JPH09111748A - Building device of ground improvement column provided with accompanying turning preventive mechanism for excavated clod of earth - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent excavated clods of earth from turning in accompanyment and construct a good quality column with high efficiency when improving a weak ground by constructing a soil cement column. SOLUTION: An excavation blade 6 is provided on the lower end of a rotary rod 5 while an agitation blade 9 is provided on the upper side. A bearing 11 is positioned on the upper side of the agitation blade 9 and provided on the bearing 11 turnably around its axis. The base end area of a together turning preventive blade 17, which projects in the radial direction of the rotary rod 5, is pivoted on the bearing 11.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a soil for improving a soft ground by constructing a soil cement column (hereinafter referred to as a column). The present invention relates to a construction device for an improved column.

[0002]

2. Description of the Related Art As an effective construction method for improving soft ground, a construction method of building a column in the ground has been adopted. The construction method of the column is to excavate while injecting the solidified material liquid into the ground, mechanically mix and stir the soil mass in the excavation hole and the solidified material liquid, and solidify the solidified material liquid to form the column in the ground. At that time, it was necessary to prevent co-rotation of earth and sand in the excavation hole in order to increase the stirring and mixing efficiency.

An apparatus disclosed in Japanese Patent Publication No. 58-29374 has been proposed as a co-rotation preventing means. As shown in FIG. 9, the apparatus comprises a prevention blade a and a stirring blade b having a diameter larger than the excavation diameter mounted on a rotating rod c so as to be rotatable in a horizontal plane. By causing d to penetrate into the ground e around the excavation hole, its rotation is prevented, and only the elevating operation is performed. However, the earth mass excavated by the excavation wing f at the lower end of the rotating rod rotates in the rotation direction of the excavation wing, but the rotation is stopped by the prevention wing a in the stopped state, and corotation is prevented. there were.

As another co-rotation prevention means, the one shown in FIG. 10 has been proposed. This is configured such that the rotating rod g is a double tube, the inner rod h rotates, and the outer rod j does not rotate. And the inner rod h
And a rotating drum n integrally including a cutting blade k and a stirring blade m.
And a stop wing o is provided on the outer rod j, and the stop wing o in a fixed state is configured to prevent co-rotation of the earth mass.

[0005]

According to the former device, the prevention wings gradually descend into the ground as the excavation proceeds, but the penetration is performed relatively smoothly on the extremely soft ground. Therefore, it could be used without much trouble.
However, when the ground around the excavation hole is hard or there are obstacles such as gravel on the ground, the prevention wing hits them and hinders excavation. Therefore, excavation has to be continued through a troublesome operation of once pulling up the rotating rod to change the direction of the prevention wing, then centering and reinserting the rotating rod into the drilling hole. At times, it has become difficult to raise the rotating rod, and a large-scale operation of excavating the rotating rod to lift the rotating rod is required. If the wings could not be excavated by changing the direction of the wings, the wings had to be removed and excavated. In this case, the excavated soil mass would rotate together, and a column of uniform quality could not be built.

In addition, the apparatus having the double-pipe rotating rod has a problem that the structure is large and the manufacturing cost is increased, and that the apparatus is heavy and the handling is inferior. there were.

An object of the present invention is to provide an apparatus for constructing a ground improvement column capable of solving such problems.

[0008]

In order to solve the above problems, the present invention employs the following means. That is, the construction device of the ground improvement column according to the present invention is provided with a digging wing for digging the ground with the rotation at the lower end side of the rotating rod that can rotate around the vertical axis, and is positioned above the digging wing. hand,
The rotary rod is provided with a stirring blade for stirring and mixing the earth mass and the solidified material liquid in the drilling hole toward the inner peripheral surface of the drilling hole. Further, by being positioned above and / or below the stirring blade,
The rotating rod is provided with a bearing rotatable around its axis, and the bearing is pivotally attached to a base end portion of a co-rotation prevention wing protruding toward the inner peripheral surface of the drilling hole. It is rotatable in a horizontal plane, and the co-rotation is on the near side in the rotation direction of the rotating rod, near the vertical line intersecting the vertical surface passing through the center of the rotating rod and the center of the pivot and the inner peripheral surface of the drilling hole. The length of the co-rotation prevention wing is set so that the tip portion of the prevention wing contacts the inner peripheral surface of the excavation hole, and the counter-rotation prevention wing in the corresponding contact state does not rotate relative to the bearing. As described above, the anti-corotation wing is supported by the receiving portion of the bearing.

