JPH053116B2 - - Google Patents

Description

[Detailed Description of the Invention] [Objective of the Invention] (Industrial Application Field) The present invention provides a system for placing various electrical equipment and facilities underground to protect them from abnormal high-voltage currents caused by lightning damage, etc. The present invention relates to a grounding (earth) electrode, and more specifically, to the structure of a grounding pipe that constitutes the grounding electrode.

(Prior Art) Conventionally, when a particularly low grounding resistance value is required, a boring machine is used to drill a vertical hole that reaches a good conductive layer deep underground, and a good conductive layer is placed inside the vertical hole. A ground electrode is constructed by inserting and burying a pipe-shaped (rod-shaped) ground rod (hereinafter referred to as a ground pipe) made of a flexible metal.

In order to further ensure the low earth resistance value mentioned above, a solution of a ground resistance reducing agent (hereinafter referred to as the reducing agent) is injected and filled between the earth pipe and the vertical hole to maintain a constant level. A method is adopted in which the earth pipe is hardened after a period of time and a good contact state between the earth pipe and the soil on the inner wall of the vertical hole is maintained via the reducing agent.

(Problems to be Solved by the Invention) According to the above-mentioned conventional technology, the process of inserting a ground pipe into a vertical hole drilled by a boring machine while adding it to form a ground electrode is as follows.

First, a vertical hole is excavated to the required depth using a boring machine.

After this, a hollow boring rod (drilling pipe) used during boring and still placed in the shaft is used to extract the circulating water used for boring in the shaft and to obtain a low resistance value. ) Press the reducing agent in.

In other words, when the reducing agent is passed through the boring rod (drilling pipe) and ejected from the tip of the bit, which is the drilling blade, the reducing agent pushes up the circulating water, and the entire amount is finally discharged out of the hole, and the reducing agent is replaced by the reducing agent. will remain in the vertical hole.

After that, the boring rod (excavation pipe) is immediately pulled up from the vertical hole, and the grounding pipe of a predetermined length is inserted into the vertical hole where the reducing agent accumulates, adding earth pipes of a predetermined length one by one. (ground) constitutes an electrode.

In this case, the excavation depth of the vertical hole formed by boring may reach more than 100 m, and there is a strong demand to streamline the work of sequentially connecting and burying earth pipes of a predetermined length.

This is based on the following reasons.

That is, since the conventional method of connecting the earth pipes described above is a screw connection, it takes a long time to connect them, and as a result, it is not possible to connect and insert a predetermined number of earth pipes within the curing time of the reducing agent. This is because there are cases where the insertion of the ground pipe has to be abandoned midway through.

In addition, in the conventional earth electrode installation method described above, the connection method of each earth pipe is screw connection, so the contact of the registration connection is unstable.
There are disadvantages such as the screw connection part being susceptible to corrosion and the processing cost being high, so the development of a more appropriate connection method is awaited.

The present invention makes it possible to improve the efficiency of the work and to obtain sufficient earthing characteristics over a long period of time in a device in which a ground electrode is disposed using a vertical hole with a deep excavation depth formed by the above-mentioned boring. This is an attempt to provide a structure for an earth pipe.

[Structure of the Invention] (Means for Solving the Problems) To summarize the present invention, the present invention utilizes a vertical hole excavated by a boring machine, and a hollow excavated pipe placed in the vertical hole. Insert well-conductive earth pipes 1 of a predetermined length into the vertical hole one after another by crimping and connecting the rear end of the leading earth pipe and the tip of the trailing earth pipe near the above-ground opening of the vertical hole,
A grounding lead wire is fixed to the rear end of the last grounding pipe, and a reducing agent is injected around the connected grounding pipe, and the excavation pipe is removed to form the grounding electrode. The structure of a highly conductive earth pipe 1 of a predetermined length for use is as follows: (i) The crimp fixing part 2 at one end fits into the rear end of another preceding earth pipe, and the rear end is crimped. It has a connecting protrusion 4 for connecting an earth pipe, which sometimes connects another earth pipe by crimping,
and (ii) when the earth pipe connecting protrusion 4 fixed to the tip of another trailing earth pipe is fitted to the other end, and the other end is crimped, the earth pipe goes behind. The present invention relates to a structure of an earth pipe for an earth electrode, characterized in that it has a crimp part 3 for crimping and connecting another earth pipe.

