JP5788446B2 - Telephone pole installation method - Google Patents

Description

  The present invention greatly improves the workability when installing a utility pole by efficiently forming a construction pole hole for constructing a utility pole and a ground hole for embedding a grounding pole, and effectively reduces the grounding resistance value. The present invention relates to the installation method of electric poles to be reduced.

In order to discharge the electric charge accumulated in the utility pole for installing the overhead wire to the ground, it is obliged to install a grounding pole when newly installing the utility pole.
The method of installing a grounding pole is, for example, a power pole with a grounding rod (grounding pole) of about 10 mm in diameter and about 1.5 m in length attached to the lower end of the power pole in a pole pole for burying a power pole excavated at the time of the construction pole. And a grounding rod and an overhead ground wire are electrically connected (for example, Patent Document 1). This method has the advantage that the work efficiency is good because the construction of the ground electrode can be performed simultaneously with the construction pole of the utility pole.

JP 2006-336382 A

When installing a grounding electrode, it is obliged to ensure a grounding resistance value below the specified value. If it is found that a predetermined ground resistance value has not been obtained after the installation of the ground electrode, it is necessary to add a ground electrode to ensure a specified ground resistance value. In construction to add a grounding electrode, an additional grounding rod (grounding electrode) is driven into the ground from the ground surface, or a new grounding hole is dug to embed an additional grounding electrode in the ground. . Then, the previously installed grounding electrode and the additional grounding electrode are connected in parallel so that the combined grounding resistance value becomes a specified value or less.
The construction to add a grounding electrode will increase labor costs and construction costs, so it is desirable to avoid them as much as possible.
The present invention has been made in view of the above-described circumstances, and greatly improves the workability of installing a utility pole by efficiently forming a construction pole hole for constructing a utility pole and a ground hole for embedding a grounding pole. And it aims at providing the installation method of the new utility pole which aims at effective reduction of a grounding resistance value.

In order to solve the above-mentioned problem, the invention according to claim 1 is characterized in that a building pillar hole is formed in the ground from the ground surface by the excavating means, and the lower end portion of the utility pole is buried, An excavation process for simultaneously excavating a grounding hole for embedding a grounding pole having a diameter smaller than that of the building pillar hole from the center of the lower surface and a grounding for disposing the grounding electrode in the grounding hole It has a pole arrangement | positioning process and the building pillar process which embeds the lower end part of the said electric pole in the said building pillar hole, It is characterized by the above-mentioned.
As the tip of the grounding electrode is buried deeper, the grounding resistance value decreases, and the charge accumulated in the utility pole can be efficiently discharged to the ground. In the invention of claim 1, the grounding resistance is effectively reduced by forming the grounding hole below the building pillar hole and disposing the grounding electrode in the grounding hole.
According to a second aspect of the present invention, the grounding electrode disposing step includes a step of disposing the grounding electrode in the grounding hole, and a step of filling a grounding resistance reducing agent in the grounding hole in which the grounding electrode is disposed. It is characterized by.
In the invention of claim 2, since the grounding resistance reducing agent is filled in the grounding hole, the grounding resistance value can be further reduced. Further, by forming the grounding hole, a sufficient amount of grounding resistance reducing agent can be filled, and the grounding resistance reducing effect of the grounding resistance reducing agent can be maximized.

According to a third aspect of the present invention, the excavating means includes a first rotating shaft that is rotationally driven by a rotating machine, and a first excavating blade that is spirally formed around the first rotating shaft. Pillar hole excavating means for excavating a hole, and a ground hole excavating means for excavating the ground hole by being attached to the tip of the pillar hole excavating means coaxially with the first rotation shaft and relatively unrotatable. It is characterized by having.
In the invention of claim 3, since the ground hole drilling means is coaxially fixed to the tip of the pillar hole excavating means conventionally used for excavating the pillar hole, the conventional construction machine used for the pillar is It can also be effectively used in the method of the present invention.
According to a fourth aspect of the present invention, the grounding hole excavating means includes a second rotating shaft that rotates integrally with the first rotating shaft, a second excavating blade that is spirally formed around the second rotating shaft, It is characterized by having.
According to the ground hole drilling means of claim 4, the ground hole can be reliably drilled.
The invention according to claim 5 is characterized in that the grounding hole excavating means includes a second rotating shaft including a coupled portion that is detachably coupled to a tip of the first rotating shaft.
In the invention of claim 5, when the ground hole excavating means is broken, it can be easily replaced.

