JPH05302320A - Agitation impeller of ground improvement device - Google Patents

Abstract

PURPOSE:To prevent excavated earth and sand from rotating together to efficiently mix earth and sand with a hardener. CONSTITUTION:Since an excavation impeller 3 has an enclined angle alpha, earth and sand is taken up during excavation and the earth and sand thus taken up acts upon a joint-rotation prevention impeller 5 having an inclined angle betareverse to that of the impeller 3 to give a turning effect on the impeller 5 in a direction opposite to that of the rotation of an excavation axis 1. When the axis 1 is lifted up, the axis 1 is turned in a direction opposite to the direction during the excavation and a mixing impeller 4 also has the same inclined angle alpha as the impeller 3, and hence earth and sand is depressed by the impeller 4 and the earth and sand thus depressed acts on the impeller 5 to give a turning effect thereon in a direction opposite to that of the axis 1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mixing and stirring blade device for a ground improvement machine for improving soft ground. More specifically, it is a mixing and stirring blade device for a ground improvement machine that mechanically mixes and solidifies soil and a hardening agent in foundation work or the like and improves the ground into a columnar shape.

[0002]

2. Description of the Related Art Conventionally, a ground improvement machine for improving soft ground into a columnar shape has an excavation shaft provided with an excavation blade and a stirring blade, which is rotationally excavated by a predetermined excavation mechanism so that the excavation shaft is placed in the excavation shaft during excavation or extraction. While excavating a solidifying agent such as cement milk from the provided passage, the excavated soil is forcibly stirred to solidify the ground in a cylindrical shape.

However, since this type of ground improvement machine is forcibly mixed and stirred with the solidifying agent and the earth and sand, it can be easily applied to sandy soil or silt type ground, but clay is particularly hard and viscous. In the case of soil, it was not possible to efficiently mix and stir the excavated soil excavated by the ground to be improved and the stirring blade coexisting with the solidifying agent.

For this reason, for example, Japanese Patent Publication No. 58-2937.
Japanese Patent Publication No. 4 discloses a mixing and stirring blade device having a co-rotation preventing blade having a diameter larger than the diameter of the excavating blade.

In this prior art, since the co-rotation preventing blade is fixed to the excavation wall surface, a force for press-fitting is required at the time of excavation and there is resistance for this. Further, it has been proposed that the excavation shafts are doubled, the excavation blades are attached to the respective excavation shafts, and the excavation blades are rotated in opposite directions. This double pipe type tends to have a complicated structure.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to provide a mixing and stirring blade device for a ground improvement machine, which can efficiently stir soil and sand and a solidifying agent.

[0007]

The present invention adopts the following means in order to solve the above problems.

An excavation shaft (1) which is driven to rotate, an excavation blade (3) fixedly provided on the excavation shaft (1) for excavating and kneading the ground, and above the excavation blade (3). Of the excavation shaft (1) fixed to the excavation shaft (1) and for agitating the excavated ground, and the excavation shaft (4) between the excavation blade (3) and the agitation blade (4). 1) A boss (7) rotatably provided, and a co-rotation preventing blade (5) fixed to the boss (7) and having a blade diameter smaller than the excavation diameter of the excavation blade (3). And the excavation blade (3)
And the stirring blades (4) form an angle in which their blade surfaces are inclined in the same circumferential direction of the excavation axis (1) with respect to a plane perpendicular to the axis of the excavation axis (1), and the co-rotation prevention is performed. The blade (5) has its blade surface at an angle with respect to a plane perpendicular to the axis of the excavation shaft, which is inclined in a direction opposite to the inclination direction of the excavation blade (3) and the stirring blade (4). Is a mixing and stirring device.

A bite (2) is provided at the lower end of the excavation shaft (1).

[0010]

During excavation, the excavation shaft 1 is rotationally driven in one direction, whereby the bite bit 2 and the excavation blade 3 rotate in the same direction, and the ground is excavated in a columnar shape. At the same time, the stirring blade 4 also rotates and the excavated earth and sand are kneaded and stirred.

