JP3016341B2 - Ground improvement equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a ground improvement device,
Specifically, in civil engineering and construction foundation work, a lime-based or cement-based slurry-type solidifying agent (hereinafter, also simply referred to as solidifying agent) is discharged while excavating the ground into a columnar shape, and the solidifying agent and excavated soil are excavated. The present invention relates to a soil improvement device for solidifying, shaping and improving the ground in a columnar shape by mixing, stirring and solidifying the ground.

[0002]

2. Description of the Related Art Conventionally, a technique described in Japanese Patent Publication No. 58-29374 is known as this type of ground improvement apparatus. In this apparatus, a drilling blade and a stirring blade are provided near the tip of a rotating drilling shaft, and the outer diameter of the drilling blade (the drilling diameter) is provided between the drilling blade and the stirring blade or between the stirring blades. ) An anti-corotating wing having a larger diameter (length) is rotatably mounted on an excavation shaft via a boss to prevent co-rotation of the excavated earth mass.

In the technique disclosed in Japanese Patent Publication No. 58-29374, when the ground (soil) is digged by the rotation of the digging wing, the ground is excavated into a columnar shape having substantially the same diameter as the outer diameter of the digging wing. Are simultaneously stirred by the stirring blade.
At this time, since the anti-corotating wing has a diameter larger than that of the excavating wing, both ends are pushed into a cylindrical portion, which is not excavated, that is, outside the cylindrical body, and penetrate into the ground. . Then, since the co-rotation prevention wings are not excavated at both ends in a plan view and are constrained by the hard ground, they do not rotate around the axis of the excavation shaft. Thereby, in this excavation process, the earth mass which is going to rotate together with the excavating blade and the stirring blade is loosened without rotating together because the rotation is prevented by the anti-rotation blade. Then, under this, while the solidifying agent is discharged from the tip of the excavation shaft, this is mixed with the excavated soil, stirred, and then solidified, whereby the ground is improved into a columnar shape. That is, according to the technology described in the above-mentioned publication, the rotating excavating blade and the stirring blade, and the non-rotating anti-rotating wing do not cause the excavated soil to co-rotate as a lump around the excavating axis, and mix and stir together with the solidifying agent. By doing so, the ground is uniformly improved in a columnar shape.

[0004]

In the technique described in the above publication, the excavated soil is stirred only around the axis of the excavation shaft. In other words, mixing and agitation are performed in the circumferential direction of the cylindrical body, but they are not positively mixed in the vertical direction. Therefore, the technique described in the above publication has a problem that the entire columnar body is not uniformly mixed and stirred. Such a problem is remarkable when the soil is hard cohesive soil or peat layer ground, for example, because it tends to form a cobble mass and co-rotate, and the degree of ground improvement tends to be insufficient. Was. For this reason, in the technology described in the above publication, much time is required for uniform mixing and stirring. In addition, in order to ensure a high degree of solidification, the solidification agent must be added in a larger amount than necessary, which has led to an increase in cost.

The present invention has been made in view of the above-mentioned problems of the conventional ground improvement apparatus, and is intended to mix excavated soil simply around the axis of the excavation axis, that is, in the circumferential direction of the cylindrical body.
It is an object of the present invention to provide a ground improvement device capable of performing not only stirring but also mixing and stirring over the entire body including the vertical direction of a cylindrical body.

[0006]

According to a first aspect of the present invention, there is provided a ground improvement apparatus including a digging wing provided near a tip end of a rotating digging shaft.
A ring that is rotatable about the axis of the digging shaft is mounted on the digging shaft above the digging wing and extends laterally when viewed from the axial direction of the digging shaft. A horizontal shaft body is provided, and the horizontal shaft body has a tip portion outwardly of a circumference drawn by the tip of the excavation wing when the excavation wing rotates as viewed from the axial direction of the excavation axis. A tubular body having a length that is positioned and rotatable around the axis of the horizontal shaft body inside the circumference thereof, and further, the tubular body includes:
As a means for mixing and stirring the excavated soil, the excavation shaft has at least three protruding pieces extending outwardly of the cylindrical body at substantially equal angular intervals when viewed from the axial direction of the cylindrical body. When the excavating shaft rotates under the condition that the horizontal shaft is not allowed to rotate around the axis of the excavating shaft, the projecting piece is rotated together with the tubular body around the axis of the horizontal shaft when the excavating shaft rotates. Characterized in that at least one rotation drive unit is provided.

