JP2001040987A - Propulsion pipe joint structure and method for joining the same by welding - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a propulsion pipe joint structure which can enhance the efficiency of entire propulsion construction work, which can cope with axial displacement and bending displacement caused by tension and compression at junctions during propulsion, and which is excellent in corrosion resistance and to provide a method for joining the structure by welding. SOLUTION: A leading propulsion steel pipe 1a comprises a main pipe 2a, a sheath pipe 3a and a mortar layer 4 packed therebetween. A following propulsion steel pipe 1b comprises a main pipe 2b, a sheath pipe 3b and a mortar layer 4 packed therebetween. The main pipe 2a of the leading propulsion steel pipe 1a is butted against the main pipe 2b of the following propulsion steel pipe 1b before propulsion work, and partial welding is performed from their outer surfaces. Subsequently, propulsion work is performed and similar partial welding and propulsion work for the main pipes are repeated to perform main welding from the inner surfaces at a time within a period of time that does not affect the propulsion work, so as to join the pipes together.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a joint structure for propulsion in which main pipes are welded to each other, and to a method of welding and joining the same.

[0002]

2. Description of the Related Art Heretofore, the following are known as welding and joining methods for a propulsion pipe joint.

(A) A fume pipe or a steel pipe having a diameter larger than the main pipe is used for the sheath pipe, and after the pushing of the sheath pipe is completed, the main pipe is inserted or pulled in to continuously weld the main pipe. It is a construction method. In this method, mortar or the like is filled between the main pipe and the sheath pipe.

(B) A double steel pipe using a steel pipe having a diameter larger than that of the main pipe as a sheath pipe. Both ends of the main pipe are exposed from the sheath pipe in advance, and a material such as mortar is placed between the main pipe and the sheath pipe. In this method, the main pipes exposed from the sheath pipes are welded and joined together in a shaft, and the exposed portions including the welded portions are subjected to anticorrosion coating and the like, and then propelled. In this method, welding and propulsion are alternately repeated.

(C) According to the technique disclosed in Japanese Utility Model Publication No. 63-47344, the leading end of the main pipe is exposed in advance and the rear end is retracted into the sheath pipe with a double steel pipe of the main pipe and the sheath pipe. At the rear end of the main pipe, a backing ring is provided so as to extend beyond the pipe end, and furthermore, a rubber ring cover for waterproofing is provided at the outer periphery of the backing ring so as to extend beyond the rear end thereof. During this period, a material filled with a material such as mortar between the sheath tube and the rubber ring cover for waterproofing is manufactured.

[0006] In the propulsion operation, after the propulsion of the preceding double steel pipe is completed, the exposed end of the main pipe of the following double steel pipe is inserted into a backing ring provided on the main pipe of the preceding double steel pipe. Then, the rear end of the preceding main pipe and the front end of the following main pipe are brought into abutment.
At this time, a quick-hardening filler is press-fitted into the gap between the preceding double steel pipe and the following double steel pipe and fixed. As described above, the propulsion work is performed again after connecting the preceding and succeeding double steel pipes without welding them, and the propulsion work is similarly repeated to finish the propulsion work.

Thereafter, the joint portion of the main pipe of the double steel pipe is collectively welded from the inner surface of the pipe.

[0008]

However, in the above-mentioned prior art, there is a problem in applicability of a pipe joint for propulsion as a welding joining method in terms of workability and reliability.

The method (a) is a two-step method in which the main pipe is pulled in and joined after completion of the propulsion of the sheath pipe, and it is necessary to include a step of injecting a filler between the main pipe and the sheath pipe on site. Yes, the construction period is very long, and the construction cost increases.

In the method (b), the pipe is formed simultaneously with propulsion because the pipe is a double pipe in which the main pipe and the sheath pipe are integrated, and the connection of the main pipe is a butt welding, which results in extremely high reliability. However, since all of the main welding of the main pipe and the corrosion protection of the joints are performed in the vertical hole, the propulsion work is intermittent and the time required for the propulsion work becomes long, which greatly hinders the improvement of the construction efficiency of the entire propulsion work. ing.

In the method (c), continuous propulsion is possible, but the reliability of the sealing performance of the rubber ring is reduced due to the concentration of deformation at the joint during propulsion. Since the propulsion is performed in an unreliable state, there is a risk that the direction controllability of the propulsion may be reduced due to insufficient bending rigidity.

