ASSEMBLED UTILITY POLE, POLE BUILDING METHOD AND REBUILDING METHOD

TECHNICAL FIELD

The present disclosure relates to an assembly type utility pole, a method for constructing the same, and a method for replacing the same.

BACKGROUND ART

FIG. 1 illustrates a utility pole. A large number of utility poles are laid all over the country in order to wire communication cables and power cables at high places, share telephones and electricity with users and are recognized as social infrastructures.

FIG. 2 is an end view of the utility pole. It can be seen that the utility pole is made of concrete and steel wires. The utility pole is heavy (see, for example, Non Patent Literature 1) because components are concrete and steel wires.

FIG. 3 illustrates a typical method for constructing a utility pole.

Excavation step by manpower: in order to prevent an accident of damaging a buried object, excavation by hand is performed for a section where there is a high possibility that another company's buried object exists.

- (1) A small portion of a surface layer is dug with a scoop, or the like (a search hole is dug).
- (2) A probe is manually inserted into the dug hole, and it is confirmed whether there is no buried object in an excavation direction (determined by whether or not something comes into contact with a tip of the probe).
- (3) The hole is further dug with the scoop up to a range searched by the probe.
- (4) Steps (2) and (3) described above are repeated until an excavation depth becomes about 1.5 m.

Excavation Step by Heavy Equipment:

- (5) In a case where there is no buried object, a hole for building with a target depth from the excavation depth of 1.5 m or more of the search hole is mechanically excavated by an earth auger of a pole construction track.

Lifting and Building Step:

- (6) The utility pole is lifted with a crane and is built in the excavated hole for building. In this event, it is dangerous if the utility pole swings when being lifted, so that it is necessary to prevent swinging of the utility pole with a rope, or the like.

Vertical Adjustment and Backfilling Step:

- (7) The utility pole is held by the crane and adjusted so as to be perpendicular to the ground.
- (8) After a vertical position of the utility pole is confirmed, soil is returned to the hole for building, and backfilling is performed.
- (9) After backfilling is completed, the ground is compacted by a compactor, or the like, and compaction is performed.

As illustrated in FIG. 3, in a typical method for constructing a utility pole, first, a ground is dug in order to build the utility pole. A combination of a utility pole, having a total length of about 8.0 m to 9.0 m, to which only a communication line is attached and a utility pole, having a length of about 14.0 to 18.0 m, to which a communication line and a power line are attached are often used, and, in order to stably build the utility poles, each part having a length of about 1.5 m to 3.0 m, which is ⅙ of the length of each utility pole, is required to be driven into the ground. In other words, a hole is dug by 1.5 m to 3.0 m. There is a high probability that buried pipes, and the like, of social infrastructure facilities such as electricity, gas, and water are present at about 1.5 m from the ground surface, and thus, excavation by manpower is performed so as not to cause damage. After the hole is dug to the target depth, the utility pole is built by lifting the utility pole with heavy equipment and a person, raising the heavy utility pole, and entering the utility pole into the hole.

CITATION LIST
Non Patent Literature

Non Patent Literature 1: Dainichi Concrete Industry Co., Ltd., technical data (http://www.dainichi-x.co.jp/wp/wp-content/uploads/2017/11/technical_data.pdf), retrieved on Feb. 25, 2021.

SUMMARY OF INVENTION
Technical Problem

[First Problem]

In the ground, a large amount of power cables, water pipes, gas pipes, and the like, which are social infrastructure facilities, are buried. When a utility pole is built, a depth of 1.5 m to 3.0 m is dug, and thus, the utility pole may hit a buried object such as a power cable. This is not acceptable, because the buried object would be destroyed by being hit, which may affect users over a wide range. It is therefore very important to confirm that there is no buried object. As a method for confirming a buried object, a primitive method in which a hole is slightly dug and a worker performs confirmation using a probe, or the like, is repeatedly performed.