A second aspect of the present invention is a ground improvement apparatus including a digging wing near a tip end of a rotating digging shaft, wherein the digging shaft is provided above the digging wing. A ring that is rotatable about the axis of the excavation shaft is mounted on the ring, and a horizontal shaft that extends laterally when viewed from the axial direction of the excavation shaft is disposed on the ring; The body is
When viewed from the axial direction of the excavation axis, the tip has a length located outside the circumference drawn by the tip of the excavation wing when the excavation wing rotates, and inside the circumference, A tubular body rotatable around the axis of the horizontal shaft body, and further comprising a mixing and stirring means for excavated soil, and an axis of the tubular body at a position near the excavation axis. The excavation shaft has at least three protruding pieces extending outwardly of the cylindrical body at substantially equal angular intervals when viewed from the direction, while the horizontal shaft body is provided around the axis of the excavation shaft. When the excavating shaft rotates under the condition that rotation is impossible, at least one rotation drive unit is provided for rotating the protruding piece together with the tubular body around the axis of the horizontal shaft body when hitting the protruding piece. It is characterized by the following.

Further, in the ground improvement apparatus according to claim 2, the mixing and stirring means comprises a plurality of protrusions extending outwardly of the cylindrical body at substantially equal angular intervals when viewed from the axial direction of the cylindrical body. It should be made of pieces. In any of the above-described configurations of the invention, it is preferable that the horizontal shaft is located on both outer sides of the ring when viewed from the axial direction of the excavation shaft. Further, in the configurations of these inventions, the rotation drive unit may be provided on the excavation blade instead of the excavation shaft, or a stirring blade may be provided on the excavation shaft, and the rotation The drive unit may be provided on a stirring blade provided on the excavation shaft instead of the excavation shaft.

[0009]

According to the first aspect of the present invention, the excavation axis is rotated, excavation proceeds by the excavation wing, and the tip of the horizontal shaft body is formed by the excavation diameter on the ground surface (the circumference drawn by the excavation wing rotating and its tip is drawn). ), The horizontal shaft body penetrates into the excavated soil, and the horizontal shaft body is constrained by the hard soil that has not been excavated at the tip, and around the axis of the excavation axis Will not rotate. Therefore, the earth mass which is rotated in the rotation direction by the excavation wing is prevented from rotating coaxially around the axis of the excavation axis in the horizontal shaft body, and thus is appropriately mixed and stirred around the excavation axis. On top of that, the rotation drive unit provided on the excavation shaft and rotating together with the excavation shaft hits the projecting piece of the tubular body provided on the horizontal shaft body, and this rotates together with the tubular body around its (horizontal) axis. Rotate. Thus, the excavated soil is mixed and stirred around the axis of the horizontal shaft by the projecting pieces provided on the cylindrical body.

According to the second aspect of the present invention, the excavation axis is rotated, excavation proceeds with the excavation wing, and the tip of the horizontal shaft body is formed with the excavation diameter on the surface of the ground (the circumference drawn by the rotation of the excavation wing and the tip is drawn). ), The horizontal shaft body penetrates into the excavated soil, and the horizontal shaft body is constrained by the hard soil that has not been excavated at the tip, and around the axis of the excavation axis Will not rotate. Therefore, the earth mass which is rotated in the rotation direction by the excavation wing is prevented from rotating coaxially around the axis of the excavation axis in the horizontal shaft body, and thus is appropriately mixed and stirred around the excavation axis. A rotary drive unit provided on the excavation shaft and rotating together with the excavation shaft hits a protruding piece of the cylindrical body provided on the horizontal shaft body, and this, the cylindrical body and the mixing and stirring means are combined with the horizontal shaft body. Rotate around the axis of. Thus, the excavated soil is mixed and stirred around the axis of the horizontal shaft by the mixing piece and stirring means provided on the cylindrical body.