The present invention has been made to solve the above problems, and can improve the efficiency of the entire propulsion work.
An object of the present invention is to provide a pipe joint structure for propulsion that can cope with axial displacement and bending displacement of tension and compression at a joint portion during propulsion and has excellent anticorrosion properties, and a welding joint method thereof.

[0013]

The invention of claim 1 is a propulsion pipe joint structure in which main pipes are welded to each other, wherein the connection portion is a main welded portion from an inner surface side and a main welded portion from an outer surface side. A propulsion pipe joint structure comprising a sub-weld portion.

According to the present invention, the joining portion is divided into two parts, a main welding portion from the inner surface side and a sub-welding portion from the outer surface side. Then, since it is only necessary to maintain a strength enough to withstand the propulsion work, unlike the main welding portion, welding is easy and the time can be reduced. On the other hand, the main welded portion from the inner side can be intensively welded at a time that does not affect the propulsion work. Therefore, when the joint structure for a propulsion pipe according to the present invention is adopted as a joint structure for a propulsion pipe by a propulsion method, high reliability can be ensured and construction efficiency can be improved.

According to a second aspect of the present invention, the joint between the main pipes exposed from the outer pipe comprises a main welded portion from the inner surface side and a sub-welded portion from the outer surface side, and is provided on the outer surface of the exposed portion including the welded portion. A propulsion pipe joint structure comprising an anticorrosion layer formed thereon and an outer pipe spacer disposed thereon.

According to the present invention, when the propulsion pipe is a double pipe consisting of a main pipe and an outer pipe, the joint between the main pipes is formed by a main welding portion from the inner surface side and a sub-welding portion from the outer surface side. Since the structure is divided into two, even in the case of a double pipe, high reliability can be ensured and construction efficiency can be improved as in the case of the first aspect of the invention. Further, since the anticorrosion layer is formed on the outer surface of the exposed portion including the welded portion, it is hardly corroded. Further, since the outer tube spacer is disposed thereon, the anticorrosion layer is protected.

According to a third aspect of the present invention, in the second aspect of the invention, a heat insulating layer and an anticorrosive layer covering the heat insulating layer are formed on the outer surface of the exposed portion including the welded portion, and the outer tube spacer is disposed thereon. Propulsion pipe joint structure.

According to the present invention, since the heat insulating layer is formed on the outer surface of the exposed portion including the welded portion and the anticorrosion layer covering the heat insulating layer is formed, when welding is performed from the inner surface to form the main welded portion. Further, it is possible to prevent the corrosion protection layer from being decomposed by the generated high welding heat. Further, by appropriately adjusting the degree of heat insulation, the anticorrosion layer can be sufficiently softened or adhered by melting, and the anticorrosion performance can be further improved.

The invention of claim 4 is the invention of claim 2 or claim 3.
The propulsion pipe joint structure according to the invention, wherein the outer pipe spacer is a box type spacer.

According to the present invention, the rigidity and strength of the pipeline with respect to the propulsion load of the joint and the earth pressure of the surrounding ground after the propulsion can be ensured without using a filler such as mortar. Therefore, when the propulsion pipe joint structure according to the present invention is employed as a connection structure for propulsion pipes by the propulsion method, high reliability is ensured and construction efficiency can be further improved.

The invention of claim 5 is the invention of claim 2 or claim 3.
In the invention, the outer pipe spacer is a mortar block type outer pipe spacer.

According to the present invention, the outer pipe spacer, which is formed by blocking the mortar on the inner surface of the outer pipe spacer main body and made into a block in advance, is disposed on the outer surface of the anticorrosion layer on the spot, and the seam is formed. Can be fixed only by welding. As a result, normal welding of the outer tube and the outer tube spacer can be omitted, and the welding time in the shaft can be further reduced.

According to a sixth aspect of the present invention, there is provided a method for welding a joint of a propulsion pipe joint, wherein a main pipe of a preceding propulsion pipe and a main pipe of a subsequent propulsion pipe before propulsion are butt-joined in a shaft, Propulsion work is performed by performing partial welding, and similarly, the main pipe of the subsequent propulsion pipe is butt-sequentially repeated, and the propulsion work is repeatedly performed by performing partial welding from the outer surface side, and does not affect the propulsion work. This is a method for welding and joining a propulsion pipe joint, wherein main welding is performed from the inner side at a time.

