JPH05149077A - Earth adhesion preventing device of ground boring machine - Google Patents

Abstract

PURPOSE:To make an auger of a ground boring machine as a minus electrode of direct current power supply generate an electroendosmose phenomenon and an electrolysis phenomenon and to prevent or reduce the adhesion of earth to the auger. CONSTITUTION:A plurality of antecedent piles 4 are driven in the ground E in the vicinity of a ground boring machine in advance by a pile driver. An auger 3 is lowered while forwarding it in parallel with the antecedent piles 4 in the ground E in the vicinity of the nearest antecedent pipe 4a, so that it bores and stirs the inside of the ground E, and then, it is drawn up while reversing it. The auger 3 is connected to a minus side of direct current power supply 5. The nearest antecedent pile 4a is connected to a plus side of direct current power supply 5, as a result, an electroendosmose phenomenon making the auger 3 and the antecedent pile 4a as the minus and plus electrodes respectively is generated and, at the same time, hydrogen gas is generated on the surface of the auger 3 as the minus side.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a soil adhesion preventing device for a ground drilling machine which prevents adhesion of earth and sand to an auger by utilizing an electroosmosis phenomenon caused by hydrogen gas and direct current generated by electrolysis.

[0002]

2. Description of the Related Art When excavating cohesive soil using a ground boring machine, the adhesion of earth and sand to the boring auger poses a problem.
For example, when excavating the ground by using a ground drilling machine to build a steel material or to construct a soil cement pile, it is necessary to leave the mixed soil at the current position. In this case, it is sufficient to pull up the driven auger while reversing it. Particularly, the cohesive soil is apt to adhere to the outer periphery of the auger shaft or the blade, and the phenomenon that the auger rises as it adheres easily occurs. When it is desired to drill a hole, it can be pulled up while rotating in the normal direction, but in many cases, the sediment deposited in a columnar shape around the auger is pulled up as it is.

In any case, conventionally, the adhered earth and sand was scraped off manually with a scoop or the like, or it was scraped off while rotating the blade, but it could not be efficiently removed. ..

[0004]

By the way, the present inventors have paid attention to the fact that the adhesion of earth and sand can be prevented by applying a direct current. That is, when a direct current is passed through the soil, the water content in the soil moves to the negative electrode side due to the electroosmosis phenomenon. Along with the movement of water, the water content in the adhered cohesive soil is increased, and in addition to the generation of hydrogen gas bubbles near the electrode, the adhesion force of the earth and sand to the electrode is reduced.

The present invention has been made on the basis of the above-mentioned points of view, and its object is to attach a soil to a ground boring machine, which is easy to work and can effectively prevent or reduce the attachment of a soil to an auger. A device is provided.

[0006]

In order to achieve the above-mentioned object, the present invention is to connect an auger for ground drilling to the negative side of a direct current power source, and to connect a conductor arranged close to the auger to the direct current. It is connected to the positive side of the power supply. Further, in the present invention, a positive electrode plate may be arranged in an electrically insulated state on the outer peripheral portion of the shaft of the auger so as to face each portion of the auger blade integrated with the outer periphery of the shaft.

[0007]

[Function] When a direct current is passed through the earth and sand, the water content in the earth moves to the outer periphery of the auger on the negative electrode side due to the electroosmosis phenomenon. Further, when hydrogen gas bubbles are generated on the outer periphery of the auger due to the electrolysis phenomenon, the earth and sand already attached to the auger is separated from the surface of the auger as if it were floating.

[0008]

Embodiments of the present invention will be described in detail below with reference to the drawings. FIG. 1 shows a first embodiment of the present invention. In the figure, a turret 2 is vertically arranged at the tip of a base machine 1 of a ground drilling machine, and an auger 3 is held along the turret 2 so as to be rotatable and vertically movable. The auger 3 has a hollow auger shaft 3a and auger blades 3 for ground agitation around the auger shaft 3a.
In addition to arranging b in a spiral shape, an auger bit 3c for excavation is arranged at the tip. Several preceding piles 4 have already been driven into the ground E near the punching machine by a pile driving machine (not shown). The auger 3 descends in the ground E in the vicinity of the nearest preceding pile 4a while rotating in the same direction as the preceding pile 4 while rotating forward, stirring the inside of the ground E, and then lifting it while reversing.

In this state, the auger 3 is connected to the negative side of the DC power source 5. Further, the closest preceding pile 4a is connected to the positive side of the DC power source 5, and as a result, an electroosmosis phenomenon occurs in which the auger 3 and the preceding pile 4a serve as negative and positive electrode portions, respectively.

Due to this electroosmosis phenomenon, the water content in the soil moves to the periphery of the auger 3 which is a negative electrode as shown by the arrow in the figure, and the water content in the soil around the auger 3 increases, and as a result, It will reduce the adhesion.

At the same time, hydrogen gas is generated around the auger 3 due to the electrolysis phenomenon, and oxygen gas is generated on the side of the preceding pile 4a. Then, due to the generation of this hydrogen gas, the earth and sand already attached to the periphery of the auger 3 is peeled off so as to float from the surface of the auger 3. As a result, the amount of earth and sand adhered to the auger 3 is reduced, and even if it is pulled up while adhering, it can be easily scraped off by other human power or mechanical means. As the DC power supply 5, a battery mounted on the base machine 1 can be used. Further, since the current capacity is determined by the distance between the leading pile 4a and the auger 3, it is sufficient to set the conditions for causing the electroosmosis phenomenon in advance according to the distance.