Hereinafter, the configuration and embodiments of the present invention will be described in detail based on the drawings.

FIG. 1 is a front view showing the structure of the earth pipe 1 of the present invention.

The earth pipe 1 of the present invention is made of a good conductive metal tube and has a predetermined length, and has a structure in which the front and rear earth pipes are efficiently crimped and connected. That is, a connecting protrusion 4 for connecting an earth pipe that fits into the rear end of the preceding earth pipe and connects the preceding earth pipe by crimping is fixed to the crimping fixing part 2 at one end, and a connecting protrusion 4 for connecting the earth pipe is crimped and fixed to the other end. This has a structure in which a crimping part 3 is provided for fitting a connecting protrusion 4 for connecting the earth pipe which is crimped and fixed to the trailing earth pipe and connecting the trailing earth pipe by crimping.

When connecting a plurality of the earth pipes 1 described above of the present invention, the earth pipe 1 to be connected and inserted into the vertical hole is crimped and fixed to the crimping part 3 at the rear end of the preceding earth pipe 1. The connecting protrusion 4 for connecting the ground pipe is fitted, and the crimping part 3 is
They can be connected by crimping them using a hydraulic crimping machine or the like.

FIG. 2 shows the last earth pipe 1 after a plurality of earth pipes 1 are connected as described above.
2 is a partially cutaway front view of the structure of a lead terminal 5 used for fixing a grounding lead wire to the end of the lead terminal 5. FIG.

As shown in FIG. 2, the lead wire fixing terminal 5
The lead wire fixing terminal comprises a lead wire fixing terminal connecting protrusion 4' for crimping and fixing the lead wire fixing terminal 5 to the end of the last earth pipe 1, and a lead wire fixing part for fixing the lead wire 6.

Although FIG. 2 shows a lead wire fixing section in which the lead wire is inserted into a recess and fixed therein, the present invention is not limited to this structure.

Next, an example of a construction method of sequentially connecting the above-described earth pipes 1 of the present invention to form an earth electrode will be explained with reference to the drawings.

In order to sequentially connect and bury the above-described earth pipes 1 of the present invention to form an earth electrode, first,
As shown in Figure 3, a vertical hole is drilled using a boring machine to reach a conductive layer deep underground.

FIG. 3 shows the vertical hole thus drilled and formed by the boring machine, and is a sectional view of the boring rod, that is, the drilling pipe 7 placed in the vertical hole.

In FIG. 3, reference numeral 8 indicates an excavation blade (bit) attached to the tip of the excavation pipe 7, and numeral 9 indicates a connecting screw for connecting the excavation blade 8 to the excavation pipe 7.

Then, as shown in FIG. 4, the next work step is started.

(i) Inside the excavation pipe 7, multiple earth pipes 1,
1,... to the connecting protrusion for connecting the earth pipe 4, 4,
Insert while crimping and connecting via...

Although the desired number of earth pipes 1, 1, . . . are not connected to each other in FIG. 4, it goes without saying that they are crimped and connected near the opening of the vertical hole. . Specifically, in the vicinity of the opening of the vertical hole, the tip of the earth pipe that is about to be connected to the rear end of the preceding earth pipe, that is, the crimp portion 3 of the preceding earth pipe, that is, the connecting protrusion for connecting the earth pipe. 4, and crimped and connected using a hydraulic caulking machine or the like.

(ii) Fix the ground wire fixing terminal 5 shown in FIG. 2 to the end of the last ground pipe 1.

(iii) Inject the reducing agent 10 from the rear of the excavation pipe 7.

(iv) Simultaneously with the injection of the reducing agent in (iii) above, the excavation pipe 7 is gradually pulled out leaving the excavation blade 8 attached to its tip.

(v) The reducing agent is sequentially filled into the vertical hole from the bottom by ejecting the reducing agent from the opening at the tip of the excavated pipe 7 and pulling the excavated pipe up. Through this operation, the circulating water for boring or groundwater that remains in the vertical hole can be replaced with a reducing agent whose specific gravity is several times larger than that of the circulating water or groundwater.