In a more preferred aspect of the device, in addition to the above configuration, a restricting portion for restricting a tip portion of the co-rotation prevention wing from rotating toward a forward end of the crossing vertical line in a rotation direction of the rotating rod is provided. , Provided on a bearing. With such a configuration, in the case of a sandy layer or a gravel soil layer which is likely to collapse, it is advantageous for the following reasons. That is, in the case of a sandy layer or a gravel soil layer, during excavation, the excavation hole is liable to be partially collapsed. The anti-corotating wing
This causes the tip to rotate to a state where it is located on the leading side of the intersection vertical line. In this case, the co-rotation prevention wing does not perform the co-rotation prevention function. Therefore, by providing the restricting portion as described above, it is possible to prevent the co-rotation prevention wing from rotating to a state where the tip portion is located on the leading side of the crossing vertical line. Then, after passing through the collapsed portion, the co-rotation prevention blade can be returned to the co-rotation prevention position.

In each of the above devices, the number of co-rotation prevention blades is set to one or more. In particular, when setting multiple co-rotating wings, from the viewpoint of improving the construction speed,
The following configuration is preferable so that the co-rotation preventing action can be obtained regardless of whether the rotating rod rotates in the normal or reverse direction. That is,
When the excavation wing rotates forward, a part of the tip of the co-rotation prevention wing abuts on the inner peripheral surface of the digging hole on the near side of the intersection vertical line in the rotation direction of the rotation rod, and The anti-corotating wing in the state is supported by the bearing of the bearing so that the anti-corotating wing does not rotate relative to the bearing. In order to be unlocked, on the other hand, when the excavation wing reversely rotates, the tip of the other anti-corotating wing,
On the near side of the crossing vertical line in the direction of rotation of the rotating rod, the co-rotating wing abuts against the inner peripheral surface of the excavation hole and is in the corresponding contact state so as not to rotate relative to the bearing. It is preferable that the anti-rotation wing be supported by a bearing of the bearing, and the part of the anti-rotation wing be configured not to be locked on the inner peripheral surface of the excavation hole.

In this case as well, for the same reason as above, the bearing is provided with a restricting portion for restricting the tip portion of the co-rotation preventing blade from rotating forward of the crossing vertical line in the rotational direction of the rotating rod. Is good.

In the present invention, stirring blades may be provided in a plurality of upper and lower stages in order to improve the stirring efficiency and increase the construction speed. In this case, it is preferable to provide co-rotation preventing blades between the upper and lower stirring blades. Good.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS First Embodiment An embodiment of the present invention will be described below with reference to the drawings.
1 to 4, a ground improvement column building device (hereinafter, referred to as a device) 1 according to the present invention includes a rotating rod 5 that can rotate around a vertical axis and that is connected to a connecting rod 3 (FIG. 3) at an upper end portion 2. An excavation blade 6 for excavating the ground according to its rotation is provided at the lower end of the excavation blade, and the excavation blade 6 is positioned above the excavation blade 6 with a vertical interval between the soil and the solidified material liquid in the excavation hole 7. The stirring blades 9 for stirring and mixing are provided so as to project in the radial direction toward the inner peripheral surface 10 of the excavation hole.

[0014] Further, it is located between the upper and lower stirring blades 9, 9;
Each of the rotary rods 5 is provided with a bearing 11 that is rotatable about its axis, which is located above the upper stirring blade 9a. In the present embodiment, the bearing 11 is provided with a semi-annular split piece 12, 12 and a shaft 13 of the rotary rod.
Are held together and the ends 15, 15 are bolted together (FIG. 4), and upper and lower holding pieces 16, 16 are provided at the left and right opposing portions, respectively, as shown in FIGS. Are protruded at required intervals. And the holding piece 1
A base end portion 19 of a co-rotation preventing blade 17 protruding in the radial direction toward the inner peripheral surface 10 of the drill hole is pivotally attached to the blades 6 and 16.

