JPH11217820A - Soil improvement device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the common rotation of excavated soil around excavation shafts by a soil improvement device having a plurality of excavation shafts and, at the same time, to enable the mixing and stirring of the excavated soil three-dimensionally. SOLUTION: Excavation shafts 1 are connected to each other with a shaft-like joint member 4 between circular bodies 5 providing the excavation shafts to them in a rotatable manner, and a rotatable cylindrical body 12 is provided around the axis G 2 of the joint member 4. Projected bodies 13a and 13b as mixing stirring sections of excavated soil are provided to the outside of the cylindrical body 12. Stirring wings 3 of the excavated soil are provided to the excavation shafts 1, and in the case the excavation shafts 1 are rotated, the stirring wings 3 are brought into contact with the long projected body 13a to rotate the projected bodies 13a and 13b around the axis G2 together with the cylindrical body 12. The excavated soil is rotated around the excavation shafts 1, and the common rotation is prevented by the cylindrical body 12 standing still in a plane view and, at the same time, the excavated soil is also mixed and stirred around the coaxial line G2 with the projected bodies 13a and 13b rotated around the axis G2 of the cylindrical body 12.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a soil improvement device, and more particularly, to a lime-based soil excavating a plurality of excavating shafts into columns, walls, or cylinders in civil engineering and construction foundation work. Or a cement-based slurry-type solidifying agent (hereinafter, also simply referred to as a solidifying agent), and the solidifying agent is mixed with the excavated soil, stirred, and solidified to form a columnar, wall, or The present invention relates to a ground improvement device for solidifying, forming and improving a cylindrical shape.

[0002]

2. Description of the Related Art Hitherto, as this type of ground improvement apparatus, one shown in FIGS. 10 and 11 has been known. This ground improvement device is provided with a plurality of excavating shafts 1 provided with stirring blades 3 above the excavating blades 2, and the rotation of each of the excavating shafts 1 is free above the respective excavating blades 2 so that the respective excavating shafts are mutually connected. The connection is maintained by the connection member 4 while maintaining the interval. In the figure, an excavator composed of two excavating shafts 1 is illustrated. This one is
The interval P between the excavating shafts 1 is set to be smaller than the outer diameter D of the excavating wing 2 (excavating diameter of one excavating shaft) D, and a shape in which two circles partially overlap each other (in a figure-eight shape) in plan view. It is configured to improve the ground in a columnar shape.

In the figure, two excavating shafts 1 are simultaneously excavated by, for example, rotating at the same rotation speed in opposite directions, and excavating blades 2 and agitating blades 3 provided on the excavating shaft 1 are formed. The positions and rotation speeds in plan view are set so as not to interfere with those provided on adjacent excavation axes during rotation. In this case, the soft ground is excavated at each of two adjacent excavation axes 1 at a constant interval P, and the ground is improved into a columnar shape (or wall shape) in a plan view "8-shape" by mixing and stirring. When the ground (soil) is excavated by the rotation of each excavation wing 2, the ground is excavated into a columnar shape having substantially the same diameter as the outer diameter D of each of the excavation wings 2, and the excavated soil is simultaneously rotated and stirred. It is configured to be mixed and stirred by the blade 3.

[0004]

However, in such excavation, the excavated soil excavated by each excavation shaft 1 is rotated around each excavation shaft even if the adjacent excavation shafts 1 are rotated in opposite directions. The so-called co-rotation, such as the rotation with the rotation of the excavation wing 2 and the stirring wing 3, occurs, and the excavated soil is not loosened well.
There was a problem that they were not mixed well. These problems are more prominent when the soil is hard clayey soil or peat layer soil, etc., because it tends to form a cobble mass and cause co-rotation, and the degree of soil improvement tends to be insufficient. Was.

[0005] Also, even if they do not rotate together,
The excavated soil is only agitated around each excavation axis 1, and the agitation is planar, and three-dimensional mixing and agitation in which the excavated soil is added is not performed. Thus, in the above-mentioned conventional technology, co-rotation is likely to occur, and three-dimensional mixing,
There was a problem that uniform ground improvement was not performed because stirring was not performed. Therefore, in the above-mentioned conventional technology, there is a problem that it is necessary to repeat advancing and retreating (vertical movement) of the excavating shaft 1 a lot, and it takes a lot of time for construction. In order to ensure a high level of solidification, the solidification agent must be added in a larger amount than necessary, leading to an increase in cost.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems of a conventional ground improvement device having a plurality of excavating shafts. An object of the present invention is to provide a ground improvement device capable of positively performing three-dimensionally mixing and stirring of soil.

