JP6912062B2 - Stirring mixer for mechanical stirring and ground improvement method using it - Google Patents

Description

The present invention relates to a stirring and mixing device for mechanical stirring and a ground improvement method using the stirring and mixing device.

In the mechanical stirring type deep mixing treatment method, a method in which a cement-based solidifying material is mixed with water to form a slurry is generally used as an improving material. In the mechanical stirring type deep mixing treatment method, a method of discharging the ground improvement material from the lower end of the rotating shaft (stirring shaft) is generally used. The outline of the construction method is as shown in FIG.

The conventional ground improvement work using such a cement-based deep mixing treatment method has the following problems.

Generally, when the target soil is soft and the water content is high, the amount of solidifying material mixed tends to be large, and for soil with a water content exceeding 200%, a solidifying material of 500 kg or more per ^{1 m 3 of soil to be improved should be used.} It may be used.

Since the water-cement ratio is set at about 80% as the lower limit, if there are many improved materials, it will take time to discharge into the ground and the construction efficiency will drop.

When the target soil is ultra-soft soil such as organic soil or humus soil, the required strength cannot be obtained with general cement. Therefore, an expensive special ground improvement material suitable for organic soil, humus soil, etc. is used as a solidifying material.

Since the solidification material cost accounts for a large proportion of the construction cost, the construction cost will increase significantly when improving the ultra-soft ground.

Approximately 80% of the amount of slurry put into the ground is discharged to the surface as raised soil (industrial waste), and the amount increases in proportion to the solidified material.

In the prior art, the improved material is generally discharged from one point at the lower end of the rotating shaft (see FIG. 2A). Stirring and mixing is due to the movement of the plate-shaped stirring blades extending radially from the rotation axis rotating around the rotation axis, so that it is difficult to mix inside and outside.

It was also considered to discharge a material with low fluidity from the lower end of the stirring shaft into the soil in the original position, but when such a material is discharged, the improved material is difficult to diffuse over the entire improvement target range, so it is homogeneous. It takes time to stir and mix in order to improve.

When a material with low fluidity is discharged, the material may be blocked in the flow path of the rotating shaft due to the low fluidity, making construction impossible.

Since a low-fluidity material is difficult to stir and mix, the quality of the improved product to be produced tends to be inhomogeneous when such a material is used.

When the ground improvement material is branched in the flow path in the rotating shaft, if the cross-sectional area of the flow path after the branch is smaller than that before the branching, there is a possibility that the material is blocked in the rotating shaft.

Therefore, in view of the above-mentioned problems of the prior art, an object of the present invention is, for example, even when the target soil is soft and has a high water content ratio or when the soil is organic soil, the construction efficiency is higher than before and the construction is performed at low cost. It is an object of the present invention to provide a stirring and mixing device for mechanical stirring, which makes it possible to create a high-quality improved body, and a soil improvement method using the stirring and mixing device.

Such an object has a rotating shaft provided with a flow path of the ground improving material, and a stirring blade provided with a plurality of discharge ports for discharging the ground improving material guided via the rotating shaft. This is achieved by a stirring and mixing device for mechanical stirring, which is provided on the stirring blade so that the plurality of discharge ports are located at different distances from the rotation axis.

In the stirring / mixing device, the flow path provided by the rotating shaft preferably branches into a plurality of individual flow paths in the middle, and in this case, the plurality of individual flow paths includes a plurality of individual flow paths provided by the stirring blade. It communicates individually to the discharge port.

Further, in the stirring / mixing device, it is preferable that each of the plurality of individual flow paths provided by the rotating shaft has dimensions such that the cross-sectional area does not decrease in the process of passing the ground improvement material.

Further, in the above-mentioned stirring / mixing device, the cross-sectional area of the portion through which the ground improvement material passes may be different in the plurality of individual flow paths.

Further, in the flow path provided by the rotation shaft of the stirring / mixing device, it is preferable that the inlet of the branch portion divided into a plurality of individual flow paths is tapered.

Further, the stirring / mixing device may further have an opening / closing means for repeatedly opening / closing a plurality of individual flow paths individually communicating with the plurality of discharge ports with a time lag.

