JP2007327281A - Stirring/mixing apparatus and soil improvement method using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a stirring/mixing apparatus which is used for a soil improvement method for residential soil, has stirring efficiency higher than that of a conventional apparatus, and capable of being constructed in a short time at low cost. <P>SOLUTION: The stirring/mixing apparatus 1 includes a rotating rod 11 having a passage for supplying a solidification agent, an excavation vane 21 disposed on the lower side of the rotating rod 11, stirring vanes 31 and 41 for stirring and mixing excavated soil and the solidification agent, and an upper discharge opening 51 and a lower discharge opening 52 that communicate with the passage 13 of the rotating rod 11. In a process of driving in the rotating rod 11, the solidification agent is discharged from the lower discharge opening 52, while being in a process of pulling out the rotating rod 11, the solidification agent is discharged from the upper discharge opening 51. As a result, the discharged solidification agent is constantly stirred and mixed by the stirring vanes 21 and 31, 41 in both processes of driving and pulling out. The solidification agent and excavated soil, therefore, are mixed and stirred sufficiently in one cycle of the processes of driving and pulling out without repeating the cycle twice as in a conventional case. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an agitating and mixing apparatus for creating a column-shaped improved body for improving the supporting force of the ground when building a house on a site with poor ground conditions such as soft ground, and a ground improvement for residential ground using the same. It relates to the construction method.

In the method of constructing a cylindrical ground improvement body in the ground by stirring and mixing solidified material such as cement milk and excavated soil, a rotary having a drilling blade at the lower end and a stirring blade on the rod circumference The ground improvement body is constructed by rotating the rod and rotating to the target depth while discharging the solidified material liquid and then pulling out the excavated soil and the solidified material liquid while stirring.
Japanese Examined Patent Publication No. 58-029374

The outline of the construction procedure of the ground improvement method will be described in the order of steps based on FIG. 17 as follows.
Step a: Set the column core.
Step b: Complete the empty moat. When the empty moat is completed, the solidification material injection starts and the mixing and stirring starts.
Step c: Mix and stir while excavating.
Step d: The column end is reached.
Step e: Pulling up while mixing and stirring.
Step f: Reach the column head. Complete slurry injection. Re-stirring started.
Step g: Mix and stir to the end of the column.
Step h: Reach the column tip.
Step i: Pull up again with mixing and stirring.
Process j: Complete column pillar.

  The excavation stirring device used in the conventional method described above includes a discharge port on the tip side of the rotating rod and below the stirring blade. In such a configuration, when the rotating rod is lowered (step c), the solidified material discharged from the tip of the rod is stirred with the excavated soil by the following stirring blade, but when the excavating rod is raised (step). In e), since the stirring blade precedes the discharge port, sufficient stirring and mixing is not performed.

  Therefore, in the ground improvement method using the conventional excavation stirring device, the excavation process (process c) and the lifting process (process e) are performed one step at a time, that is, only one cycle is performed, and the solidified material and the excavated soil are sufficiently stirred. Since mixing was not possible, it was necessary to perform stirring and mixing for two cycles in a substantially W shape as shown in FIG.

  However, the illustrated W-type two-cycle agitation method requires a longer construction time than one cycle, which increases the construction cost and may adversely affect the surrounding environment due to noise that continues to be generated over a long period of time. There is also. Thus, the civil engineering industry to which the technical field belongs has strongly desired a method that can shorten the construction time without reducing the construction quality.

  The problems related to the prior art described above are solved by the stirring and mixing apparatus and the ground improvement method described in the following (1) to (16).

