JP2001032262A - Double rotary shaft type ground stirring and mixing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve stirring and mixing effect between upper soil and lower soil and between soil and a ground improving material by setting a vertical space between stirring blades in inner and outer shafts of a double rotary shaft type ground stirring and mixing device to a value satisfying a predetermined expression. SOLUTION: In this double rotary shaft type ground stirring and mixing device, a stirring blade 3 on an outer shaft 1 and a stirring blade 4 on an inner shaft 2 rotate in the opposite directions mutually, and a vertical space S between the stirring blades 3, 4 is set so as to satisfy the following expression: max (H1.Sin 45 deg., H2.Sin 45 deg.)<=S<=(H1.Sin 45 deg.)+(H2.Sin 45 deg.), H1 is a rotating directional projection height of the stirring blade 3 in the outer shaft 1, and H2 is a rotating directional projection height of the stirring blade 4 in the inner shaft 2. In this setting, the width of soil pressed down by the stirring blade 3 and the width of soil pushed up by the stirring blade 4 overlap with each other, so that upward and downward movements of the soil collide mutually and become complicated, and consequently, stirring and mixing effect between upside soil and downside soil and between the soil and a ground improving material can be greatly improved.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a double rotation shaft type ground stirring and mixing apparatus.

[0002]

2. Description of the Related Art A double rotation shaft type ground stirring / mixing apparatus in which agitating blades protruding from the lower ends of both inner and outer shafts are rotated in opposite directions to agitate and mix ground soil and soil improvement material. Is well known in the art (for example, see JP-A-9-3196).
No. 9), and no particular consideration is given to the vertical spacing between the stirring blades of the inner and outer shafts.

[0003]

The problem to be solved by the present invention (object of the present invention) is to improve the stirring and mixing effect by specifying the upper and lower intervals between the stirring blades of the inner and outer shafts. It is an object of the present invention to provide a double rotation shaft type ground stirring and mixing processing apparatus.

[0004]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, a double-rotating-shaft ground stirring and mixing apparatus (hereinafter, simply referred to as an apparatus of the present invention) of the present invention has an inner and an outer rotating in opposite directions. The upper and lower intervals between the stirring blades of the shaft are set so as to satisfy the above formula (1).

[0005]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In FIGS. 1 and 2 showing a main part of a rotating shaft in an apparatus of the present invention, reference numeral 1 denotes an outer shaft of a rotating shaft, 2 denotes an inner shaft, and an outer shaft 1 comprises, for example, a turn shaft. In a table system, the inner shaft 2 is rotated in opposite directions by, for example, a motor attached to the upper end.

[0006] At the lower end of the outer shaft 1 and at the lower end of the inner shaft that penetrates the outer shaft 1 and protrudes downward, agitating blades 3 and 4 are provided in a radial direction, respectively. Discharge ports (not shown) for soil improvement materials such as cement milk are provided near the bases 3 and 4, and the agitating blades 3 and 4 rotate in opposite directions when the rotary shaft penetrates into the ground and when the rotary shaft is pulled out. The soil and the ground improvement material discharged from the discharge port are stirred and mixed.

[0007] By applying a generally known support force theory based on plastic deformation, when the stirring blade rotates horizontally in the ground, a wedge 5 of the soil is formed on the front surface thereof, and the wedge 5 is formed. When it is considered that the soil in the front of the turning direction is divided up and down and moves as shown in FIG. 3, the original ground soil is considered to be a soil whose internal friction angle is almost 0 in the viscous ground,
The base angle α of the wedge 5 is 45 °, and the width W of the soil that moves up and down is

(Equation 2) The movement of the soil at this time is, for example, wedge 5
The soil which was below the top of the wedge 5 is initially pushed downward along an arc having a radius of one side of the wedge 5, and is moved in such a way as to be sequentially driven to the rear of the stirring blade.

FIG. 4 shows the downward movement of the soil in front of the stirring blade 3 and the front of the stirring blade 4 when the stirring blade 3 of the outer shaft 1 and the stirring blade 4 of the inner shaft 2 rotate in opposite directions. Although the upward movement of the soil is shown, the vertical distance S between the stirring blades 3 and 4 is

(Equation 3) In the case of (when S is larger than the sum of W1 and W2), the stirring blades 3 and 4 are too far apart vertically, and the width of the stirring blade 3 pushing the soil downward and the stirring blade 4 push the soil upward. Since the widths do not overlap each other, the effect of reversely rotating the stirring blades 3 and 4 cannot be obtained.

The interval S is

(Equation 4) (When S is smaller than the maximum of W1 and W2)
Since the force of the stirring blade 3 for pushing the soil downward or the force of the stirring blade 4 for pushing the soil upward is reduced by hitting the other stirring blade, the stirring blades 3 and 4
The effect of reverse rotation of is reduced.

On the other hand, in the case of the apparatus of the present invention in which the interval S satisfies the above equation (1) (where S is equal to or larger than the maximum of W1 and W2 and W1 and W2 In the case of equal to or smaller than the sum), the width of the stirring blade 3 pushing the soil downward and the width of the stirring blade 4 pushing the soil upward overlap each other, and the movement of the soil downward and the soil upward And the soil moves in a complicated manner, and the effect of reverse rotation of the stirring blades 3 and 4 is sufficiently exhibited, and the soil between the upper and lower soils, and the soil and ground improvement material And the effect of stirring and mixing with is significantly improved.

[Brief description of the drawings]

FIG. 1 is a front view of a main part of a rotating shaft in a device according to the present invention.

FIG. 2 is a side view of the same.

FIG. 3 is a basic explanatory diagram of soil movement by a stirring blade.

FIG. 4 is a diagram showing a state of movement of soil by upper and lower stirring blades in the apparatus of the present invention.

[Explanation of symbols]

1: outer shaft, 2: inner shaft, 3: stirring blade, 4: stirring blade, 5:
wedge.

Claims (1)

[Claims] An upper and lower space S between stirring blades of both inner and outer shafts rotating in opposite directions is expressed by the following equation. A double-rotation-shaft ground stirring and mixing processing apparatus characterized by satisfying the following.