According to the present invention, the main pipe of the preceding propulsion pipe and the main pipe of the subsequent propulsion pipe before the propulsion are abutted in the shaft, and partial welding is performed from the outer surface to speed up the propulsion process. Plan,
Since the main welding is performed from the inner side during the time that does not affect the propulsion work, the ratio of welding in the propulsion work process can be significantly reduced, and the work efficiency can be improved.

According to a seventh aspect of the present invention, there is provided a method for welding a joint of a propulsion pipe joint comprising a main pipe and an outer pipe, wherein the main pipe is exposed from the outer pipe of the preceding propulsion pipe in the shaft. The main pipe exposed from the outer pipe of the subsequent propulsion pipe before propulsion is butt-butted and partially welded from the outer surface side, and a heat insulating layer and an anticorrosion layer covering it are formed on the outer surface of the exposed portion including the welded portion, After arranging the outer tube spacer on it and then performing the propulsion work, similarly repeating the propulsion work by sequentially butting the main pipes of the subsequent propulsion pipes and performing partial welding from the outer surface side ,
This is a welding and joining method for a pipe joint for propulsion, wherein main welding is performed from the inner side at a time that does not affect the propulsion work.

According to the present invention, in the shaft, the main pipe exposed from the outer pipe of the preceding propulsion pipe and the main pipe exposed from the outer pipe of the subsequent propulsion pipe before propulsion are joined to each other from the outer surface side. Partial welding is performed to speed up the propulsion process, and the main welding is performed from the inner side at a time that does not affect the propulsion work, so the proportion of welding in the propulsion work process can be significantly reduced, and construction efficiency is improved. In addition, by using welding heat adjusted by the heat insulating layer, the anticorrosion layer on the outer surface of the exposed portion can be melted or softened by the welding heat from the inner surface side and adhered.

[0027]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 1 is a partially cutaway side view showing an example of an embodiment according to the present invention, and FIG. 2 is an enlarged view of a main part indicated by symbol A in FIG.

The joint structure for propulsion is roughly classified into a multi-pipe structure method and a single-pipe structure method. In general, a multi-pipe structure method, particularly a double-pipe structure method, is often used. The pipe joint structure for propulsion using pipes will be described in detail.

The propulsion steel pipe 1a comprises a main pipe 2a and an outer pipe 3
a and a mortar layer 4 filled between them, and the subsequent propulsion steel pipe 1b is composed of a main pipe 2b, an outer pipe 3b, and a mortar layer 4 filled between them.

Steel pipe 1a for propulsion and steel pipe 1b for subsequent propulsion
Are joined by butt welding of X grooves provided at the pipe ends of the main pipe 2a and the main pipe 2b, and the joined portions are formed into the sub-weld portion 5 from the outer surface side and the main weld portion 6 from the inner surface side. It is configured.

In this example, a steel pipe is used as the main pipe, but other metal pipes, composite material pipes, and composite structure pipes that can be subjected to butt welding can also be used.

The main pipes 2a and 2b are made of polyethylene on the inner and outer surfaces.
It has anticorrosion layers 7 and 8 coated with a material having an anticorrosion function such as polyurethane, coal tar enamel, and glass fiber reinforced plastic (FRP). The outer diameter of the outer tubes 3a, 3b constituting the double tube is determined by the outer diameter of the main tubes 2a, 2b, the thickness of the mortar layer 4, and the thickness of the outer tube. Also,
The thickness of the outer tube is set to be equal to or less than the thickness of the main tubes 2a and 2b, and the thickness of the mortar layer 4 is set to 2 to 30 times the thickness of the main tubes 2a and 2b. These dimensions are specifically the propulsion length, propulsion load,
Further, the strength is set in consideration of the strength and rigidity required for the pipe such as the burial depth and the laying environment.

As the outer pipes 3a and 3b, steel pipes provided with projections 9 in the circumferential direction are used in order to increase the integration strength of the mortar layer 4 and the outer pipes 3a and 3b. Exterior tube 3
The lengths of a and 3b and the mortar layer 4 are set shorter than those of the main pipes 2a and 2b. The position is the same as or slightly centered on the anticorrosion layer.

