JP2008291618A - Ground improving agitating device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a ground improving agitating device for providing high mixing agitating action. <P>SOLUTION: This ground improving agitating device has a rotary shaft, an excavation member arranged on the tip of the rotary shaft, an agitating member arranged on the outer periphery of the rotary shaft, and a co-rotation preventive member pivotally arranged on the outer periphery of the rotary shaft so that rotation of the rotary shaft is not propagated, and forms a columnar body in the ground by mixing and agitating excavation earth and a ground solidifying material by rotating the agitating member by excavating the ground by rotating the excavation member. The ground improving agitating device is characterized in that the agitating member is deformed in response to resistance of the excavation earth or a mixture of the excavation earth and the ground solidifying material when mixing and agitating. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an improvement of a ground improvement stirring device.

When building houses on soft ground, one way to strengthen the ground is to excavate the ground to form vertical holes, and then mix the excavated soil and ground solidification material (cement milk) to create vertical holes. There is a ground improvement method that builds a columnar body to increase the support capacity of the ground. This construction method is performed by, for example, the ground improvement stirring device 100 shown in FIG. First, the rotating shaft 101 provided so as to be rotatable up and down penetrates the ground while rotating, and the ground is excavated by the excavating member 102 at the tip thereof (see FIGS. 8B and 8C). After excavation to a predetermined depth, the ground solidified material is discharged from a discharge port 105 provided at the tip of the rotating shaft 101 and the rotating shaft 101 is pulled up while rotating. As a result, the excavating member 102 and the stirring blades 103 and 104 projecting laterally on the rotating shaft 101 rotate to mix and stir the excavated soil and the ground solidification material. At this time, the co-rotation preventing member 106 prevents the excavated soil and the ground solidification material from co-rotating with the excavating member 102 and the stirring blades 103 and 104, thereby increasing the mixing and stirring action. In this way, columnar bodies are created in the ground to improve the ground.
In this construction method, a higher ground improvement effect can be obtained by creating a columnar body with high strength. In order to create a high-strength columnar body, it is necessary to mix and stir the excavated soil and the ground solidifying material more uniformly. However, the rod-shaped or plate-shaped excavating member 102 and the stirring blades 103 and 104 having the above-described configuration are excavated soil. It was difficult to uniformly mix the soil solidification material with the ground. Therefore, Patent Document 1 discloses a configuration in which a pin protruding in the vertical direction is provided on a bar-like or plate-like stirring blade. In the ground improvement stirring device disclosed in Patent Document 1, a plurality of metal pins are provided on the stirring blade, and the area where the stirring blade is in contact with the mixture of excavated soil and ground solidifying material is increased to enhance the mixing stirring action. Yes.

JP-A-8-13473

In the ground improvement stirrer provided with pins on the stirring blades, the gravel and stones in the excavated soil are sandwiched between the adjacent pins of the stirring blades and the gravels and stones and the pins interfere with each other. It was falling. In addition, the blades deteriorated early due to the gravel and stones interfering with the pins.
On the other hand, in order to create a high-strength columnar body, when the rotary shaft 101 is pulled up, the rotary shaft 101 needs to be repeatedly raised and lowered to mix and agitate the excavated soil and the ground solidification material. That reduced workability. In order to prevent such a decrease in workability, it is conceivable to increase the number of stirring blades to enhance the mixing and stirring action. Certainly, if the number of stirring blades is increased, the mixing and stirring action will increase, but on the other hand, the spacing between the stirring blades will be narrowed, and to the stirring blades such as gravel or stone in the excavated soil between adjacent stirring blades Therefore, the stirring and mixing action as a whole is not improved. Furthermore, if the number of stirring blades is increased, the torque on the rotating shaft increases accordingly, and the burden on the rotary drive system increases. In particular, when the ground includes cohesive soil, this torque is remarkably increased, which places a heavy burden on the rotary drive system.
Then, this invention makes it one subject to provide the ground improvement stirring apparatus which provides a high mixing stirring action. Another issue is to reduce the deterioration of the impeller caused by gravel and stone in the excavated soil. It is another object of the present invention to provide a ground improvement agitation apparatus with less burden on the rotational drive system.