That is, according to the first and second aspects of the invention, the excavated soil forming the columnar body is rotated around the axis of the excavation shaft by the excavation wing, and the horizontal shaft and the cylindrical body are rotated around the axis of the excavation shaft. The rotation of the excavated soil is prevented by the rotation of the excavated soil, and the cylindrical body is rotated around the axis of the horizontal shaft. Mixing and stirring are also performed in the lateral direction of the cylinder, that is, around the axis having substantially the diameter of the cylinder. Therefore, the excavated soil is
Mixing and agitation are performed by three-dimensional movement around the axis of the excavation axis and the axis of the horizontal shaft.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a ground improvement apparatus according to the present invention will be described in detail with reference to FIGS. However, each of the following embodiments is configured by a welding structure in which the steel components are joined by welding or the like. In the figure, reference numeral 1 denotes a substantially cylindrical (or hollow cylindrical) excavation shaft (rotation drive shaft) which is configured to be rotated by rotation drive means (not shown), and has a ground near its tip. A digging wing 2 having a predetermined diameter (length) D1 for digging is provided in a projecting manner in a direction substantially perpendicular to the digging shaft 1 by welding. In this example, a stirring blade 3 having a diameter (length) D2 slightly smaller than the diameter D1 of the drilling wing 2 and stirring the excavated soil k by rotating integrally with the drilling shaft 1 is provided above. They are integrally fixed by welding. However, the stirring blade 3 has a strip shape, and its width W direction is substantially parallel to the direction of the axis G1 of the excavating shaft 1. A discharge port 1a of a slurry-like solidifying agent is provided in the vicinity of the tip of the excavating shaft 1, and a solidifying agent (not shown) is discharged from the pressure feed source into the excavated soil k through the inside of the excavating shaft 1. It is configured to be.

As will be described in detail below, a horizontal shaft 4 is disposed between the excavating blade 2 and the stirring blade 3 in the excavating shaft 1 in a direction substantially perpendicular to the excavating shaft 1. That is, as shown in FIGS. 1 to 4, in the present example, the outer periphery of the excavation shaft 1 is rotatable around the axis G1 of the excavation shaft 1 between the excavation blade 2 and the stirring blade 3. An annular body 5 having a cylindrical shape (circular tube) with a slight gap is mounted. However, ring 5
The excavation shaft 1 at the position where the upper end surface and lower end surface of the
Rings 6 a and 6 b having a diameter larger than the excavation shaft 1 are integrally provided around the excavation shaft 1, and regulate the vertical movement of the ring body 5. The horizontal shaft 4 is provided on both outer sides in the diameter direction of the ring 5 as follows. However, in this example, the horizontal body 4 is provided symmetrically with respect to the axis G1 of the excavation shaft 1 by a welding structure. That is, the horizontal shaft 4 is
A circular rod portion 7 having a circular cross section and extending substantially linearly in a direction substantially perpendicular to the excavation shaft 1, and a substantially rectangular plate piece 9 is provided at a tip end thereof via a rectangular flange portion 8. When viewed from the direction of the axis G1 of the excavating shaft 1, the flange portion 8 and the plate piece 9
It is joined and formed by welding so as to form a T-shape (see FIG. 4), and the diameter (length) L1 between the distal ends of the plate pieces 9, 9 of the left and right horizontal shaft bodies 4, 4 is the diameter D1 of the excavating wing 2. On the other hand, the diameter (length) L2 between the flange surfaces of the flange portion 8 is smaller than the diameter D1 of the excavation wing 2 while being formed larger. It should be noted that enlarged diameter portions 10 and 11 having a diameter larger than that of the circular rod 7 are provided on the base end side and the distal end side of the circular rod 7 respectively.