As shown in FIGS. 1 and 4, the anti-corotation wing 17 is formed in an elongated box shape having a U-shaped cross section opened to the front side A in the rotation direction of the rotary rod 5, and A portion 20 of the distal end portion opposite to the open end is loosely curved. As shown in FIG. 2, the co-rotation prevention wings 17 are provided with insertion holes 23, 23 at the upper and lower side pieces 22, 22 of the base end portion 19 so as to be aligned with the holes. A bolt having a portion 19 inserted substantially closely between the upper and lower holding pieces 16, 16 and supported by holding holes 25, 25 provided in the central portions of the base end portions of the upper and lower holding pieces 16, 16. The pivot 26 as the above-mentioned insertion hole 23, 2
3 so that the anti-corotating wings 17
Are rotatable in a substantially horizontal plane.

The length of the anti-corotating wing 17 is determined by a vertical line 31 (FIGS. 4 to 5) which intersects a vertical plane 30 passing through the center 27 of the rotating rod and the center 29 of the pivot and the inner peripheral surface 10 of the borehole. )of,
On the front side A in the rotation direction of the rotating rod, as shown in FIG.
It is set so as to contact 0.

Also, the tip portions of the upper and lower holding pieces 16
At one corner, as shown in FIGS. 1 and 4, the co-rotation preventing blade 17 is rotated by a required angle in the direction opposite to the rotation direction F of the rotating rod, and the upper and lower side pieces 22, 22 are rotated. A receiving portion 33 serving as a bolt for receiving the edge portion is held and attached to the upper and lower holding pieces 16, 16.

The procedure for constructing a column using such an apparatus will now be described. As shown in FIG. 3, the solidifying material liquid mainly composed of cement is discharged from the discharge holes 35 of the excavation blade and is advanced into the ground. At this time, in view of the dimensional relationship of the co-rotation prevention blade 17, as shown in FIG.
The tip portion 32 of the co-rotation preventing blade 17 can be brought into contact with the inner peripheral surface 10 of the excavation hole, and the co-rotation preventing blade 17 and the bearing 11 in the corresponding contact state are prevented from rotating relative to each other. The co-rotation preventing blade 17 is received by the receiving portion 33.

Accordingly, due to the flow resistance of the solidified material liquid and the earth mass in the excavation hole 7 which is rotated in the rotation direction F of the excavation blade 6, the tip portion 32 of the co-rotation prevention wing becomes the inner peripheral surface of the excavation hole. 1
0, and the co-rotation prevention blade 17 is locked (position fixed) with respect to the rotation direction of the rotating rod 5. Thereby, the co-rotation of the excavated soil mass is prevented by the resistance of the anti-rotation blades 17, 17, and the stirring of the soil mass and the solidified material liquid by the stirring blades 9 and the crushing of the soil mass are performed satisfactorily. Will be done. When an obstacle 36 such as gravel is present in the ground around the excavation hole as shown in FIG. 4, the anti-corotating wing 17 hits the obstacle 36 and cannot be excavated. Reverse. At this time, it is preferable to appropriately raise the rotating rod 5. Thereby, the co-rotation preventing blades 17, 17 supported by the receiving portion 33 and integrated with the bearing 11 receive the flow resistance between the soil mass in the excavation hole and the solidified material liquid (the thick broken line in FIG. 4). For example, as shown by an alternate long and short dash line in FIG. 4, the position can be changed by rotating around the axis of the rotary rod 5 so as to avoid the obstacle, and the obstacle can be escaped. As a result of this, when the rotating rod 3 is returned to the normal rotation state, excavation is continued while the co-rotation prevention wing smoothly descends in a pressed state, and a high-strength column can be built, and improvement of soft ground can be achieved. Becomes

Second Embodiment FIGS. 6 and 7 show another embodiment of the device according to the present invention, which prevents rotation of the rotating rod in both forward and reverse directions. An effect can be obtained.