In other words, a construction work of a utility pole requires a large number of man-hours for a step of confirming a buried object, which is a first problem that it is difficult to reduce the number of man-hours.

[Second Problem]

After installation of the utility pole is completed, a material is deteriorated due to aging. Loads, generated by a cable hung on the utility pole, a transformer installed on the utility pole, or the like, is ideally balanced. However, in reality, a load caused by wind pressure, or the like, is unevenly generated. Thus, in a state where the utility pole is deteriorated, strength may decrease and the utility pole may be broken. For this reason, it is necessary to replace the degraded utility pole with a new one.

A general replacement work method is illustrated in FIG. 4.

Excavation Step:

- (1) A hole for building of a new utility pole is excavated in the vicinity of the utility pole to be replaced. The excavation step is the same as the excavation step by manpower and the excavation step by the heavy equipment described in FIG. 3.

New Pole Building, Vertical Adjustment, and Backfilling Step:

- (2) A new utility pole is built in the vicinity of the utility pole to be replaced therewith and the hole for building is backfilled, in accordance with procedure similar to that in the lifting and building step and the vertical adjustment and backfilling step in FIG. 3.

Cable Relocating Step:

- (3) Existing cables are relocated to the new utility pole using a high-place work vehicle, or the like.

Removal Step of Pole to be Replaced:

- (4) The ground of the utility pole to be replaced is excavated, the pole is lifted with a crane, or the like, and the pole is removed. In this event, it is dangerous if the utility pole swings when being lifted, and thus, it is necessary to prevent swinging with a rope, or the like.
- (5) Soil is put into the hole after removal to perform backfilling.
- (6) After backfilling is completed, the ground is compacted by a compactor, or the like, and compaction is performed.
- (7) In a case where a landowner, or the like, requests replacement to the same position as the utility pole to be replaced, after completion of work (5), the steps of work (1) to (6) are performed again to perform replacement to the original position.

As illustrated in FIG. 4, a typical method for replacing a utility pole indicates a series of procedure of first building a new utility pole next to a utility pole to be replaced, relocating cables to the newly built utility pole, and removing the utility pole to be replaced. In addition, depending on the owner of the land, the position may not be allowed to change when the utility pole is replaced. In this case, after the replacement by the new utility pole is completed in accordance with the above procedure, repeated procedure is required in which newer utility pole is built again at the same position as that of the removed utility pole to be replaced, the cables are moved, and the nearby utility pole is removed.

In other words, the replacement work of the utility pole also requires many man-hours, which is a second problem that it is difficult to reduce the man-hours.

[Third Problem]

The above-described construction work and replacement work of the utility pole require not only man-hours but also many workers. If necessary workers cannot be secured, it is difficult to perform the construction work and the replacement work as described above. In other words, there is a third problem that it is difficult to perform the construction work and the replacement work of the utility pole with a small number of workers.

Thus, in order to solve the above problems, an object of the present invention is to provide an assembly type utility pole, a method for constructing the assembly type utility pole, and a method for replacing the assembly type utility pole, which can simplify and improve efficiency of work at the time of new installation and replacement and can shorten a work period.

Solution to Problem

In order to achieve the above object, an assembly type utility pole according to the present invention is a utility pole including a plurality of members stacked in a height direction and includes a mechanism for excavating the ground in a lowermost member to be buried in the ground.

Specifically, an assembly type utility pole according to the present invention includes a pole, and an anchor that is a substantially cylindrical object having a diameter larger than a diameter of the pole and has a hole into which one end of the pole is fitted, and

- when one end of the pole is fitted into the hole of the anchor, the pole and the anchor becomes coaxial.

A method for constructing a utility pole according to the present invention includes: burying an anchor of a substantially cylindrical object having a diameter larger than a diameter of a pole in a ground such that one end of a bottom surface of the substantially cylindrical object substantially matches a ground surface; and fitting one end of the pole into a hole of the anchor in which the pole and the anchor are coaxial.