In addition, the above-mentioned purpose is
This is a ground improvement method using a stirring and mixing device for mechanical stirring, which has a stirring blade provided with a plurality of discharge ports for the ground improvement material and is provided so that the plurality of discharge ports swivel with different diameters.
In the process of penetrating the stirring and mixing device having the rotating shaft and the stirring blade into the ground and / or pulling out from the ground, the ground improving material is pumped through the rotating shaft provided with the flow path.
Ground improvement material is discharged from each of a plurality of discharge ports that rotate with different diameters.
It is achieved by the ground improvement method characterized by this.

In the above-mentioned ground improvement method, the ground improvement material may be discharged discontinuously from a plurality of discharge ports.

Further, in the above-mentioned ground improvement method, a low-fluidity material having an aggregate such as mortar may be used as the ground improvement material.

The stirring / mixing device for mechanical stirring according to the present invention has a rotating shaft and a stirring blade, and the stirring blade has a plurality of discharge ports for discharging the ground improvement material guided through the flow path of the rotating shaft. It is equipped. The plurality of discharge ports are connected to the flow path in the rotating shaft and are provided on the stirring blade so as to be located at different distances from the rotating shaft (that is, to have different turning diameters).
By adopting such a configuration and injecting the ground improvement material into the target ground from a plurality of (for example, 2 to 4) discharge ports at different distances from the rotation axis, the ground improvement material is injected into the target ground from the inside to the outside in the stirring mixing region by the stirring blade. It is possible to evenly distribute the ground improvement material up to, and it is possible to efficiently construct a homogeneous improvement material. Further, the stirring and mixing time can be significantly shortened as compared with the discharge from one place as shown in FIG. 2 (a). See FIG. 2 (b).
Therefore, according to the present invention, even when a low-fluidity material such as mortar is used as the mixing material, efficient mixing and stirring can be performed by the stirring blade.
Further, in the stirring / mixing device for mechanical stirring according to the present invention, an existing deep mixing / processing machine can be used as the machine to be used, and there is no need to modify the main body of the construction machine.

Further, in the present invention, the flow path provided by the rotating shaft is branched into a plurality of individual flow paths in the middle of the flow path, and the plurality of individual flow paths are individually communicated with the plurality of discharge ports provided by the stirring blade. There is. That is, the flow path provided by the rotating shaft is a flow path that is branched into a plurality of flow paths from the middle of the flow path, and the plurality of branched flow paths are individually connected to the corresponding discharge ports. By adopting such a branch structure, it is possible to smoothly divide and input the ground improvement material (discharge of the ground improvement material from a plurality of discharge ports).
In addition, by providing a plurality of individual flow paths individually connected to the plurality of discharge ports in the rotation shaft, the delivery pressure of the ground improvement material is sufficiently transmitted to all of the plurality of discharge ports, so that the discharge pressure is surely transmitted from all the discharge ports. The ground improvement material can be discharged.

Further, in the present invention, each of the plurality of individual flow paths provided by the rotating shaft is set to a dimension in which the cross-sectional area (passing area) does not decrease in the process of passing the ground improvement material. The "cross-sectional area" here is the cross-sectional area of the passage portion of the ground improvement material in the flow path.
As a result, the cross-sectional area (passing area) does not decrease in the process of the ground improvement material passing through the rotating shaft (that is, the flow path does not narrow in the middle), so that the flow path is branched within the rotating shaft. Even if it is made, resistance when passing through the improving material is unlikely to occur, and the flow rate of the ground improving material in the rotating shaft is stable.
Therefore, by guiding the ground improvement material to a plurality of discharge ports via a rotating shaft provided with such a flow path, the improvement material is dividedly charged into the target ground (discharge of the ground improvement material from the plurality of discharge ports). Can be done smoothly without delay. See FIGS. 1 and 2 (b).

Further, in the present invention, in the flow path provided by the rotating shaft, the entrance of the branch portion divided into a plurality of individual flow paths is tapered. This taper processing plays a role of reducing the resistance received by the ground improvement material flowing in the rotating shaft.
By applying such tapering, the resistance at the entrance of the branch that divides into individual flow paths is reduced (that is, the loss of pressure for pumping the ground improvement material is reduced), and the flow of the ground improvement material is smoother. The flow rate becomes stable, and the frequency of material blockage in the rotating shaft can be further reduced. See FIG.
Such features are particularly useful when using low fluidity materials.

