JPS6120106Y2 - - Google Patents

Description

[Detailed description of the invention] The present invention relates to an injection stirring type soil improvement machine, and as its improvement material discharge mechanism, the improvement material is evenly mixed over the entire rotation trajectory of the stirring blade, and the cross-sectional strength of the improved column is improved. Concerning the stabilization of

Chemical improvement materials such as quicklime and cement are mixed with cohesive soil (sludge) on soft ground by forced stirring.
By creating column-shaped solidified parts in the ground,
The ground improvement method for improving soft ground is well known, but as an improved machine for this improvement method, the improvement material is injected into the ground to be improved along with pressurized air, and the material is forcibly stirred and mixed using rotary blades. Ground improvement machines of the jet agitation type are also known. This improved machine has a hollow rotary shaft that can freely move in and out of the ground to be improved, and serves as a pressure path for the improved material together with compressed air.Agitation blades are installed at the lower end of the rotary shaft and project out in a radial direction. This type of improved machine mixes the clay and the improvement material by stirring and mixing the cohesive soil and the improvement material with the stirring blade. However, the following problems still need to be solved. In other words, when the improved material is injected along with pressurized air inside the stirring blade in the length direction of the blade, the blade itself acts as a guide cover during the injection of the improved material, and the improved material is pushed by the stirring blade due to inertia. There is a risk that the improved material will not be sufficiently supplied to the vicinity of the rotation axis, and the improved material will be in a position where it will fly out beyond the blade tip, or in some cases beyond the blade tip, to the outside of the rotation trajectory of the stirring blade. Needless to say, within the rotation locus of the stirring blade, there is a columnar part that is solidified and improved.
In other words, it is a cross-section of the improved column, and each part within this cross-section, regardless of distance from the center,
It is necessary to mix the improving material evenly, and if the improving material sprayed under the stirring blade is distributed thinly from tip to tip, the improved strength in the cross section perpendicular to the axis of the improved column will not be uniform over the entire surface. This results in unstable improvement results with variations in the strength of each part.

The present invention was developed to solve the above-mentioned problems, and it is possible to easily mix the improved material in a substantially uniform distribution in the cross section of the improved column, and its characteristics are as follows. , a rotary shaft that can freely enter and exit the ground to be improved and is rotatable around the axis, and whose hollow interior is used as a pumping path for the soil improvement material; In an injection stirring type ground improvement machine comprising a stirring blade inside which an improvement material is ejected from the pressure feeding path, the improvement material injection pipe from the pressure feeding path is located near the middle of the stirring blade in the blade length direction. The blade has an opening, and a dispersion plate for distributing the improvement material over the blade length direction is provided in the blade immediately below the opening.

The present invention will be described in detail below based on the illustrated embodiments.

Figure 1 shows the conventional construction method. In the same figure, 1 is a rotating shaft. Although not shown, the rotating shaft 1 is rotatably attached to a slide frame or the like installed on the main body of the improved machine so that it can be raised and lowered. It is supported in a downwardly protruding manner and is installed in the ground to be improved so that it can be moved up and down and rotated freely. A passage 5 is formed, and in this pressure passage 5, soil improvement material (powder, granules, slurry, etc.) from the improvement material plant on the improvement machine main body side is carried along with pressurized air from an air compressor, etc. or a slurry pump. It will be fed under pressure. Stirring blades 2 are provided on the lower end circumferential side of the rotating shaft 1 to protrude in the radial direction. Although the stirring blade 2 shown in the figure has two blades arranged 180 degrees symmetrically, the number of blades is arbitrary. The lower end of the pressure feed path 5 of the rotating shaft 1 is connected to the shaft 1 of the stirring blade 2.
It is opened as a spout 3 at the attachment base of the
Assuming that the rotating shaft 1 rotates counterclockwise as shown by the arrow as shown in the figure, the improvement material that is spouted out from the spout 3 together with pressurized air or in the form of a slurry is on the opposite side of the rotating direction. The jet is provided so as to be ejected along the length direction of the blade 2.
Therefore, the rotating shaft 1 penetrates into the ground to be improved to a predetermined depth position, rotates and ascends from the same point, and the improved material from the pressure feed path 5 is removed by the stirring blade 2 that rotates together with the shaft 1. towards the space behind the wing.
When ejected from the jet nozzle 3 along the blade span direction, the improving material concentrates in quantity on the tip side of the blade 2 as shown by arrow a, or extends beyond the tip as shown by arrow c.
This tends to cause an unbalanced ejection distribution state in which the improving material does not rotate sufficiently near axis 1 as shown by arrow b. For this reason, the present invention proposes a new discharge mechanism as shown in FIGS. 2 and 3.