The basic structure of the device 1 is the same as that described above, but there is a difference in the structure for mounting the anti-corotating wing. This will be described with reference to FIGS.

That is, the apparatus 1 is rotatable about a vertical axis and is connected to a connecting rod 3 at an upper end 2 (FIG. 3). And agitating blades 9, 9 which are positioned above the excavating wings 6 and are slightly spaced up and down to agitate and mix the soil mass and the solidified material liquid in the excavating holes 7 with the inner peripheral surface of the excavating hole. It projects in the radial direction toward 10.

[0023] Further, it is located between the upper and lower stirring blades 9, 9;
Each of the rotary rods 5 is provided with a bearing 11 having the same configuration as that described above, which is rotatable about its axis, and is positioned above the upper stirring blade 9a. Upper and lower holding pieces 16 and 16 are respectively provided on the left and right facing portions of the bearing 11 so as to project at required intervals. The holding pieces 16, 16 are provided with
The base portion 19 of the anti-rotation wing 17 radially projecting toward zero is pivotally connected.

As shown in FIGS. 6 and 7, one of the co-rotation prevention wings 17a is formed in an elongated box shape having a U-shaped cross section opened to the front side A in the rotation direction of the rotary rod. The portion 20 opposite to the open end of the tip portion is slightly curved. The other co-rotation prevention wing 17b is formed in an elongated box shape having a U-shaped cross section that is open to the front side B in the rotation direction of the rotating rod (the open state is opposite to the one of the one co-rotation prevention wing 17a). The portion 20 opposite to the open end of the distal end portion is slightly curved. These anti-corotating wings 17a, 17b are attached to upper and lower side pieces 22, 22 of the base end portion 19 in the same manner as shown in FIG.
Insertion holes 23, 23 are provided in alignment with the holes, and the base end portion 19 is inserted approximately closely between the upper and lower holding pieces 16, 16, and the upper and lower holding pieces 16, 16 are inserted.
A pivot 26 as a bolt supported by holding holes 25 provided in the central portion of the base end portion of the
23, so that the co-rotation preventing wing 17
Are rotatable in a substantially horizontal plane.

As shown in FIG. 7, the length of the anti-corotating wing 17 is, as shown in FIG. 7, a vertical plane 30 passing through the center 27 of the rotating rod and the center 29 of the pivot, and the inner peripheral surface 10 of the borehole. On the near side A in the rotation direction of the rotating rod of the vertical line 31 (FIG. 5), the tip 32 of the co-rotation prevention blade 17 is set to contact the inner peripheral surface 10 of the excavation hole.

As shown in FIG. 7, the tip of each of the upper and lower holding pieces 16, 16 for holding the one anti-rotational wing 17a is provided at one corner thereof, as shown in FIG.
The receiving portion 33 as a bolt for receiving the edge portions of the upper and lower side pieces 22, 22 (FIG. 2) in a state where the upper and lower holding pieces 16, 22 are rotated by a required angle in the direction opposite to the rotation direction F 1 of the rotating rod
16 and is attached. Also, the corner portions on one side of the tip portions of the upper and lower holding pieces 16, 16 for supporting the other co-rotation prevention wing 17b are provided with the co-rotation prevention wing 17b.
The receiving portion 33 as a bolt for receiving the edge portions of the upper and lower side pieces 22, 22 is held and attached to the upper and lower holding pieces 16, 16 in a state where is rotated by a required angle in the rotation direction F 1 of the rotary rod. I have.