[0007]

According to a first aspect of the present invention, there is provided a ground improvement apparatus having a plurality of excavating shafts, wherein each of the excavating blades includes a plurality of excavating blades. In a configuration in which a rotatable ring is mounted and the rings are connected to each other by a connecting member to maintain the interval between the respective excavation shafts, the connecting member is formed in a shaft shape,
A cylindrical body rotatable around the axis of the connecting member is provided, and a mixing and stirring unit (mixing and stirring means) for excavated soil is provided on the cylindrical body.
While the mixing and agitating section is rocked or rotated around the axis together with the cylindrical body by using the rotation of the excavation shaft.

A second aspect of the present invention is a ground improvement apparatus provided with a plurality of excavating shafts, wherein a rotatable ring is mounted on each of the excavating shafts above each of the excavating blades, and the ring is provided with a plurality of excavating shafts. In a configuration in which the distance between the respective excavation shafts is maintained by connecting each other with a connecting member, the connecting member is formed in an axial shape, and the ring member is provided on the substantially axial extension of the connecting member. A horizontal axis is provided so as to extend, and a rotatable cylindrical body is provided around the axis of the connecting member and around the axis of the horizontal axis, and the cylindrical body is provided with a mixing and stirring unit for excavated soil, The mixing and stirring section is rocked or rotated around the axis together with the cylindrical body by using the rotation of a drilling shaft.

In the present invention, during excavation by the excavation wing, the connecting member does not rotate around the excavation axis. For this reason, excavated soil (clod) trying to rotate in the direction of rotation of the excavation axis
The rotation is stopped or suppressed by the connecting member. Therefore, the mixing and stirring of the excavated soil can be performed well. According to the second aspect of the present invention, the co-rotation prevention effect is further enhanced by the presence of the horizontal axis.

According to the present invention, a rotatable tubular body is provided, and the tubular body is provided with a mixing and stirring section for excavated soil, and the mixing and stirring section is rotated using the rotation of the excavating shaft. Since the rock is swung or rotated about the axis together with the cylindrical body, the excavated soil is three-dimensionally mixed and stirred in the excavation process.

In the first and second aspects of the present invention, the mixing and stirring section only needs to be configured so that the mixing and stirring of the excavated soil can be performed by rotation of the cylindrical body around the axis. What is necessary is just to set a structure suitably according to soil properties. Means for swinging or rotating the mixing and stirring section about the axis together with the cylindrical body using the rotation of the excavating shaft is a two-axis that intersects at right angles, such as a bevel gear mechanism or a simplified rotation mechanism thereof. A well-known rotation (transmission) mechanism that can transmit rotation between the excavation shaft and the cylindrical body may be provided. However, without using such a mechanism, the following structure is simplified. It is preferable from a chemical viewpoint.

That is, according to a third aspect of the present invention, in the ground improvement apparatus according to the first or second aspect, a stirring blade of excavated soil is provided on the excavation shaft, and the stirring blade is rotated when the excavation shaft rotates. The mixing and stirring unit may be swung or rotated around the axis together with the cylindrical body when the mixing and stirring unit is contacted. In this type of apparatus, a stirring blade is usually provided on the excavation shaft, so that the rotation (transmission) mechanism can be simplified.

According to a fourth aspect of the present invention, there is provided a ground improvement device according to the first or second aspect, wherein a driving projection is provided on the excavation shaft instead of the stirring blade.
When the excavating shaft rotates, the driving projection may contact the mixing and stirring unit, and the mixing and stirring unit may be swung or rotated about the axis together with the tubular body.

According to a fifth aspect of the present invention, in place of the stirring blade or the like, in the ground improvement apparatus according to the first or second aspect, when the excavation shaft is rotated, the excavation blade is connected to the mixing blade. The mixing / stirring unit may be swung or rotated around the axis together with the tubular body in contact with the stirring unit.