  According to the present invention, since the building pillar hole and the grounding hole are excavated simultaneously, the workability of installing the utility pole can be significantly improved. In addition, since the ground hole is formed below the pillar hole, the ground electrode can be buried deeply, and the ground resistance value can be effectively reduced.

(A) is a figure which shows the outline | summary of the grounding electrode embed | buried by the conventional construction method, (b) is a figure which shows the outline | summary of the grounding electrode embed | buried by the construction method of this invention. It is the graph which showed the relationship between the embedding depth of a grounding rod, and a grounding resistance value. It is a side view which shows the general | schematic structure of an excavation pillar car, and the excavation process of an architectural pillar hole and a grounding hole. It is a disassembled perspective view of an excavation means. (A), (b) is a side view which shows the arrangement | positioning process of a grounding electrode. It is a side view which shows the building pole process of an electric pole.

  First, the ground resistance value obtained by the conventional construction method and the ground resistance value obtained by the construction method of the present invention will be described. FIG. 1A is a diagram showing an outline of a ground electrode embedded by a conventional method, and FIG. 1B is a diagram showing an outline of a ground electrode embedded by a method of the present invention.

  In the conventional method, as shown in FIG. 1A, a pole hole 103 is excavated from the ground surface 101 in order to embed the lower end portion of the electric pole 107, and a grounding electrode 105 (grounding rod) is placed in the pillar hole 103. It was arranged and embedded together with the lower end of the electric pole 107. For this reason, the embedding depth of the ground electrode 105 (the depth from the ground surface at the tip of the ground electrode) is the same as the depth of the excavated building pillar hole 103. In this figure, the depth of the pillar hole 103 is 2.5 m. Further, it is assumed that the ground electrode 105 is a single connection type ground rod having a length of 1.5 m. Reference numeral 109 in the figure is a lead wire for guiding charges from an imaginary ground wire (not shown) to the ground electrode 105.

FIG. 2 is a graph showing the relationship between the buried depth of the grounding rod and the grounding resistance value. This figure is excerpted from Electric Joint Research Vol. 63, 1P28. In this graph, the soil resistivity is 100 Ω · m, but in the following description, the earth resistivity is 300 Ω · m (three times the soil resistivity). As shown in the drawing, the grounding resistance decreases as the grounding rod is buried deeper, and decreases as the diameter of the grounding rod increases (the surface area increases).
When the diameter of the ground electrode 105 embedded in FIG. 1A is 10 mm, the ground resistance value obtained by one ground electrode 105 is “45Ω × 3 = 135Ω” from FIG. 2. Here, when it is necessary to secure a ground resistance value of 54Ω, since the ground electrode 105 alone has only a ground resistance value of 135Ω, a construction for adding new ground electrodes 111 and 111 is performed to perform the ground resistance value. Need to be reduced.

As additional grounding poles 111 and 111, a grounding rod having a diameter of 10 mm (two connecting grounding rods each having a length of 1.5 m are connected in the longitudinal direction to have a total length of 3 m) is driven into two places. Then, consider the case of connecting in parallel with the ground electrode 105 previously installed via the lead wire 113.
When the embedment depth of the additional grounding electrodes 111 and 111 is 3.75 m, the grounding resistance value obtained by the additional grounding electrode 111 alone is “35Ω × 3 = 105Ω”, respectively. Therefore, the combined resistance value of the additional ground electrodes 111 and 111 is “1.3 × 105 × 105 / (105 + 105) = 68Ω”. The combined grounding resistance value obtained by the grounding pole 105 and the additional grounding poles 111 and 111 previously constructed is “1.2 × 135 × 68 / (135 + 68) = 54Ω”. The numerical values “1.3” and “1.2” are coupling coefficients obtained empirically.
Thus, in the conventional method, the depth of the tip of the ground electrode 105 is the same as the depth of the pillar hole 103, and therefore there is a limit to the ground resistance value that can be secured only by the ground electrode 105 embedded at the time of the pillar. As a result, work for adding the grounding electrodes 111 and 111 is likely to be required.