That is, in the embodiment shown in FIG. 2, the stirring blades 2 are protruded in the radial direction on the outer periphery of the lower end of the rotary shaft 1, which is movable up and down and rotatable around its axis, and whose hollow interior is used as a pumping path 5 for the soil improvement material. (either removable or fixed mounting structure is acceptable). In this embodiment, the cross-sectional shape of the stirring blade 2 is as shown in FIG. The lower end of the pressure feed path 5 in the rotary shaft 1 is opened on the circumferential side above the blades 2 of the shaft 1, and one end of the pumping path 5 is connected to this opening 5a to eject improved material. The other end of the conduit 6 is connected and opened near the middle of the blade span direction from the root to the tip at the top 2a of the blade 2, and the blade 2 immediately below the opening position is opened.
A dispersion plate for distributing the improvement material jetted from the open end of the jetting pipe 6 onto the blade 2 substantially uniformly over the entire blade length direction using the both side walls 2b, 2b inside the blade. 4 is provided. That is, the distribution plate 4
is the slit 4 in the spanwise direction directly facing the opening of the conduit 6.
One side shows an inclined plate 4b with an appropriate inclination angle toward the root of the wing, and an inclined plate 4c with an appropriate inclination angle towards the tip of the wing 2, which are placed opposite each other across the wing a. Plate 4b, 4
c is fixed at both ends to the side walls 2b, 2b. The configuration of the dispersion plate 4 is not limited to the central slit 4a and the left and right inclined plates 4b, 4c as shown in the figure, but the configuration of the dispersion plate 4 is not limited to the central slit 4a and the left and right inclined plates 4b, 4c.
The same effect can be obtained if the blade is equipped with a guide structure that appropriately divides and diffuses the improvement material that is injected into the blade together with the pressurized air into the central portion, root portion, tip portion, etc. in the blade span direction. In addition, the cross-sectional shape of the stirring blade 2 used in the present invention is not limited to the one shown in Fig. 2 A and B;
The same effect can be achieved even with cross-sectional shapes as illustrated in Figures A, B, C, and D. In other words, what is shown in Figure A is
Both side walls 2b, 2b are inclined to widen towards the top 2a to have a trapezoidal cross section, and the one shown in FIG. shows a modified gutter-shaped cross section with a vertical plate (rearward in the direction of travel) and the opposite side wall 2b is an inclined plate (front in the direction of travel), and the one shown in FIG. shows a cross-sectional shape with approximately semicircular curved wall surface,
The one shown in FIG.
The figure shows a substantially triangular cross-sectional shape, and the effect is the same regardless of the cross-sectional shape, and the tip of the blade 2 is
As illustrated in Figure A, it has a closed end surface 2c.

According to the injection stirring type ground improvement machine of the present invention, the second
As shown in FIG. It is ejected into the air and diffused into the inner space of the blade surrounded by the side walls 2b, 2b of the top part 2a, but due to the presence of the dispersion plate 4 disposed directly below the ejection part, the air is ejected directly below the central slit 4a. As shown by the arrow in the figure, the air is divided into those that fall, those that are guided toward the root of the wing by the inclined plate 4b, and those that are guided toward the tip of the wing by the inclined plate 4c. This allows the dispersion content to be distributed approximately evenly over the entire length of the blade, eliminating the unbalance of the conventional technique where the blade is thick at the tip side and thin at the root side of the blade. At the same time, the result of uniform mixing of the improved material over the entire area of the blade's rotation trajectory is obtained, and the improved strength is made uniform over the entire surface of the improved column centered on the rotational axis 1 and whose radius is the blade length diameter, eliminating instability due to variations in excess and deficiency. It is possible. And according to this, the pressure feed path 5
The jetting pipe 6 connecting the blades 2 and 2 also serves as a reinforcing support for the blades, and is effective as an improvement to the improvement material discharging mechanism in this type of injection stirring type ground improvement machine.

[Brief explanation of the drawing]

Fig. 1 is a side sectional view of a main part of a conventional discharge mechanism in an injection stirring type ground improvement machine, Fig. 2 is a side sectional view including a cross section taken along line A-A of the main part of an embodiment of the present invention discharge mechanism, and Fig. 3
The figures are sectional views of examples of the stirring blade cross-sectional shape. 1... Rotating shaft, 2... Stirring blade, 3... Spout port,
4... Dispersion plate, 5... Pressure feed line, 6... Ejection pipe line.

Claims (1)

[Scope of utility model registration request] A rotary shaft that can freely move in and out of the ground to be improved and is rotatable about its axis and whose hollow interior is used as a pumping path for the ground improvement material; In an injection stirring type ground improvement machine comprising a stirring blade into which the improvement material from the pressure feeding path is jetted, the improvement material injection pipe from the pressure feeding path is located near the middle of the top of the stirring blade in the blade length direction. 1. An injection agitation type ground improvement machine, characterized in that the blade has an opening, and a dispersion plate for distributing improvement material over the length of the blade is provided in the blade immediately below the opening.