cross-sectional view is an enlarged cross-sectional view of the lower side (the bottom side of the pipe body 1) in FIG. 1. As can be seen from FIG. 3, the first base portion 32 and the second base portion 35 of the water-stopping member 3 are arranged on both sides of the induction joint 2 formed in the pipe body 1. The extension portion 31 of the water-stopping member 3 is arranged so that its center faces the induction joint 2, and the induction joint 2 and its vicinity are covered by the extension portion 31. The water-stopping member 3 is pressed toward the inner circumferential surface 11 of the pipe body 1 by the presser plates 4, 5, 7, and 9 via the base plates 6, 8, and 10, and is pressure-bonded to the inner circumferential surface 11.

[0021] As a method for crimping the water-stopping member 3 onto the inner surface 11 of the pipe body 1, for example, as shown in Patent Document 1, a method can be used in which the pressure plates 4, 5, 7, and 9 are expanded in the radial direction Y (see Figure 1) using a jack.

[0022] The first pressing plate 4 is provided in the circumferential direction Z in Fig. 1, spanning the first base portion 32 of the water-stopping member 3 and a portion of the extension portion 31 closer to the first base portion 32 (substantially the left half). The second pressing plate 5 is provided in the circumferential direction Z in Fig. 1, spanning the second base portion 35 of the water-stopping member 3 and a portion of the extension portion 31 closer to the second base portion 35 (substantially the right half).

[0023] The base plate 6 is provided in the circumferential direction Z in FIG. 1 so as to cover the entire extension portion 31 of the water-stopping member 3, and is interposed between the water-stopping member 3 and the pressure plates 4 and 5. Therefore, the first pressure plate 4 presses against a part of the first base portion 32 of the water-stopping member 3 and approximately the left half of the extension portion 31 via the base plate 6, and the second pressure plate 5 presses against a part of the second base portion 35 of the water-stopping member 3 and approximately the right half of the extension portion 31 via the base plate 6. In addition, a gap 12 is provided between the first pressure plate 4 and the second pressure plate 5 near the center of the extension portion 31 of the water-stopping member 3, separating these pressure plates 4 and 5 in the axial direction X in FIG. 1. The position of this gap 12 corresponds to the position of the induction joint 2 formed in the pipe body 1.

[0024] The third press plate 7 is provided in the circumferential direction Z in Figure 1 and is housed together with the bottom plate 8 in a first cavity 33 formed in the first base 32 of the water-stopping member 3. The bottom plate 8 is not essential to the present invention and may be omitted. The fourth press plate 9 is also provided in the circumferential direction Z in Figure 1 and is housed together with the bottom plate 10 in a second cavity 36 formed in the second base 35 of the water-stopping member 3. The bottom plate 10 is also not essential to the present invention and may be omitted.

[0025] First teeth 34 are formed on the surface of the first base 32 that faces the inner circumferential surface 11 of the tubular body 1. These first teeth 34 function to increase the pressure of the first base 32 against the inner circumferential surface 11 of the tubular body 1 when the presser plates 4, 7 press against the first base 32. Second teeth 37 are formed on the surface of the second base 35 that faces the inner circumferential surface 11 of the tubular body 1. These second teeth 37 also function to increase the pressure of the second base 35 against the inner circumferential surface 11 of the tubular body 1 when the presser plates 5, 9 press against the second base 35.

[0026] FIG. 4 shows a portion of a cross section of the pipe 1 including the first pressure plate 4 when viewed from the axial direction X in FIG. 1. The water-stopping member 3 is pressed by the first pressure plate 4 via the base plate 6, and is in close contact with the inner peripheral surface 11 of the pipe 1. Multiple first pressure plates 4 are provided in the circumferential direction Z, and are connected via a diameter-expanding member P (corresponding to the edge-cutting portion in Patent Document 1). The base plate 6 is made of a single member, and is provided so that parts of it overlap. Although not shown, the same structure as above also applies to the cross section including the second pressure plate 5.