On the other hand, in the method of the present invention shown in FIG. 1B, a grounding hole 123 for embedding a grounding electrode is formed below the building pillar hole from the lower surface 121 a of the building pillar hole 121, and the grounding electrode 125 is placed in the grounding hole 123. Buried. For example, when a grounding hole 123 having a depth of 2.0 m is drilled downward from the lower surface 121a of the pillar hole 121 having a depth of 2.5 m, the embedding depth of the grounding electrode 125 (depth of the tip of the grounding electrode) is 4.5 m. It becomes. If a grounding rod (length: 1.5 m) having a diameter of 50 mm is embedded in the grounding hole 123 as the grounding electrode 125, the grounding resistance value is “18Ω × 3 = 54Ω” from FIG.
As described above, in the construction method of the present invention, since the embedding depth of the ground electrode 125 can be determined regardless of the depth of the pillar hole 121, it is easy to secure a desired ground resistance value. Further, since the ground electrode 125 is positioned below the pillar hole 121, the ground resistance value can be effectively reduced even with the ground electrode 125 alone. Therefore, the additional work of the grounding electrode, which was necessary in the past, becomes unnecessary, and the construction cost and labor cost associated with the additional work can be greatly reduced.

  Hereinafter, the method of the present invention will be specifically described. However, the components, types, combinations, shapes, relative arrangements, and the like described in this embodiment are merely illustrative examples and not intended to limit the scope of the present invention only unless otherwise specified. .

  The utility pole installation method according to one embodiment of the present invention is a construction of a pillar hole 121 formed in the ground from the ground surface 101 for embedding the cylindrical lower end of the utility pole, and a bottom surface center of the pillar hole 121. It has a drilling process in which a grounding hole 123 for burying a grounding pole 125 having a diameter smaller than that of the building pillar hole 121 is formed in the drilling pillar car at the same time by a drilling means formed below the building pillar hole 121. There is a feature.

First, an excavation pillar car will be described with reference to FIG. FIG. 3 is a side view showing a schematic configuration of a digging pillar car and a digging process of a pillar hole and a grounding hole.
The excavated pillar car 10 includes a vehicle body 11, a swivel base 12 that is mounted on the car body 11 so as to be horizontally swivelable, and a boom 13 that is provided at the top of the swivel base 12 and that can be raised and lowered. Yes.
The boom 13 includes a proximal boom 13a, an intermediate boom 13b, and a distal boom 13c from the swivel base 12 side, and the three-stage boom is configured to be telescopically telescopic. An auger support member 14 that supports the excavating means 30 is disposed at the tip of the boom 13. An auger reducer 15 (rotary machine) is attached to the auger support member 14, and the auger support member 14 supports the excavating means 30 via the auger reducer 15. The auger reducer 15 decelerates the rotation of a hydraulic motor (not shown) as a driving means and transmits it to the excavating means 30 to rotate the excavating means 30.

FIG. 4 is an exploded perspective view of the excavating means. The excavating means 30 includes a pillar hole excavating means 31 and a ground hole excavating means 51.
The pillar hole excavating means 31 is means for excavating the pillar hole 121, and is supported by the auger speed reducer 15 (rotary machine: see FIG. 3) and is rotated by the auger speed reducer 15 (first rotating shaft 33). 33a, 33b), the first excavating blade 35 formed in a spiral around the first rotating shaft 33 (33a), and the diameter from the side surface near the tip of the first rotating shaft 33 (the side surface of the first rotating shaft 33b). An auger head 37 that protrudes in the direction, and a coupling portion 39 that is disposed at the tip of the first rotating shaft 33 (33b) and removably couples the ground hole excavating means 51.
The building pillar hole excavating means 31 has a length and a diameter capable of excavating a building pillar hole corresponding to the size of the lower end portion of the power pole to be buried. For example, when the installed utility pole is about 0.3m in diameter and the length of the lower end of the utility pole buried in the ground is 2.5m, drilling a pillar hole of about 0.5m in diameter and about 2.5m in total length A column hole excavating means 31 having an axial length and a radial length as possible is used.
The connecting portion 39 is a means for connecting and integrating the ground hole excavating means 51 so as not to rotate relative to each other, and has a square hole 39a having an opening at the front end surface of the first rotary shaft 33 and extending toward the rear end in the axial direction. A through hole 39b is formed through the first rotating shaft 33 in a direction orthogonal to the axial direction. The through hole 39b is formed at an axial position corresponding to the square hole 39a of the first rotary shaft 33, and the through hole 39b communicates the outside of the first rotary shaft 33 with the inside of the square hole 39a.

