JP2000120100A - Auger excavation method and auger head for it - Google Patents

Abstract

PROBLEM TO BE SOLVED: To contrive the improvement of agitating efficiency and excavation efficiency by preventing adhesion of soil and sand on a blade by performing excavation while an edging aggregate is supplied between the spiral blade and soil and sand. SOLUTION: A set hole 12a is penetrated from the surface to the reverse at the planned set position of the jet nozzle of spiral blades 12A, 12B. The jet nozzle 20 having a flange 20a is fitted and fixed to connect the nozzle 20 and a soil and sand adhesion prevention supply opening by a connection pipe 21. The nozzle 20 is provided to position a jet opening more inner than a blade surface, and a diffusion passage part 23 is formed for diffusing prevention liquid on the surface of the blade. During excavation, excavation water supplies ground improvement liquid through the connection pipe 21 to the nozzle 20 for ground improvement, and the excavation is executed while it is fed to the surface of the blades 12A, 12B. Thereby the adhesion and deposit of soil and sand for the spiral blades 12A, 12B are eliminated to contrive the improvement of agitating efficiency and excavation efficiency.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an auger excavating method for excavating ground by providing spiral blades around a rod axis and penetrating the ground while rotating around the rod axis, and an auger head therefor. About.

[0002]

2. Description of the Related Art For example, in drilling, foundation piles, soil cement columns or continuous walls, ground improvement by various mechanical mixing methods, or the like, drilling holes are formed in the ground, or a solidified material and earth and sand are mixed. In order to stir and mix in situ, an excavator having an auger head attached to the tip of a rod that can rotate about a vertical axis is used.

As shown in FIG. 5, the auger head includes a pair of left and right spiral blades 52A around a head shaft 51.
A plurality of excavating claws 53, 53 are provided on the lower end edges of the spiral blades 52A, 52B so that the excavating claws 53, 53 cut off earth and sand with the rotation of the head shaft 51. While excavating, the spiral blade 52A,
The earth and sand removed by 52B is stirred with the ground improvement material injected from the lower end of the head shaft 51, and in the case of a hole, the excavated earth and sand is directly transported to the ground side. This type of auger head is mainly applied to a relatively soft stratum such as a silt layer, a clay layer, and a sand layer, and is used for construction of an auger stirrer for ground improvement or a Nakahori pile.

[0004]

However, when the ground excavated by the auger head is a sticky geological material such as a silt or a viscous soil, the spiral blade 52 is required.
A and 52B had problems such as silt or cohesive soil adhering and accumulating. More specifically, since silt or viscous soil adheres and accumulates on the surfaces of the spiral blades 52A and 52B, the shear boundary surface becomes shear between soil and soil, so that frictional resistance increases and the rod shaft rotates. The torque value increases. In addition, when the viscous soil adhered and deposited on the surfaces of the spiral blades 52A and 52B is included, the thickness of the spiral blades 52A and 52B is about 2-3 times larger than the original plate thickness of the spiral blades 52A and 52B. However, there have been problems such as a decrease in stirring efficiency or excavation efficiency due to reasons such as an increase in penetration resistance.

[0005] Therefore, a main object of the present invention is to eliminate the adhesion of earth and sand to the spiral blades of the auger head, and to improve the stirring efficiency and the excavation efficiency.

[0006]

According to the present invention, there is provided an auger excavating method for excavating a ground using an auger shaft on which spiral blades are fixed along the outer surface of the ground penetrating shaft. The present invention is characterized in that excavation is performed while supplying an edge-cutting sliding material between the spiral blade and earth and sand, thereby preventing the adhesion of earth and sand to the spiral blade.

[0007] In this case, examples of the edging lubricant for preventing the adhesion of the earth and sand include excavation water for drilling, ground improvement liquid for ground improvement, and compressed air supplied from a compressor lesser. It is preferably used.

[0008] On the other hand, the auger head according to the present invention includes a spiral blade fixedly provided along the periphery of the head shaft at least on the front end side of the head shaft, and excavation claws at a lower end edge of the spiral blade. An auger head mounted on the tip of a rod shaft penetrating therethrough and excavating the ground by being rotated around the axis together with the rod shaft. And the inside of the head shaft are connected by a supply path, so that a sliding material for edging for preventing adhesion of earth and sand can be supplied between the spiral blade and earth and sand. In this case, the injection nozzle is located inside the outer surface of the spiral blade and the injection nozzle is provided in a buried state, and a diffusion channel portion having a fan shape in a plan view is provided on an inclined flow path portion from the injection port to the outer surface of the spiral blade. It is desirable that a lip for preventing the adhesion of earth and sand sprayed from the spray port be diffused to the outer surface of the spiral blade.

[0009] In the present specification, the "excavation" includes not only the case where the earth is completely removed like a hole but also the case where the earth and sand is agitated at the original position or the case where the earth removal type deep mixing process is performed. This includes various meanings, such as when a part of the stirred earth and sand is discharged.

[0010]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a front view of a digging head portion of a three-axis auger stirrer to which the present invention is applied, and FIG. 2 is a bottom view thereof.

Each of the auger heads 1A to 1 in the present invention
C is connected to the lower end port of the rod shaft R indicated by a dashed line via a connecting portion 10 and is rotated with the rotation of the rod shaft R around the axis, whereby the spiral blades 12A,
The ground is excavated by 12B. In this example, 3
Since the shaft type is used, the lower end positions of the left excavation head 1A and the right excavation head 1C are the same, and the excavation head 1
B is positioned above and as shown in the bottom view of FIG.
In plan view, the three axes are excavated in an overlapping manner. During drilling or stirring, drilling water or ground improvement liquid is injected into the ground through discharge ports 30 provided at the lower end of the head shaft 11.