Further, in the present invention, the plurality of individual flow paths provided by the rotating shaft may be set to have the same cross-sectional area so that the flow rate of the ground improvement material is the same in each individual flow path, or a disconnection thereof. The area may be different so that the flow rate may be different.
As in the latter case, when each dimension of a plurality of individual flow paths is set so that the cross-sectional area of the portion through which the ground improvement material passes is different, the discharge amounts at the plurality of discharge ports should be different. Is possible. See FIG.
Such a feature is useful when it is desired to set different discharge amounts for a plurality of discharge ports.

Further, in the present invention, there may be further provided "opening / closing means" for repeatedly opening and closing a plurality of individual flow paths individually communicating with the plurality of discharge ports with a time lag.
Such a time difference type opening / closing means can be realized by using, for example, a rotation prevention blade. For example, a flow path opening / closing portion capable of opening / closing an individual flow path is provided in the rotation prevention blade attachment portion, and the ground improvement material is distributed to a plurality of discharge ports through the flow path opening / closing portion.
Specifically, a rotation prevention blade is attached to the rotation shaft so as to block the branched individual flow paths, and an opening (hole) through which the ground improvement material can pass is provided in the rotation prevention blade only for a part of the individual flow paths. prepare. See FIGS. 5 and 6. As a result, among the plurality of individual flow paths, the flow paths that can pass through change from moment to moment, and each flow path is temporarily shut off with a time lag, so that the material is discharged discontinuously.
In the case of continuous discharge from all discharge ports at the same time, if one discharge port is blocked, the material is discharged from the other discharge ports, so the blockage cannot be resolved, but by temporarily blocking each flow path, The blocked state can be eliminated by concentrating the pressure on the closed discharge port and pushing out the clogged improving material from the closed discharge port.

Further, in the present invention, one of the branched individual flow paths may be intentionally closed according to the specifications of the improved body to be created. For example, it is possible to create a hollow improved body by blocking the individual flow path leading to the innermost discharge port. See FIG.

It is also possible to make a difference in strength between the inside and the outside of the improved body by changing the positions of one or more of the plurality of discharge ports.

Further, in the present invention, the number of stages of the stirring blade is not particularly limited, and one stage may be used, or a plurality of stages of two or more stages may be provided. The number of discharge ports can be increased by providing the stirring blades in multiple stages (for example, 2 to 4 stages) (see FIG. 8), and the materials can be more evenly distributed by increasing the number of discharge ports.

Further, as a specific example of the ground improvement material that can be used in the present invention, a low fluidity material having an aggregate such as mortar can be mentioned.
By using such a low-fluidity material as a ground improvement material in the improvement of soft ground such as organic soil with a high water content and few soil particles, the soil particles of aggregates increase in the gaps in the organic soil. The amount of material input into the ground can be significantly reduced compared to cement-based solidifying materials.
Further, by using a low-fluidity material as a ground improvement material, strength development can be expected without using an expensive special ground improvement material suitable for organic soil as a solidifying material.
In addition, as a result of reducing the amount of material input into the ground, it is possible to reduce the material cost, which has a high composition ratio in the construction cost.
In addition, by using raised soil as an aggregate of a low-fluidity material such as mortar, it is possible to reduce the cost of disposing of industrial waste of generated soil.
In addition, by reducing the amount of material input into the ground, the amount of raised soil is also reduced, so the cost of disposing of residual soil can also be reduced.
Further, since the amount of material input into the ground is significantly reduced as compared with the cement-based solidifying material, the stirring time is shortened and the construction efficiency is improved, and as a result, the construction period can be shortened.

In addition, by carrying out ground improvement work using the above-mentioned stirring and mixing device for mechanical stirring,
For example, even when the target soil is soft and has a high water content, or when it is organic soil, the construction efficiency is higher than before, it is possible to construct at low cost, and it is possible to create a high quality improved body. ..