The ground hole excavating means 51 is a means for excavating the ground hole 123, a second rotating shaft 53 that is coaxially attached to the front end of the pillar hole excavating means 31 and is relatively non-rotatable, and a second rotating shaft 53. A second excavating blade 55 formed in a spiral shape around the rotary shaft 53, a cutting drill portion 57 provided at the tip of the second rotary shaft 53, and a rear end of the second rotary shaft 53. And a coupled portion 59 detachably coupled to the portion 39. The second rotating shaft 53 coupled to the first rotating shaft 33 rotates integrally with the first rotating shaft 33.
The ground hole excavating means 51 has a length and a diameter capable of excavating a ground hole corresponding to the size of the buried ground electrode. For example, when the grounding electrode to be embedded is a long rod-shaped grounding rod (grounding electrode 125) having a total length of 1.5 m and a diameter of 50 mm as shown in FIG. 1B, a grounding having a total length of about 2 m and a diameter of about 54 mm. A grounding hole excavating means 51 having an axial length and a radial length so that the hole can be excavated is used.

  The coupled portion 59 is formed so as to protrude from the rear end of the second rotating shaft 53 in the axial direction and to be fitted into the square hole 39a, and to penetrate the rectangular column portion 59a in a direction perpendicular to the axial direction. Through-holes 59b. The square column part 59a of the grounding hole excavating means 51 is fitted into the square hole 39a of the building pillar excavating means 31, and the two through holes 39b and 59b are connected to each other, the bolt B is inserted, and the nut N is fastened. Thus, the grounding hole excavating means 51 can be fixed to the building hole excavating means 31 so as not to rotate relative to the building pillar excavating means 31 (so as to rotate integrally). As described above, since the ground hole excavating means 51 is detachably coupled to the tip of the first rotating shaft 33, the ground hole excavating means 51 corresponding to the size of the grounding electrode to be embedded can be attached to the first rotating shaft 33. it can. Further, when the ground hole excavating means 51 is broken, it can be easily replaced.

When excavating the pillar hole and the grounding hole by the excavating means 30, the hydraulic motor (not shown) of the excavating pillar car 10 shown in FIG. The shaft 33 and the second rotating shaft 53 are integrally rotated. When the excavating means 30 is pierced into the ground surface 101 from the ground hole excavating means 51 arranged on the tip side thereof and the ground is gradually excavated, the ground hole 123 is excavated by the ground hole excavating means 51 and at the same time The pillar hole 121 can be excavated by the hole excavating means 31.
In the present embodiment, the building column hole excavating means 31 and the contact hole excavating means 51 are rotated about the first rotating shaft 33 and the second rotating shaft 53 by the auger reducer 15 to thereby form the building column hole 121 and the contact hole 123. Since excavation is performed, the pillar hole 121 and the grounding hole 123 are formed coaxially (concentrically), and the two holes communicate with each other. Further, since the building pillar hole 121 having a diameter larger than that of the grounding hole 123 is formed at the rear end (upper side) of the small diameter grounding hole 123, the building pillar hole 121 and the grounding hole 123 have a stepped shape in a side sectional view.

As shown in FIG. 4, the first rotating shaft 33a includes a coupling portion 39 at the tip, the first rotating shaft 33b includes a coupled portion 59 at the rear end, and the auger head 37 includes the first rotating shaft 33a. It is comprised so that attachment or detachment is possible. For this reason, you may couple | bond the to-be-joined part 59 of the 2nd rotating shaft 53 directly with the coupling | bond part 39 of the 1st rotating shaft 33a.
In this example, the ground hole excavating means 51 provided with the spiral second excavating blade 55 is shown as the ground hole excavating means that can reliably excavate the ground hole. Of course, the ground hole drilling means can have a shape other than the above as long as it can drill a ground hole of a predetermined size.

  By the way, the earth auger of the digging column car 10 (see FIG. 3) as the excavating means for excavating the building pillar hole 103 in the conventional method shown in FIG. A bit adapter 131 and a pilot bit 133 are fixed at the tip. The bit adapter 131 includes a coupled portion 59 at the rear end in the axial direction, and is configured to be detachable from the first rotating shaft 33a. The grounding hole excavating means 51 used in the present invention utilizes a part of an earth auger conventionally used for excavating the pillar hole 103, so that existing construction machines can be used effectively.