Then, the circular rod-shaped portion 7 of each horizontal shaft 4 has
Cylindrical bodies 12, 12 each having a cylindrical (circular tube) shape are rotatably fitted (freely fitted) around the axis G2 of the horizontal shaft (circular bar-shaped portion 7) 4, and the movement in the direction of the axis G2 is , Expanded part 1
It is regulated by 0,11. Further, the cylindrical body 12
Is a horizontal shaft (cylindrical body 1) as a mixing and stirring means for excavated soil k.
2) The cylindrical bodies 1 are arranged at substantially equal angular intervals when viewed from the direction of the axis G2 of 4.
2, an appropriate number (in this example, right and left, four each) of protruding pieces (round bars) 13 of a predetermined length extending radially (cross-shaped) outward are provided by welding. On the other hand, the ring 6a provided on the excavation shaft 1 is provided with rods 14 on both outer sides by welding. The rod 14 is composed of a plate 9 at the tip of the
When the excavation shaft 1 is rotated when the excavation shaft 9 rotates, the protruding pieces 13,
13 and the projecting piece 13 together with the tubular body 12
A rotation drive unit that rotates around the axis G2. However, in this example, the rod 14 is formed on the outer periphery of the ring 6a so as to protrude in the diameter direction (linear shape) when viewed from the direction of the axis G1 of the excavation shaft 1.

Thus, the left and right horizontal shaft members 4 and 4 rotate together with the excavating shaft 1 around the axis G1 of the excavating shaft 1 unless an external force that stops the rotation around the excavating shaft 1 is applied thereto. Then, the plate pieces 9, 9 at both ends of the horizontal shaft body 4 bite into the periphery of the excavation hole, and when the rotation of the horizontal shaft body 4 around the excavation axis 1 stops, the excavation shaft 1 serves as a rotation drive unit. The rod 14 hits the projecting piece (mixing and stirring means) 13, and rotates the projecting piece 13 around the axis G <b> 2 of the horizontal shaft 4 by a predetermined angle, and intermittently rotates. In the present example, the protruding pieces 13 of the left and right horizontal shaft members 4 and 4 rotate in directions opposite to each other when viewed from the direction of the axis G2.

Next, the operation and effect of the thus configured apparatus of this embodiment will be described. When the excavating shaft 1 enters the soil while rotating, excavation is started by the excavating wing 2, and the ground is excavated in a columnar shape with substantially the same diameter as the diameter D1 of the excavating wing 2. At this time, before the plate pieces 9, 9 near both ends thereof reach the ground, the horizontal shaft 4 rotates substantially integrally with the rotation of the excavation shaft 1 in the same direction. Then, when the excavation proceeds and the plate pieces 9 and 9 of the horizontal shaft body 4 enter the hard ground which has not been excavated, that is, the outer edge of the cylindrical body (the circumference E drawn by the tip of the excavating wing 2 rotating). This acts as a detent for the horizontal shaft 4 about the excavation shaft 1. Thereby, the rotation of the horizontal shaft body 4 about the axis G1 of the excavation shaft 1 is stopped.
A rod 14 serving as a rotation drive unit that rotates together with the excavating shaft 1 is provided with projecting pieces 13, 13 provided on the cylindrical body 12.
In this case, the projecting piece 13 and the cylindrical body 12 are rotated around the axis G2 of the horizontal shaft body 4, and excavation proceeds in that state. In this example, since the stirring blades 3 enter the excavated soil k while rotating together with the excavating shaft 1, the mixing and stirring operations are performed efficiently.