(1) Used when building a house on a site with poor ground conditions. While discharging the solidified material from the rotating rod having the excavating blade and the stirring blade, the rotating rod is rotated and the excavated soil and the solidified material are stirred and mixed. In a stirring and mixing device that creates a substantially columnar improvement in the ground,
A rotating rod having a flow path for feeding solidified material;
A drilling blade provided on the lower end side of the rotating rod;
A stirring blade for stirring and mixing the excavated soil and the solidified material;
An upper discharge port provided above the stirring blade and communicating with the flow path of the rotating rod;
A lower discharge port provided below the stirring blade and communicating with the flow path of the rotating rod;
An agitation and mixing apparatus configured to discharge a solidified material from the lower discharge port in a digging process and to discharge a solidified material from the upper discharge port in a drawing process.

(2) It is configured to be able to selectively block between the flow path and the upper discharge port, or between the flow path and the lower discharge port, and depending on the advancing and retreating direction of the rotating rod, The stirring and mixing apparatus as set forth in (1), further comprising switching means for discharging the fed solidified material from one of the upper and lower discharge ports.

(3) The switching means includes a flow path switching valve provided to be displaceable between two positions with respect to the rotating rod, and the flow path switching valve communicates the upper discharge port with the flow path and The upper discharge position that blocks the lower discharge port and the lower discharge position that blocks the upper discharge port and communicates the lower discharge port with respect to the flow path are displaceable. The stirring and mixing apparatus according to (2) above.

(4) The flow path switching valve is formed of a substantially cylindrical member provided to be rotatable between two positions with respect to the rotating rod, and integrally includes a stirring blade ( 3) The stirring and mixing apparatus as described.

(5) The rotating rod includes a double pipe configured to have two independent flow paths capable of feeding a solidified material, and one path is connected to the upper discharge port, The stirring / mixing device according to any one of (1) to (4), wherein a path is connected to the lower discharge port.

(6) The stirring and mixing device has a free blade provided so as to be rotatable with respect to the rotating rod,
The free blade has a slope inclined with respect to the rod axis direction,
The free blade is biased in a direction opposite to the rod rotation direction by earth pressure acting on the slope of the free blade during the excavation process and the pulling process. The stirring and mixing apparatus according to any one of (1) to (5) above.

(7) The stirring and mixing device has a free blade provided so as to be rotatable with respect to the rotating rod,
The free blade has a blade body extending in the radial direction of the rotating rod, and inclined blades provided on the upper end side and / or the lower end side of the blade body and inclined with respect to the rod axis direction,
The free blade is urged in the direction of rotation opposite to the rod rotation direction by earth pressure acting on the inclined blade in the excavation process and the pulling process (above) The stirring and mixing apparatus according to any one of 1) to (5).

(8) The stirring and mixing device has a free blade that is rotatably provided to the rotating rod,
The free blade has a blade body extending in the radial direction of the rotating rod and having a length exceeding the stirring diameter of the stirring blade, and a detent member for preventing the rotation of the free blade during stirring and mixing. And
The anti-rotation member is provided in the blade body in a state of extending substantially along the outer periphery of the stirring diameter so that the side surface is in contact with the side wall of the surrounding ground outside the stirring diameter,
Any of the above (1) to (5), wherein the rotation of the free blade is prevented by the resistance of earth and sand acting on the anti-rotation member during the excavation process and the lifting process. The stirring and mixing apparatus described in 1.

(9) The stirring and mixing device according to the above (8), wherein the rotation preventing member is fixed to the blade body in a state of protruding in a substantially U shape.

(10) The stirring and mixing device has a free blade provided so as to be rotatable with respect to the rotating rod,
The free blade has a blade body extending in the radial direction of the rotating rod, and a guide blade for guiding the free blade in a direction opposite to the rod rotating direction during stirring and mixing.
The guide blade is provided on the tip side of the blade body in an inclined state with respect to the rod axis direction so as to extend beyond the stirring diameter of the stirring blade,
The free blade is biased in the direction opposite to the rod rotation direction by earth pressure acting on the guide blade outside the stirring diameter during the excavation process and the pulling process. The stirring and mixing apparatus according to any one of (1) to (5) above.

