JPH0365634B2 - - Google Patents

Description

[Detailed Description of the Invention] (Purpose of the Invention) A. Field of Industrial Application The present invention is intended for use in equipment installed underground to protect various electrical equipment and facilities from abnormal high-voltage currents caused by lightning damage, etc. This article relates to a method for burying a ground electrode.

B. Prior art If the above-mentioned grounding requires a particularly low resistance value, use a boring machine to drill a vertical hole that reaches a good battery layer deep underground, and then install a grounding layer made of a round rod of a good conductive metal in the vertical hole. An effective method is to insert and bury the rods one after the other.

In order to further ensure the effect, a ground resistance reducing agent (hereinafter referred to as reducing agent) solution is usually injected and filled into the gap between the grounding rod and the vertical hole, and the reducing agent hardens after a certain period of time. A method is adopted to maintain good contact between the ground rod and the soil on the inner wall of the vertical hole.

C. Problems to be Solved by the Invention According to the above-mentioned conventional technology, the steps of filling a reducing agent into a vertical hole drilled by a boring machine and inserting a grounding rod are as follows.

Figure 5 shows the state immediately after the drilling to the required depth has been completed using a boring machine. Inject solution E under pressure.

The reducing agent E solution that passes through the boring rod 5 and jets out from the tip of the bit 6 has a specific gravity several orders of magnitude higher than that of the circulating water D, so it pushes up the circulating water D from below the vertical hole A, and finally drains the entire amount out of the hole. The reducing agent E solution stays in the vertical hole A instead.

After that, immediately move the boring rod 5 to the vertical hole A.
Then, the ground rod 7 of a predetermined length is successively inserted into the vertical hole A where the reducing agent E solution is retained, but problems often occur at this stage.

Since the reducing agents that are currently widely used are so-called cement-based reducing agents whose main component is lime, the time limit from solution to hardening must be considered to be at most one hour.

That is, if the above steps are followed, it is necessary to finish inserting the grounding rod 7 within one hour after starting to inject the reducing agent E solution.

However, if the excavation depth exceeds 100 m, it may take nearly an hour just to pull out the boring rod 5, and in that case, by the time the grounding rod 7 is inserted, the reducing agent E in the vertical hole A has already been removed.
The solution leaves the solution state and begins to harden, and in the worst case, insertion of the ground rod 7 must be abandoned midway through. (Fig. 6) (Structure of the Invention) D. Means for Solving the Problems The biggest cause of problems in the above conventional technology is that the circulating water D is removed from the vertical hole A through the boring rod 5. This is where the reducing agent E solution is injected.

Therefore, even after the reducing agent E solution is filled into the vertical hole A, various tasks that cannot be completed in a short time, such as pulling out the boring rod 5 together with the bit 6 and inserting the grounding rod 7 while adding it, are still necessary. It is very difficult to complete these operations within an hour, especially when the excavation depth is large.

Therefore, the present invention allows the vertical hole A to be opened immediately after the completion of excavation.
The bit 6 and the boring rod 5 are pulled out from the pipe, and the ground electrodes 1, 1, which are made of a hollow metal tube and have a spout 4 only at the tip, are inserted into the vertical hole A where the circulating water D stays. The reducing agent E solution was injected through the hollow interior of the electrodes 1, 1, and the circulating water D was gradually pushed up from the tip of the vertical hole A, so that the entire amount was discharged out of the hole.

When the discharge of the circulating water D is completed, the reducing agent E solution automatically stays in the vertical hole A, so that the insertion of the ground electrodes 1 and 1 and the filling of the reducing agent E solution are already completed at this point.

Various operations performed after filling the reducing agent E solution as in the conventional technology are omitted, and the ground electrodes 1, 1 are connected to the vertical hole A.
The problem caused by the conventional technique is solved because the work of inserting the reducing agent into the fluid is completed at an early stage before the injection of the reducing agent E solution.