Since the excavation blade 3 has the inclination angle α,
The sand and sand are scooped up, and the scooped up sand and sand act on the co-rotation preventive blade 5 having an inclination angle β in the opposite direction to the excavation blade 3 to give a rotational force in the direction opposite to the rotation of the excavation shaft 1. .. Therefore, the excavated earth and sand do not co-rotate,
It is sufficiently kneaded by the stirring blade 4.

When the excavation shaft 1 is pulled up, the excavation shaft 1 is rotationally driven in the direction opposite to that at the time of excavation, whereby the excavation blades 3 and the stirring blades 4 rotate in the same direction, and the excavated soil is rubbed. Since the stirring blade 4 also has the inclination angle α similarly to the excavation blade 3, the stirring blade 4 pushes down the earth and sand, and the pushed down sand acts on the co-rotation prevention blade 5 to rotate the excavation shaft 1. Gives a rotational force in the opposite direction. Therefore,
The excavated earth and sand are sufficiently kneaded by the excavation blade 3 and the stirring blade 4 without co-rotating, and the excavated earth and sand and the solidifying agent are sufficiently stirred and mixed.

[0013]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a front view showing a mixing and stirring blade device. FIG. 2 is a sectional view taken along the line AA of FIG.

The excavation shaft 1 is a hollow shaft, and a rod 10 is fixed to the upper end of the shaft, and the rod 10 is fixed to a chuck of a ground improvement machine (not shown) to apply a rotational force and an axial thrust. A bit 2 is provided at the lower end of the excavation shaft 1. On the excavation shaft 1, an excavation blade 3 is provided above the bite bit 2 and a stirring blade 4 is further provided above it.

In this embodiment, the four excavation blades 3 are fixed to the excavation shaft 1 by welding at an angle of 90 degrees.
Each excavation blade 3 forms an inclination angle α in the circumferential direction of the excavation shaft 1 with respect to a plane perpendicular to the axis of the excavation shaft 1. Each excavation blade 3
Has a discharge port 6 for discharging the solidifying agent supplied through the inside of the excavation shaft 1.

The stirring blade 4 has the same shape as the excavation blade 3 except that the discharge port 6 is not provided, and the stirring blade 4 has 90
Four pieces are fixed by welding at an angle of degrees. The stirring blade 4 also makes an inclination angle α in the same direction as the excavation blade 3 with respect to a plane perpendicular to the axis of the excavation shaft 1.

On the excavation shaft 1 between the excavation blade 3 and the stirring blade 4,
The co-rotation preventing blade 5 is provided via the boss 7. The boss 7 is rotatably provided on the excavation shaft 1 and is immovable in the axial direction of the excavation shaft 1 by the pair of stoppers 8, 8. Four co-rotation preventing blades 5 are fixed to the boss 7 by welding at an angle of 90 degrees. Each co-rotation preventing blade 5 forms an inclination angle β in a direction opposite to the inclination direction of the excavating blade 3 and the stirring blade 4 with respect to a plane perpendicular to the axis of the excavating shaft 1.

Experiments have shown that it is desirable that the inclination angle α is in the range of about 15 ° to 30 ° and the inclination angle β is in the range of about 45 ° to 85 °, although it depends on the soil properties of the target ground. ing. That is, if the inclination angle α is too large, the excavation resistance becomes large, and if the inclination angle β is too small, the co-rotation preventing effect is weakened.

Ground improvement method The ground improvement method using the mixing and stirring blade device of the ground improvement machine will be described below. FIG. 3 is a cross-sectional view showing how excavation proceeds and the ground is kneaded.

The excavation shaft 1 is rotationally driven by a ground improvement machine via a rod (not shown) and is pushed into the ground. In the case of this embodiment, the excavation shaft 1 is rotationally driven clockwise when viewed from above during excavation. As a result, the bite 2 and the excavation blade 3 rotate in the same direction, and the ground is excavated in a cylindrical shape. At the same time, the stirring blade 4 also rotates and the excavated earth and sand are kneaded and stirred.

Since the excavation blade 3 has an inclination angle α, that is, a rake angle, the earth and sand are scooped up, and the scooped up sand and sand acts on the co-rotation prevention blade 5 in a direction opposite to the rotation of the excavation shaft 1. It gives a turning force. Therefore, the excavated earth and sand are sufficiently kneaded by the stirring blades 4 without co-rotating.