(11) The stirring and mixing device has a free blade that is rotatably provided to the rotating rod,
The free blade has a blade body that extends in the radial direction of the rotating rod, and a guide roller that can rotate as the stirring and mixing device digs and pulls out,
The guide roller is rotatably provided on the tip side of the blade body so as to extend beyond the stirring diameter of the stirring blade,
Any of the above (1) to (5), wherein the rotation of the free blade is prevented by the guide roller biting into the ground outside the stirring diameter in the excavation process and the pulling process A stirring and mixing apparatus according to claim 1.

(12) The stirring and mixing device has a free blade provided so as to be rotatable with respect to the rotating rod,
The free blade is capable of rotating as the stirring and mixing device digs and pulls out while guiding the free blade in the direction opposite to the rod rotating direction during stirring and mixing, and the blade body extending in the radial direction of the rotating rod And a guide roller
The guide roller is rotatably provided at the tip side of the blade body in an inclined state with respect to the rod axis direction so as to extend beyond the stirring diameter of the stirring blade.
During the excavation process and the pulling process, earth pressure acts on the guide roller that has digged into the ground outside the stirring diameter, so that the free blade is biased in the direction opposite to the rod rotation direction. The stirring and mixing apparatus according to any one of (1) to (5) above, wherein

(13) The stirring and mixing device according to any one of (6) to (12), wherein each of the stirring blades and the free blade has a plurality of comb-shaped stirring claws.

(14) In the ground improvement method for residential ground using the apparatus according to any one of (1) to (13) above,
Discharging the solidification material from the lower discharge port of the stirring and mixing device, and digging up the stirring and mixing device so that the stirring blade follows the lower discharge port; and
A ground improvement method characterized by including a step of discharging the solidification material from the upper discharge port of the stirring and mixing device and pulling up the stirring and mixing device so that the stirring blade follows the upper discharge port.

(15) In the ground improvement method for residential ground using the apparatus according to any one of (6) to (13) above,
A ground improvement method characterized by digging up or pulling up a stirring and mixing device while rotating a rotating rod in a direction opposite to a rotating direction in which a free blade is energized.

(16) The ground improvement method according to (14), wherein the construction of one improved body is completed in one cycle including the excavation process and the lifting process one step at a time.

According to the present invention described in (1) above, the discharge ports are respectively provided above and below the stirring blades, and solidifying material (solidifying material slurry such as cement milk) is discharged from the lower discharge port during the process of digging the rotating rod. On the other hand, in the process of pulling out the rotating rod, the solidified material is discharged from the upper discharge port. Therefore, in the excavation process, the discharged solidified material and the excavated soil are stirred and mixed by the stirring blade that follows the lower discharge port. In the drawing process, the discharged solidified material and the excavated soil are stirred and mixed by the stirring blade that follows the upper discharge port.
With such a configuration, the solidified material discharged in both the digging and drawing processes is always stirred and mixed by the stirring blade, so that the digging process and the drawing process need not be repeated two cycles as in the prior art. Also, the solidified material and the excavated soil can be sufficiently stirred and mixed in one cycle. As a result, since the stirring efficiency is improved, it becomes possible to complete the construction in a shorter time than before without lowering the construction quality, and the construction cost can be reduced.

  According to the present invention described in (2) above, it is possible to switch the discharge port from which the solidified material is discharged in accordance with the advancing / retreating direction of the rotating rod.

  According to the present invention described in (3) above, it is possible to easily and reliably switch the discharge port from which the solidified material is to be discharged.

  According to the present invention described in (4) above, the flow path switching valve can be rotated by the resistance of the earth and sand received by the stirring blade when the rotation direction of the rotating rod is switched. For example, the substantially cylindrical flow path switching valve can be rotated by a predetermined angle in the circumferential direction by the resistance received by the stirring blade when the rotating rod that has been normally rotated is rotated in the reverse direction. Therefore, according to such a configuration, the flow path switching valve can be reliably switched by simply changing the rotation direction of the rotating rod without providing special power for rotating the flow path switching valve. .