As a result of this construction, when the rotary rod 5 is digging with the forward rotation F1 as shown in FIG. 7, as shown in FIG.
At the front side A of the crossing vertical line 31 (FIG. 5) in the rotation direction of the rotary rod, the rotary shaft is brought into contact with the inner peripheral surface 10 of the excavation hole, and the anti-corotation prevention blade 17 a and the bearing 1 in the corresponding contact state
1 is held by the receiving portion 33 so as not to rotate relatively. On the other hand, the other counter-rotating wing 17
b is subjected to the flow resistance of the soil mass in the drill hole and the solidifying material liquid,
The tip portion 32 of the corotation prevention wing is not locked on the inner peripheral surface 10 of the drilling hole. Therefore, the co-rotation of the earthen block in the excavation hole is prevented not only by the resistance of the one co-rotation prevention wing 17a but also by the other co-rotation prevention wing 17b supported by the receiving portion 33 and fixed. The resistance is also prevented to prevent.

In order to improve the stirring and mixing of the solidified material and the solidified material liquid, the rotating rod may be reversely rotated F2 (FIG. 7). The tip portion 32 of the wing 17 b is
On the near side in the rotation direction of the rotary rod, the bearing portion 11 is brought into contact with the inner peripheral surface 10 of the drilling hole, and the bearing 11 is not rotated relative to the co-rotation prevention wing 17b in the contact state. Will be retained. On the other hand, the one counter-rotating wing 17a receives the flow resistance of the solidified material liquid and the earth mass in the drilling hole, and the tip portion 32 of the counter-rotating wing is not locked on the inner peripheral surface 10 of the drilling hole. Becomes Therefore, the co-rotation of the earth mass in the excavation hole is prevented not only by the resistance of the other co-rotation prevention blade 17b, but also by the receiving portion 3
3 is also prevented by receiving the resistance of the one co-rotation prevention blade 17a which is supported and is fixed.

When an obstacle 36 such as gravel exists in the ground around the excavation hole as shown in FIG. 7, the co-rotation prevention wing 17 hits the obstacle 36 and cannot excavate.
In that case, the rotating rod 5 is reversed. At this time, it is preferable to appropriately raise the rotating rod 5. Thereby, the anti-corotating wings 17a and 17b supported by the receiving portion 33 and integrated with the bearing 11 receive the flow resistance between the earth mass in the excavation hole and the solidified material liquid, and are indicated by, for example, a dashed line in FIG. As shown, it can rotate to change its position to avoid the obstacle and escape the obstacle.

As a result, when the rotating rod 3 is returned to the normal rotation state, excavation is continued while the co-rotation prevention wing is smoothly lowered in the pressed state, and a column of high strength can be built, so that the soft ground can be improved. Can be achieved.

In another embodiment, the tip portion 32 of the anti-rotation wing is connected to the intersection vertical line 3.
1 (FIG. 5), as shown in FIG. 1, FIG. 4 or FIG. 6, FIG. It is preferable to provide, for example, a shaft-like restricting portion 39 that can abut on the surface side so as to bridge the upper and lower holding pieces. As shown in FIG. 8, the restricting portion 39 can be configured as a bearing portion that can come into contact with the protruding portion 40 provided on the co-rotation prevention wing 17, or as a protruding portion provided on the holding body.

With this configuration, the following special effects can be obtained. That is, in the case of a sandy layer or a gravel soil layer, during excavation, the excavation hole is liable to be partially collapsed. For example, as shown by a two-dot chain line in FIG. 4, the anti-corotation blade 17 rotates to a state B in which the tip end portion 32 is located on the front side of the cross vertical line 31 (FIG. 5). In this case, the co-rotation prevention blade 17 does not perform the co-rotation prevention function. Therefore, by providing the restricting portion 39 as described above, the co-rotation preventing wing 17 can be formed as shown in FIG.
7 can be held as shown by a three-dot chain line, or as shown by a two-dot chain line in FIG. 7, so that the tip portion 32 can be prevented from rotating to a position located on the front side of the cross vertical line 31. After this collapsed portion, the co-rotation prevention blade 17 can be returned to the co-rotation prevention position as shown by the solid line in FIGS.

As shown in the above embodiment, the co-rotation prevention wing is formed in a box shape that is opened to the front side in the rotation direction of the rotation rod, because flow resistance can be effectively received. Although it is preferable, it may be constituted as a simple flat plate.

