JP2006200692A - Protecting member for non-open cut propelling technique - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a protecting member to be propelled in a ground while preventing the separation of a coating resin. <P>SOLUTION: The protecting member 3 is provided for protecting a connection portion of a connection steel pipe 1 consisting of a plurality of resin coated steel pipe 2 (2a, 2b) axially connected to one another and each having a primary pipe 21 (21a, 21b), an anticorrosive layer (22a, 22b) covering the outer peripheral face thereof and a protecting layer 23 (23a, 23b) applied to the outer peripheral face thereof. It comprises an anticorrosive member 31 to be applied to the anticorrosive layers 22 on both sides of a joint portion formed with the primary pipe 22 whose end faces abut on each other, and a resin sleeve 32 which is longer than the anticorrosive member 31 and either end of which has a diameter smaller than that of the protecting layer 23 and is welded to the anticorrosive layer 22. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention is applied to a non-cutting propulsion method in which a resin-coated steel pipe is propelled in the ground without digging a road, and is used for protection of a corrosion-resistant member that protects a connection portion in this construction method. The present invention relates to a protective member.

  In various pipes such as gas pipes and water pipes, in order to prevent corrosion of pipes buried in the ground, resin-coated steel pipes with the surface of the original pipe (steel pipe) covered with an anticorrosion layer made of polyethylene or the like are used. In particular, when the resin-coated steel pipe has a large diameter, a resin-coated steel pipe in which the surface of the anticorrosion layer is covered with a protective layer made of crosslinked polyethylene or the like is used from the viewpoint of ease of handling. When embedding (laying) resin-coated steel pipes in the ground, in order to reduce construction costs and shorten the construction period, the buried pipes, such as resin-coated steel pipes, are expanded while expanding the underground without cutting the road. A non-open-cut propulsion method that pulls the connected steel pipes connected to each other has been developed and is being considered for practical use. This connecting steel pipe is manufactured by butt welding the end faces and attaching a corrosion-proof member to the outer periphery of the welded portion.

  However, when a resin-coated steel pipe is pulled and propelled into the ground, an anticorrosion member that protects the connecting portion by earth pressure is turned over, and a countermeasure has been proposed. For example, in Patent Document 1, a stepped step is formed in advance at the end of a steel pipe that has been factory coated except for a joint on the outer periphery of the pipe, and after welding at the site, the stepped portion is coated. It is described that construction is performed on site so that the height of the main pipe joint coating does not protrude from the factory coating by forming (for example, covering with an adhesive heat-shrinkable tube).

  Patent Document 2 discloses a plurality of close contact / adhesive heat shrinks in which a step-like anticorrosion coating portion is formed in advance on the front and rear end portions of a steel pipe anticorrosion coating, the joint portion is welded, and the inner surface of the end portion is an adhesive adhesive. Anti-corrosion of the steel pipe anti-corrosion coating so that the end of the tube overlaps the first or more anti-corrosion coating staircase, excluding the uppermost anti-corrosion coating step of the anti-corrosion coating on both sides of the welded joint. It is described that the film is coated by heat shrinkage so as not to protrude from the film.

  Patent Document 3 discloses a heat-shrinkable heat-shrinkable tube provided with a heat-shrinkable heat-shrinkable tube and a heat-shrinkable tube heat-shrinkable and heat-shrinkable tube heat-shrinkable with a heat-shrinkable tube that is fused to a plastic coating layer of a steel pipe. A protective tube is described.

JP-A-9-96378 (pages 3 to 4, FIG. 1) Japanese Patent Laid-Open No. 9-178079 (pages 2 and 3, FIG. 1) JP-A-10-281354 (second page, FIG. 1)

  According to the construction method described in Patent Document 1, the heat-shrinkable tube does not protrude from the anticorrosion coating surface, but a stepped step is formed at the end of the resin coating of the steel pipe (the coating layer is exposed). ) Is transported from the factory to the site, it is predicted that the coating layer will be damaged during the process. In addition, when performing operations such as cutting of resin-coated steel pipes and beveling before welding on site, the method cannot be applied and the construction method is limited.

  In the anticorrosion coating method described in Patent Document 2, it is necessary to adhere both end surfaces of the uppermost heat-shrinkable tube to the uppermost anticorrosion coating, but the length is such that such a state can be obtained. It is practically difficult to peel off the anticorrosion film. Moreover, since the heat-shrinkable tube is only in close contact (adhesion) with the coating layer, it is predicted that the heat-shrinkable tube peels off from the anticorrosive film when the resistance of the earth and sand increases.