The propulsion pipe joint structure is as shown in FIG.
The main pipes 2a and 2b are penetrated through the outer pipes 3a and 3b to expose the pipe ends 10a and 10b, and the X grooves provided at the pipe ends 10a and 10b are butt-welded. This joint comprises a sub-weld portion 5 from the outer side and a main weld portion 6 from the inner side.
It is composed of

At the pipe ends 10a and 10b, a predetermined size of the anticorrosion layer is peeled off from the pipe end so that the anticorrosion layers 7 and 8 made of polyethylene or the like on the inner and outer surfaces of the main pipe are not affected by heat during welding. The size is usually about 100 to 300 mm.

On the exposed portion including the welded portion, a heat insulating layer 11 and an anticorrosive layer 12 covering the heat insulating layer 11 are formed on the outer surface, and an outer pipe spacer 13 is provided thereon, and the anticorrosive layer 12 and the outer pipe spacer 1 are provided.
The mortar layer 4 is formed by filling the mortar into the gaps between the mortar layers 3.

In general, the heat insulating layer 11 is made of an inorganic material such as glass wool having excellent heat resistance. Heat insulation layer 1
Regarding 1, when the area of the outer surface of the exposed portion is small and the time of exposure to high temperature by the welding heat of the inner surface welding is short,
By using a heat-resistant anticorrosive material, the heat insulating layer 11 can be omitted.

The anticorrosion layer 12 is made of a thermoplastic resin such as polyethylene, or a material having excellent anticorrosion properties such as coal tar enamel, which is softened or melted by heat and adheres. Further, for the anticorrosion layer 12, a shrink tube or a shrink tape can be used.

The outer tube spacer 13 is of a circumferentially divided type and is joined and fixed to the tube ends of the outer tubes 3a and 3b.

The mortar layer 4 is formed by providing an injection hole nozzle 14 and an air vent nozzle 15 in the outer tube spacer 13 and injecting the air from the injection hole nozzle 14 into the gap. The injection hole nozzle 14 and the air vent nozzle 15 are integrated by screwing a plug or welding. Therefore, the mortar injected into the gap can be integrated with the mortar in the outer tubes 3a and 3b before and after the outer tube spacer 13. It should be noted that a rapidly curing mortar is generally used as the mortar.

As the outer tube spacer, in addition to a mortar filling type on site, a box type spacer described later or a block type spacer in which mortar is fixed to the inner surface of the main body can be used.

According to the above-described propulsion pipe joint structure, as described later, the joining by welding is such that the sub-welding portion 5 from the outer surface side is formed first, and then the main welding portion 6 from the inner surface side is formed. It is composed.

Therefore, according to the embodiment shown in FIGS. 1 and 2, the main pipe 2a of the preceding propulsion pipe 1a and the main 2b pipe of the subsequent propulsion pipe 1b before propulsion are abutted in the shaft, and the outer surface is formed. The propulsion operation is performed by performing partial welding from the side, and the main welding is performed and joined from the inner surface side at a time that does not affect the propulsion operation, whereby the propulsion pipe joint structure according to the present invention can be obtained.

The time that does not affect the propulsion work is generally the time when the propulsion work is completed. However, when the propulsion process is long, a stop time may be provided in the middle of the propulsion work. Including.

Therefore, when the above-described propulsion pipe joint structure is employed for laying a pipeline by the propulsion method, the propulsion process can be sped up. In addition, the ratio of welding in propulsion work is greatly reduced, and work efficiency can be improved.

Further, since the heat insulating layer 11 and the anticorrosion layer 12 are formed on the outer surface of the exposed portion including the welded portion, the heat insulating layer 11 prevents deterioration of the anticorrosion layer 12 and the mortar 5 due to welding heat during construction. Therefore, the function of the anticorrosion layer 12 and the mortar layer 4 can be sufficiently exhibited.

Next, the welding method of the propulsion pipe joint will be described in detail. FIG. 3 is a side view showing a state in which a secondary welding is performed in the starting-side vertical hole by the welding joining method of the present invention.
FIG. 5 is an enlarged view of a main part indicated by a symbol B in FIG. 3, and FIG. 5 is a side view showing a state where main welding is performed in a reaching-side vertical hole by the welding joining method of the present invention. 1 and 2 have the same reference numerals.

