JP2018010196A - Repair method of cable for direct embedding - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a repair method of a cable for direct embedding, which can be recovered at a short time in disaster.SOLUTION: There is provided a repair method of a cable for direct embedding which comprises an inside first sheath (inner sheath) and outside second sheaths (reinforcement type coatings 10), in which the second sheaths are loosely fitted to the first sheath. The method comprises at least the steps of: identifying a damaged part of the second sheath; a step for drawing the inside cable core (optical cable core 20) covered with the first sheath, from the second sheath; cutting the damaged part of the second sheath; connecting a cylindrical repair sheath 30 to each second sheath provided on each of both sides of a cable longitudinal direction of the cut damaged part; and inserting a new cable core into the repair sheath and each second sheath.SELECTED DRAWING: Figure 3F

Description

  The present invention relates to a method for repairing a direct embedment cable, and more specifically, a direct embedment cable that includes an inner first sheath and an outer second sheath, and the second sheath is loosely fitted to the first sheath. It relates to the repair method.

  In Japan, efforts are being made to eliminate the use of utility poles from the viewpoints of improving road disaster prevention, securing safe and comfortable traffic spaces, creating good landscapes and promoting tourism. Currently, a method of laying electric wires in underground pipes (also referred to as an electric wire co-groove method) is most often used for this effort to eliminate electric poles. However, this method is difficult to embed pipes on roads with narrow sidewalks or roads without sidewalks, and the application cost is limited due to high equipment costs.

One of the methods to solve the difficulty of burial of pipes and the increase in equipment costs in these undergrounding methods is the method of burying wires directly in the soil (especially because lower costs can be expected) The application of the direct burial method is also being considered.
However, when a communication cable is directly buried in the soil, there is a concern that the cable may be damaged or bent due to cable compression due to earth pressure, thereby adversely affecting the transmission characteristics and mechanical characteristics of the cable.

  For example, Patent Document 1 discloses a direct-embedded optical fiber cable in which an outer sheath formed by winding a high-hardness / high-rigidity plastic tape on a core cable and integrated with an outer sheath on the outer sheath is disclosed. Has been.

JP-A-7-33478

  However, the optical fiber cable described in Patent Document 1 is reinforced with a high-hardness plastic tape to withstand earth pressure, and the cable core is tightly fixed to the exterior. There was a problem that it was difficult to repair and maintain. That is, when repairing and maintaining the optical cable core, it is necessary to bury the entire cable after digging up a range corresponding to the entire length of the cable, and thus it may take a great deal of time and money to recover.

Also, when replacing only the repaired part with a new optical cable core, after digging up the range, install a new closure, etc., and the optical fiber of the optical cable core that does not require repair and the optical fiber of the new optical cable core Are all connected, making recovery in a short time difficult. The communication service is stopped until it is restored, so there is a high possibility that it will not be allowed by the user.
In addition, there is a method of laying a hard duct and then laying an optical fiber cable in the duct, but in that case, the duct and the optical fiber cable are separately laid, and the laying man-hour is almost 2 Double.

  Therefore, it is conceivable that the optical cable core is kept loose relative to the exterior so that repair and maintenance can be completed in a short time, and the optical cable core can be easily pulled out and inserted from the exterior. Even so, it is desirable to restore the cable directly for burial in a short time when it is damaged (also called affliction).

  The present invention has been made in view of the above circumstances, and an object thereof is to provide a method for repairing a direct burying cable that can be restored in a short time when a disaster occurs.

The direct burying cable repair method according to one aspect of the present invention includes an inner first sheath and an outer second sheath, and the second sheath is loosely fitted to the first sheath. A method of repairing a cable, comprising: identifying a damaged portion of the second sheath; disconnecting an inner cable core covered with the first sheath from the second sheath; and Cutting the damaged portion; connecting a tubular repair sheath to each of the second sheaths located on both sides in the cable longitudinal direction of the cut damaged portion; and a new cable core A repair sheath and inserting into each said second sheath.
The direct burying cable repair method according to one aspect of the present invention includes an inner first sheath and an outer second sheath, and the second sheath is loosely fitted to the first sheath. A method for repairing an embedded cable, the step of identifying a damaged portion of the second sheath, the step of excising the damaged portion of the second sheath to expose the first sheath, and a slit in the longitudinal direction of the cable Placing the formed repair sheath over the first sheath exposed by excision of the damaged portion of the second sheath.