The shape, arrangement, and number of the mixing and stirring sections in claims 3 to 5 may be appropriately set in relation to the stirring blade, the driving projection, or the excavating blade. Further, in any of the above means, it is preferable that three or more mixing and stirring sections are provided around the cylindrical body at intervals. In particular, it is preferable to provide them at substantially equal angular intervals around the cylindrical body. This is because if provided in this manner, it is easy to smoothly rotate the mixing and stirring section around the axis.

Further, in the inventions according to the third to fifth aspects, the stirring blade or the like contacts the mixing and stirring portion forming the driven convex portion, and the mixing and stirring portion is swung or rotated about the axis together with the cylindrical body. However, a driven projection may be provided separately from the mixing and stirring section. That is, as in the invention according to claim 7, in the ground improvement device according to claim 1 or 2, a driven convex portion is provided at a portion of the cylindrical body near the excavation axis, while A stirring blade may be provided, and when the excavation shaft rotates, the stirring blade may hit the driven convex portion to swing or rotate the mixing / stirring unit together with the tubular body around the axis. .

According to the eighth aspect of the present invention, in the ground improvement apparatus according to the first or second aspect, while the driven convex portion is provided at a portion of the cylindrical body near the excavation axis, the excavation axis is provided. A driving convex portion is provided, and when the excavating shaft rotates, the driving convex portion hits the driven convex portion, and the mixing / stirring portion swings around the axis with the cylindrical body or You may make it rotate.

Further, a driven projection different from the mixing and stirring section may be rotated by the excavating blade without using the stirring blade or the like. That is, as in the ninth aspect of the present invention, in the ground improvement device according to the first or second aspect, the driven excavation shaft is rotated while the driven convex portion is provided in the cylindrical body near the excavation axis. At this time, the excavating wing may hit the driven convex portion to swing or rotate the mixing and stirring section around the axis together with the cylindrical body.

Even in the case where a driven projection is provided separately from the mixing and stirring section as described above, it is preferable to provide three or more driven projections at intervals around the cylindrical body. Then, as described above, it is preferable to provide them at substantially equal angular intervals around the cylindrical body.

[0020]

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. In the figure, reference numeral 1 denotes a substantially cylindrical (hollow columnar) excavation shaft (rotation drive shaft), which is configured to rotate on both the right and left sides by rotation drive means (not shown), and has a vicinity of its tip. An excavation wing 2 having a predetermined diameter (length) D for excavating the ground and having an excavation claw 2a is provided in a projecting manner in a direction substantially perpendicular to the excavation axis 1 by welding.

In this example, each excavating shaft 1 has a diameter (length) slightly smaller than the diameter D of the excavating wing 2 above.
A stirring blade 3 formed so as to stir the excavated soil by rotating integrally with the excavating shaft 1 is integrally fixed by welding. However, the stirring blade 3 has a strip shape, and its width 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 through the inside of the excavating shaft 1. It is configured to:

Further, between the excavating blade 2 and the stirring blade 3 in the excavating shaft 1, as described in detail below, the excavating shaft 1
The connecting member 4 is disposed in a direction substantially perpendicular to the direction. 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, rings 6a and 6b having a larger diameter than the excavation shaft 1 are integrally formed around the excavation shaft 1 at a position where the upper end surface and the lower end surface of the ring body 5 come into contact with each other by welding or the like. ,
The vertical movement of the ring body 5 is regulated. A connecting member 4 composed of a shaft-like member having a circular cross section is provided so as to connect the annular members 5 to each other, and a space P between the left and right excavating shafts 1 is provided.
Is kept constant.

A cylindrical body 12 having a cylindrical shape (circular pipe) is rotatably fitted (freely fitted) around the axis G2 of the connecting member 4, and is fitted in the direction of the axis G2. The movement is regulated by the rings 5,5. Further, the cylindrical body 12 extends radially (cross-shaped) as a mixing and stirring section for excavated soil outside the cylindrical body 12, and protruding bodies (round bars) 13 having different lengths.
a and 13b. However, the protrusions 13a,
13b are provided at intervals in the longitudinal direction of the connecting member 4 and are substantially equiangular (90 degrees in this example) when viewed from the direction of the axis G2 of the connecting member (tubular body 12) 4 (see FIG. 4). It is provided in. In addition, the lengths of the protruding bodies 13a and 13b are set so that they do not extend outside a region (a region indicated by a two-dot chain line E in FIG. 3) drawn by the tip of the excavation wing 2 in plan view.