It is sectional drawing which shows 1st Embodiment of the stirring mixing apparatus for mechanical stirring. FIG. 2 (a) shows the relationship between the ground improvement material discharge port and the stirring and mixing area in the prior art, and FIG. 2 (b) shows the relationship between the ground improving material discharge port and the stirring and mixing area in the first embodiment of the present invention. Shows the relationship. It is a figure which shows an example of the taper processing applied to the branch part entrance of the flow path in a rotating shaft. It is sectional drawing which shows the 2nd Embodiment of the stirring mixing apparatus for mechanical stirring. It is a partial cross-sectional view which shows the 3rd Embodiment of the stirring mixing apparatus for mechanical stirring. It is a perspective view which shows the function and operation of the rotation prevention blade (opening and closing means) provided in the stirring mixing apparatus for mechanical stirring of 3rd Embodiment. It is a figure which shows the other embodiment of the stirring mixer for mechanical stirring. It is a figure which shows the other embodiment of the stirring mixer for mechanical stirring. It is a figure which shows an example of the construction equipment of the ground improvement work using the stirring mixer for mechanical stirring. It is a figure which shows an example of the construction procedure of the deep layer mixing processing method by mechanical stirring.

(First Embodiment of Stirring Mixer)
The stirring / mixing device 11 for mechanical stirring of the first embodiment has a cross-sectional shape as schematically shown in FIG. 1, and a leader or a rotation at a construction site where a construction machine as shown in FIG. 9 is arranged. It is used by being attached to a construction machine main body 91 provided with a drive device or the like. By suspending the stirring / mixing device along the leader provided in the main body of the construction machine and applying the rotational force of the rotation driving device to the rotating shaft of the stirring / mixing device, the ground is rotated while rotating the entire stirring / mixing device. It can be penetrated or pulled out.

As shown in FIG. 1, the stirring / mixing device 11 for mechanical stirring of the present embodiment mainly uses.
-Rotating shaft 21 (stirring shaft) including the flow path 23 of the ground improvement material, and
-It has stirring blades 41 and 42 that are rotatably provided integrally with this rotating shaft.

The stirring blades 41 and 42 are provided below the rotating shaft 21 at predetermined intervals so as to extend in the horizontal direction, and play a role of excavating the ground and stirring and mixing the excavated soil and the ground improvement material.

Further, as shown in FIGS. 1 and 2 (b), the stirring blade 41 has a stirring blade 41.
-The flow path 45 leading to the individual flow paths 31, 32, 33 branched from the flow path 23 in the rotating shaft 21 and
-It is provided with a plurality of discharge ports 1, 2, and 3 for discharging the ground improvement material guided via the rotating shaft 21.
The positional relationship between the discharge ports 1, 2, and 3 on the stirring blade 41 is as shown in FIG. 2 (b).

The number of discharge ports provided by the stirring blade 41 is not particularly limited as long as the number of discharge ports is plurality, and in the present embodiment, as an example, the stirring blade 41 is provided with three discharge ports.

As shown in FIG. 2B, the discharge ports 1, 2, and 3 provided by the stirring blade 41 are located at different distances from the rotating shaft 21.

In this embodiment,
The distance from the rotating shaft 21 to the discharge port 1 (first discharge port) is D1,
The distance from the rotating shaft 21 to the discharge port 2 (second discharge port) is D2,
When the distance from the rotating shaft 21 to the discharge port 3 (third discharge port) is D3,
Discharge ports 1, 2, and 3 are provided on the stirring blade 41 so that D1 <D2 <D3.

The intervals between the turning loci of the discharge ports 1, 2 and 3 do not necessarily have to be equal, and the position where the discharge ports are provided can be changed according to the specifications of the improved body to be created. By changing the position of the discharge port in this way, for example, it is possible to make a difference in strength between the inside and the outside of the improved body to be created.

The rotating shaft 21 is a shaft portion that becomes the center of rotation when the stirring / mixing device 11 is rotationally driven.
As shown in FIG.
-Flowers 23, 31, 32, 33 of the ground improvement material provided inside the
・ Excavation head 35 provided at the lower end,
Etc. are provided.

As shown in FIG. 1, the flow path 23 included in the rotating shaft 21 branches in the middle and is divided into three individual flow paths 31, 32, 33. The individual flow paths 31, 32, and 33 are individually communicated with the discharge ports 1, 2, and 3 (see FIG. 2B) provided in the stirring blade 41 on a one-to-one basis. That is, the flow path 23 included in the rotating shaft 21 is a flow path that is branched into a plurality of flow paths from the middle of the flow path, and the individual flow paths 31, 32, 33 that are branched are the corresponding discharge ports 1, 2, and 3, respectively. Are individually connected to.