The auger heads 1A to 1C (hereinafter referred to as 1) are provided with a pair of spiral blades 12A and 12B along the peripheral surface on the lower end side of the head shaft 11, and at the lower edges of the spiral blades 12A and 12B. The spiral blades 12A, 12B and the drilling claws 1 are provided.
The auger 2 is composed of 5, 15,....

The excavating claws 15, 15 are held by a cutter cassette 14 for removably accommodating the three excavating claws 15, 15,. Then, the excavating claw 15 is replaced with the rod shaft R.

In the auger heads 1A and 1B,
The two spray nozzles 20, 20 are provided at a relatively lower position of the spiral blades 12A, 12B and in the width direction of the spiral blades 12A, 12B in a substantially buried state.
The ground improvement liquid and the like sent through the inner space 13 of the head shaft 11 to the surfaces of 2A and 12B can be continuously supplied as a trimming sliding material for preventing sediment adhesion. The injection nozzle 20 has a width of 3 in the width direction.
Or more spiral blades 12 may be provided.
You may make it supply simultaneously also to the back surface of A, 12B.

Specifically, as shown in FIGS. 3 and 4, installation holes 12a penetrating from front to back are formed at positions where the injection nozzles 20 of the spiral blades 12A and 12B are to be disposed. A cylindrical injection nozzle 20 integrally having a flange 20a is fitted and fixed, and the injection nozzle 20 is connected to a sediment adhesion preventing liquid supply port 22 formed on the lower end side of the head shaft 11 by a connection pipe 21. Like that. Regarding the arrangement of the connection pipe 21, the spiral blades 12A, 12A,
The reinforcing ribs 12b and 12c formed on the side edges of 12B are arranged along the inside.

In this embodiment, the connecting pipe 21 is connected to the spiral blade 1
Although it is arranged so as to be exposed to the outside of the spiral blades 12A and 12B, a small-diameter tube may be embedded in the spiral blades 12A and 12B so as not to protrude to the outside.
A, a liquid supply path is formed directly in 12B and the injection nozzle 20
You may make it inject more earth and sand adhesion prevention liquid.

On the other hand, as shown in FIG. 4, the injection nozzle 20 is disposed with the injection port 22b positioned inside the spiral blade surface, and
Spiral blades 12A, 1
In order to diffuse to the surface of 2B, a fan-shaped diffusion flow path portion 23 is formed in the inclined portion from the injection port 22b to the surface of the spiral blades 12A and 12B in plan view.

In excavation, a liquid used for excavation, specifically, in the case of drilling, drilling water supplied to the auger portion through the rod shaft R and the inside of the head shaft 11,
In the case of soil improvement, the soil improvement liquid which is agitated and mixed into the earth and sand is sent to the injection nozzle 20 through the connecting pipe 21 as a trimming sliding material for preventing adhesion of the earth and sand, and the spiral blades 12A and 12B from the injection nozzle 20. Excavation is performed while feeding the surface. Note that, instead of the excavation water and the ground improvement liquid, compressed air supplied from a compressor can be used as a trimming sliding material.

When excavation is performed in a state where the sediment adhesion preventing liquid is supplied to the spiral blades 12A and 12B, the soil is interposed between the spiral blades 12A and 12B and the earth and sand so that the earth and sand are separated. It is cut off with 12A, 12B,
The excavated earth and sand does not adhere to or accumulate on the spiral blades 12A and 12B, and a good excavation state can always be maintained.

[0020]

As described above in detail, according to the present invention, adhesion and accumulation of earth and sand on the spiral blade are eliminated, so that the stirring efficiency and the excavation efficiency can be improved.

[Brief description of the drawings]

FIG. 1 is a front view of a digging head part of a three-axis auger stirrer to which the present invention is applied.

FIG. 2 is a bottom view thereof.

FIG. 3 is a plan view of an injection nozzle arrangement portion.

FIG. 4 is a cross-sectional view thereof (a line IV-IV in FIG. 3).

FIG. 5 is a side view of a conventional auger type drilling head.

[Explanation of symbols]

1A to 1C: auger head, 2: auger, 11: head shaft, 12A / 12B: spiral blade, 13: inner space, 1
4—Cutter cassette, 15—Drilling claw, 20—Injection nozzle, 21—Connecting pipe, 22—Soil-adhesion prevention liquid supply port, 23
... Diffusion channel

Claims (4)

[Claims] When excavating the ground using an auger shaft on which spiral blades are fixed along the outer surface of the ground penetrating shaft, excavation is performed while supplying a trimming sliding material between the spiral blades and earth and sand. An auger excavation method, wherein the method prevents soil and sand from adhering to the spiral blade. 2. The auger excavation method according to claim 1, wherein drilling water, ground improvement liquid, or compressed air is used as the edging lubricant for preventing the adhesion of the earth and sand. 3. A rod shaft fixedly provided along the periphery of the head shaft on at least the tip end side of the head shaft, and excavation claws provided on a lower end edge of the spiral blade, and a rod shaft penetrating into the ground. An auger head mounted on the tip for excavating the ground by being rotated about the axis with the rod shaft, wherein an injection nozzle is provided for the spiral blade, and the injection nozzle and the inside of the head shaft are supplied. An auger head, wherein the auger head is connected by a road, and is capable of supplying a trimming sliding material between the spiral blade and the earth and sand for preventing adhesion of earth and sand. 4. A diffusion channel having a fan shape in a plan view at an inclined flow path portion extending from the injection port to the outer surface of the spiral blade, wherein the injection nozzle is located inside the outer surface of the spiral blade and the injection nozzle is provided in a buried state. 4. The auger head according to claim 3, wherein a portion is formed so that a trimming sliding material sprayed from said spray port for preventing adhesion of earth and sand is diffused to the outer surface of the spiral blade.