When the excavation hole reaches the set depth, the rotation and feed of the excavation shaft 1 are stopped, and then a solidifying agent such as pressurized cement slurry is supplied into the excavation shaft 1 and the discharge port 6 is discharged.
Discharge from. In this state, as shown in FIG. 4, the excavation shaft 1 is pulled up while being rotated in a direction opposite to that at the time of excavation, that is, counterclockwise when viewed from above. The solidifying agent may be supplied not only when pulling up the excavation shaft 1 but also during excavation.

By reversing the excavation shaft 1, the excavation blade 3 and the stirring blade 4 rotate in the same direction, and the excavated earth and sand are kneaded. Since the stirring blade 4 also has the inclination angle α like the excavation blade 3, the stirring blade 4 pushes down the earth and sand, and the pushed down sand acts on the co-rotation prevention blade 5 and is opposite to the excavation shaft 1. Gives a rotational force in the direction. On the other hand, the excavation blade 3 also pushes down the earth and sand, but the excavation blade 3 does not act on the co-rotation prevention blade 5 at all. Therefore, the excavated earth and sand are sufficiently kneaded by the excavating blade 3 and the stirring blade 4 without co-rotating, and the excavated earth and sand and the solidifying agent are sufficiently stirred and mixed.

[Other Embodiments] The excavating blade 3, the stirring blade 4, and the co-rotation preventing blade 5 should be such that the inclination angles of the excavating blade 3, the stirring blade 4 and the co-rotation preventing blade 5 are opposite to each other. For example, these blades 3, 4 and 5 may be provided in the opposite direction to the above-mentioned embodiment. In this case, the direction of rotation of the excavation shaft 1 during excavation and pulling up is opposite to that of the above-described embodiment.
Further, although the excavating blade 3, the stirring blade 4 and the co-rotation preventing blade 5 of the above-described embodiment are four blades, the number of blades is not limited.
Further, in the above-mentioned embodiment, the co-rotation preventing blade has one stage, but the number of these may be any number as required.

[0025]

As described above in detail, according to the present invention, the co-rotation preventing blade is given a rotational force in the direction opposite to the rotation of the excavation shaft both during the ground excavation and the injection of the solidifying agent. The excavated earth and sand do not co-rotate with the excavated blade, and the earth and sand and the solidifying agent can be efficiently stirred.

[Brief description of drawings]

FIG. 1 is a front view of a mixing and stirring blade device of a ground improvement machine.

FIG. 2 is a cross-sectional view taken along the line AA of FIG.

FIG. 3 is a cross-sectional view showing a state during excavation.

FIG. 4 is a cross-sectional view showing a state where a solidifying agent is being injected.

[Explanation of symbols]

 1 ... Excavation axis 2 ... Bit bit 3 ... Excavation blade 4 ... Stirring blade 5 ... Co-rotation prevention blade 6 ... Discharge port

Claims (2)

[Claims] 1. An excavation shaft (1) which is rotationally driven, an excavation blade (3) fixed to the excavation shaft (1) for excavating and kneading the ground, and an excavation blade (3). A stirring blade (4) fixed to the excavation shaft (1) above the ground and for rubbing the excavated ground
A boss (7) rotatably provided on the excavation shaft (1) between the excavation blade (3) and the stirring blade (4), and fixed to the boss (7), The excavation wing (3)
Co-rotation prevention wing having a diameter smaller than the excavation diameter (5)
The excavation blade (3) and the stirring blade (4) are arranged in the same circumferential direction of the excavation axis (1) with respect to a plane whose blade surfaces are perpendicular to the axis of the excavation axis (1). The wing surface of the co-rotation preventing blade (5) has an inclined angle, and the wing surface thereof is the excavation axis (1).
A mixing and stirring device having an angle inclined in a direction opposite to a tilting direction of the excavation blade (3) and the stirring blade (4) with respect to a plane perpendicular to the axis line of. 2. A mixing and stirring blade device for a ground improvement machine according to claim 1, wherein a bite (2) is provided at a lower end of said excavating shaft (1).