The anchor has a larger diameter than a body of a utility pole on the ground and has higher ground support force. Thus, the hole for building the assembly type utility pole on the ground can be made shallower than the hole for building the utility pole in related art on the ground. The depth of the hole is shallow, so that it is possible to reduce a period for digging, reduce a probability of hitting a buried object, and reduce work for confirming a buried object.

In addition, the assembly type utility pole includes a plurality of parts, and thus, only a degraded portion needs to be replaced, so that it is possible to shorten replacement work.

Further, the assembly type utility pole includes a plurality of parts, and thus, each part is smaller than that of the utility pole in related art, so that it is possible to simplify work.

Thus, the present invention can provide a utility pole and a method for constructing the utility pole, which can simplify and improve efficiency of work at the time of new installation and replacement and can shorten a work period.

The anchor of the assembly type utility pole according to the present invention includes an earth auger on a surface thereof.

When the anchor in the ground is buried in the method, for constructing the utility pole according to the present invention, the anchor is rotated in an axial direction, and the ground is dug with the earth auger installed on the surface of the anchor.

A pre-hole can be expanded by simply rotating the earth auger, and the anchor is buried in the ground. This eliminates the need of backfilling and compaction.

The pole of the assembly type utility pole according to the present invention can be divided into at least two portions in a longitudinal direction.

In the method for constructing the utility pole according to the present invention, when the pole is divided into two or more portions in the longitudinal direction, stacking another divided pole on the other end of the pole after one end of the pole is fitted into the hole.

This enables replacement of only part of the utility pole.

The assembly type utility pole according to the present invention further includes a lock member that fills a gap between the pole and the hole, and the gap is generated when one end of the pole is fitted into the hole of the anchor.

By selecting a type of a spacer, utility poles (poles) of various diameters can be built.

A method for replacing the assembly type utility pole according to the present invention is a method for replacing an assembly type utility pole including:

- a pole that can be divided into two or more portions in a longitudinal direction; and
- an anchor that is a substantially cylindrical object having a diameter larger than a diameter of the pole and is buried in the ground such that one end of a bottom surface of the substantially cylindrical object substantially matches the ground surface,
- in which one end of the pole is fitted into a hole of the anchor in which the pole and the anchor are coaxial, the method including:
- dividing the pole;
- lifting up an upper portion of the divided pole;
- removing a lower portion of the divided pole from the anchor;
- fitting one end of a lower portion of a new pole into the hole of the anchor; and
- connecting one end of an upper portion of the pole that is being lifted to the other end of a lower portion of the new pole.

Replacement work can be simplified by allowing only part of the parts of the assembly type utility pole to be replaced.

Each of the above inventions can be combined as far as possible.

Advantageous Effects of Invention

According to the present invention, it is possible to provide a utility pole and a method for constructing the utility pole, which can simplify and improve efficiency of work at the time of new construction and replacement and can shorten a work period.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a view for explaining an example of a utility pole.

FIG. 2 is a view for explaining an end surface of the utility pole.

FIG. 3 is a view for explaining a typical method for constructing a utility pole.

FIG. 4 is a view for explaining a typical method for replacing a utility pole.

FIG. 5 is a view for explaining an assembly type utility pole according to the present invention.

FIG. 6 is a view for explaining an anchor of the assembly type utility pole according to the present invention.

FIG. 7 is a view for explaining the assembly type utility pole according to the present invention.

FIG. 8 is a view for explaining a lock member of the assembly type utility pole according to the present invention.

FIG. 9 is a view for explaining a method for replacing the assembly type utility pole according to the present invention.

FIG. 10 is a view for explaining a method for constructing the assembly type utility pole according to the present invention.

DESCRIPTION OF EMBODIMENTS

An embodiment of the present invention will be described with reference to the accompanying drawings. The embodiment described below is an example of the present invention, and the present invention is not limited to the following embodiment. Note that components having the same reference numerals in the present specification and the drawings indicate the same components.