[0027] FIG. 5 shows a portion of a cross section including the third press plate 7 when the pipe body 1 is viewed from the axial direction X in FIG. 1. The water-stopping member 3 is pressed by the third press plate 7 via the base plate 8, and is in close contact with the inner peripheral surface 11 of the pipe body 1. Multiple third press plates 7 are provided in the circumferential direction Z, and are connected via a diameter-expanding member Q (corresponding to the edge-cutting portion in Patent Document 1). The base plate 8 is not a single member like the base plate 6 in FIG. 4, but is made up of multiple members partially provided corresponding to the locations of the diameter-expanding member Q. Although not shown, the same structure as above also applies to a cross section including the fourth press plate 9.

[0028] Next, the function of the above-described water stop device 100 will be explained with reference to Fig. 6, assuming that an earthquake has occurred. Fig. 6(a) shows a normal state in which no earthquake has occurred. This state is the same as Fig. 3, and the extension part 31 covering the induction joint 2 maintains its bellows shape.

[0029] Figure 6(b) shows a state in which a crack CR has occurred in the induction joint 2 due to a large earthquake, causing the pipe 1 to be separated into left and right parts (axial direction X) at the induction joint 2. In this case, the separated pipe 1a on the left side is displaced in direction a (towards the manhole) in conjunction with the manhole rising due to liquefaction. In reality, pipe 1a would be displaced diagonally upward, but for the sake of explanation, it is displaced horizontally here. On the other hand, the separated pipe 1b on the right side is separated from the manhole by the occurrence of the crack CR and is also subjected to earth pressure from the surrounding ground, so it hardly displaces at all.

[0030] Therefore, in the right-side pipe 1b, the second base 35 of the water-stopping member 3, the second pressure plate 5, the fourth pressure plate 9, and the base plate 10 do not displace and remain in the same state as in FIG. 6(a). In contrast, in the left-side pipe 1a, as the pipe 1a displaces in the direction a, the first base 32 of the water-stopping member 3 moves in the direction a together with the pipe 1a while remaining pressed against the inner surface 11 of the pipe 1a by the first pressure plate 4 and the third pressure plate 7. Furthermore, because the first pressure plate 4 and the base plate 6 are both made of metal such as stainless steel and friction between them is low, the first pressure plate 4 slides on the base plate 6 and moves in the direction a together with the first base 32. As a result, the gap 12 between the first pressure plate 4 and the second pressure plate 5 expands.

[0031] As a result of this movement of the first base portion 32 in the direction a, the accordion-shaped extension portion 31 of the water-stopping member 3 is pulled by the first base portion 32 and stretched linearly, as shown in FIG. 6(b). The separated region S of the pipes 1a, 1b caused by the crack CR is then covered by the stretched linear extension portion 31. The floor plate 6 also moves slightly in the direction a, with its left end portion sandwiched between the first holding plate 4 and the extension portion 31. However, the right end portion of the floor plate 6 is sandwiched between the second holding plate 5 and the extension portion 31 and does not move away from the second holding plate 5 in the direction a, so most of the linear extension portion 31 remains covered by the floor plate 6.

[0032] Therefore, as shown in Figure 6(c), even if external water pressure indicated by the arrows acts on the extension part 31 of the waterstop member 3 due to groundwater seeping in from the separation area S of the pipe bodies 1a, 1b, the extended extension part 31 is covered by the base plate 6 at least in the area of ​​the gap 12, so the extension part 31 does not swell and protrude into the pipe from the gap 12. Furthermore, even after the extension part 31 is extended linearly, the first base part 32 and the second base part 35 of the waterstop member 3 remain pressed against the pipe bodies 1a, 1b, so groundwater does not seep into the pipe.

[0033] As described above, with the waterstop device 100 of the present invention, even if cracks CR occur in the joints 2 of the pipe body 1 during an earthquake and the pipe body 1 is separated into left and right halves, the extension portion 31 of the waterstop device 100 extends to cover the separated area S of the pipe body 1, thereby preventing groundwater from seeping into the pipe body 1. Furthermore, even if groundwater pressure is applied to the extension portion 31 of the waterstop member 3, the extension portion 31 does not expand and protrude into the pipe, thereby suppressing an increase in water flow resistance within the pipe body 1. Furthermore, in addition to the function of allowing the first retaining plate 4 to slide smoothly in the direction a during an earthquake, the base plate 6 also functions as a protective cover that suppresses the expansion of the extension portion 31 due to external groundwater pressure, eliminating the need for a dedicated protective cover and reducing costs.