Further, in the present embodiment, the individual flow paths 31, 32, and 33 included in the rotating shaft 21 each have dimensions such that the cross-sectional area does not decrease in the process of passing the ground improvement material. The "cross-sectional area" here is the cross-sectional area of the passage portion of the ground improvement material in the flow path.

For example, in the embodiment shown in FIG.
The total cross-sectional area of the individual flow paths 31, 32, 33 in the bb cross section is
It is substantially the same as or larger than the cross-sectional area of the flow path 23 in the aa cross section.

Due to such a feature, the cross-sectional area (passing area) does not decrease in the process of passing the ground improvement material through the rotating shaft 21 (that is, the flow path does not narrow in the process of flowing the ground improvement material). ), Even if the flow path is branched in the rotating shaft 21, resistance when passing through the improving material is unlikely to occur, and the flow rate of the ground improving material in the rotating shaft is stable.
Therefore, by guiding the ground improvement material to the plurality of discharge ports via the rotating shaft 21 provided with such a flow path, the improvement material is dividedly charged into the target ground (discharge of the ground improvement material from the plurality of discharge ports). ) Can be performed smoothly without delay.

Further, in the flow path provided by the rotating shaft 21, it is desirable that the branch portion inlet 37 divided into the individual flow paths 31, 32, 33 is tapered as illustrated in FIG. This tapering process plays a role of reducing the resistance received by the ground improving material flowing in the rotating shaft 21. By applying such taper processing, the resistance at the branch inlet 37 divided into the individual flow paths 31, 32, and 33 is reduced (that is, the loss of pressure for pumping the ground improving material is reduced), and the ground is improved. The flow of the material becomes smoother, and the frequency of material blockage in the rotating shaft 21 can be further reduced. Such features are particularly useful when using low fluidity materials.

(Ground improvement using a stirring mixer)
The stirring / mixing device having the above-described configuration is attached to the construction machine main body 91 as shown in FIG. 9, for example.
Then, when the rotary shaft 21 is rotated by the rotary drive device and penetrates into the ground (ground soil), the rotary drive of the rotary shaft 21 excavates the ground with the excavation head 35 at the lower end of the rotary shaft 21 while stirring the blades. 41 and 42 penetrate into the ground.
Then, when the lower end of the stirring / mixing device reaches the target improvement depth, the stirring blades 41 and 42 are rotated to pull out the stirring / mixing device while stirring at a predetermined speed.
The procedure and timing of penetration and withdrawal of the stirring and mixing device are the same as those of the conventional mechanical stirring type deep layer mixing treatment method as illustrated in FIG.

Then, in one or both of the process of penetrating the stirring / mixing device into the ground and the process of pulling out the stirring / mixing device from the ground, the ground improving material is introduced into the ground through a plurality of discharge ports. That is, the ground improvement material is supplied substantially evenly into the excavated ground from the discharge ports 1, 2 and 3 provided on the stirring blade 41, and the excavated soil and the ground improvement material are stirred by the rotational drive of the stirring blades 41 and 42. Mix.

The ground improvement material to be put into the target ground is pumped by a pump and sent to the flow path 23 in the rotating shaft, passes through a plurality of individual flow paths 31, 32, 33 branched in the middle of the flow path, and further agitates blades. It is guided to the discharge ports 1, 2 and 3 through the flow path 45 in the 41, is discharged from each discharge port, and is charged into the stirring and mixing area (rotation area of the stirring blade) of the stirring blade in the ground.

Then, when the ground improvement material is discharged from the discharge ports 1, 2 and 3 of the stirring blade 41 in one or both processes of penetration and extraction of the stirring and mixing device, the excavated soil and the ground improving material are stirred by the stirring blade 41. Be mixed. By pulling out the stirring and mixing device from the target ground through such stirring and mixing, a substantially columnar improved body is created at a predetermined position on the ground soil.

The type of ground improvement material applicable to the stirring / mixing device is not particularly limited, and specific examples thereof include low-fluidity materials having an aggregate such as mortar.
By using such a low-fluidity material as a ground improvement material, soil particles for aggregates increase in the gaps in the organic soil, and the amount of material input into the ground is reduced compared to cement-based solidifying materials. Can be done.
Further, by using a low-fluidity material as a ground improvement material, strength development can be expected without using an expensive special ground improvement material suitable for organic soil as a solidifying material.
In addition, as a result of reducing the amount of material input into the ground, material costs can be reduced.
In addition, by reducing the amount of material input into the ground, the amount of raised soil is also reduced, so the cost of disposing of residual soil can also be reduced.
In addition, the stirring time can be shortened by reducing the amount of material input into the ground as compared with the cement-based solidifying material.