A starting shaft 17 and a reaching shaft 18 are provided on the ground 16. The construction of the construction by the propulsion method
This is a method of press-fitting a sewer buried from the starting pit 17 to the reaching pit 18, and the propelling pipe buried is pushed in by jack pressure. In the propulsion line, a plurality of propulsion tubes connected to a leading conduit 19 having a cutting edge are propelled,
The rear end of the trailing propulsion tube 1a protrudes from the starting shaft 16.

The subsequent propulsion tube 1b adjacent to the preceding propulsion tube 1a is inserted into the starting shaft 21. As shown in FIG. 4, before propulsion, the main propulsion pipe 1 b is
The X-grooves provided at the pipe ends 10a and 10b of the main pipe 2a of the preceding propulsion pipe 1a are butted and welded from the outer surface side to form the sub-welded portion 5. A heat insulating layer 11 and an anticorrosive layer 12 covering the heat insulating layer 11 are formed on the outer surface of the exposed portion including the welded portion. An outer tube spacer 13 is provided thereon. Mortar is injected from the injection hole nozzle 14 into the gap between the anticorrosion layer 12 and the outer tube spacer 13 to form the mortar layer 4.

Thereafter, the preceding propulsion steel pipe 1a and the subsequent propulsion pipe 1b are propelled together with the preceding propulsion steel pipe, and are propelled from the starting shaft 16 to the reaching shaft 18. Similarly, the propulsion work is repeatedly performed by sequentially butting the main pipes of the subsequent propulsion steel pipes and performing partial welding from the outer surface side. Then, as shown in FIG.
Reaches the arrival-side standing hole 18, and the propulsion pipe is laid in the propulsion conduit. The head tube 19 is removed at the arrival side standing hole 18.

After a series of propulsion work is completed, a series of propulsion steel pipes including the preceding propulsion steel pipe 1a and the subsequent propulsion steel pipe 1b are intensively welded from the inner side. Thereafter, a non-destructive test and an internal corrosion protection treatment are performed, and the construction by the propulsion method is completed.

According to the propulsion method shown in FIGS. 3, 4, and 5, the anticorrosion layer 12 provided on the outer surface of the exposed portion including the welding portion is interposed through the heat insulating layer 11 during the main welding from the inner surface side. Thereby, the welding heat from the main pipes 2a and 2b is reduced, and is softened or melted and adhered by appropriate heat insulation adjustment.

The reason for using the heat insulating layer 11 is as follows. Generally, the maximum temperature of the outer surface by inner surface welding is 500-70.
0 ° C, and as it is, the allowable temperature is 100-200 ° C.
The organic anticorrosive layer is thermally decomposed and carbon or the like diffuses and penetrates into the outer surface side weld metal, thereby deteriorating welding quality. Therefore, the heat insulating layer 11 reduces the welding heat, and empirically selects a material, a layer thickness, and the like so that the welding heat can be used. And make it adhere well. Also, the allowable temperature is 80 to 90 ° C (approximate 100
(° C. or less) is also prevented.

In addition, since the diameter of the main pipe of each propulsion steel pipe is generally a large diameter of 800 mm or more,
The main welding from the inner side can be easily performed.
Even when the diameter is less than 800 mm, the inner surface can be welded by an automatic welding machine or the like. After the completion of the inner surface welding, the inner surface is coated with a thermoplastic resin such as polyethylene or coal tar enamel.

As described above, according to the present invention, the pipe ends of the main pipe are butt-butted, and a minimum partial welding necessary for securing strength during propulsion is performed from the outer surface side to speed up the propulsion process. Plan,
Since the main welding is performed from the inside during the time that does not affect the propulsion work, the ratio of welding in the propulsion work process can be significantly reduced, and the work efficiency is improved.

Also, by utilizing the welding heat at the time of the main welding from the inner surface, the heat insulating layer is used to prevent the deterioration of the anticorrosion layer and the mortar layer, and to appropriately adjust the heat insulation to soften or melt the anticorrosion layer. It can be sufficiently adhered.

Further, since a minimum welding required for the propulsion work is performed by abutting the main pipes to secure the rigidity and strength required for the propulsion, the reliability is high.