The present invention has been made to solve at least one of the above problems, and has the following configuration. That is,
A rotation axis;
A drilling member provided at the tip of the rotating shaft;
A stirring member provided on an outer periphery of the rotating shaft;
A co-rotation preventing member pivoted on the outer periphery of the rotating shaft so as not to propagate the rotation of the rotating shaft;
The ground excavation member rotates to excavate the ground, the stirring member rotates to mix and stir the excavated soil and the ground solidifying material to form a columnar body in the ground,
In the ground improvement stirring device, the stirring member is deformed in accordance with a resistance of the excavated soil or a mixture of the excavated soil and the ground solidifying material during the mixing and stirring.

  According to the ground improvement stirrer configured as described above, the stirring member is deformed according to the resistance of the excavated soil or the mixture of the excavated soil and the ground solidifying material, so that the gravel, stones and clay soil in the excavated soil Even if it interferes with the stirring member, the stirring member is deformed and the influence of the interference is minimized. As a result, a decrease in the mixing and stirring action is prevented. Furthermore, since the interference between the gravel, the stone and the viscous soil in the excavated soil and the stirring member is minimized, the deterioration of the stirring member due to the gravel, the stone and the viscous soil in the excavated soil is reduced. In particular, when the excavated soil is a viscous soil, the excavated soil is crushed. In addition, the stirring member is deformed according to the resistance of the excavated soil or the mixture of excavated soil and ground solidification material, so that the torque of the rotating shaft is prevented from excessively increasing, and the rotation drive system of the apparatus is The burden is reduced.

Hereafter, the component in the ground improvement stirring apparatus of this invention is demonstrated in detail.
The rotating shaft is hollow and is erected so that it can be rotated up and down along a guide by an elevating and rotating drive. A drilling member is provided at the tip of the rotating shaft. The form of the excavation member is not particularly limited as long as the excavation member can be excavated by rotating with the rotation of the rotation shaft. Usually, the excavation member includes a plurality of excavation claws protruding downward, and the plural excavation claws excavate the ground as the rotary shaft rotates. The size of the excavating member is determined in consideration of the size of the columnar body to be produced.
Further, a discharge port is formed near the tip of the rotating shaft. The rotating shaft is connected to a ground solidifying material injector, and the ground solidified material injected from the ground solidifying material injector is discharged from the discharge port through the hollow portion of the rotating shaft. In addition, the ground solidification material used here is not particularly limited, and can be appropriately selected from known ground solidification materials in consideration of the composition of the ground, the size of the columnar body to be produced, and the like.

  A stirring member is provided on the outer periphery of the rotating shaft. The stirring member rotates in the circumferential direction of the rotating shaft as the rotating shaft rotates, and mixes and stirs excavated soil or a mixture of excavated soil and ground solidifying material in cooperation with a co-rotation preventing member described later. The agitating member is deformed according to the resistance of the excavated soil or the mixture of excavated soil and the ground solidifying material during mixing and agitation. The shape of the stirring member is not particularly limited, and may be a plate shape, a rod shape, or the like. The length of the stirring member can be determined in consideration of the size of the columnar body to be formed. You may provide a some stirring member in the outer periphery of a rotating shaft. For example, a plurality of stirring members may be provided at different positions in the vertical direction of the rotating shaft (that is, positions having different heights).

The stirring member is preferably flexible. If it does in this way, the repulsive force with respect to the excavation soil or the mixture of excavation soil and ground solidification material will arise in an agitating member with the reduction of the interference by the gravel, stones, and clay soil in excavated soil. Due to this repulsive force, the stirring member crushes the excavated soil and makes it fine. As a result, the mixing and stirring action of the excavated soil and the ground solidifying material is further improved. In particular, when excavated soil is made of viscous soil, the repulsive force generated in the agitating member pulverizes the viscous soil to make it finer, thereby further improving the mixing and agitating action of the excavated soil and the ground solidifying material. Examples of the material constituting the flexible stirring member include elastomers such as natural rubber and synthetic rubber, and plastics. If an elastomer is used as the material constituting the stirring member, the stirring member will have high flexibility. Therefore, interference due to gravel, stones and clay soil in the excavated soil is further reduced, and excavated soil (especially viscous soil) ) Crushing effect increases.
Moreover, what shape | molded the metal material in the shape of a leaf | plate spring and the shape of a coil spring can also be utilized as a stirring member. Even if it is a metal material, since it will show high flexibility (elasticity) if it is such a shape, the said repulsive force will be obtained and the improvement of a mixing stirring action will be aimed at. In addition, by making the shape of the stirring member into a chain shape or a wire shape, not only the above materials but also various metal materials, fiber materials, and the like can be adopted as the material of the stirring member. The stirring member may be formed by combining the above materials. For example, the stirring member may be formed from a composite in which a metal wire is included in the elastomer. If it does in this way, it can be set as the stirring member which has both the flexibility by an elastomer, and the rigidity by metal wires.