The receiving portion 33 may be formed in a shaft shape as in the above-described embodiment, or may be a protrusion integrally provided with a bearing (including a holding piece).

[0035] Three or more anti-corotating blades may be provided in an angular arrangement such as an angular pitch of 120 degrees or 90 degrees.

The anti-corotating blade is arranged on both the upper side and the lower side of the stirring blade, and may be arranged on either one of them.

[0037]

The present invention has the following excellent effects. According to the present invention, the anti-corotating wing does not bite into the surrounding ground of the excavation hole as in the prior art, but receives the flow resistance of the solid mass and the solidified material liquid in the excavation hole, and the It is only in the pressed state. Therefore, the co-rotation prevention wing can be easily lowered in the pressed state, and the excavation is smoothly performed. Since the co-rotation prevention wing is locked in the pressed state, the co-rotation of the earth mass in the excavation hole can be prevented. Therefore, the stirring and mixing by the stirring blades is performed smoothly and efficiently, the crushing of the earth mass proceeds reliably, a column with high strength can be built, and the soft ground can be effectively improved.

[0038] Even if there is an obstacle such as gravel in the periphery of the excavation hole and the anti-corotating wing cannot be lowered in response to the obstacle, if the rotating rod is appropriately rotated in the reverse direction, the inner peripheral surface of the excavation hole is removed. The anti-corotating wing, which is only in the pressed state, can easily change its pressed position and escape an obstacle. Therefore, by returning to the normal rotation state again, excavation can be continued. Thus, when according to the present invention, unlike the related art, it is not necessary to go through a troublesome operation such as pulling up and re-adjusting the rotating rod, and from the beginning to the end, it is possible to excavate smoothly while reliably co-rotating, High quality columns can be built.

In particular, when the apparatus according to the present invention is configured to exhibit the co-rotation preventing action in both the forward rotation and the reverse rotation of the rotating rod, the mixing and stirring is performed by repeating the forward rotation and the reverse rotation of the rotating rod. Can be performed satisfactorily, and improvement in construction efficiency can be expected.

The device according to the present invention has a configuration in which a co-rotation prevention blade is rotatably attached to a conventional device in which a drilling blade and a stirring blade are provided on a rotating rod. Thus, the structure is simpler than that of the device having the above, and the manufacturing cost and the weight can be reduced.

[Brief description of the drawings]

FIG. 1 is a perspective view illustrating an apparatus of the present invention.

FIG. 2 is a cross-sectional view illustrating a pivotally attached state of a co-rotation preventing blade to a bearing.

FIG. 3 is a sectional view illustrating the construction of a column by the apparatus of the present invention.

FIG. 4 is a cross-sectional view illustrating the operation of the co-rotation prevention blade.

FIG. 5 is a perspective view illustrating a vertical line intersecting a vertical plane passing through the center of the rotating rod and the center of the pivot and an inner peripheral surface of the excavation hole.

FIG. 6 is a partial perspective view illustrating another embodiment of the device of the present invention.

FIG. 7 is a cross-sectional view illustrating the operation of the co-rotation prevention blade.

FIG. 8 is a cross-sectional view illustrating a regulating portion that regulates rotation of the co-rotation prevention blade.

FIG. 9 is a cross-sectional view illustrating an example of a conventional device.

FIG. 10 is a cross-sectional view illustrating another embodiment of the conventional device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Apparatus 5 Rotating rod 6 Excavating wing 9 Stirring wing 11 Bearing 17 Anti-corotating wing 31 Intersecting vertical line 33 Receiving part 39 Restriction part

Claims (7)