  According to the present invention described in (5) above, it is possible to reliably feed the solidified material to each of the upper discharge port and the lower discharge port.

  According to the present invention described in (6) above, the free blade has an inclined surface that is inclined with respect to the rod axis direction (digging / pulling up direction). With such a configuration, earth pressure acts on the slope of the free blade while digging (or pulling up) while rotating the rod, and the free blade is biased in the reverse rotation direction. Can do. As a result, even if affected by the excavated soil that rotates with the agitating blade, at least the agitating blade and the free blade are prevented from rotating in the same direction (the soil condition of the surrounding ground and the properties of the excavated soil). In some cases, the free blade rotates in the opposite direction with respect to the stirring blade). Therefore, since the relative rotation of the agitating blade with respect to the free blade is always maintained, co-rotation of the agitating blade and excavated soil is surely prevented, and the solidified material and excavated soil are agitated and mixed reliably and efficiently. Is possible.

  According to the present invention described in (7) above, the free blade has inclined blades that are inclined with respect to the rod axis direction (digging / pulling up direction). With such a configuration, during excavation while rotating the rod (or while pulling up), earth pressure acts on the slope of the inclined blade, and the free blade can be urged in the reverse rotation direction. it can. As a result, similar to the invention described in (6) above, it is possible to reliably prevent the stirring blade and the excavated soil from co-rotating.

  According to the present invention described in the above (8), the free blade has the detent member protruding along the outer periphery (rotation locus of the tip of the stirring blade) having a substantially stirring diameter. Since the anti-rotation member is positioned so that its side surface is in contact with the side wall (hole wall) of the surrounding ground outside the stirring diameter, a frictional resistance acts between the side wall and the anti-rotation member at the time of stirring and mixing. Therefore, since the brake effect due to frictional resistance acts on the anti-rotation member, it is possible to maintain the free blade in a stationary state (non-rotating state) in the soil regardless of the nature and behavior of the excavated soil. As a result, it becomes possible to more reliably prevent the stirring blade and the excavated soil from co-rotating.

  According to the present invention described in (9) above, the anti-rotation member is provided on the blade body in a state of projecting in a generally U shape (mountain shape). With such a shape, since the top and bottom are both inclined, it is possible to reduce as much as possible the resistance acting on the anti-rotation member during excavation and extraction. As a result, it is possible to prevent the stirring blade and the excavated soil from co-rotating without hindering the advancing and drawing of the stirring and mixing device.

  According to the present invention described in (10) above, the free blade has the guide blade inclined with respect to the rod axis direction. The guide blade is provided on the tip side of the blade body so as to extend beyond the stirring diameter of the stirring blade. By providing such a guide blade, the guide blade bites into the surrounding ground outside the stirring diameter during construction, and earth pressure (soil resistance of the surrounding ground) acts on the inclined guide blade during the excavation and lifting processes. By doing so, the free blade can be rotated in the direction opposite to the rod rotation direction. Therefore, in the stirring and mixing process, the free blade always maintains the reverse rotation state (the reverse rotation state with respect to the stirring blade) even under the influence of excavated soil that rotates with the stirring blade. As a result, it is possible to more reliably prevent the stirring blade and the excavated soil from co-rotating and to more efficiently stir and mix the solidified material and the excavated soil than when the free blade is simply stationary. Become.

According to the present invention described in the above (11), the free blade has the guide roller that can rotate as the stirring and mixing device digs and pulls out. The guide roller is provided on the tip side of the blade body so as to extend beyond the stirring diameter of the stirring blade. By extending such a guide roller, the guide roller will bite into the surrounding ground outside the stirring diameter during construction. It will be kept stationary (non-rotating state).
In addition, since the guide roller is rotatably provided and rotates as the stirring and mixing device digs and pulls out, the penetration resistance and the drawing resistance acting on the free blades during digging and drawing can be reduced. Therefore, by extending such a guide roller, the digging resistance and the pulling resistance are greatly reduced as compared with the case where the dimensions of the blade body are simply increased, and the construction can be efficiently performed.