(Second Embodiment of Stirring Mixer)
In the second embodiment of the stirring / mixing device, as shown in FIG. 4, the cross-sectional dimensions of the plurality of individual flow paths are characterized.

That is, in the first embodiment described above, the individual flow paths 31, 32, and 33 included in the rotating shaft 21 are set to have the same cross-sectional area, and the flow rates of the ground improvement materials are substantially equal in each individual flow path. However, the individual flow paths 31, 32, and 33 in the second embodiment have different cross-sectional areas of the portions through which the ground improvement material passes.

In this way, by setting each dimension of the individual flow paths 31, 32, 33 so that the cross-sectional area of the portion through which the ground improvement material passes is different, the discharge amount at the discharge ports 1, 2, and 3 is different. It is possible to have. Such a feature is useful when it is desired to set different discharge amounts for a plurality of discharge ports.

(Third Embodiment of a stirring mixer)
In the third embodiment of the stirring / mixing device, an opening / closing means for repeatedly opening / closing a plurality of individual flow paths individually communicating with the plurality of discharge ports with a time lag is further provided.

The so-called rotating phenomenon may occur in which the in-situ ground adheres to the stirring blade and the soil mass in the in-situ ground rotates together with the stirring blade, which may reduce the effect of stirring and mixing, and prevents such a rotating phenomenon. A "rotation prevention wing" is known as a means of doing so. In the present embodiment, the above-mentioned "opening / closing means for repeatedly opening / closing individual flow paths with a time lag" is realized by using the rotation prevention blade 61 as illustrated in FIGS. 5 and 6 as an example. ing.

The rotation prevention blade 61 included in the stirring and mixing device of the present embodiment is provided at a position separated from the stirring blade 41 by a predetermined gap, and is relatively rotatable and rotatable with respect to the rotating shaft 21. It is attached. The rotation prevention blade 61 extends to the outside of the stirring blade 41. Therefore, when the stirring and mixing device rotates in the ground, the outer end of the rotation prevention blade 61 is in a state of being pierced into the hole wall of the excavation hole, and does not rotate or rotates with the stirring blade 41. It's getting harder. Therefore, under the condition that the stirring and mixing device rotates in the ground, the rotation prevention blade 61 is maintained in a state in which the rotation prevention blade 61 does not rotate or is difficult to rotate, while the stirring blade 41 with respect to the rotation prevention blade 61. It keeps rotating relatively.

Further, in the present embodiment, a flow path opening / closing portion 63 capable of opening / closing the individual flow paths 31, 32, 33 is provided at the attachment portion of the rotation prevention blade 61 with respect to the rotating shaft 21. An opening 65 is formed in the flow path opening / closing portion 63, and the ground improvement material is distributed to the discharge ports 1, 2 and 3 of the stirring blade 41 through the opening 65.

Specifically, the rotation prevention blade 61 is attached to the rotation shaft 21 so that the flow path opening / closing portion 63 blocks the branched individual flow paths 31, 32, 33. The flow path opening / closing portion 63 of the rotation prevention blade 61 is provided with an opening 65 (hole) through which the ground improvement material can pass only in a part of the individual flow paths.

The shape and number of openings 65 provided in the flow path opening / closing portion 63 are not particularly limited to those shown in FIG. 5, and the time difference between opening / closing the individual flow paths and the shape of the individual flow paths are taken into consideration. The design can be changed as appropriate.
For example, in the embodiment illustrated in FIG. 5, one opening 65 is provided in the flow path opening / closing portion 63, and the opening shape is substantially fan-shaped according to the cross-sectional shape of the individual flow paths 31, 32, 33. As in the embodiment illustrated in 6, two openings 65 may be provided, and the opening shape may be substantially circular according to the cross-sectional shape of the individual flow paths 31, 32, 33.

When the stirring / mixing device having such a configuration is rotated in the ground, the rotation prevention blade 61 is restrained so as not to move, as shown in order in FIGS. 6A, 6B, and 6C as an example. Under such circumstances, the stirring blade 41 rotates relative to the rotation prevention blade 61.