[Claims] An excavation wing for excavating the ground with the rotation is provided at a lower end side of a rotating rod rotatable around a vertical axis, and the excavation wing is mounted on the rotating rod by being positioned above the excavation wing. Stirring blades for stirring and mixing the earth mass in the hole and the solidifying material liquid are provided so as to protrude toward the inner peripheral surface of the drilling hole, and are positioned above and / or below the stirring blade, and the rotating rod is A rotatable bearing is provided around the axis, and the base of the anti-corotating wing protruding toward the inner peripheral surface of the borehole is pivotally attached to the bearing, and the anti-corotating wing is rotatable in a substantially horizontal plane. In addition, on the front side in the rotation direction of the rotating rod, of the vertical line crossing the vertical plane passing through the center of the rotating rod and the center of the pivot portion and the inner peripheral surface of the drilling hole, the tip of the co-rotation prevention wing is The length of the co-rotation prevention wing is set so that it contacts the inner peripheral surface of the borehole. An apparatus for constructing a ground improvement column provided with a mechanism for preventing co-rotation of excavated earth mass, wherein the co-rotation prevention wing is supported by a bearing portion of the bearing so that the anti-rotation wing does not rotate relative to the bearing. . 2. An excavation wing for excavating the ground along with the rotation thereof is provided at a lower end side of a rotating rod rotatable around a vertical axis, and is positioned above the excavation wing. Stirring blades for stirring and mixing the earth mass in the hole and the solidifying material liquid are provided so as to protrude toward the inner peripheral surface of the drilling hole, and are positioned above and / or below the stirring blade, and the rotating rod is A rotatable bearing is provided around the axis, and the base of the anti-corotating wing protruding toward the inner peripheral surface of the borehole is pivotally attached to the bearing, and the anti-corotating wing is rotatable in a substantially horizontal plane. In addition, on the front side in the rotation direction of the rotating rod, of the vertical line crossing the vertical plane passing through the center of the rotating rod and the center of the pivot portion and the inner peripheral surface of the drilling hole, the tip of the co-rotation prevention wing is Set the length of the anti-corotating wing so that it contacts the inner peripheral surface of the borehole, and The anti-rotation wing is supported by a bearing portion of the bearing so that the rotation-prevention wing does not rotate relative to the bearing, and the tip of the co-rotation prevention wing is rotated by the rotation of the rotation rod in the cross vertical line. A construction device for a ground improvement column provided with a mechanism for preventing a co-rotation of excavated soil mass, wherein a regulating portion for regulating rotation to a tip side is provided on a bearing. 3. The construction apparatus for a ground improvement column provided with a mechanism for preventing co-rotation of an excavated earth mass according to claim 1, wherein one of the co-rotation prevention blades is pivotally mounted on a bearing. 4. The apparatus for constructing a ground improvement column according to claim 1, wherein a plurality of co-rotation preventing blades are pivotally attached to a bearing. 5. A ground improvement column construction apparatus provided with a co-rotation prevention mechanism for excavated earth mass according to claim 4, wherein a plurality of co-rotation prevention blades are pivotally mounted on a bearing, when the excavation blade rotates forward. The tip of the anti-corotating wing partially abuts against the inner peripheral surface of the excavation hole on the near side of the crossing vertical line in the rotation direction of the rotary rod, and is in the corresponding contact state. The anti-corotating wings are supported by bearings so that they do not rotate relative to the bearings, and the other anti-corotating wings are not locked on the inner peripheral surface of the borehole. On the other hand, when the excavation wing rotates in the reverse direction, the tip portion of the other co-rotation prevention wing abuts on the inner peripheral surface of the digging hole on the near side of the intersection vertical line in the rotation direction of the rotating rod, and The anti-corotating wings in contact with each other do not rotate relative to the bearing. The anti-corotating wing is supported by a receiving portion of a bearing so that the part of the anti-corotating wing is not locked on the inner peripheral surface of the excavation hole. Construction equipment for a ground improvement column equipped with a mechanism to prevent co-rotation of earth mass. 6. A bearing is provided with a restricting portion for restricting a tip portion of the co-rotation prevention wing from rotating toward a forward end of the crossing vertical line in a rotation direction of a rotating rod. 5. An apparatus for building a ground improvement column, comprising: a mechanism for preventing co-rotation of an excavated earth mass according to item 5. 7. The improved soil improvement column according to claim 1, wherein the anti-corotating blade is disposed between the upper and lower stirring blades. Construction equipment.