  The installation method of the utility pole by embodiment of this invention is demonstrated based on FIG.3, FIG.5 and FIG.6. FIGS. 5A and 5B are side views showing a ground electrode disposing step. FIG. 6 is a side view illustrating a pole pole building process.

(Process 1: Excavation process)
As shown in FIG. 4, the bit adapter 131 and the pilot bit 133 are removed from the pillar hole excavating means 31 in advance, and the excavating means 30 in which the ground hole excavating means 51 is fixed to the tip of the auger head 37 is prepared.
In the excavation process, as shown in FIG. 3, a building pillar hole 121 for burying the cylindrical lower end portion of the utility pole is formed in the ground from the ground surface 101 by the excavating means 30, and has a smaller diameter than the building pillar hole 121. A grounding hole 123 for burying the grounding electrode is formed by excavation from the center of the lower surface of the building pillar hole 121 to below the building pillar hole 121. That is, a hydraulic motor (not shown) of the digging pillar 10 is driven to rotate, and the auger reducer 15 integrally rotates the first rotating shaft 33 and the second rotating shaft 53 of the excavating means 30. The excavation means 30 is pierced into the ground surface from the ground hole excavation means 51 arranged on the tip side thereof and gradually digged, so that the building pillar hole excavation means 31 and the ground hole excavation means 51 are grounded. The hole 123 is drilled simultaneously.

(Process 2: Ground electrode placement process)
In the ground electrode arrangement step, as shown in FIG. 5, a ground electrode 125 is arranged in the ground hole 123 excavated in the excavation step. In this step, first, the ground electrode 125 having the lead wire 109 connected to the rear end is disposed (inserted) in the ground hole 123 (FIG. 5A). Subsequently, the ground resistance reducing agent 127 is filled in the ground hole 123 in which the ground electrode 125 is disposed (FIG. 5B). Although it is not essential to fill the ground resistance reducing agent, filling the ground resistance reducing agent can effectively reduce the ground resistance value, and the work for adding the ground electrode is reduced.

(Process 3: Building Pillar Process)
In the building pillar process, the lower end portion of the utility pole 107 is embedded in the building pillar hole 121. As shown in FIG. 6, the rope 19a wound around the upper end side of the electric pole 107 is hung on the hook 18, the wire 17 is wound up by the winch 16, the boom 13 is operated, and the electric pole 107 is lifted in a standing posture. To move. The operator M performs a guide such as drawing the rope 19b wound around the lower end side of the electric pole 107 as appropriate, and arranges the lower end side of the electric pole 107 in the building pole hole 121 (see FIG. 1B). While confirming whether or not the electric pole 107 is standing vertically, soil is put into the gap between the electric pole 107 and the building pole hole 121 and hardened, and the lower end portion of the electric pole 107 is embedded in the building pole hole 121.
After building the utility pole 107, the lead wire 109 of the grounding pole 125 is connected to an aerial ground wire (grounding wire: not shown).

  In the above description, the ground hole drilling means and the ground electrode are configured separately, but the ground hole drilling means and the ground electrode may be used together to drill the ground hole using the ground pole. In this case, in the excavation process, the pillar hole is excavated by the pillar hole excavating means 31, and at the same time, the ground hole is excavated by the ground electrode as the ground hole excavating means 51. In the grounding electrode installation process, the ground hole excavating means as the grounding electrode is left in the grounding hole, and a ground resistance reducing agent is injected into the grounding hole (or in the ground around the grounding electrode) as necessary. What is necessary is just to implement a process.

The effect by embodiment of this invention is described.
(Effect 1)
Compared to the case where a ground pole is buried in a building pillar hole excavated at the time of a construction pole as in the prior art (FIG. 1A), the depth of embedding of the ground electrode can be increased in this embodiment (FIG. 1B). The ground resistance value can be effectively reduced. According to this embodiment, since it becomes easy to ensure a prescribed ground resistance value, the construction for adding a grounding electrode is reduced, and the labor cost and the construction cost can be reduced.

(Effect 2)
For example, when drilling a pillar hole and a grounding hole in multiple stages by the boring method, the process of drilling the grounding hole from the ground surface using the auger screw for grounding hole drilling and the auger screw for grounding hole drilling The process of exchanging the auger screw for excavation and the process of excavating the pillar hole from the ground surface so as to widen the inner diameter of the grounding hole using the auger screw for excavating the pillar hole, which increases the work process There is a problem. The excavation means of this embodiment has both a ground hole excavation means and a pillar hole excavation means, and since the ground hole and the pillar hole are excavated simultaneously in multiple stages, the work process and work time can be reduced. The workability is greatly improved.
Moreover, since the excavation means used in the embodiment of the present invention uses a part of an auger screw generally used for excavating a conventional pillar hole (see FIG. 4), a construction vehicle or the like. Effective use of existing construction machines.