[0034] Figure 7 shows another embodiment of a water stopping device according to the present invention. In this water stopping device 200, a first recess 38 is provided in the first base 32 instead of the first cavity 33 of Figure 3, and a second recess 39 is provided in the second base 35 instead of the second cavity 36 of Figure 3. The third press plate 7 and the floor plate 8 are housed in the first recess 38, and the fourth press plate 9 and the floor plate 10 are housed in the second recess 39. The rest of the structure is basically the same as that of the water stopping device 100 of Figure 3, and the function is also the same as that of the water stopping device 100 of Figure 3, so detailed description thereof will be omitted.

[0035] In the above embodiment, the pipe 1 has been used as an example, but the water stop device of the present invention can also be used for a pipe that has been subjected to rehabilitation treatment (rehabilitated pipe). Figure 8 shows an example of this. Figure 8 is a cross-sectional view of the upper side (ceiling side) of the pipe 1.

[0036] In FIG. 8, in order to repair the deteriorated inner peripheral surface 11 of a pipe body 1, a lining material 40 such as rigid polyvinyl chloride is provided by a known construction method to cover the entire inner peripheral surface 11. A backfill material 41 such as mortar is filled between the lining material 40 and the inner peripheral surface 11. The pipe body 1, the lining material 40, and the backfill material 41 constitute a rehabilitated pipe W. The lining material 40 and the backfill material 41 form a lining layer LN. In this lining layer LN, induction joints 42 are formed at locations corresponding to the induction joints 2 formed in the pipe body 1. Similar to the induction joints 2 of the pipe body 1, these induction joints 42 are intended to induce cracks.

[0037] The water stop device 100 is the same as the water stop device 100 shown in Figure 1 and other figures. This water stop device 100 is installed on the inner surface of the rehabilitation pipe W, with the water stop member 3 pressed against the lining material 40 by pressure plates 4, 5, 7, and 9. The water stop member 3 covers the induction joint 42 of the lining layer LN and the area around it. If a crack occurs in the induction joint 2 of the pipe body 1 during an earthquake, a crack will also occur in the induction joint 42. However, because the induction joint 42 is covered by the water stop member 3, groundwater will not seep into the pipe through the induction joints 2 and 42.

[0038] In the embodiment of Fig. 8, the water stop device 100 is installed after lining the pipe body 1, but conversely, as shown in Fig. 9, the water stop device 100 may be installed on the pipe body 1, and then lining treatment may be performed using a lining material 40 and a backfill material 41. In this case, even if a crack occurs in the guiding joint 2 during an earthquake, groundwater will not seep into the pipe through the guiding joint 2 because the guiding joint 2 is covered with the water stop member 3.

[0039] In the case of Figure 8, if a crack occurs in a part of the lining layer LN that is not covered by the water-stopping member 3 during an earthquake, there is a risk that groundwater will infiltrate into the pipe from the induction joint 2 at that part, so it is necessary to provide an induction joint 42 in the lining layer LN at that part that is covered by the water-stopping member 3. In contrast, in the case of Figure 9, no matter where a crack occurs in the lining layer LN, the water-stopping member 3 will prevent groundwater from infiltrating through the induction joint 2, so there is no need to provide an induction joint 42 as shown in Figure 8 in the lining layer LN.

[0040] The present invention can employ various embodiments other than those described above. For example, in the above embodiment, the pipe body 1 is a sewer pipe, but the pipe body 1 may be a water pipe, a drainage pipe, a water conveyance tunnel, etc. Furthermore, the pipe body 1 may be an existing pipe or a new pipe.

[0041] In the above embodiment, an example was given in which the waterproof device of the present invention was provided at the guide joint of the pipe body, but the waterproof device of the present invention can also be provided at the joint portion of the pipe body.

[0042] In the above embodiment, an example was given in which the extension portion 31 of the water-stopping member 3 is formed in a bellows shape, but the extension portion 31 is not limited to a bellows shape as long as it has a shape that extends in the axial direction X of the tubular body 1. For example, it may have a linear shape that can be deformed into a flat shape or a folded shape.