Thus, the excavated soil k is mixed and stirred around the excavation axis 1 by the excavating blades 2 and the stirring blades 3. At this time, the excavated soil k which turns into the earth mass around the excavation axis 1 is:
The rotation is stopped by the horizontal shaft body 4 which does not rotate in plan view. That is, since the horizontal shaft body 4 performs an action of preventing the excavated soil k from rotating together, the excavated soil k is loosened. Further, the cylindrical body 12 mounted on the circular rod-shaped portion 7 of the horizontal shaft body 4 has a structure shown in FIG.
As shown by the arrow in the middle, the excavated soil k is rotated around the axis G2, and the excavated pieces 13 are mixed and stirred around the horizontal axis G2 by the protruding pieces 13, 13. Therefore, when the slurry-type solidifying agent is injected under the slurry, it is mixed with the excavated soil k. In this mode, the extruded soil k is mixed and stirred in the same direction as the rotation direction of the excavating blade 2 and the stirring blade 3. At the same time, the rotation of the protruding piece 13 causes mixing and stirring around the axis G2 of the horizontal shaft 4. In other words, the solidifying agent is mixed not only in the circumferential direction in the cross section of the cylindrical body but also in the vertical direction by the rotation of the projecting piece 13,
Since the stirring is performed, the solidifying agent is more efficiently and uniformly stirred. As a result, a columnar body having a uniform strength can be obtained with an appropriate amount of the solidifying agent. In this example, since the stirring blade 3 is separately provided in addition to the excavation blade 2, the stirring is particularly efficiently performed.

In this embodiment, the protruding piece 13 as the mixing and stirring means of the horizontal shaft 4 is a round bar, but the shape is determined according to the soil quality, such as tongue shape, while maintaining the required strength. What is necessary is just to design it into a thing of an appropriate shape and structure. In the case of soil with high viscosity such as clayey, a steel rod like this example is suitable, while in the case of soil with relatively low viscosity such as sandy soil, the resistance during mixing and stirring is rather low. The larger the one, the better the mixing and stirring efficiency. Therefore, in such a case, it can be said that the protruding piece serving as the mixing and stirring means is preferably a wide strip, but it may have an appropriate configuration capable of mixing and stirring the excavated soil k. Note that the projecting piece described above is rotated intermittently or continuously around the horizontal shaft 4 together with the cylindrical body 12 by the rotation drive unit (the rod 14 in this example) provided on the excavation shaft 1. It is sufficient if they are provided so as to be able to be provided. Therefore, it is sufficient if there are at least three at substantially equal angular intervals when viewed from the direction of the axis G2 of the cylindrical body 12. Further, in order to rotate the protruding piece as smoothly as possible by the rotation driving unit such as the rod 14, it is preferable that the rotation driving unit and the protruding piece are set so that the resistance becomes small when both are engaged.

The annular body 5 mounted on the excavating shaft 1 and provided with the horizontal shaft 4 is not limited as long as it is cylindrical or annular and can rotate stably around the axis G1 of the excavating shaft 1. In the above embodiment, the case where the horizontal shaft 4 is provided on both sides from the ring 5 is exemplified. However, if the performance is reduced due to imbalance, it can be provided on only one side. It is also possible to provide radially when viewed from the direction of the axis G1 of the excavating shaft 1.

In this embodiment, a plate piece 9 is provided at the tip of the horizontal shaft body 4 so that its width direction or length direction is aligned with the direction of the excavation shaft 1.
Since it penetrated into the soil from the side edge of the plate piece 9, it is easy to bite into the edge of the cylindrical body (digging hole). Further, in the present invention, the horizontal shaft 4 is formed such that when viewed from the direction of the axis G1 of the excavation shaft 1, the extremity of the excavation wing 2 rotates and the extremity of the axle 4 extends outward of the circumference E drawn by the excavation wing 2. It has a length which is located, and the tip (plate piece 9 in the above-mentioned example) should just bite into the hole edge. Further, the tubular body 12 may be provided rotatably around the axis G2 of the horizontal shaft body 4 inside the circumference E.

The projecting piece 13 provided as a mixing and stirring means for excavated soil provided on the cylindrical body 12 is provided with an axis G of the cylindrical body 12.
It extends outwardly of the cylindrical body 12 at substantially equal angular intervals when viewed from two directions, and the number thereof may be such that it rotates intermittently, and therefore, if at least three as described above, On the other hand, the rotation drive unit of the excavating shaft 1 is the rod 14 in the above embodiment, which is provided on both sides of the ring 6a in plan view, but the horizontal shaft 4 cannot rotate around the axis G1 of the excavating shaft 1. When the excavating shaft 1 rotates under the condition that the excavating shaft 1 rotates, the projecting piece 13 hits the protruding piece 13 of the tubular body 12 and can be rotated intermittently around the axis G2 of the horizontal shaft body 4 together with the tubular body 12. It suffices if possible, and therefore at least one.