  According to the above, it is not necessary to work for a long time occupying a sidewalk or a shoulder, and the construction period can be shortened. In addition, since a short period of time is sufficient, prior occupation permission is unnecessary. As a result, it is possible to provide a method for repairing a direct burying cable suitable for emergency recovery.

It is a perspective view which shows an example of the cable for direct embedment concerning one embodiment of the present invention. It is a front view of the cable for direct burial. It is a figure which shows the damage of the cable for direct burial. It is a figure which shows the disconnection of a cable core. It is a figure which shows excision of the damaged part of a 2nd sheath. It is a figure which shows installation of the sheath for repair. It is a figure which shows insertion of a wire tool. It is a figure which shows insertion of a cable core. It is a figure which shows the state which repair was completed. It is a figure which shows another example of the damage of the cable for direct burying. It is a figure which shows the excavation of the both ends of a damaged part. It is a figure which shows removal of a damaged part. It is a figure which shows installation of the sheath for repair. It is a figure which shows protection by a tape. It is a figure which shows soil covering. 6 is a diagram for explaining a repair sheath of Example 2. FIG. It is a figure for demonstrating the jig | tool which mounts the sheath for repair.

[Description of Embodiment of the Present Invention]
First, the contents of the embodiment of the present invention will be listed and described.
A method of repairing a direct burying cable according to an aspect of the present invention includes (1) an inner first sheath and an outer second sheath, and the second sheath is loosely fitted to the first sheath. A method for repairing a direct burying cable, the step of identifying a damaged portion of the second sheath, the step of disconnecting an inner cable core covered with the first sheath from the second sheath, A step of excising a damaged portion of the two sheaths, a step of connecting and installing a cylindrical repair sheath to each of the second sheaths located on both sides in the longitudinal direction of the cable of the excised damaged portion, and a new cable Inserting a core into the repair sheath and each of the second sheaths. Since it is not necessary to install new closures on both sides of the damaged portion of the second sheath, the work that occupies the sidewalk and the shoulder becomes unnecessary, and the construction period can be shortened. In addition, prior occupation permission is unnecessary. As a result, it is possible to provide a method for repairing a direct burying cable suitable for emergency recovery.

(2) A method for repairing a direct embedment cable comprising an inner first sheath and an outer second sheath, wherein the second sheath is loosely fitted to the first sheath, wherein the second sheath A step of identifying a damaged portion, a step of excising the damaged portion of the second sheath to expose the first sheath, and a repair sheath having a slit formed in the longitudinal direction of the cable, the damaged portion of the second sheath And covering the first sheath exposed by cutting. Since the second sheath is repaired without repairing the first sheath, the construction period can be shortened as compared with the case where the second sheath is repaired after the first sheath is removed. As a result, it is possible to provide a method for repairing a direct burying cable suitable for emergency recovery. Further, since the cable core is not cut or removed, the communication service does not have to be stopped.
(3) The repair sheath is formed of the same material and shape as the second sheath. If the repair sheath is made of the same material and shape, it has the same strength and reliability as the second sheath. can do.

[Details of the embodiment of the present invention]
Hereinafter, a specific example of a method for repairing a direct burying cable according to the present invention will be described with reference to the accompanying drawings. FIG. 1 is a perspective view showing an example of a direct burying cable according to an embodiment of the present invention, and FIG. 2 is a front view of the direct burying cable.
The direct burying cable 1 includes an optical cable core 20 and a reinforced outer jacket 10 disposed outside the optical cable core 20. The optical cable core 20 corresponds to the cable core of the present invention.

  Although details of the optical cable core 20 are not shown, the optical cable core 20 has a core portion 21 of about 8 cores such as a drop cable for dropping a subscriber. The periphery of the core portion 21 is covered with an inner sheath 22 made of, for example, PE (polyethylene), PVC (polyvinyl chloride), or the like. The inner sheath 22 corresponds to the first sheath of the present invention.

The optical cable core 20 (inner sheath 22) has an outer diameter of about 4 mm to 20 mm, and the optical cable core 20 is formed in a round shape, for example.
The core portion 21 is a cable in which the outer side of a cable (for example, up to about 200 cores) bundled with multi-fiber optical fiber ribbons or the like, such as a low-comfort cable for a branch line, is held with a press-wound tape or the like. There may be.
The core portion 21 may be a slot cable or a slotless cable, and the shape thereof is not limited as long as it is a multi-core optical fiber cable.