The projecting body 13a on the right side of the excavating shaft 1 in FIG. 1 is formed to be longer than the other, so that when the excavating shaft 1 rotates, the agitating blades 3 provided on the projecting body 3 hit the projecting body 13a. Have been. During the excavation, the agitating blades 3 provided on the excavating shaft 1 are protruded from the protruding body (mixing / agitation unit) 13.
a, the protruding bodies 13a, 13b are aligned with the axis G of the cylindrical body 12.
When the right excavation shaft 1 makes two rotations in this example, the protrusion 13
a and 13b rotate one time around the axis G2 together with the tubular body 12.

In the apparatus of this embodiment, as shown in FIG. 3, the ground is excavated in a plan view in an approximately figure-eight shape, and the excavated soil k inside is excavated by the excavating blade 2 and the stirring blade 3.
Each is mixed and stirred around the excavation axis 1. On this occasion,
The excavated soil k that is to be co-rotated around the excavation axis 1 in the form of an earth mass is a connecting member 4 and a cylindrical body 12 that do not rotate in plan view.
Stops the rotation. That is, the cylindrical body 12 performs the function of preventing the excavated soil k from rotating together.

Further, the stirring blade 3 rotating together with the excavating shaft 1 on the right side in FIG. 1 hits a protruding body 13a provided on the cylindrical body 12, and the protruding bodies 13a, 13b and the cylindrical body 12 are indicated by arrows in FIG. As described above, the rotation is made around the axis G2.
As a result, the excavated soil k is mixed and stirred around the axis G2 by the rotating protruding bodies 13a and 13b. As described above, according to the apparatus of the present embodiment, the excavated soil is mixed and stirred without rotating around the excavation axis 1 and is also mixed and stirred around the axis G2 of the connecting member 4 to mix three-dimensionally. It is agitated.

Thus, it is not necessary to repeatedly advance and retreat the excavation axis as in the prior art, and relatively uniform mixing and stirring of excavated soil can be obtained in a short time. That is, the solidifying agent discharged below is mixed and stirred not only in the circumferential direction in the cross section of the column made of excavated soil but also in the vertical direction by the rotation of the projections 13a and 13b. As a result, it is possible to obtain an improved column having a uniform strength with an appropriate amount of the solidifying agent. As described above, in the present example device, the quality of the mixing and stirring of the excavated soil is improved,
It is also possible to reduce the construction time and the work cost.

In this embodiment, the cylindrical body 12 is used as the mixing and stirring section.
Are provided with rod-shaped protrusions 13a and 13b, but the shape and the like may be designed to have an appropriate shape and structure according to the soil properties, such as a tongue-like shape, while maintaining the required strength.
In the case of soil with high viscosity such as clayey, the round bar as in this example is suitable.On the other hand, in the case of soil with relatively low viscosity such as sandy soil, the resistance during mixing and stirring is rather large. Has good mixing and stirring efficiency. Therefore, in such a case,
The protruding body as the mixing and stirring unit may be a wide band plate.

Next, an embodiment of the device according to claim 2 will be described with reference to FIGS. However, this is separately provided on the opposite side to the connecting member 4 in the ring 5 of the left and right excavating shafts 1 in the above-described embodiment.
The tubular member is provided so as to extend in a direction substantially perpendicular to the excavating shaft 1 and on an extension of the connecting member 4 in a direction substantially along the axis G2, and is also rotatable around the axis G2 of the horizontal shaft. The mixing and stirring section of the excavated soil is also provided on the outside of the cylindrical body 15, and the mixing and stirring section is rocked or rotated together with the cylindrical body 15 around the axis G <b> 2 using the rotation of the excavating shaft 1. Only the differences described above are the only differences, and there is no essential difference from the above-described embodiment, and it can be called an improvement of the above-described embodiment. Therefore, only the differences will be described, and the same portions will be denoted by the same reference numerals. stop. The same applies to the following embodiments.