Further, since the main welding is performed from the inner surface side after propulsion to form an integral structure, the displacement of the surrounding ground after the laying is absorbed on average, so that a large displacement of the entire pipeline is obtained. Absorption is possible, and high earthquake resistance can be secured even in soft ground.

Next, the form of the outer tube spacer used in the present invention will be described with reference to FIGS. FIG. 6 is a perspective view showing an assembled state of the mortar injection type outer tube spacer used in the present invention. 1 and 2 are denoted by the same reference numerals, and a part of the description is omitted.

The main pipes 2a and 2b penetrate the outer pipes 3a and 3b, and the pipe ends 10a and 10b are exposed. After the X-grooves provided at the pipe ends 10a and 10b are butt-welded to form a sub-weld portion, the exposed portion including the welded portion forms a heat insulating layer 11 and an anticorrosion layer 12 covering the outer surface, The divided mortar injection type outer tube spacer 20 is arranged on the outer surface of the anticorrosion layer 12. If necessary, three or more divisions can be used.

The mortar injection type outer tube spacer 20 is fixed by girth welding or the like. Anticorrosion layer 12 and outer tube spacer 1
The mortar is injected from the injection hole nozzle 14 into the gap between the mortars 3 to form the mortar layer 4. Further, an air vent nozzle 15 for filling the mortar is provided.

FIG. 7 is a perspective view showing an assembled state of the box type outer tube spacer used in the present invention. 1 and 2 are denoted by the same reference numerals, and a part of the description is omitted.

The main pipes 2a, 2b penetrate the outer pipes 3a, 3b, and the pipe ends 10a, 10b are exposed. After the X-grooves provided at the pipe ends 10a and 10b are butt-welded to form a sub-weld portion, the exposed portion including the welded portion forms a heat insulating layer 11 and an anticorrosion layer 12 covering the outer surface, The divided box-shaped outer tube spacer 21 is arranged on the outer surface of the anticorrosion layer 12. If necessary, three or more divisions can be used. Pressure receiving plates 21a, 21b are provided inside the outer pipe ends 3a, 3b of the preceding propulsion steel pipe 1a and the subsequent propulsion steel pipe 1b.
Is provided. The mounting of the box type outer tube spacer 20 is easy by the pressure receiving plates 21a and 21b.

The ends of the pressure receiving plates 21a, 21b and the main pipe 2a,
A gap is formed between the main pipes 2a and 2b so as not to affect the electrical protection of the main pipes 2a and 2b. According to the present embodiment, the mortar layer on the inner surface can be omitted by securing the rigidity and strength by the box-type outer tube spacer 21.

FIG. 8 is a perspective view showing an assembled state of the mortar block type outer tube spacer used in the present invention. 1 and 2 are denoted by the same reference numerals, and a part of the description is omitted.

The main pipes 2a, 2b penetrate the outer pipes 3a, 3b, and the pipe ends 10a, 10b are exposed. After the X-grooves provided at the pipe ends 10a and 10b are butt-welded to form a sub-weld portion, the exposed portion including the welded portion forms a heat insulating layer 11 and an anticorrosion layer 12 covering the outer surface, and a mortar. The block spacer outer tube 23 is arranged on the outer surface of the anticorrosion layer 12.

The mortar block type outer tube spacer 23 is fixed by seam welding. The mortar block type outer tube spacer 23 is a mortar block 24 in which mortar is fixedly integrated with the inner surface of the outer tube spacer main body 23a.
Then, it is manufactured in a factory or the like in advance.

By preparing the mortar block type outer tube spacer 23 in advance, it is possible to use the
2 and can be fixed only by seam welding, so that ordinary welding of the outer tube and the outer tube spacer can be omitted, and the welding time in the shaft can be further reduced.

[0070]

As described above, according to the present invention, in the welding and joining method, the joints of the main pipes are constituted by a sub-weld portion from the outer surface side and a main weld portion from the inner surface side, and each weld portion is separately formed. In this way, the efficiency of the entire propulsion work can be improved, and it is possible to cope with the axial displacement and the bending displacement of the tension and compression at the joint during propulsion. Further, the function of the anticorrosion layer of the steel pipe joint for propulsion after laying in the pipeline can be sufficiently exhibited.

[Brief description of the drawings]

FIG. 1 is a partially cutaway side view showing an embodiment of the present invention.

FIG. 2 is an enlarged view of a main part indicated by symbol A in FIG.