  In one aspect of the present invention, the stirring member includes a stirring blade protruding from the outer periphery of the rotating shaft and a flexible auxiliary stirring portion attached to the stirring blade. By providing a flexible auxiliary stirring unit, the contact area to the excavated soil or the mixture of excavated soil and ground solidifying material increases, and the repulsive force against the excavated soil or excavated soil and ground solidifying material increases the auxiliary stirring unit. This increases the effect of grinding excavated soil (especially cohesive soil). A plurality of auxiliary stirring portions may be formed on the stirring blade. For example, a plurality of pin-shaped auxiliary stirring portions may be arranged on the stirring blade at equal intervals. The number of auxiliary stirrers to be used and the interval between them can be appropriately determined in consideration of the ratio of gravel, stones and clay soil contained in the ground, the strength of the columnar bodies to be formed, and the like. When using multiple auxiliary stirrers, the material and shape may all be the same, as well as the proportion of gravel, stones and clay soil contained in the ground, and the strength of the columnar body to be formed. Some materials and shapes may be different from others.

  The co-rotation preventing member is pivotally provided on the outer periphery of the rotation shaft so that the rotation of the rotation shaft does not propagate. The co-rotation prevention member prevents the excavated soil or the mixture of excavated soil and ground solidification material from rotating as the agitating member rotates during mixing and agitation, thereby improving the mixing and agitation function. . The co-rotation preventing member preferably has flexibility. Similar to the above-described flexible agitating member, a repulsive force against the excavated soil or the mixture of excavated soil and ground solidification material is generated in the co-rotation preventing member, and the co-rotation preventing member crushes the excavated soil and pulverizes it. In addition, the mixing and stirring action of the excavated soil and the ground solidifying material is further improved. In particular, when excavated soil is made of cohesive soil, this repulsive force pulverizes the cohesive soil to make it finer, thereby further improving the mixing and stirring action of the excavated soil and the ground solidifying material. Examples of the material constituting the flexible co-rotation preventing member include elastomers such as natural rubber and synthetic rubber, plastics, and the like, similar to the above-described flexible stirring member. If an elastomer is used as the material constituting the stirring member, the stirring member will have high flexibility. Therefore, interference due to gravel, stones and clay soil in the excavated soil is further reduced, and excavated soil (especially viscous soil) ) Crushing effect increases. While using the said stirring member which has flexibility, it is preferable to use the co-rotation prevention member which has flexibility. This is because interference due to gravel, stones and cohesive soil in the excavated soil is further reduced, and the excavating soil (particularly, cohesive soil) is further crushed. Although the shape of a co-rotation prevention member is not specifically limited, For example, it can be set as the rod shape or plate shape which protrudes in a horizontal direction with respect to a rotating shaft.

  In another aspect of the present invention, the co-rotation preventing member has a frame shape, and protrudes toward the rotation axis with respect to the vertical frame, a horizontal frame perpendicular to the rotation axis, a vertical frame parallel to the rotation axis, and the vertical frame. The auxiliary stirrer having flexibility is provided. By providing a flexible auxiliary stirring unit, the contact area to the excavated soil or the mixture of excavated soil and ground solidifying material increases, and the repulsive force against the excavated soil or excavated soil and ground solidifying material increases the auxiliary stirring unit. This increases the effect of grinding excavated soil (especially cohesive soil).