The reinforced jacket 10 is loosely fitted to the optical cable core 20 and covers the periphery of the optical cable core 20 to protect the optical cable core 20. The reinforced outer jacket 10 corresponds to the second sheath of the present invention.
The reinforced outer jacket 10 is made of hard plastic such as high density polyethylene (HDPE). If the reinforced casing 10 is made of HDPE, that is, polyethylene having a density of 0.942 (g / cm ³ ) or more, it can sufficiently withstand the compressive force and bending force applied to the cable due to earth pressure.

Further, the reinforced jacket 10 may be a metal such as iron or SUS. If the reinforced casing 10 is made of metal, it can sufficiently withstand the compressive force and bending force applied to the cable due to earth pressure, as described above, but in consideration of handleability, hard plastic is preferred.
Alternatively, the reinforced outer jacket 10 may be formed of a hard plastic whose main material is polypropylene (PP). If the reinforced casing 10 is made of PP, the required strength can be maintained even if the allowable wall thickness is small compared to the case of forming it with HDPE.

  Further, the reinforced outer jacket 10 is formed in, for example, a bellows shape, and a longitudinal section thereof is formed in a waveform. Specifically, the reinforced outer jacket 10 has ridges 11 and valleys 12 formed along a direction orthogonal to the longitudinal direction, and these ridges 11 and valleys 12 are alternately provided along the longitudinal direction of the cable. It has been. In addition, the inner diameter of the reinforced outer jacket 10 (the valley portion 12) is configured to be about 30 mm, and the reinforced outer jacket 10 is also formed in a round shape, for example.

  As described above, the inner sheath 22 of the optical cable core 20 is loose with respect to the reinforced jacket 10, and the optical cable core 20 is easily pulled out of the reinforced jacket 10 when the optical cable core 20 is repaired or maintained. In addition, since the new optical cable core 20 can be easily inserted into the reinforced jacket 10, the optical cable core 20 can be repaired and maintained in a short time.

In addition, if the reinforced jacket 10 is formed into a corrugated shape, it can withstand earth pressure, and the ridges 11 and the valleys 12 formed alternately can provide the same flexibility as a general optical cable. Can be handled easily.
In addition, in the figure, although the example of the bellows-shaped reinforcement | strengthening envelope which the direction of a mountain valley is orthogonal to a longitudinal direction was mentioned and demonstrated, the reinforcement type | mold jacket of this invention is a spiral shape which the direction of a mountain valley intersects with a longitudinal direction It may be a bellows. It is also possible to form one of the outer peripheral surface and the inner peripheral surface of the reinforced outer jacket flat and make the other corrugated.

  By the way, as described above, the inner sheath 22 of the optical cable core 20 is in a loose state with respect to the reinforced jacket 10, but even in such a structure, the reinforced jacket 10 and the optical cable core 20 are temporarily provided. In the event of a disaster, it is desirable to recover in a short time. Therefore, the following construction method was created.

3A to 3G are views for explaining the repair method according to the first embodiment. In the first embodiment, the direct burying cable 1 is buried in the soil between manholes (or handholes, the same shall apply hereinafter) 55a and 55b. For example, a bucket of a construction machine is directly connected to the burying cable 1. It is assumed that both the reinforced jacket 10 and the optical cable core 20 are damaged.
In order to clarify the optical cable core 20 in the reinforced jacket 10, in the following drawings, the optical cable core 20 is shown so as to be visible even when it is arranged inside the reinforced jacket 10.

When the direct burying cable 1 is damaged in this way, first, a damaged portion of the reinforced outer jacket 10 is specified as shown in FIG. 3A. In addition, you may specify the damaged part of the optical cable core 20 collectively. Alternatively, if the extent of damage to the optical cable core 20 can be estimated from the damage content of the reinforced outer jacket 10, the damaged portion of the optical cable core 20 need not be confirmed.
Next, the damaged optical cable core 20 is disconnected from the damaged reinforced jacket 10. Specifically, the damaged optical cable core 20 is removed from the existing closure 45 through the manholes 55a and 55b located at both ends of the damaged direct burying cable 1, respectively. Next, for example, the optical cable core 20 is extracted at the position of the manhole 55b and wound on, for example, a drum (not shown) on the ground, and then the optical cable core 20 is extracted at the position of the manhole 55a as shown in FIG. 3B. When the optical cable core 20 is not cut, the optical cable core 20 may be extracted only at the position of the manhole 55a.