FIG. 3 is a side view showing a state of sub-welding in a starting-side vertical hole by the welding joining method of the present invention.

FIG. 4 is an enlarged view of a main part indicated by a symbol B in FIG.

FIG. 5 is a side view showing a state in which main welding is performed in a reaching-side vertical hole by the welding joining method of the present invention.

FIG. 6 is a perspective view showing an assembled state of a mortar injection type outer tube spacer used in the present invention.

FIG. 7 is a perspective view showing an assembled state of a box type outer tube spacer used in the present invention.

FIG. 8 is a perspective view showing an assembled state of a mortar block type outer tube spacer used in the present invention.

[Explanation of symbols]

 1a Pre-propulsion steel pipe 1b Subsequent propulsion steel pipe 2a, 2b Main pipe 3a, 3b Outer pipe 4 Mortar layer 5 Secondary welded part 6 Main welded part 7, 8, 12 Corrosion prevention layer 9 Projection 10a, 10b Pipe end 11 Heat insulation layer 13 Outer tube spacer 14 Injection hole nozzle 15 Air release nozzle 16 Ground 17 Starting shaft 18 Reaching shaft 19 Front conduit 20 Mortar injection type outer tube spacer 21 Box type outer tube spacer 22a, 22b Pressure receiving plate 23 Mortar block type outer tube spacer 24 Mortar block

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) // B23K 101: 10 (72) Inventor Akihiko Kato 1-2-1, Marunouchi, Chiyoda-ku, Tokyo (72) Inventor Nobuhisa Suzuki 1-2-2 Marunouchi, Chiyoda-ku, Tokyo F-term (reference) 2D054 AC01 AD33 EA07 3H024 EA02 EC04 EC07 EC08 ED04 EE02 EF09 EF10 EF14 EF19 4E081 AA08 BA02 BA27 DA11 FA01 YB08 YX02

Claims (7)

[Claims] 1. A propulsion pipe joint structure in which main pipes are welded and joined to each other, wherein the joining portion is composed of a main welding portion from an inner surface side and a sub-welding portion from an outer surface side. Pipe joint structure for propulsion. 2. A propulsion pipe joint structure comprising a main pipe and an outer pipe, wherein a joint between the main pipes exposed from the outer pipe has a main welded portion from the inner surface side and a main welded portion from the outer surface side. A propulsion pipe joint structure comprising a secondary welded part, an anticorrosion layer formed on an outer surface of an exposed part including the welded part, and an outer pipe spacer disposed thereon. 3. The propulsion pipe joint structure according to claim 2, wherein a heat insulating layer and an anticorrosion layer covering the heat insulating layer are formed on an outer surface of the exposed portion including the welded portion, and an outer tube spacer is disposed thereon. 4. The propulsion pipe joint structure according to claim 2, wherein the outer pipe spacer is a box type outer pipe spacer. 5. The joint structure for propulsion according to claim 2, wherein the outer tube spacer is a mortar block type outer tube spacer. 6. A method of welding and joining a propulsion pipe joint,
In the shaft, the main pipe of the preceding propulsion pipe and the main pipe of the subsequent propulsion pipe before propulsion are abutted, and partial welding is performed from the outer surface to perform the propulsion work. Welding and joining method for pipe joints for propulsion, characterized in that after main pipes are butt-jointed, partial welding is performed from the outer surface and propulsion work is repeated, then main welding is performed from the inner surface at a time that does not affect the propulsion work . 7. A method for welding a joint for a propulsion pipe, wherein the propulsion pipe comprises a main pipe and an outer pipe, wherein a main pipe exposed from an outer pipe of a preceding propulsion pipe and a subsequent pipe before propulsion are set in a shaft. The main pipe exposed from the outer pipe of the propulsion pipe is butt-butted, and partial welding is performed from the outer surface side.A heat insulating layer and an anticorrosion layer covering it are formed on the outer surface of the exposed portion including the welded portion, and the outer pipe is formed thereon. After placing the spacers and then performing the propulsion work, the propulsion work was repeated after repeating the propulsion work by repeating the propulsion work by sequentially butting the main pipes of the subsequent propulsion pipes and performing partial welding from the outer surface side Welding and joining method for propulsion pipe joints, characterized in that main welding is performed from the inner surface during non-working hours.