Examples of the present invention will be described below.
The side view of the ground improvement stirring apparatus 1 which is an Example of this invention is shown in FIG. As shown in FIG. 1, the ground improvement stirring device 1 includes an operation unit 2, a guide 21 connected to the operation unit 2, and a rotating shaft 3 erected along the guide 21. An excavation member 4 is attached to the lower end of the rotating shaft 3. Further, stirring members 5 and 6 and a co-rotation preventing member 7 are provided below the rotating shaft 3. Moreover, the ground improvement stirring apparatus 1 is connected with the mixer 8 via the pipe 81, and a ground solidification material (cement milk) is supplied from the mixer 8.
FIG. 2 shows a partially enlarged perspective view near the lower end of the rotating shaft 3. As shown in FIG. 2, the stirring member 5 includes a stirring blade 50 and an auxiliary stirring unit 53. The stirring blade 50 has a rod shape, and is provided on the side surface of the rotation shaft 3 so as to protrude from the left and right with respect to the rotation shaft 3. An auxiliary stirring portion 53 is attached to the lower edge of the stirring blade 50 by an iron fixing plate 51 and a bolt 52. The auxiliary stirring part 53 is made of an elastomer, and the shape thereof is a horizontally long rectangular flat plate. The stirring member 6 includes a stirring blade 60 and auxiliary stirring units 63 and 64. The stirring blade 60 has a rod shape, and is provided on the side surface of the rotary shaft 3 as a pair of left and right projections with respect to the rotary shaft. An auxiliary stirring portion 63 is attached to the upper edge of the stirring blade 60 by a fixing plate 61 and a bolt 62. An auxiliary stirring portion 64 is attached to the lower edge of the stirring blade 60 by a fixing plate 61 and a bolt 62. The auxiliary stirring portions 63 and 64 are made of elastomer and have the same shape as the auxiliary stirring portion 53. The agitating member 5 and the agitating member 6 are disposed so as to be orthogonal to each other when viewed from the axial direction of the rotating shaft 3.
The co-rotation preventing member 7 includes a flat plate portion 70 and auxiliary stirring portions 73 and 74. The flat plate portion 70 is pivoted in a pair on the left and right sides with respect to the side surface of the rotating shaft 3 so that the rotation of the rotating shaft does not propagate. An auxiliary stirring portion 73 is attached to the lower edge of the flat plate portion 70 by an iron fixing plate 71 and a bolt 72. An auxiliary stirring portion 74 is attached to the upper edge of the flat plate portion 70 by an iron fixing plate 71 and a bolt 72. The excavation member 4 includes a claw portion 41 that protrudes laterally with respect to the rotation shaft 3 and faces downward, and a tip portion 42 formed at an acute angle on the axis of the rotation shaft 3. An auxiliary stirring portion 43 is attached to the upper edge of the excavating member 4. The auxiliary stirring blade 43 is made of an elastomer and has the same shape as the auxiliary stirring portion 53. A discharge port 31 is formed near the tip of the rotating shaft 3. The discharge port 31 discharges the cement milk supplied from the mixer 8.