  Although the heat shrinkable protective tube described in Patent Document 3 is fused at both ends to the covering layer, the weld joint protrudes from the covering layer, so that the resistance of earth and sand protrudes when propelling the ground. There is a problem of being concentrated on the part and peeling off from the coating layer.

  Accordingly, an object of the present invention is to provide a protective member for non-cutting propulsion method (hereinafter referred to as a protective member) in which peeling of the coating resin is prevented when propelling in the ground.

  In order to achieve the above object, the protective member of the present invention is a connection in which a plurality of resin-coated steel pipes having an original pipe, an anticorrosion layer covering its outer peripheral surface, and a protective layer coated on the outer peripheral surface are connected in the axial direction. A member that protects the connecting portion of the steel pipe, and has a length that surrounds the outer peripheral portion of the anticorrosion member that is attached to the anticorrosion layer on both sides of the joint portion formed by abutting the end faces of the original pipe Both ends are formed of a resin sleeve having a smaller diameter than the protective layer and fused to the anticorrosion layer.

  In this invention, it is preferable that the sealing material which consists of soft resin which covers the edge part of the said anticorrosion layer is closely_contact | adhered to the internal peripheral surface of the said resin sleeve.

  In the present invention, the resin sleeve preferably contains a substance capable of absorbing laser light at least at both ends of the inner peripheral surface thereof.

  In this invention, it is preferable that the said resin sleeve is closely_contact | adhered to the outer peripheral surface of the said anticorrosion member over the full length.

  According to the present invention, the anticorrosion member in close contact with the joint portion of the steel pipe is covered with a longer resin sleeve, and both ends of the resin sleeve are formed to have a smaller diameter than the protective layer, and the anticorrosion layer of the resin-coated steel pipe Therefore, when the connecting steel pipe is propelled in the ground, the member covering the connecting portion is prevented from being peeled off even when subjected to the resistance of earth and sand.

  Details of the present invention will be described below with reference to the accompanying drawings. 1 is a cross-sectional view schematically showing a state in which a resin-coated steel pipe is welded, FIG. 2 is a cross-sectional view schematically showing a state in which the protective member of the present invention is fused to the anticorrosion layer, and FIG. FIG. 4 is a schematic cross-sectional view showing a state in the middle of the non-cutting method to which the protective member is applied, and FIG. 4 is a schematic cross-sectional view showing another state in the middle of the non-cutting method to which the protective member of the present invention is applied.

  The connecting steel pipe 1 to which the protective member of the present invention is applied is prepared by the following procedure. That is, as shown in FIG. 1, the anticorrosion layers 22a and 22b applied to the outer peripheral surfaces of the original tubes 21a and 21b of the pair of resin-coated steel pipes 2a and 2b, and the protective layers 23a and 23b applied to the outer peripheral surfaces. After the end portion of the protective layer 23a and 23b is peeled off by a predetermined length L1, the end portions of the protective layers 23a and 23b are peeled off by a predetermined length L2 (where L2> L1), and the end surface of the original tube 21a and the end surface of the original tube 21b Are joined together, for example, by welding to form the welded portion 24. The connecting steel pipe 1 may be one in which three or more resin-coated steel pipes are connected in the axial direction.

  After grinding and cleaning the outer peripheral surface of the welded portion 24, the protective member 3 is attached to the outer peripheral surface of the welded portion 24 and both sides thereof as shown in FIG. The protective member 3 includes seal materials 30a and 30b that cover end portions of the anticorrosion layers 22a and 22b, a substantially cylindrical anticorrosion member (heat-shrinkable tube 31) that covers the welded portion 24 and the seal materials 30a and 30b, and heat shrinkage. It is comprised from the resin sleeve 32 which covers the outer peripheral surface of the property tube 31. FIG. In the present embodiment, the heat-shrinkable tube 31 is used as the anticorrosion member, but the invention is not limited to this, and various anticorrosion members (for example, an anticorrosion tape made of vinyl chloride, etc.) may be used. it can.