FIG. 5 is a view for explaining an assembly type utility pole of the present embodiment. This assembly type utility pole includes a pole 11 and an anchor 12 that is a substantially cylindrical object having a diameter larger than a diameter of the pole 11 and has a hole 12a into which one end of the pole 11 is fitted, and when one end of the pole 11 is fitted into the hole 12a of the anchor 12, the pole 11 and the anchor 12 become coaxial. Here, the pole 11 can be divided into at least two portions in a longitudinal direction (portions 11-1 and 11-2). Further, the anchor 12 has an earth auger 12b on a surface thereof.

Here, the pole 11 can be divided into at least two portions in a longitudinal direction (portions 11-1 and 11-2). Further, the anchor 12 has an earth auger 12b on a surface thereof. The assembly type utility pole further includes a lock member 13 that fills a gap between the pole 11 and the hole 12a, which is generated when one end of the pole 11 is fitted into the hole 12a of the anchor 12.

As in the example of FIG. 5, the assembly type utility pole includes four structures. A typical utility pole is a single cylindrical structure, and thus, the structure of the utility pole is largely different from that of the assembly type utility pole. Each structure will be described.

The anchor 12 is a structure to be buried in the ground. The anchor 12 has a plurality of blades (earth augers) 12b on the surface. FIG. 6 is a view for explaining a function of the anchor 12. The anchor 12 rotates to excavate earth in the ground by the earth auger 12b, and the entire anchor 12 dives into the ground. In other words, the anchor 12 can be buried in the ground.

Further, the anchor 12 is provided with a hole 12a in advance at the center. The hole 12a is a hole for accommodating the pole 11. FIG. 7 is a view when the portion 11-2 which is a lower step portion of the pole 11 is inserted into the anchor 12 buried in the ground. After the anchor 12 is buried in the ground, one end of the portion 11-2 is inserted into the hole 12a, so that the portion 11-2 can stand perpendicular to the ground.

Then, as illustrated in FIG. 7, the lock member 13 is passed through from the other end (opposite anchor side) of the portion 11-2 and fitted into the gap between the hole 12a and the portion 11-2 to fix the anchor 12 and the portion 11-2. FIG. 8 is a two-view drawing illustrating the lock member 13. (A) is a top view, and (B) is a side view. A hole 13a through which the portion 11-2 passes is formed in the lock member 13. The hole 13a has a diameter according to a type (diameter) of the utility pole. Further, the lock member 13 includes a spacer 13b that fills a gap between the portion 11-2 and the hole 12a of the anchor 12. The spacer 13b has a size according to a type (diameter) of the utility pole.

A convex portion 11a is provided at the other end (opposite anchor side) of the portion 11-2. In addition, a concave portion 11b to be fitted with the convex portion 11a is provided at one end (anchor side) of the portion 11-1. The portion 11-2 and the portion 11-1 are connected by fitting the convex portion 11a and the concave portion 11b. In this way, as illustrated in FIG. 5, the pole 11 can stand in the vertical direction of the anchor 12. The pole 11 serves as a utility pole, and a communication cable or a power cable is bridged over the utility pole.

[Expected Effects]

Solution of the above-described three problems by the above-described assembly type utility pole will be described.

(Solution to Problem 1)

The anchor 12 has a structure having a larger diameter in the lateral direction than a buried portion of a utility pole in related art. Thus, ground supporting force is high, and thus, there is an advantage that a distance (depth) for digging a hole is shorter than before. In other words, the depth of the hole is reduced. Even if an inspection is performed visually, the distance for digging is reduced, so that the work period of a step of confirming the buried object can be shortened in the present assembly type utility pole.