[0043] In the above embodiment, a gap 12 is provided between the first pressure plate 4 and the second pressure plate 5, but the gap 12 may not be provided and the first pressure plate 4 and the second pressure plate 5 may be structured so that they abut at their respective ends.

[0044] In the above embodiment, an example was given in which the floor plate 6 was made of a metal material, but the floor plate 6 may also be made of a flexible hard resin material.

[0045] In the above embodiment, no cloth is embedded in the water-stopping member 3, but the strength of the water-stopping member 3 may be improved by embedding cloth with fibers woven lengthwise and widthwise in the water-stopping member 3.

[0046] In the above embodiment, the first pressure plate 4 and the second pressure plate 5 are exposed in the flow path 20 as shown in Fig. 1, but as a measure against rust, the pressure plates 4 and 5 may be covered with heat-shrinkable tubing. In this case, grease may be interposed between the pressure plates 4 and 5 and the heat-shrinkable tubing. [Industrial Applicability]

[0047] The water stop device of the present invention can be used as a means to prevent groundwater from entering pipes laid underground, such as sewer pipes, water pipes, and drainage pipes, in the event of an earthquake or land subsidence. [Explanation of symbols]

[0048] 1. Body 2 Guide joint 3. Water-stopping materials 4 First holding plate 5 Second pressure plate 6 Bottom plate 7 Third holding plate 9 Fourth holding plate 11 Inner surface 12 Gap 31 Extension part 32 1st base 33 First cavity 34 1st tooth part 35 Second base 36 Second cavity 37 2nd tooth 38 First recess 39 Second recess 40 Lining material 41 Backfill material 42 Guide joint 100, 200 Water stop device S Divided Area X-axis direction Y radial direction Z circumferential direction

Claims

1. A water stop device that is installed at a predetermined location within a pipe laid underground so as to cover the entire inner circumferential surface of the pipe, a waterproofing member made of an elastic body; a pressing plate that presses the water-stopping member toward the inner circumferential surface of the pipe; a base plate interposed between the water-stopping member and the pressing plate, The water-stopping member is a first base portion provided on one side of the pipe body in the axial direction; a second base portion provided on the other axial side of the pipe body; an extension portion provided between the first base portion and the second base portion and capable of elastically deforming and extending in the axial direction of the tubular body, The pressing plate is a first pressing plate provided across the first base portion and a portion of the extension portion closer to the first base portion; a second pressing plate provided across the second base portion and a portion of the extension portion closer to the second base portion, A watertight device for a pipe body, characterized in that the base plate is interposed between the watertight member and the first and second pressure plates so as to cover the extension portion.

2. the extension portion extends to cover the divided region when the pipe body is divided in the axial direction at a predetermined location, 2. The watertight device for a pipe body according to claim 1, wherein the base plate covers the extended extension portion to prevent the extension portion from expanding due to external water pressure.

3. 2. A water-stopping device for a pipe body as described in claim 1, characterized in that a gap is provided between the first pressure plate and the second pressure plate near the center of the extension portion, separating these pressure plates in the axial direction.

4. the first base portion has a first tooth portion on a surface facing an inner circumferential surface of the pipe body, The watertight device for a pipe according to claim 1, wherein the second base portion has second teeth on a surface facing the inner peripheral surface of the pipe.

5. a third pressing plate that presses the first base portion toward the inner circumferential surface of the pipe; The watertight device for a pipe according to claim 1, further comprising a fourth pressing plate that presses the second base portion toward the inner peripheral surface of the pipe.

6. the first base portion has a first hollow portion in which the third pressing plate is housed, The watertight device for a pipe body according to claim 5, wherein the second base portion has a second hollow portion in which the fourth pressing plate is housed.

7. the first base portion has a first recess portion in which the third pressing plate is housed, The watertight device for a pipe body according to claim 5, wherein the second base portion has a second recess portion in which the fourth pressing plate is housed.

8. the first base portion and the second base portion are disposed on both sides of an induction joint formed in the pipe body to induce crack generation; The extension portion is arranged so that its center portion faces the guide joint, 8. The waterproofing device for a pipe body according to claim 1, wherein the guide joint and its vicinity are covered with the extension portion.

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