After specifying the damage range of the reinforced outer jacket 10, soil around the damaged part (about several meters) is dug out.
Subsequently, as shown in FIG. 3C, the damaged portion of the reinforced outer jacket 10 is excised. More specifically, for example, a tool such as a cutter is used to cut both ends in the cable longitudinal direction at the damaged portion of the reinforced outer jacket 10, and the reinforced outer jacket 10 connected to one manhole 55a and the reinforced continuous to the other manhole 55b. Separated into a mold jacket 10.

Next, as shown in FIG. 3D, the cylindrical repair sheath 30 is applied to each of the reinforced outer jackets 10 separated into one and the other using, for example, a joint (coupling) 32 having a locking claw on the inner surface. Connect each one.
The repair sheath 30 is formed of, for example, the same material and the same shape as the reinforced outer jacket 10. If the repair sheath 30 has the same outer diameter, strength, and reliability as the reinforced outer jacket 10, even if the reinforced outer jacket 10 is repaired, it becomes a direct embedment cable.

  Thereafter, the excavated soil is returned and the repair sheath 30 is filled (also referred to as soil covering). Subsequently, as shown in FIG. 3E, for example, at the position of the other manhole 55 b, the wire connecting tool 40 is inserted into the reinforced jacket 10 and the repair sheath 30. When the wiring tool 40 reaches one manhole 55a, the new optical cable core 20 is connected to the tip thereof.

Next, as shown in FIG. 3F, the wire 40 is pulled from the other manhole 55b, and the connected optical cable core 20 is inserted into the reinforced jacket 10 and the repair sheath 30 from one manhole 55a.
When the inserted optical cable core 20 reaches the other manhole 55b, as shown in FIG. 3G, the existing optical fiber of the inserted optical cable core 20 is used in both manholes 55a and 55b. The optical fiber of the existing optical cable core 50 is connected.

  According to this repair method, it is not necessary to install a new closure on both sides of the damaged portion of the reinforced outer jacket 10 and connect the optical fiber of the optical cable core. It becomes unnecessary and the construction period can be shortened. In addition, since a short period of time is sufficient, prior occupation permission is unnecessary. As a result, it is possible to provide a method for repairing a direct burying cable suitable for emergency recovery.

4A to 4F are diagrams for explaining the repair method of the second embodiment, and FIG. 5 is a diagram for explaining the repair sheath of the second embodiment. In the second embodiment, it is assumed that, for example, the bucket of the construction machine directly touches the burying cable 1 and the reinforced outer jacket 10 is damaged, but the optical cable core 20 is not damaged.
When the reinforced outer jacket 10 is damaged, first, a damaged portion of the reinforced outer jacket 10 is specified as shown in FIG. 4A. Thereafter, as shown in FIG. 4B, the soil around the damaged portion is dug out.

  Subsequently, the damaged portion of the reinforced jacket 10 is excised. Specifically, in the same manner as in the first embodiment, for example, a tool such as a cutter is used to divide the reinforced outer jacket 10 connected to one manhole 55a and the reinforced outer jacket 10 connected to the other manhole 55b. However, in Example 2, since the optical cable core 20 is not disconnected as in Example 1, as shown in FIG. 4C, when the damaged portion of the reinforced outer jacket 10 is removed, the optical cable core 20 is exposed. Become.

Next, as shown in FIG. 4D, the repairing sheath 30 covers the optical cable core 20 exposed by removing the damaged portion of the reinforced outer jacket 10.
The repair sheath 30 is also formed in the same shape with the same material as that of, for example, the reinforced jacket 10 as in the first embodiment. However, as shown in FIG. A slit 31 is formed along the line. For this reason, the repair sheath 30 of the second embodiment can be opened at the position of the slit 31.

  In order to cover the optical cable core 20 with the repair sheath 30 described in the second embodiment, it is easy to use a sheath mounting jig, for example. Various structures are known for this jig. For example, as shown in FIG. 6A, the jig 70 includes a cylindrical cable insertion portion 71 and a rod-shaped sheath guide portion 72. It consists of. The sheath guide part 72 extends obliquely from the cable insertion part 71 and is connected to the outer surface of the cable insertion part 71.