FIG. 2 shows a second embodiment of the present invention, in which the auger blade 3 is provided on the outer periphery of the auger shaft 3a.
The positive electrode plate 6 is spirally fixed at the same pitch as the pitch b, and faces each part of the auger blade 3b. The upper end of the electrode plate 6 is connected to the plus side of the DC power source 5 via a slip ring 7 in an insulated state. The auger shaft 3a itself is connected to the negative side of the DC power supply 5.

The plus electrode plate 6 is attached to the outer periphery of the auger shaft 3a in an insulating state, and has the attachment structure shown in FIG.

That is, the plus electrode plate 6 is installed on the surface of the auger shaft 3a through the insulating neoprene rubber 8 and the mounting holes 6a are formed at the respective places.
The mounting hole 6a is provided with a stud bolt 9 protruding from the surface of the auger shaft 3a, an insulating nylon washer 10
And is fixed to the outer periphery of the auger shaft 3 by tightening the protruding end of the stud bolt 9 with the cap nut 11.

In this embodiment, the auger shaft 3a and the auger blade 3 which serve as a negative electrode are provided as in the above embodiments.
As a result of the electroosmosis phenomenon and the electrolysis phenomenon occurring between the positive electrode plate 6b and the positive electrode plate 6, earth and sand are less likely to adhere to the surfaces of the auger shaft 3a and the auger blades 3b. Also,
It is suitable when there is no suitable electric conductor such as a leading pile nearby as in the above-mentioned embodiment or when it is used for a simple drilling work, and the auger shaft 3a and the auger blades forming the plus side electrode plate 6 and the minus electrode are used. Since the distance from 3b is constant, the current capacity for causing the electroosmosis phenomenon is also constant.

FIG. 4 shows another embodiment of the mounting structure of the positive electrode plate 6, in which the positive electrode plate 6 is mounted on the outer peripheral surface of the auger shaft 3a via an insulating neoprene rubber 8.
Is installed. In the fixed portion, a screw hole is formed on the auger shaft 3a side, while an insulating nylon washer 20 is arranged on the inner periphery of the mounting hole 6a of the positive electrode plate 6, and the flat bolt is inserted through the washer 20. Two
1 is screwed into the auger shaft 3a side, and the plus electrode plate 6 is fixed to the outer periphery of the auger shaft 3a. The head portion 21a of the flat head bolt 21 is flush with the surface of the positive electrode plate 6, and the structure has a structure in which earth and sand are hard to adhere by eliminating unnecessary irregularities.

FIG. 5 shows an embodiment of still another mounting structure of the positive electrode plate 6. In this structure, a spiral groove 30 is formed on the outer peripheral portion of the auger shaft 3a, and the positive electrode plate 6 is flush with the outer peripheral surface of the auger shaft 3a through an insulating neoprene rubber 31 having a concave cross section. It was buried so that In addition,
The fixing structure is the same as that of the above-mentioned embodiment, a nylon washer 20 for insulation is arranged on the inner periphery of the mounting hole 6a of the plus electrode plate 6, and the countersunk bolt 21 is screwed to the auger shaft 3a side through this washer 20. The positive electrode plate 6 is fixed by being mixed in.

In this embodiment, since there are no protrusions on the surface of the auger shaft 3a, it is more difficult for soil and sand to adhere than in the above embodiments. Moreover, even before the countersunk bolt 21 is screwed in, the plus electrode plate 6 and the like can be temporarily fixed to the auger shaft 3a, and the assembling work is easy.

[0019]

As described above in detail with reference to the respective embodiments, in the earth and sand adhesion preventing device of the present invention, when a direct current is applied to the earth and sand, the water content in the earth becomes a negative electrode due to the electroosmosis phenomenon. When it moves to the outer periphery of the auger which is the side, the water content in the adhered cohesive soil increases, and when hydrogen gas bubbles are generated on the outer periphery of the auger due to the electrolysis phenomenon, the earth and sand already attached to the auger rises due to the gas generation. Coupled with peeling from the surface,
In particular, when perforating a cohesive ground, it is possible to prevent or reduce the adhesion of sediment to the auger by simply adding a simple structure, and it is useful as a measure to prevent sediment adhesion.

[Brief description of drawings]

FIG. 1 is a cross-sectional explanatory view according to a first embodiment of the present invention.

FIG. 2 is an enlarged explanatory view of an auger according to a second embodiment of the present invention.

FIG. 3 is a partial cross-sectional view showing a mounting structure for a plus electrode plate.

FIG. 4 is a partial cross-sectional view showing an example of another mounting structure for a plus electrode plate.

FIG. 5 is a partial cross-sectional view showing an example of still another attachment structure of the positive electrode plate.

[Explanation of symbols]

 3 Auger 3a Auger shaft 3b Auger blade 4a Leading pile (conductor) 5 DC power supply 6 Positive electrode plate

Claims (2)

[Claims] 1. A ground boring machine, wherein an auger for boring ground is connected to a negative side of a DC power source, and a conductor arranged close to the auger is connected to a positive side of the DC power source. Sediment adhesion prevention device. 2. A positive electrode plate is disposed in an electrically insulated state on the outer peripheral portion of the shaft of the auger so as to face each portion of the auger blade integrated with the outer periphery of the shaft. Soil adhesion prevention device for ground drilling machine.