(Effect 3)
Although depending on the size of the utility pole to be built, the pillar hole is typically about 50 cm in diameter and about 2.5 m in depth. For example, in order to drive a connecting ground rod into the ground from the lower end of the pillar hole, various difficulties such as being unable to be driven vertically and the ground rod being easily bent are accompanied. Furthermore, when the ground is hard, such as rock, the grounding rod may not be driven in itself, and in any case, it is difficult to bury the grounding rod deeply in the ground.
In the present invention, the grounding hole excavating means excavates the grounding hole for burying the grounding electrode. Therefore, there is no possibility that the grounding electrode is bent during the installation work of the grounding electrode.

(Effect 4)
When a grounding electrode (grounding rod) is directly driven into the ground by a conventional construction method, a grounding resistance reducing agent (liquid) can be injected into the ground to reduce the grounding resistance. However, since there is almost no gap between the ground and the grounding rod and it is difficult to sufficiently fill the grounding resistance reducing agent, there is a possibility that a desired grounding resistance reducing effect cannot be obtained. In the present invention, since the grounding rod is buried by excavating the grounding hole, a sufficient amount of grounding resistance reducing agent can be filled between the grounding rod and the side surface of the grounding hole. Can make the best use of it.

  DESCRIPTION OF SYMBOLS 10 ... Hole digging pillar, 11 ... Vehicle body, 12 ... Swivel base, 13 ... Boom, 13a ... Base end boom, 13b ... Intermediate | middle boom, 13c ... Tip boom, 14 ... Auger support member, 15 ... Auger reduction gear, 16 ... winch, 17 ... wire, 18 ... hook, 19a ... rope, 19b ... rope, 30 ... excavating means, 31 ... building hole excavating means, 33, 33a, 33b ... first rotating shaft, 35 ... first excavating blade, 37 ... auger head, 39 ... coupling part, 39a ... square hole, 39b ... through hole, 51 ... grounding hole drilling means, 53 ... second rotating shaft, 55 ... second drilling blade, 57 ... drill part, 59 ... coupled , 59a ... prismatic part, 59b ... through hole, 101 ... ground surface, 103 ... building pillar hole, 104 ... ground pole, 105 ... ground pole, 107 ... utility pole, 109 ... lead wire, 111 ... ground pole, 113 ... lead Line, 121 ... pillar hole, 121a Lower surface, 123 ... ground hole 125 ... ground electrode, 127 ... grounding resistance reducers, 131 ... bit adapter, 133 ... pilot bit

Claims (5)

A drill hole formed in the ground from the ground surface by the excavating means, and a lower part of the power pole is embedded from the center of the lower surface of the pole hole to the lower side of the pillar hole. A drilling process for simultaneously drilling a grounding hole for embedding a small-diameter grounding pole,
A grounding electrode disposing step of disposing the grounding electrode in the grounding hole;
A building pillar step of burying the lower end of the utility pole in the building pillar hole;
The installation method of the electric pole characterized by having.   The ground electrode disposing step includes a step of disposing the ground electrode in the ground hole, and a step of filling a ground resistance reducing agent in the ground hole in which the ground electrode is disposed. Installation method of telephone poles as described in 1. The excavation means has a first rotation shaft that is rotationally driven by a rotating machine, and a first excavation blade that is formed in a spiral shape around the first rotation shaft, and excavates the building column hole. Drilling means;
2. A grounding hole excavating means for excavating the grounding hole attached to the tip of the pillar hole excavating means coaxially with the first rotating shaft and not relatively rotatable. Or the installation method of the utility pole of 2.   The grounding hole excavating means includes a second rotating shaft that rotates integrally with the first rotating shaft, and a second excavating blade that is spirally formed around the second rotating shaft. The installation method of the utility pole of Claim 3.   5. The utility pole according to claim 3, wherein the grounding hole excavating means includes a second rotating shaft including a coupled portion that is detachably coupled to a tip of the first rotating shaft. Installation method.

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