The outline | summary of the usage condition of the ground improvement stirring apparatus 1 is shown to Fig.3 (a)-(d). First, the ground improvement stirring device 1 is installed at a predetermined position, and the rotating shaft 3 is rotated and lowered (FIG. 3A). Along with this, the excavating member 4 rotates and is pressed against the ground, and penetrates into the ground while excavating the ground (FIG. 3B). After excavating to a predetermined depth, the rotary shaft 3 is rotated in the reverse direction while discharging the cement milk from the discharge port 31 to rotate upward (FIG. 3C). Then, the ground improvement stirring apparatus 1 is pulled up from the ground (FIG.3 (d)).
Here, as shown in FIG. 3B, the rotating shaft 3 rotates and drops, whereby the stirring members 5 and 6 rotate in the circumferential direction of the rotating shaft 3. Thereby, the excavated soil 9 excavated by the excavating member 4 is agitated. A schematic diagram of a longitudinal section when the stirring member 6 stirs the excavated soil 9 is shown in FIG. As shown in FIG. 4A, since the stirring member 6 includes auxiliary stirring portions 63 and 64, the area in contact with the excavated soil 9 is larger than when the stirring blade 60 is used. On the other hand, since the co-rotation preventing member 7 is pivoted so that the rotation of the rotating shaft 3 does not propagate, the co-rotation preventing member 7 does not rotate with the stirring member 6. Thereby, it is prevented that the excavated soil 9 and the excavated soil 9 positioned between the agitating member 6 and the co-rotation preventing member 7 rotate together with the agitating member 6 and the stirring action is lowered. Further, since the co-rotation preventing member 7 also includes the auxiliary stirring portions 73 and 74, the area in contact with the excavated soil 9 is larger than in the case of the flat plate portion 70 alone. Thereby, the stirring action to the excavated soil 9 is enhanced.
Furthermore, as shown in FIG. 4B, even if the gravel 90 contained in the excavated soil 9 comes into contact with the auxiliary stirring unit 63, the elastomeric auxiliary stirring unit 63 receives resistance from the gravel 90, and the gravel 90 Deform to avoid. Similarly, the auxiliary stirring unit 73 receives resistance from the gravel 90 and is deformed so as to avoid the gravel 90. As a result, the gravel 90 is prevented from excessively interfering with the auxiliary stirring portions 63 and 73, and the stirring action on the excavated soil 9 does not decrease. Furthermore, since excessive force is prevented from being applied to the auxiliary stirring parts 63 and 73, the stirring member 6 is prevented from being deteriorated at an early stage. In addition, the torque of the rotating shaft 9 is prevented from excessively increasing, and the burden on the rotation drive system of the apparatus is reduced. The stirring member 5 also exhibits the same stirring action as the stirring member 6.
Further, as shown in FIGS. 3C and 3D, the agitating members 5 and 6 also rotate in the circumferential direction of the rotating shaft 3 as the rotating shaft 3 rotates in the reverse direction and rotates upward. Thus, the excavated soil 9 and the cement milk discharged from the discharge port 31 are mixed and stirred. FIG. 5A shows a schematic diagram of a longitudinal section when the stirring member 6 mixes and stirs the excavated soil 9 and the cement milk 91. Since the agitation member 6 includes the auxiliary agitation parts 63 and 64 as in the agitation of the excavated soil 9, the agitation member 6 has a large area in contact with the excavated soil 9 and the cement milk 91 and exhibits a high mixing agitation action. As a result, a mixture 92 of the excavated soil 9 and the cement milk 91 is formed. Furthermore, as shown in FIGS. 5B and 5C, the auxiliary stirring portions 63 and 64 are made of elastomer, and accordingly when a resistance force is received from the mixture of the excavated soil 9 and the cement milk 91, Deform. Therefore, an excessive force is prevented from being applied to the auxiliary stirring unit 63, and the stirring member 6 is prevented from premature deterioration. In addition, the torque of the rotating shaft 9 is prevented from excessively increasing, and the burden on the rotation drive system of the apparatus is reduced. On the other hand, the deformed auxiliary stirring parts 63 and 73 generate a force to return to the original state. That is, a repulsive force is generated on the mixture of the excavated soil 9 and the cement milk 91 as indicated by the white arrow F in FIG. As a result, an action of pressing and solidifying the mixture of the excavated soil 9 and the cement milk 91 is obtained. Furthermore, as shown in FIG. 5C, when receiving a stronger resistance force from the mixture of the excavated soil 9 and the cement milk 91, the auxiliary stirring parts 63 and 73 are deformed more greatly. Accordingly, a larger repulsive force F ′ is generated in the auxiliary stirring parts 63 and 73, and the mixture of the excavated soil 9 and the cement milk 91 is pressed. In particular, as shown in FIG. 5 (c), when the clay soil mass 93 of the excavated soil 9 exists, the auxiliary stirring parts 63 and 73 are pressed against the mass 93 by the repulsive force F ′, and the clay The lump 93 is ground and the mixing and stirring with the cement milk 91 is promoted. As a result, the mixing and stirring action is further enhanced. The agitating member 5 also exhibits the same action as the agitating member 6. By these, the intensity | strength of the columnar body formed by solidifying after extracting the ground improvement stirring apparatus 1 will increase. In the ground improvement stirring device 1, the auxiliary stirring portion 43 is also provided on the upper edge of the excavation member 4. Thereby, the effect brought about by the above-mentioned auxiliary stirring parts 63 and 73 between the auxiliary stirring part 43 and the auxiliary stirring part 74, that is, the mixing stirring action is improved, the grinding effect is exerted, and the torque is prevented from being excessively generated. The burden on the drive system is reduced.