E. Functions and Examples An embodiment of the present invention will be described with reference to the drawings. Fig. 1 shows a grounding electrode 1 made of a hollow, good-conducting metal tube, with a screw 2 internally installed at the tip for a connecting leg, and a screw 2 at the rear. A hollow nipple 3 is attached to the end.

FIG. 2 shows the tip electrode 1 used at the first node of the ground electrode 1 which is inserted into the vertical hole A, and the tip is provided with a spout 4 for the reducing agent E solution to be press-fitted. A hollow nipple 3 is attached to the rear end to connect with the ground electrode 1.

Figure 3 shows that after the boring machine has finished drilling to the required depth and the bit 6 and boring rod 5 have been pulled out and withdrawn from the vertical hole A, the hollow ground electrode 1 is removed.
is inserted into the vertical hole A while adding it to the rear of the tip electrode 1, and the reducing agent E is passed through the hollow inside of the ground electrode 1.
Shows the state in which the solution is being pressurized.

In the figure, the white arrow is the reducing agent E solution, and the black arrow is the circulating water D. Since the reducing agent E solution, which has a specific gravity several orders of magnitude higher, is press-fitted, the circulating water D is gradually introduced from the hollow inside of the ground electrode 1. After being pushed out and reaching the spout 4 of the tip electrode 1, the entire amount of the circulating water D is finally discharged into the water retention tank C outside the hole through the gap B between the ground electrodes 1, 1 and the vertical hole A.

At this stage, the ground electrodes 1, 1 are inserted into the vertical hole A, and at the same time, the filling of the reducing agent E solution is completed, and after the predetermined curing time has elapsed, the inside and outside of the ground electrodes 1, 1 are The remaining reducing agent E solution hardens, and the ground electrodes 1, 1 come into good intimate contact with the soil on the inner wall of the vertical hole A via the reducing agent E.

(Effects of the Invention) According to the present invention, the discharge of the circulating water D and the injection and filling of the reducing agent E solution can be performed on the hollow ground electrodes 1 and 1.
, the integration of the grounding electrodes 1 and 1 with the reducing agent E and the close contact between the reducing agent E and the soil on the inner wall of the vertical hole A can be achieved reliably, and after filling the reducing agent E solution, the conventional technique can be achieved. Since the various operations required for this method are omitted, there is no need to adjust the curing speed of the reducing agent, and inexpensive quick-drying reducing agents can also be used, contributing to a reduction in construction costs.

[Brief explanation of drawings]

The drawings relate to the ground electrode embedding method of the present invention; FIG. 1 is a side view showing the shape of the ground electrode 1, and FIG. 2 is a side view showing the shape of the tip electrode 1. 3 and 4 are partially cut-away side views for explaining the process, and FIGS. 5 and 6 are partially cut-away side views for explaining the prior art. Notes: 1... Ground electrode, 1... Tip electrode, 2...
Screw, 3... Nipple, 4... Spout, 5... Boring rod, 6... Bit, 7... Ground rod,
A... Vertical hole, B... Gap, C... Retention tank, D...
Circulating water, E...reducing agent.

Claims (1)

[Claims] 1 After drilling a vertical hole to the required depth using a boring machine under the circulating water method, the pit and boring rod are pulled out of the vertical hole, and a hollow conductive metal is inserted into the vertical hole where the circulating water still remains. A grounding electrode consisting of a tube with a spout hole drilled only at the tip is inserted, and then a grounding resistance reducing agent solution with a higher specific gravity than the circulating water is injected through the hollow interior of the grounding electrode to blow out the tip of the grounding electrode. The circulating water is ejected from the hole and the entire amount is discharged to the outside of the vertical hole. At the same time, the vertical hole is filled with the ground resistance reducing agent solution. After a predetermined period of time, the earthing resistance reducing agent is poured into the hollow of the ground electrode inside the vertical hole. A method for burying a ground electrode, characterized by hardening it inside and between the ground electrode and the vertical hole.