  This protective member 3 is attached to the connecting steel pipe 1 as follows. First, the sealing materials 30a and 30b are wound around the ends of the anticorrosion layers 22a and 22b, for example, only one turn. Next, a substantially cylindrical heat-shrinkable tube 31 is covered so as to cover the entire outer peripheral surface of the sealing materials 30a and 30b and the welded portion 24, and the sealing material is roasted from the outer peripheral surface with, for example, a gas burner (not shown). It adheres closely to the whole outer peripheral surface of 30a, 30b, the welding part 24, and the anticorrosion layers 22a, 22b. The length of the heat-shrinkable tube 31 after adhesion is indicated by L4 (where L4> L3, L3: distance between both end faces of the sealing material). After confirming that the heat-shrinkable tube 31 is free of pinholes and cleaning the tube surface, the axial length of the anticorrosive layers 22a and 22b and the outer surface of the heat-shrinkable tube 31 is L5 (however, L2> The resin sleeve 32 is attached so that L5> L4). Further, the thickness and length of the resin sleeve 32 are set so as to have an outer diameter (D2) smaller than the outer diameter (D1) of the protective layer. This resin sleeve 32 contains a substance capable of absorbing laser light inside a cylindrical body made of a material having heat shrinkability and capable of transmitting laser light, and the substance capable of absorbing laser light is at least of the cylindrical body. Dispersed so as to exist on the inner peripheral surfaces of both ends. Therefore, when the laser light irradiated from the outer periphery of the resin sleeve 32 reaches the inner peripheral surface, fused portions 33a and 33b are formed at the interface between the inner peripheral surface of the resin sleeve 32 and the anticorrosion layers 22a and 22b. In the example of FIG. 3, the inner peripheral surface of the resin sleeve 32 has an equal diameter over the entire length, and the portion (L6) excluding both ends is fixed so as to be separated from the heat-shrinkable tube 31.

  Said sealing material 30a, 30b can be formed with soft resin, such as mastic and dammar.

  In addition to the heat-shrinkable tube, various anticorrosion tapes can be used for the anticorrosion member. The material of the heat-shrinkable tube and various anticorrosion tapes is, for example, vinyl chloride, polyolefin (cross-linked PE, PP, etc.), fluorine-based resin (PFA, PTFE, etc.) or thermoplastic elastomer (styrene-based, olefin-based, PVC-based, etc.) ) Can be used.

  The resin sleeve 32 is a material that has thermoplasticity, can be welded to the anticorrosion layers 22a and 22b, and can transmit laser light having a wavelength in the infrared region (preferably the near infrared region) to the visible region. For example, olefin resins such as polyethylene (PE) and polypropylene (PP), polyester resins such as polyethylene terephthalate (PET) and polybutylene terephthalate (PBT), polyamide resins such as nylon 6 and nylon 66, vinyl chloride resins, It can be made of a known resin such as a fluororesin.

Moreover, it is preferable that the resin sleeve 32 contains the substance which absorbs a laser beam in a part or whole of an internal peripheral surface. As a substance that absorbs laser light, a compound (dye and pigment) that can selectively absorb light having a wavelength in the visible region (wavelength: 380 to 780 nm), or a near infrared region (wavelength: 780 to 3000 nm). A functional dye having a property of selectively absorbing light having a wavelength can be used. Specifically, in order to absorb laser light, it is preferable to add the following pigments or dyes to the thermoplastic resin. In order to absorb light having a wavelength in the visible region, dark pigments such as black pigments such as ceramic black, iron oxide (inorganic pigment), carbon black, bone black (organic pigment), chrome yellow, ceramic yellow Yellow pigments such as zinc chromate yellow (inorganic pigments), nickel azo green yellow (organic pigments), green pigments such as hydrochrome oxide green, chromium green (inorganic pigments), chromium oxide dull green, and phthalocyanine green (organic pigments) Can be used. In order to absorb light having a wavelength in the near infrared region, for example, black pigment dyes, cyanine dyes, phthalocyanine, thiol nickel complex, indophenol metal complex, naphthoquinone, azo, Dyes such as triazole methane and intermolecular CT dyes can be used.

Each step of the non-cutting propulsion method when using a connecting steel pipe to which the protective member of the present invention is applied will be described with reference to FIGS. As shown in FIG. 3, after penetrating the penetrating shaft 11 and the starting shaft 12 on one side of the construction section of the road 10 and excavating the reaching shaft 13 on the opposite side of the construction section of the road 10, The drill machine 14 is installed in By driving the drill machine 14, a propulsion rod 15 with a drill 18 attached to the tip is fed into the ground from the penetrating shaft 11, and the drill 18 of the propulsion rod 15 is propelled to the reaching shaft 13 to form a retracting tunnel. . A connecting steel pipe 1 made up of a plurality of resin-coated steel pipes 2 is prepared in the backyard 17 located in front of the reach shaft 13. Next, the tip drill is replaced with a back reamer (retracting tunnel diameter increasing tool) 16 and connected to the connecting steel pipe 1 with the back reamer 16 as shown in FIG. By pulling out toward the start shaft 12, the connecting steel pipe 1 is drawn into the ground. After all of the connecting steel pipe 1 is drawn into the ground of the construction section, both ends of the connecting steel pipe 1 are connected to, for example, a main pipe and a branch pipe (both not shown), and the penetrating shaft 11, the starting shaft 12, and the reaching shaft 13 is backfilled to complete the piping work. 3 and 4, arrows indicate the moving direction of the propulsion rod 15.
Further, the propulsion rod 15 is started from the reaching shaft 13 without connecting the continuous steel pipe 1 to the back reamer 16 depending on the type of resin coated on the resin-coated steel pipe, the diameter, the soil condition of the construction site, and the like. It is also possible to draw the connecting steel pipe into the ground after performing the operation (pre-reaming) several times toward the shaft 12 to further expand the diameter of the drawing tunnel.