Further, the front shape of the plate pieces 9, 9 at both ends of the horizontal shaft body 4 may be substantially triangular as shown by a two-dot chain line in FIG. By doing so, the resistance of the plate piece 9 of the horizontal shaft member 4 when it enters the hard soil outside the outer edge E of the columnar body is reduced, and the advancement into the soil is facilitated. In the above description, the case where the horizontal shaft body 4 on which the projecting piece 13 rotates is provided only in the same height portion of the excavation shaft 1 in FIG. 2 is illustrated, but may be provided in a plurality of different height portions. It is suitable when the excavation depth is deep. Further, the stirring blade 3 is not necessarily required, but may be further provided between the excavating blade 2 and the horizontal shaft 4. This is because the stirring around the axis G1 can be performed better. In addition, it is good to make each structural member from a high-strength, high-abrasion-resistant steel metal material. The same applies to the following embodiments.

An embodiment according to claim 2 of the ground improvement apparatus according to the present invention will be described with reference to FIGS. 5 to 8. This embodiment is to be referred to as an improvement of the above embodiment.
Since it is basically the same as the above embodiment, only the differences will be described, the same portions will be denoted by the same reference numerals, and the description thereof will be omitted. In other words, in the above-described embodiment, the rod 13 is applied as a rotation drive unit to the projecting piece 13 as the mixing and stirring means for the excavated soil k to rotate the projecting piece 13, thereby removing the excavated soil k. While the mixing and stirring are performed around the axis G2 of the horizontal shaft body 4, in the present embodiment, the cylindrical body 1
As in the above-described embodiment, the projecting pieces 13 extending outward from the cylindrical body 12 at substantially equal angular intervals when viewed from the direction of the axis G2 of the cylindrical body 12 are provided by welding at a position near the excavation shaft 1 of the second. At the same time, a mixing and stirring means for excavated soil such as the rod 23 is provided on the cylindrical body 12 by welding.

In this embodiment, since the mixing and stirring means such as the rod 23 is provided separately from the protruding piece 13, the mixing and stirring are performed more uniformly in the circular cross section of the cylindrical body. As a result, high quality ground improvement can be performed. The above-described embodiment is suitable for the case where the horizontal shaft 4 is relatively short, that is, for improvement to a relatively small-diameter cylindrical body. In this embodiment, however, the mixing of the rod 23 and the like separately from the protruding piece 13 is performed. The provision of the stirring means is suitable for improving the ground to a relatively large cylindrical body. In this example, the separately provided mixing and stirring means are provided radially (four each) on the cylindrical body 12 at positions substantially equidistant from the center of the excavation shaft 1 in plan view on both the left and right. They may be provided at different distances, and an appropriate number of them may be provided at appropriate positions as long as they do not interfere with the rotation of the ring 14 on both the left and right sides.
Although the mixing and stirring means has the same shape as the protruding piece 13 in this example, the shape may be appropriately designed according to the soil quality, such as a tongue piece, as described in the previous example. Is the same as However, since there is no role of transmitting the rotational force of the excavating shaft 1, its shape and strength may be set in consideration of only the effect of mixing and stirring. In this example, the horizontal shafts 4 are provided on both outer sides of the annular body 6 when viewed from the direction of the axis G1 of the excavation shaft 1 in this example, but may be provided more radially. In addition, if the performance is reduced due to the unbalance, it can be provided on only one side as in the case described above. The projecting piece 13 only needs to rotate the cylindrical body 12 around the axis G2 by a rotation drive unit such as a rod, and therefore, similar to the projecting piece 13 of the above embodiment,
It is necessary to extend three radially at equal angular intervals at least when viewed from the direction of the axis G2.