  In the ground improvement stirring device 1, the horizontally-long rectangular auxiliary stirring portions 43, 53, 63, 64, 73, and 74 made of elastomer are used, but the form of the auxiliary stirring portion is not limited to this. The example of the other form of an auxiliary | assistant stirring part is shown to Fig.6 (a)-(d). In addition, about the member substantially the same as the structure of the ground improvement stirring apparatus 1, the same code | symbol is attached | subjected and the description is abbreviate | omitted. In another embodiment shown in FIG. 6 (a), the auxiliary stirring portion 53a attached along the lower edge of the stirring blade 50 includes an elastomeric intermediate portion 54a and a steel plate 55a attached to the lower end of the intermediate portion 54a. Become. In another form shown in FIG. 6B, four metal wires 53b attached at equal intervals along the lower edge of the stirring blade 50 serve as auxiliary stirring portions. In another embodiment shown in FIG. 6 (c), a square steel plate 55c is attached in plan view to the lower ends of four metal wires 54c attached at equal intervals along the lower edge of the stirring blade 50. Becomes the auxiliary stirring section 53c. In another embodiment shown in FIG. 6C, one steel lower end 55d is attached to the lower ends of four metal wires 54d attached at equal intervals along the lower edge of the stirring blade 50, and the auxiliary stirring is performed. A portion 53d is formed. The auxiliary stirrers 53a to 53d also have the same effects as the ground improvement stirrer 1.

  FIG. 7 shows a partially enlarged perspective view of the vicinity of the tip of the rotating shaft 3 of the ground improvement stirring device 500 according to another embodiment of the present invention. The members substantially the same as the configuration of the ground improvement stirring device 1 are denoted by the same reference numerals and the description thereof is omitted. The excavation member 4 is attached to the tip of the rotating shaft 3 of the ground improvement stirring device 500. A co-rotation preventing member 700 is pivotally provided on the outer periphery of the rotating shaft 3 so that the rotation of the rotating shaft 3 does not propagate. The co-rotation preventing member 700 includes three frame portions 710, 720, and 730. The three frame-like parts 710, 720, 730 are arranged at equal intervals so that the angle formed by the axis of the rotating shaft 3 is about 120 °. The frame-shaped portion 710 has a substantially rectangular frame shape in plan view, and includes horizontal frame portions 712 and 713 and a vertical frame portion 714 perpendicular to the rotation shaft 3. The vertical frame portion 714 is substantially parallel to the rotation shaft 3, and an auxiliary stirring portion 711 projects from the side surface on the rotation shaft 3 side toward the rotation shaft 3. The auxiliary stirring unit 711 is made of an elastomer and has a substantially rectangular flat plate shape in plan view. An auxiliary stirring portion 715 made of an elastomer is attached to the lower edge of the lower horizontal frame portion 713. Similarly to the frame-shaped portion 710, the frame-shaped portions 720 and 730 are also substantially rectangular frame shapes in plan view, and are provided with auxiliary stirring portions 721 and 731 that protrude toward the rotating shaft 3 side, respectively. . Auxiliary stirring portions 725 and 735 are attached to the lower edge of the lower horizontal frame portion. On the other hand, three stirring members 601, 602, and 603 protrude from the outer periphery of the rotating shaft 3. All of the stirring members 601, 602, and 603 are made of elastomer and have a substantially rectangular flat plate shape in plan view. The agitating members 601, 602, 603 are arranged at equal intervals so that the angle formed by the shaft 3 of the rotating shaft 3 is about 120 °.

  According to the ground improvement stirring device 500, the three stirring members 601, 602, and 603 are connected to the rotating shaft 3 along with the rotation of the rotating shaft 3 at the time of mixing and stirring the excavated soil or the mixture of the excavated soil and the ground solidifying material. Rotate in the circumferential direction. On the other hand, since the co-rotation preventing member 700 is pivoted with respect to the rotation shaft 3, it does not rotate with the rotation of the rotation shaft 3. Thereby, co-rotation of excavated soil or a mixture of excavated soil and ground solidification material is prevented, and a high mixing and stirring action is exhibited. The three agitating members 601, 602, 603 and the three auxiliary agitating portions 711, 721, 731 are all made of elastomer, and deform according to the resistance of excavated soil or a mixture of excavated soil and ground solidification material. In order to generate a repulsive force, the same effects as the ground improvement stirring device 1, that is, an improvement of the mixing stirring action, an improvement of the crushing effect, a reduction in the burden on the rotary drive system by preventing excessive torque generation, and the like are achieved. Furthermore, as compared with the stirring members 5 and 6 and the co-rotation preventing member 7 of the ground improvement stirring device 1, three stirring members 601, 602, 603 and three auxiliary stirring portions 711, 721, 731 and excavated soil or Since more area in contact with the mixture of excavated soil and ground solidification material can be secured, the same or better effect than the ground improvement stirring device 1 is achieved.