That is, in the apparatus of the present embodiment, the horizontal shaft 14 having a circular cross section is connected to the right and left excavating shafts 1 in the direction opposite to the connecting member 4 in the ring 5 in a direction substantially perpendicular to the excavating shaft 1. 4 so as to extend substantially in the direction of the axis G2. However, the length from the axis G1 of the excavation shaft 1 to the tip of the horizontal axis 14 is slightly smaller than the radius of the excavation blade 2. A rotatable cylindrical body 15 is also provided around the axis G2 of the horizontal shaft 14, and a protruding body 13a is provided on the outer side of the cylindrical body 15 as a mixing and stirring section for excavated soil, similarly to the above embodiment. 13b is provided, and rotates with the cylindrical body 15 around the axis G2. An enlarged portion 16 is provided at the end of the horizontal shaft 14 to prevent the tubular body 15 from falling off.

The protruding body 13a of the tubular body 15 provided on the left and right horizontal shafts 14 is formed to be long at a position near the excavation axis 1, and when the excavation axis 1 rotates, the stirring blade 3 is moved to the protruding body 13a.
a. During the excavation, the agitating blades 3 provided on the excavating shaft 1 hit the protruding body 13a on the horizontal axis 14 in addition to the protruding body (mixing / stirring part) 13a on the connecting member 4, and the protruding bodies 13a, 13
b rotates around the axis G2 of the cylindrical body 15 in the same manner as in the above-described embodiment. However, in this example, the right and left projecting bodies 13a and 13a of the right excavation shaft 1 are structurally limited.
b rotate in opposite directions when viewed from the direction of the axis G2. When the excavation shaft 1 rotates in the same direction, the left protrusions 13a and 13b of the left excavation shaft 1 rotate in the same direction as the protrusions 13a and 13b of the connecting member 4. The length of the protruding bodies 13a and 13b is
It is set so that the tip of the excavation wing 2 does not go outside the region drawn (the region indicated by the two-dot chain line E in FIG. 6).

In the present embodiment, in addition to the above-described configuration, the ring 5 is provided with the horizontal axis 14 so as to extend substantially in the direction of the axis G2 of the connecting member 4, and also around the axis of the horizontal axis 14. Since the rotatable cylindrical body 15 is provided, and the protruding bodies 13a and 13b are provided outside the excavated soil as a mixing and stirring section for the excavated soil, the effect of preventing the co-rotation of the excavated soil around the excavation axis 1 is increased by these amounts.
Furthermore, the three-dimensional mixing and stirring effect is also high. In other words, the co-rotation prevention effect extends over the entire area in the width direction of the ground improvement portion when viewed from the front, and the vertical stirring effect extends over the entire area in the width direction when viewed in plan.

As a result, in this embodiment, more uniform mixing and stirring of excavated soil can be obtained in a shorter time than in the previous embodiment. Therefore, since the discharged solidifying agent is more efficiently and uniformly stirred, a column having a uniform strength can be obtained with a smaller amount of the solidifying agent, and the quality of the mixing and stirring can be further improved, and the construction time can be reduced and the work can be performed. Cost can be reduced.

In the above, a stirring blade for excavated soil is provided on the excavating shaft, and when the excavating shaft rotates, the stirring blade impinges on a protruding body forming a mixing / stirring portion, and swings this together with the cylindrical body around the axis. Alternatively, as illustrated in FIG. 8, the stirring blade 3 is reduced with respect to the excavation axis 1 separately from the stirring blade 3 as shown in FIG. The driving projection 21 is provided so as to be almost nonexistent.
When the is rotated, the driving projection 21 may hit the projection 13a or the like forming the mixing and agitating section to swing or rotate the projections 13a and 13b together with the cylindrical body 12 around the axis G2.

As shown by a two-dot chain line in FIG. 8, the upper edge 2b of the excavating wing 2 is formed in advance, and the driving projection 2
1 and the upper edge 2 of the excavating wing 2 when the excavating shaft 1 rotates.
b may hit the protruding body 13a forming the mixing and stirring unit, and swing or rotate these together with the tubular body 12 around the axis G2.