Next, the embodiment shown in FIG. 9 will be described. However, this is a modification of the embodiment shown in FIGS. 1 to 4, and is basically common, so only the differences will be described, and the same portions will be denoted by the same reference numerals. The description is omitted (the same applies to the following embodiments). That is, in the embodiment illustrated in FIGS. 1 to 4, the case where the rotation drive unit such as the rod 14 is separately provided on the excavation shaft 1 is illustrated. However, in the embodiment illustrated in FIG. Excavation wing 2 instead of excavation axis 1
It is provided in. However, in this example, the distance between the excavating wing 2 and the horizontal shaft 4 is reduced, and the excavating wing is rotated around the axis G2 of the horizontal shaft 4 together with the cylindrical body 12 by hitting the projecting piece 13. A belt-like plate member 24 is integrally fixed along the upper edge of the plate 2 by welding or the like to form a rotation drive unit. In this example, the ring 6b below the ring body 5 is integrated with the plate member 24. In this example, the structure is simplified because the rotation drive unit is not separately provided on the excavation shaft 1. It can be said to be suitable when the excavation depth is shallow. 10 is the same as the embodiment in FIG. 9 in the embodiment in FIGS. That is,
Instead of the excavating shaft 1 in FIGS. 5 to 8, a belt-shaped plate member 24 is integrally fixed along the upper edge of the excavating wing 2 by welding or the like to form a rotation drive unit. As before,
Since the rotation drive unit is not separately provided on the excavating shaft 1, the structure is simplified.

Next, the embodiment shown in FIG. 11 will be described. However, this is also a modification of the embodiment shown in FIGS. 1 to 4 and, since it is basically common, only the differences will be described, and the same portions will be denoted by the same reference numerals. And the description is omitted. That is, in the embodiment shown in FIGS. 1 to 4, the rotation drive unit such as the rod 14 is connected to the excavation shaft 1.
In the embodiment shown in FIG. 11, the rotating drive unit is provided with a stirring blade 3 fixed to the excavating shaft 1.
It is provided in. However, in this example, the distance between the stirring blade 3 and the horizontal shaft 4 is reduced, and the stirring blade 3 is rotated so as to rotate around the axis G2 of the horizontal shaft 4 together with the cylindrical body 12 by hitting the projection 13. A belt-like plate member 34 is integrally fixed along the lower edge of the belt 3 by welding or the like to form a rotation drive unit. In this example, the ring 6 a on the ring body 5 is integrated with the plate member 34. In this example,
Since the rotation drive unit is not separately provided on the excavating shaft 1, the structure is simplified. It can be said to be suitable when the excavation depth is shallow.
FIG. 12 shows the embodiment shown in FIGS.
This is similar to the first embodiment. That is, instead of the excavating shaft 1, a band-shaped plate member 34 is integrally fixed to the agitating blade 3 fixed to the excavating shaft 1 along the lower edge of the agitating blade 3 by welding or the like. This is a driving unit. As before, the structure is simplified because the rotation drive unit is not separately provided on the excavation shaft 1.

[0027]

According to the present invention, the excavated soil having a columnar shape in the ground is mixed and agitated three-dimensionally around the axis of the excavation axis and the axis of the horizontal shaft. As compared with the prior art in which mixing and agitation are performed only around the axis of, more uniform mixing and agitation are performed, so that a high-quality ground can be improved. In particular, according to the second aspect of the present invention, as a means for mixing and stirring excavated soil around the axis of the horizontal shaft body, in addition to the protruding piece, a separate mixing and stirring means is provided, so that the excavated soil is accordingly reduced. As a result of being mixed and stirred more uniformly in the upper and lower directions, it is possible to further improve the ground quality.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a schematic configuration of an embodiment embodying a ground improvement device of the present invention.

2 is a partially broken center longitudinal sectional view illustrating a state in which the ground is improved in the embodiment of FIG. 1;

FIG. 3 is an enlarged view of a main part of FIG. 2;

FIG. 4 is a plan view of FIG. 3;

FIG. 5 is a perspective view showing a schematic configuration of another embodiment embodying the ground improvement device of the present invention.

6 is a partially broken center longitudinal sectional view illustrating a state in which the ground is improved in the embodiment of FIG. 5;

FIG. 7 is an enlarged view of a main part of FIG. 6;

FIG. 8 is a plan view of FIG. 7;

FIG. 9 is a partially broken center longitudinal sectional view illustrating a state in which the ground is improved in another embodiment that embodies the ground improvement apparatus of the present invention.