  According to the connecting steel pipe 1 described above, both ends of the resin sleeve 32 covering the heat-shrinkable tube 31 in close contact with the welded portions 24 of the resin-coated steel pipes 2a and 2b are firmly fixed to the coating layers (corrosion protection layers 22a and 22b). Moreover, since both end portions of the resin sleeve 32 are located lower than the protective layers 23a and 23b, even if the resin-coated steel pipes 2a and 2b are drawn into the ground, the resin sleeve 32 and the heat-shrinkable tube 31 are caused by the earth pressure. Is prevented from peeling off from the anticorrosion layers 22a and 22b.

  FIG. 5 is a cross-sectional view schematically showing another state in which the protective member of the present invention is attached to the welded portion of the resin-coated steel pipe at the welded portion of the resin-coated steel pipe, and the same parts as those in FIG. The description is omitted. As shown in FIG. 5, the protective member of the present invention may have the resin sleeve 32 in close contact with the heat-shrinkable tube 31 over its entire length, so that the resin sleeve 32 and the heat-shrinkable tube 31 are more securely attached to the anticorrosion layer 22a. , 22b is prevented from peeling off

  The resin sleeve can be fused to the anticorrosion layers 22a and 22b by means other than laser light irradiation. For example, the end of the resin sleeve and the anticorrosion layer can be heat-sealed by embedding heating wires at both ends of the resin sleeve made of thermoplastic resin and supplying power to the heating wires. In addition, the ultrasonic vibrator is brought into contact with the resin sleeve to be fused to the anticorrosion layer, or the heat sleeve is brought into contact with the inner peripheral surfaces of both ends of the resin sleeve and heated, and then both ends of the resin sleeve are anticorrosive. It is also possible to heat-seal the anticorrosion layer by pressing against the layer.

It is sectional drawing which shows typically the state by which the resin-coated steel pipe was welded. It is sectional drawing which shows typically the state by which the protection member of this invention was adhered to the welding part of the resin-coated steel pipe. It is a schematic sectional drawing which shows the state in the middle of the non-cutting method to which the protection sleeve of this invention is applied. It is a schematic sectional drawing which shows another state in the middle of the non-cutting method to which the protection sleeve of this invention is applied. It is sectional drawing which shows typically the other state by which the protection member of this invention was adhere | attached on the welding part of the resin-coated steel pipe.

Explanation of symbols

1: Connection steel pipe, 2a, 2b resin-coated steel pipe, 21a, 21b: Original pipe, 22a, 22b: Anticorrosion layer, 23a, 23b: Protection layer, 3: Protection member, 30a, 30b: Seal material, 31: Heat shrinkability Tube, 32: resin sleeve, 33a, 33b: fusion part,
10: road, 11: penetration resistance, 12: start resistance, 13: arrival resistance, 14: drill machine 15: propulsion rod, 16: back reamer, 17: backyard, 18: drill

Claims (4)

A member for protecting a connecting portion of a connecting steel pipe in which a plurality of resin-coated steel pipes each having an anticorrosion layer covering the original pipe and its outer peripheral surface and a protective layer coated on the outer peripheral surface are connected in the axial direction. And having a length surrounding the outer periphery of the anticorrosion member to be attached to the anticorrosion layer on both sides of the joint formed by abutting the end faces of the two ends, both ends being formed with a smaller diameter than the protective layer, and A protective member for a non-cutting propulsion method comprising a resin sleeve fused to an anticorrosion layer. The protective member for a non-cutting propulsion method according to claim 1, wherein a sealing material made of a soft resin that covers an end portion of the anticorrosion layer is in close contact with an inner peripheral surface of the anticorrosion member. The protective member for the non-cutting propulsion method according to claim 1 or 2, wherein the resin sleeve contains a substance capable of absorbing laser light at least at both ends of the inner peripheral surface thereof. The protective member for the non-cutting propulsion method according to any one of claims 1 to 3, wherein the resin sleeve is in close contact with the outer peripheral surface of the anticorrosion member over its entire length.

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