In the above-described embodiment, the driven convex portion is a rod-shaped protrusion having a mixing and stirring action. However, in the present invention, this protrusion has no mixing and stirring action of excavated soil. Good. That is, apart from the mixing and stirring section having a mixing and stirring action such as the protruding body in the above embodiment,
A driven protrusion having a shape or size that cannot be regarded as a mixing and stirring unit is provided on the cylindrical body, and the stirring blade 3, the driving protrusion 21, the portion (upper part) of the excavation blade 2, and the like in the above are provided. To rotate the mixing / stirring unit around the axis thereof together with the cylindrical body. That is, the projecting body 13a in the above embodiment is made small (short) or thinned to such an extent that the mixing and stirring action cannot be expected, or a convex portion similar to the teeth of a bevel gear is provided on the cylindrical body, and this is driven by the driven action. It is good also as a driven convex part which forms only. Even if the stirring blade 3, the driving protrusion 21, or the portion (upper portion) of the excavating blade 2 in the above is applied to such a driven projection, the mixing and stirring section is rotated about the axis thereof together with the cylindrical body. Can be done.

As shown in FIG. 9, in the apparatus shown in FIGS. 5 to 7, the tubular body 12 provided on the connecting member 4 is divided into two left and right tubular bodies 12a, 12a. 12
a long protrusions 13a, 1
3b may be provided, and each may be separately rotated by the stirring blade 3 of each excavating shaft 1. The same applies to the apparatus shown in FIGS. 1 to 4, but in this case, the rotation is facilitated. However, in this case as well, the rotation can be performed by the driving projection 21 or the upper edge 2b of the excavation wing 1 as shown in FIG. The large-diameter portion 4a at the center of the connecting member 4
Are stop portions between the cylindrical bodies 12a.

In the above description, the horizontal axis 14 is the excavation axis 1
When viewed from the direction of the axis G1, the tip has a length that is located inside the circumference E drawn by the tip of the excavating wing 2 when the excavating wing 2 rotates. It may be located at or slightly outside of this. Further, the cylindrical body 12,
12a and 15 are not limited to cylindrical shapes as long as they are cylindrical, and may be rectangular cylindrical. Rather, it is preferable to use a triangular or quadrangular rectangular cylinder, because the mixing and stirring action is performed at the corner when the cylinder itself rotates around its axis.

In the above description, a cylindrical body provided with a mixing and stirring section is provided on the excavating blade, and a single stirring blade is provided thereon. The number and arrangement may be appropriately determined according to the excavation depth.
That is, for example, a cylindrical body is provided on a drilling wing, a stirring blade is provided thereon, a cylindrical body provided with a mixing / stirring unit is further provided thereon, and a stirring blade is further provided thereon. The number and arrangement of the bodies and the stirring blades may be appropriately set.

Further, a connecting member for connecting the excavating shafts to each other may be provided at an appropriate position, but such a connecting member is preferably made as wide as possible when viewed from the front. This is because the effect of preventing the co-rotation of the excavated soil around the excavation axis increases by itself. Then, the annular body forming the end of such a connecting member is appropriately extended so as to extend on a substantially axial extension of the connecting member in plan view, or to extend in a radial direction of the excavation axis in plan view. It is good to provide the wing body of width and length. This is because the effect of preventing co-rotation of the excavated soil around the excavation axis can be increased accordingly. In the above embodiment, the number of excavation axes is two,
The number may be 3 or more as needed. When the number of excavating axes is three or more, the plane shape may be a straight line with connecting members arranged in a line, or an annular shape in which the connecting members are sides and the excavating axis has a vertical angle (for example, four In this case, it may be a square such as a square).

[0041]

As is apparent from the above description, according to the present invention, during excavation, the connecting member does not rotate around the excavation axis, so that the excavated soil (clod) which is going to rotate together with the rotation direction of the excavation axis. In addition to the rotation of the excavated soil, a mixing and stirring unit for excavated soil is provided outside a tubular body rotatably provided around an axis, in addition to the rotation of the excavation shaft, and the mixing and stirring unit is provided. The excavated soil is three-dimensionally mixed and agitated without causing a complicated structure because the rocking member is swung or rotated around its axis together with the cylindrical body. As a result, it is possible to improve the quality of the mixing and stirring of the excavated soil, shorten the construction time, and reduce the operation cost.