(Solution to Problem 2)

Concrete and steel are mainly used as materials of the utility pole. The main cause of degradation is corrosion due to reaction with moisture and oxygen, and thus, the most of sites where degradation occurs are at the ground, which is a boundary between the ground and the utility pole. However, in a case of a utility pole in related art, in a case where degradation occurs in the utility pole, the whole utility pole is replaced.

On the other hand, in the method for replacing the assembly type utility pole, only a portion that degrades can be replaced. FIG. 9 is a view for explaining a method for replacing the assembly type utility pole. The replacement method includes:

- step S01 of dividing the pole 11;
- step S02 of lifting the upper portion 11-1 of the divided pole 11;
- step S03 of removing the lower portion 11-2 of the divided pole 11 from the anchor 12;
- step S04 of fitting one end of a lower portion 11-2a of a new pole into the hole 12a of the anchor 12; and
- step S05 of connecting one end of the upper portion 11-1 of the pole being lifted to the other end of the lower portion 11-2a of the new pole.

In FIG. 9,

- the “step of lifting the upper portion of the utility pole and a cable” corresponds to steps S01 and S02,
- the “step of replacing the lower portion of the utility pole” corresponds to steps S03 and S04, and
- the “step of connecting the lower portion of the utility pole and the upper portion of the utility pole” corresponds to step S05.

In the method in related art described with reference to FIG. 4, the entire utility pole is replaced. In this event, work of handling the utility pole and work of handling the cable are generally not performed in the same work group because heavy equipment to be used and necessary skills of workers are different. Thus, work requires at least three days taken by the work of building a utility pole (utility pole work group: one day), the work of relocating the cable (cable work group: one day), and the work of removing a utility pole to be replaced (utility pole work group: one day). In addition, in a case where a landowner requests replacement at the original position, after the above steps are completed, it is necessary to again build the utility pole at the original position, move the cable, and remove the utility pole, so that the required number of days is doubled.

On the other hand, in the present replacement method, only the lower portion 11-2 of the utility pole and the lock member 13, which are expected to degrade, are replaced. The upper portion 11-1 of the utility pole and the lower portion 11-2 of the utility pole have a fitting structure. Thus, the upper portion 11-1 of the utility pole and the lower portion 11-2 of the utility pole can be separated from each other by lifting up the upper portion 11-1 of the utility pole and the cable attached thereto with a crane.

The anchor 12 and the lower portion 11-2 of the utility pole also have a fitting structure. Thus, while the upper portion 11-1 of the utility pole is lifted, the lower portion 11-2 of the utility pole can be replaced with the lower portion 11-2a of the new utility pole without excavating work. When the replacement of the lower portion 11-2 of the utility pole and the lock member 13 is completed, the upper portion 11-1 of the utility pole being lifted is fitted into the lower portion 11-2a of the new utility pole, whereby the replacement work is completed.

With this replacement method, the number of working days required for up to six days can be reduced to one day. In addition, cable work does not occur, and thus, work can be completed only by the utility pole work group. Further, it is not necessary to perform the excavation work in association with the replacement work. This can also reduce the work period. Furthermore, partial replacement is possible, so that an amount of building materials to be used can be reduced, which is efficient, and burden on the environment is also small.

(Solution to Problem 3)

FIG. 10 is a view for explaining a method for constructing the assembly type utility pole. The present construction method includes:

- step S11 of burying the anchor 12 of a substantially cylindrical object having a diameter larger than the diameter of the pole 11 in the ground so that one end of a bottom surface of the substantially cylindrical object substantially matches a ground surface; and
- step S12 of fitting one end of the pole 11 (the lower portion 11-2 of the utility pole) into the hole 12a of the anchor in which the pole 11 and the anchor 12 are coaxial; and
- step S13 of stacking another divided pole 11 (upper portion 11-1 of the utility pole) on the other end of the pole 11 (lower portion 11-2 of the utility pole).

Here, in the present method for constructing the pole, in step S11 of burying the anchor 12 in the ground, the anchor 12 is rotated in the axial direction, and the ground is dug with an earth auger installed on the surface of the anchor 12.