  In the ground improvement stirring device 500, the three stirring members 601, 602, and 603 and the three auxiliary stirring portions 711, 721, and 731 are all made of elastomer, but are not limited thereto. For example, a part of each stirring member may be formed in combination with a metal wire, a synthetic fiber, or the like in consideration of the ratio of gravel, stones and clay soil in the ground, the strength of the columnar body to be formed, and the like. In the ground improvement stirring device 500, the co-rotation preventing member 700 is composed of the three frame-like portions 710, 720, and 730. However, the present invention is not limited to this, and the ratio of gravel, stones and clay soil in the ground In consideration of the strength of the columnar body to be formed, the number of the frame-like portions can be changed as appropriate.

  The present invention is not limited to the description of the embodiments of the invention. Various modifications may be included in the present invention as long as those skilled in the art can easily conceive without departing from the description of the scope of claims.

FIG. 1 is a schematic diagram showing a configuration of a ground improvement stirring apparatus 1 according to an embodiment of the present invention. FIG. 2 is a partially enlarged perspective view of the vicinity of the lower end of the rotating shaft 3. FIGS. 3A to 3D are diagrams showing an outline of a usage mode of the ground improvement stirring device 1. 4A and 4B are schematic views of a longitudinal section when the stirring member 6 stirs the excavated soil 9. FIGS. 5A to 5C are schematic views of longitudinal sections when the stirring member 6 mixes and stirs the excavated soil 9 and the cement milk 91. FIGS. 6A to 6D show examples of other forms of the auxiliary stirring unit. FIG. 7 shows a partially enlarged perspective view of a ground improvement stirring apparatus 500 which is another embodiment. FIG. 8 is a schematic view showing a usage mode of a conventional ground improvement stirring device.

Explanation of symbols

1, 100, 500 Ground improvement agitation device 2 Operation unit 3, 101 Rotating shaft 4 Excavation member 41 Excavation claw 42 Tip portion 5, 6 Agitation member 50, 60 Agitation blade 51, 61 Fixing plate 52, 62 Bolts 43, 63, 64 73, 74, 53, 53a to d, 601, 602, 603, 711, 721, 731, 715, 725, 735 Auxiliary stirring unit 7,700 Co-rotation preventing member 710, 720, 730 Frame portion 8 Mixer 81 Pipe 9 Excavated soil 90 Gravel 91 Cement milk 92 Mixture 93 Cohesive soil mass

Claims (6)

A rotation axis;
A drilling member provided at the tip of the rotating shaft;
A stirring member provided on an outer periphery of the rotating shaft;
A co-rotation preventing member pivoted on the outer periphery of the rotating shaft so as not to propagate the rotation of the rotating shaft;
The ground excavation member rotates to excavate the ground, the stirring member rotates to mix and stir the excavated soil and the ground solidifying material to form a columnar body in the ground,
The ground improvement stirring device according to claim 1, wherein the stirring member is deformed in accordance with a resistance of the excavated soil or a mixture of the excavated soil and the ground solidifying material during the mixing and stirring.   The ground improvement stirring according to claim 1, wherein the co-rotation preventing member is deformed in accordance with a resistance of the excavated soil or a mixture of the excavated soil and the ground solidification material during the mixing and agitation. apparatus.   The ground improvement stirring device according to claim 1 or 2, wherein the stirring member or the co-rotation preventing member has flexibility.   The said stirring member consists of a stirring blade protrudingly provided on the outer periphery of the rotating shaft, and a flexible auxiliary stirring portion attached to the stirring blade. Ground improvement stirring device.   The co-rotation preventing member has a frame shape, and is provided with a horizontal frame portion perpendicular to the rotation axis, a vertical frame portion parallel to the rotation axis, and protruding toward the rotation shaft side with respect to the vertical frame portion. The ground improvement stirring device according to claim 1, comprising an auxiliary stirring portion having flexibility.   The ground improvement stirring device according to any one of claims 1 to 5, wherein the stirring member or the co-rotation preventing member is made of a flexible elastomer, plastic, metal wire, or the like.

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