  As shown in FIG. 6B, the cable insertion portion 71 can be opened and closed, for example. When a cable is placed on the opened cable insertion portion 71 and then closed, the cable can be set therein. On the other hand, the repairing sheath 30 described with reference to FIG. 5 is inserted into the sheath guide portion 72. At this time, as shown in FIG. 6C, the slit 31 is arranged facing the cable. When the repair sheath 30 is advanced toward the cable insertion portion 71 and the slit 31 of the repair sheath 30 contacts the sheath guide portion 72, the repair sheath 30 opens at the position of the slit 31. When the repair sheath 30 is further advanced, the slit 31 is closed at the tip of the cable insertion portion 71, so that the cable (exposed optical cable core 20) can be covered.

Subsequently, as shown in FIG. 4E, a protective tape 33 is wound around the outside of the repair sheath 30 to protect the repair sheath 30. The protective tape 33 is, for example, a self-bonding tape, and is wound around the repair sheath 30 and then heated, for example, with a heat gun, so that it is dissolved and strongly bonded to the repair sheath 30.
When the optical cable core 20 is covered with the repair sheath 30, there is a gap between one of the reinforced outer jacket 10 and the repair sheath 30 and between the other reinforced jacket 10 and the repair sheath 30. Gaps can occur. For this reason, the protective tape 33 is wound so as to reach the reinforced outer jacket 10 after winding outside the gap. In addition, after winding with this self-bonding tape, you may wind further with a vinyl tape. Further, the length of the repair sheath 30 may be set so as to partially overlap the reinforced outer jackets 10 positioned at both ends in the cable longitudinal direction.

Thereafter, as shown in FIG. 4F, when the excavated soil is returned and the repair sheath 30 is filled, a series of repair work is completed.
According to this repair method, since the optical cable core 20 repairs the reinforced outer jacket 10 without repairing, the construction period can be shortened compared with the case where the reinforced outer jacket 10 is repaired after the optical cable core 20 is removed. As a result, it is possible to provide a method for repairing a direct burying cable suitable for emergency recovery. Further, since the cable core is not cut or removed, the communication service does not have to be stopped.

  The repair sheath of FIG. 5 described in the second embodiment may be used as the repair sheath of the first embodiment. Moreover, although the case where this invention was applied to the optical cable core was demonstrated as embodiment, a metal cable core may be sufficient instead of an optical cable core.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the meanings described above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

DESCRIPTION OF SYMBOLS 1 ... Cable for direct embedment, 10 ... Reinforced type jacket, 11 ... Mountain part, 12 ... Valley part, 13 ... Opening end part, 20 ... Optical cable core, 21 ... Core part, 22 ... Inner sheath, 30 ... Sheath for repair 31 ... Slit, 32 ... Joint, 33 ... Protective tape, 40 ... Wiring tool, 45 ... Closure, 50 ... Existing optical cable core, 55a, 55b ... Manhole, 70 ... Jig for attaching a sheath, 71 ... Cable insertion Part, 72 ... sheath guide part.

Claims (3)

A method for repairing a direct burying cable comprising an inner first sheath and an outer second sheath, the second sheath being loosely fitted to the first sheath,
Identifying a damaged portion of the second sheath;
Disconnecting the inner cable core covered with the first sheath from the second sheath;
Excising the damaged portion of the second sheath;
Connecting and installing a tubular repair sheath to each of the second sheaths located on both sides in the cable longitudinal direction of the excised damaged portion;
A method of repairing a direct burying cable, comprising: inserting a new cable core into the repair sheath and each of the second sheaths. A method for repairing a direct burying cable comprising an inner first sheath and an outer second sheath, the second sheath being loosely fitted to the first sheath,
Identifying a damaged portion of the second sheath;
Excising the damaged portion of the second sheath to expose the first sheath;
A method of repairing a direct embedment cable, comprising: installing a repair sheath having a slit in a cable longitudinal direction so as to cover the first sheath exposed by excision of a damaged portion of the second sheath. The method for repairing a direct burying cable according to claim 1 or 2, wherein the repair sheath is formed of the same material as the second sheath and has the same shape.

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