In FIG. 10,

- the “step of excavation (by machine/manpower) and installing the anchor” corresponds to the following steps in step S11,
- the “step of lifting” and the “step of attaching the lock member” corresponds to step S12, and
- the “step of attaching the upper portion of the utility pole” corresponds to step S13.

The utility pole has a length of about 8.0 to 18 m and is built in a hole by heavy equipment and a human. In the method in related art of FIG. 3, a hole is dug by hand up to a depth of about 1.5 m, and the hole is dug using the heavy equipment at a depth of 1.5 m or more. Thereafter, the utility pole of about 8.0 to 18 m is lifted, and the utility pole is built in the excavated hole. Under this condition, the utility pole is very long, and thus, requires carefully handling so as not to hit obstacles existing in the work environment such as surrounding buildings, utility poles, guard rails, and the like, and in some cases, requires moving to the excavation hole by a complicated route in order to avoid the obstacles. After the fitting, the utility pole is supported by a tip of the crane, or the like, because the ground is not leveled in the excavation hole, and the angle is adjusted to be vertical as much as possible. This work requires delicate work with a crane, or the like, which is very difficult. After the vertical adjustment is completed, soil is inserted into the gap of the excavation hole to perform backfilling, and the construction work is completed by pressing and solidifying with a compactor, or the like.

In the present construction method, first, work of digging a hole (excavation step) is similar to the method in related art, but the anchor 12 has a structure that is larger (thicker), in the lateral direction, than the buried portion of the utility pole in related art, and the ground support force is high, so that the distance (depth) for digging a hole is shorter than that in the method in related art. This can shorten the work period. In particular, for a utility pole of about 8.0 to 9.0 m to which only a communication line is attached, about 1.5 m, which is ⅙ of the length of the utility pole, is required to be placed in the ground in the method in related art. On the other hand, in the present construction method, the distance (depth) by which the hole is dug by the anchor 12 is shortened, so that the amount of digging work by hand can be reduced, which is efficient.

The anchor installation step is performed after the excavation is completed to the target depth. The anchor 12 is installed by being attached to the tip of a pole construction track and buried with rotation of the earth auger. In this event, the anchor 12 enters the ground by pushing and expanding a hole dug in advance in such a manner as to drive a screw into a tree, and thus, backfilling and compaction are unnecessary.

Thereafter, a lifting step of lifting the lower portion 11-2 of the utility pole and fitting the lower portion 11-2 into the anchor 12 is performed using a crane, or the like. The lower portion 11-2 of the utility pole is shorter than that of the utility pole in related art. For this reason, a risk of coming into contact with an obstacle is low, and handling is easy, so that it is possible to move to a target position through a relatively simple path.

In a step of building a utility pole on the ground in related art, delicate vertical adjustment is required because an excavated hole is not leveled. On the other hand, in the present construction method, the hole 12a of the anchor 12 has a structure for fitting the lower portion 11-2 of the utility pole, and thus, vertical adjustment is unnecessary when the lower portion 11-2 of the utility pole is fitted to the anchor 12.

In the subsequent step of attaching the upper portion of the utility pole, the construction work is completed only by fitting the end of the upper portion 11-1 of the utility pole into the upper end of the lower portion 11-2 of the utility pole.

Thus, in the present construction method, it is possible to reduce the amount of excavation work, reduce backfilling and compaction work, improve handling performance of the utility pole, and reduce the vertical adjustment work, and thus, the work is efficient.

REFERENCE SIGNS LIST

- 11 utility pole
- 11-1 upper portion of utility pole
- 11-2 lower portion of utility pole
- 12 anchor
- 12
  a hole
- 13 lock member
- 13
  a hole
- 13
  b spacer

ASSEMBLED UTILITY POLE, POLE BUILDING METHOD AND REBUILDING METHOD

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