(vi) By curing the reducing agent, the earth pipes 1, 1,
The earth electrode constructed by crimping and connecting a plurality of ... maintains good contact with the soil on the inner wall of the vertical hole.

As described above, construction of the earth electrode is completed. Figure 5 shows a sectional view at the end of the installation.

In FIG. 5, reference numeral 11 indicates the hardened reducing agent in the vertical hole, and 12 indicates the inner wall surface of the vertical hole. The surroundings of ... and the inner wall surface of the vertical hole 1
The state in which the reducing agent is cured between 2 and 3 is shown.

〔Effect of the invention〕

The present invention utilizes a vertical hole with a deep excavation depth formed by a boring machine and further applies a reducing agent to construct an earth electrode, and the structure of an earth pipe, which is a main element of the earth electrode. It is an attempt to improve the

That is, the present invention provides an earth electrode in which a plurality of good conductive earth pipes of a predetermined length are connected and inserted into a vertical hole with a deep excavation depth. It has a connecting protrusion for connecting an earth pipe that fits into another earth pipe that precedes the earth pipe and connects the preceding earth pipe by crimping, and the earth pipe is connected to the other earth pipe that is fixed to the other earth pipe that follows. It is characterized by employing a structure having a crimping part for fitting the connecting protrusion and crimping and fixing the trailing earth pipe.

Therefore, the earth pipe of the connection method of the present invention is
A simple method is to fit the earth pipe linking connecting protrusion of the earth pipe to be connected into the crimping part of the rear end of the preceding earth pipe, and crimping the crimping part of the preceding earth pipe using a hydraulic crimping machine or the like. Since the earth pipes can be reliably connected to each other, the connection work is extremely efficient.

Further, in the present invention, since the connecting means for each earth pipe is a simple method of crimping, it is more economical than conventional screw connections.
Furthermore, in the case of conventional screw connections, it is difficult to ensure stable grounding resistance over a long period of time due to poor contact or corrosion at the connection parts, but the present invention eliminates these drawbacks.

Furthermore, when applying the earth pipe of the present invention and arranging the earth electrode, there is no need to consider the hardening time of the reducer as in the past, and the earth electrode can be reliably placed in the deep excavation depth of the vertical hole. can do.

[Brief explanation of the drawing]

FIG. 1 is a front view showing the structure of the earth pipe of the present invention. FIG. 2 is a front view showing the structure of a lead wire fixing terminal fixed to the end of the earth pipe. 3 to 5 are explanatory diagrams of a method of constructing a ground electrode using the ground pipe of the present invention. FIG. 3 is a diagram illustrating an excavation pipe placed in a vertical hole excavated by a boring machine. FIG. 4 is a diagram illustrating the process of inserting a connected earth pipe into an excavation pipe and injecting a reducing agent. FIG. 5 is a diagram illustrating the completed state of construction. 1...Earth pipe, 2...Crimp fixing part, 3...
...Crimp part, 4... Connecting protrusion for connecting earth pipe, 5
...Lead wire fixed terminal, 4'...Connecting protrusion for lead wire fixed terminal, 6...Lead wire.

Claims (1)

[Claims] 1. Using a vertical hole excavated by a boring machine, a conductive earth pipe 1 of a predetermined length is sequentially placed in a hollow excavated pipe arranged in the vertical hole, after the preceding earth pipe. The end and the tip of the trailing earth pipe are crimped and connected near the above-ground opening of the vertical hole, and the earth lead wire is fixed to the rear end of the last earth pipe, and the connected earth pipe is inserted. In a structure in which a grounding electrode is constructed by injecting a reducing agent around the pipe and removing the excavated pipe, the structure of the high-conductivity grounding pipe 1 of a predetermined length for the grounding electrode includes: (i) a crimped solid at one end; The part 2 has a connecting protrusion 4 for connecting the earth pipe which fits into the rear end of another preceding earth pipe and connects the other preceding earth pipe by crimping when the rear end is crimped. ,
and (ii) when the earth pipe connecting protrusion 4 fixed to the tip of another trailing earth pipe is fitted to the other end, and the other end is crimped, the earth pipe goes behind. A structure of an earth pipe for an earth electrode, characterized in that it has a crimping part 3 for crimping and connecting another earth pipe.