Then, when any of the individual flow paths provided by the stirring blade 41 reaches the position facing the opening 65, the individual flow paths are opened and the ground improvement material can pass through. Therefore, among the individual flow paths 31, 32, 33, the flow paths that can pass through change from moment to moment, and each flow path is temporarily shut off with a time lag, so that the material is discharged discontinuously.

In addition, when a plurality of discharge ports are provided and all the discharge ports are continuously discharged at the same time, if one discharge port is blocked, the material is discharged from the other discharge ports, so that the blockage cannot be eliminated. However, by temporarily shutting off each flow path, pressure is concentrated on the closed discharge port, and the clogged improved material is pushed out from the closed discharge port, so that the blocked state can be eliminated.

(Other Embodiments of Stirring Mixer)

Further, in the present invention, one of the branched individual flow paths may be intentionally closed according to the specifications of the improved body to be created. Alternatively, any one of the plurality of discharge ports may be intentionally closed.
For example, as shown in FIG. 7, a hollow improved body can be created by closing the innermost discharge port 1 (or the individual flow path 31 leading to the discharge port).
In the embodiment illustrated in FIG. 7, the discharge port 1 located at the innermost position is closed (removably) with a closing member. By closing in this way, the material is not discharged from the discharge port 1, so that the inside of the stirring and mixing area by the stirring blade 41 is unimproved, and only the middle and outside of the stirring and mixing area are improved in a limited manner. NS. As a result, it is possible to create a hollow improved body as shown in FIG. 7 colored in gray.

Further, in the present invention, the number of stages of the stirring blade provided with the discharge port is not particularly limited, and may be one stage as in the first embodiment described above, or as illustrated in FIG. 8, the stirring blade provided with the discharge port. It is also possible to provide two or more stages. The number of discharge ports can be increased by providing the stirring blades in multiple stages (for example, 2 to 4 stages), and the materials can be more evenly distributed by increasing the number of discharge ports.

1 1st discharge port 2 2nd discharge port 3 3rd discharge port 11 Mechanical stirring stirring mixer 21 Rotating shaft (stirring shaft)
23 Flow path 31 Individual flow path 32 Individual flow path 33 Individual flow path 35 Excavation head 37 Branch inlet 41 Stirring blade 42 Stirring blade 45 Flow path 61 Circulation prevention blade (opening / closing means)
63 Flow path opening / closing part 65 Opening (hole)
91 Construction machine body

Claims (6)

A rotating shaft having a flow path for a ground improvement material made of mortar,
It has a stirring blade provided with a plurality of discharge ports for discharging the ground improvement material guided via the rotating shaft.
The plurality of discharge ports are provided on the stirring blade so as to be located at different distances from the rotation axis.
The flow path provided by the rotation shaft is branched into a plurality of individual flow paths downward in the middle of the flow path.
The plurality of individual flow paths included in the rotating shaft individually communicate with the plurality of discharge ports included in the stirring blade.
A stirring / mixing device for mechanical stirring , wherein the total cross-sectional area of the plurality of individual flow paths after branching is substantially the same as or larger than the cross-sectional area of the flow paths before branching. The plurality of individual flow paths differ in the cross-sectional area of the portion through which the ground improvement material passes.
The stirring / mixing device for mechanical stirring according to claim 1. In the flow path provided by the rotating shaft
The entrance of the branch, which is divided into multiple individual flow paths, is tapered.
The stirring / mixing device for mechanical stirring according to claim 1 or 2. The stirring for mechanical stirring according to any one of claims 1 to 3 , further comprising an opening / closing means for repeatedly opening and closing a plurality of individual flow paths individually communicating with the plurality of discharge ports with a time lag. Mixing device. The ground improvement method using the stirring and mixing device for mechanical stirring according to claim 1, which has a stirring blade provided with a plurality of discharge ports for the ground improvement material and is provided so that the plurality of discharge ports swivel with different diameters. And
A ground improvement material made of mortar is pumped through a rotating shaft having a flow path in one or both of the processes of penetrating the stirring and mixing device having a rotating shaft and a stirring blade into the ground and the process of pulling out from the ground. death,
Ground improvement material is discharged from each of a plurality of discharge ports that rotate with different diameters.
A ground improvement method characterized by this. The ground improvement method according to claim 5, wherein the ground improvement material is discharged discontinuously from the plurality of discharge ports.

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