FIG. 10 is a partially broken center longitudinal sectional view illustrating a state in which the ground is improved in another embodiment embodying the ground improvement apparatus of the present invention.

FIG. 11 is a partially broken center longitudinal sectional view illustrating a state in which the ground is improved in another embodiment embodying the ground improvement apparatus of the present invention.

FIG. 12 is a partially broken center longitudinal sectional view illustrating a state in which the ground is improved in another embodiment that embodies the ground improvement apparatus of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Excavation axis 2 Excavation blade 3 Stirrer blade 4 Horizontal shaft 5 Ring body 12 Cylindrical body 13 Projection piece (mixing and stirring means for excavated soil) 14, 24, 34 Rotating drive unit (rod) 23 Mixing and stirring means G1 Excavation axis G2 Axis of horizontal shaft (cylindrical body) E Circumference drawn by the tip of the drilling wing k Excavated soil

Claims (6)

(57) [Claims] 1. A ground improvement device comprising a digging wing provided near a tip of a rotating digging shaft, wherein the digging shaft is rotatable about the axis of the digging shaft above the digging wing. And a horizontal shaft extending in the horizontal direction as viewed from the axial direction of the excavating shaft is disposed on the circular body, and the horizontal shaft is disposed in the axial direction of the drilling shaft. As seen, the tip has a length located outside the circumference drawn by the tip of the excavation wing when the excavation wing rotates, and inside the circumference, around the axis of the horizontal shaft body. A rotatable cylindrical body is further provided, and the cylindrical body is provided at substantially equal angular intervals as viewed from the axial direction of the cylindrical body as mixing and stirring means for excavated soil. The excavation shaft has at least three projecting pieces, and the excavation shaft has the horizontal shaft body rotated about the axis of the excavation shaft. When the excavation shaft is rotated under the disabled condition, the excavation shaft is provided with at least one rotation drive unit that contacts the protrusion and rotates the protrusion together with the cylindrical body around the axis of the horizontal shaft. A ground improvement device characterized by the following. 2. A ground improvement device comprising a digging wing near a tip of a rotating digging shaft, wherein the digging shaft is rotatable about the axis of the digging shaft above the digging wing. And a horizontal shaft extending in the horizontal direction as viewed from the axial direction of the excavating shaft is disposed on the circular body, and the horizontal shaft is disposed in the axial direction of the drilling shaft. As seen, the tip has a length located outside the circumference drawn by the tip of the excavation wing when the excavation wing rotates, and inside the circumference, around the axis of the horizontal shaft body. A rotatable cylindrical body is further provided, and the cylindrical body is provided with a means for mixing and stirring excavated soil, and is provided at a position near the excavation axis at a substantially equal angle when viewed from the axial direction of the cylindrical body. The excavation shaft has at least three projecting pieces extending outwardly of the cylindrical body at intervals. When the excavating shaft rotates under the condition that the horizontal shaft is not allowed to rotate around the axis of the excavating shaft, the projecting piece is rotated together with the cylindrical body around the axis of the horizontal shaft when the excavating shaft rotates. A ground improvement apparatus, comprising: a single rotation drive unit. 3. The ground improvement device according to claim 2,
The ground improvement apparatus according to claim 1, wherein the mixing and stirring means comprises a plurality of projecting pieces extending outwardly of the cylindrical body at substantially equal angular intervals when viewed from the axial direction of the cylindrical body. 4. The ground improvement apparatus according to claim 1, wherein the horizontal shaft is located on both outer sides of the ring when viewed from the axial direction of the excavation shaft. 5. The ground improvement device according to claim 1, wherein the rotation drive unit is provided on the excavation wing in place of the excavation shaft. 6. The ground improvement device according to claim 1, wherein a stirring blade is provided on the excavation shaft, and the rotation drive unit is provided on the excavation shaft instead of the excavation shaft. The stirring blade is provided.
Or the ground improvement device according to 4.