[Brief description of the drawings]

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

FIG. 2 is a partially broken enlarged view showing a main part of FIG. 1;

FIG. 3 is a plan view of the ground improvement device of FIG. 1;

FIG. 4 is a sectional view taken along line AA of FIG. 1;

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

FIG. 6 is a plan view of the ground improvement device of FIG. 5;

FIG. 7 is a right side view of FIG. 5;

FIG. 8 is a front view showing a schematic configuration of still another embodiment of the ground improvement apparatus of the present invention.

FIG. 9 is a front view showing a schematic configuration of the embodiment of FIG. 5 obtained by dividing a tubular body provided on a connecting member.

FIG. 10 is a partially broken front view showing a schematic configuration of a conventional ground improvement device.

FIG. 11 is a plan view of FIG. 10;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Drilling shaft 2 Drilling blade 3 Stirrer blade 4 Connecting member 5 Ring 14 Horizontal axis 12, 12a, 15 Cylindrical body 13a, 13b Projection (mixing and stirring part) 21 Driving projection P Distance between drilling shafts G1 Drilling shaft G2 axis of connecting member and horizontal axis

Claims (10)

[Claims] 1. A ground improvement apparatus having a plurality of excavating shafts, wherein a rotatable ring is mounted on each of the excavating shafts above each excavating wing, and the rings are connected to each other by a connecting member. The excavation shaft is maintained at an interval between the excavation shafts, wherein the connecting member is formed in a shaft shape, and a rotatable cylindrical body is provided around the axis of the connecting member. A ground improvement apparatus, wherein a stirring section is provided, and the mixing and stirring section is rocked or rotated about the axis together with the cylindrical body by using rotation of the excavation shaft. 2. A ground improvement apparatus having a plurality of excavating shafts, wherein a rotatable ring is mounted on each excavating shaft above each excavating wing and the rings are connected to each other by a connecting member. The excavation shaft is maintained at an interval between the excavation shafts, the coupling member is formed in an axial shape, and the ring body is provided with a horizontal axis so as to extend substantially in the axial direction of the coupling member. A rotatable cylindrical body is provided around the axis of the member and around the axis of the horizontal axis, and a mixing and stirring section for excavated soil is provided on the cylindrical body. A ground improvement device, wherein a portion is rocked or rotated around the axis together with the cylindrical body. 3. A stirring blade for excavated soil is provided on the excavating shaft, and when the excavating shaft is rotated, the stirring blade impinges on the mixing / stirring unit, and the mixing / stirring unit and the cylindrical body are rotated around the axis. 3. The ground improvement device according to claim 1, wherein the ground improvement device is configured to swing or rotate. 4. A driving projection is provided on the excavation axis,
When the excavating shaft is rotated, the driving projection hits the mixing and stirring section, and the mixing and stirring section is rocked or rotated around the axis together with the tubular body. The ground improvement device according to 1 or 2. 5. When the excavating shaft rotates, the excavating blade hits the mixing / stirring unit to swing or rotate the mixing / stirring unit about the axis together with the cylindrical body. The ground improvement device according to claim 1 or 2, wherein 6. The apparatus according to claim 1, wherein three or more mixing and stirring sections are provided around the cylindrical body at intervals.
The ground improvement device according to 2, 3, 4 or 5. 7. A driven projection is provided at a position of the tubular body near the excavation axis, and a stirring blade is provided for the excavation shaft. When the excavation shaft rotates, the stirring blade is attached to the excavation shaft. The ground improvement device according to claim 1, wherein the mixing / stirring unit is swung or rotated around the axis together with the cylindrical body against a driving projection. 8. A driving projection is provided at a position of the cylindrical body near the excavation axis, while a driving projection is provided for the excavation axis, and the driving projection is formed when the excavation axis rotates. 3. The ground improvement device according to claim 1, wherein a portion of the mixing stirrer swings or rotates about the axis together with the tubular body by contacting the driven convex portion. 9. A driven convex portion is provided at a position of the cylindrical body near the excavation axis, and when the excavation shaft rotates, the excavation blade hits the driven convex portion and the mixing / stirring portion. The ground improvement device according to claim 1, wherein the device is swung or rotated around the axis together with the cylindrical body. 10. The ground improvement device according to claim 7, wherein three or more driven convex portions are provided around the cylindrical body at intervals.