According to the present invention described in the above (12), the free blade has the guide roller that can rotate as the stirring and mixing device digs and pulls out. The guide roller is provided on the tip end side of the blade body so as to extend beyond the stirring diameter of the stirring blade, and is provided in a state inclined with respect to the rod axis direction. By extending such a guide roller, the guide roller bites into the surrounding ground outside the stirring diameter at the time of construction, and earth pressure (soil resistance of the surrounding ground) on the inclined guide roller during the excavation and lifting processes As a result, the free blade can be rotated in the direction opposite to the rod rotation direction. Therefore, in the stirring and mixing process, the free blade always maintains the reverse rotation state (the reverse rotation state with respect to the stirring blade) even under the influence of the excavated soil to rotate together with the stirring blade. As a result, it is possible to more reliably prevent the stirring blade and the excavated soil from co-rotating and to more efficiently stir and mix the solidified material and the excavated soil than when the free blade is simply stationary. Become.
In addition, since the guide roller is rotatably provided and rotates as the stirring and mixing device digs and pulls out, the penetration resistance and the drawing resistance acting on the free blades during digging and drawing can be reduced. In addition, the free blade can be smoothly reversely rotated during excavation and extraction.

  According to the present invention described in (13) above, by providing the comb-like stirring claws, the stirring efficiency of the solidified material and the excavated soil can be improved.

  According to the present invention described in (14) above, the stirring blade and the free blade are prevented from rotating in the same direction (in some cases, the stirring blade and the free blade rotate relative to each other). Therefore, according to the present invention, it is possible to reliably prevent the stirring blades and the excavated soil from co-rotating regardless of the ground properties and soil properties, and to reliably mix and solidify the solidified material and the excavated soil.

According to the present invention described in (15) above, the discharged solidified material and the excavated soil are stirred and mixed by the stirring blade that follows the lower discharge port in the excavation step, and the upper discharge port follows in the drawing step. The discharged solidified material and excavated soil are stirred and mixed by the stirring blade.
With such a method, since the solidified material discharged in both the excavation and drawing processes is always stirred and mixed by the stirring blade, the dug process and the drawing process need not be repeated for two cycles as in the prior art. Also, the solidified material and the excavated soil can be sufficiently stirred and mixed in one cycle. As a result, since the stirring efficiency is improved, it becomes possible to complete the construction in a shorter time than before without lowering the construction quality, and the construction cost can be reduced.

  According to the present invention described in the above (16), the solidified material and the excavated soil can be sufficiently stirred and mixed in one cycle without repeating the excavation step and the drawing step two cycles as in the prior art. As a result, the construction can be completed in a shorter time than before without degrading the construction quality, and the construction cost can be reduced.

  Hereinafter, specific embodiments of the present invention will be described in detail with reference to the accompanying drawings.

(First embodiment)
First, based on FIG. 1 thru | or FIG. 5, the stirring and mixing apparatus which concerns on 1st Embodiment is demonstrated.
FIG. 1 is an overall view showing a stirring and mixing apparatus 1 according to the first embodiment of the present invention.
2A shows the stirring and mixing apparatus 1 in the lower discharge state, and FIG. 2B shows the stirring and mixing apparatus 1 in the upper discharge state.
3A shows the flow path switching valve 42 in the lower discharge position, and FIG. 3B shows the flow path switching valve 42 in the upper discharge position. ).
FIG. 4 is a perspective view showing a free blade 61 rotatably provided on the rotating rod 11. FIG. 4A shows the behavior of the free blade during excavation, and FIG. It shows the behavior of the free blade at the time. In FIG. 4, illustration of the stirring claws 32 and 73 is omitted.
FIG. 5 is a top view showing the free blade 61 shown in FIG. 4 and shows the positional relationship between the stirring diameter and the free blade during construction.

  The stirring and mixing device 1 has a rotating rod 11 that is dug into the ground while rotating during construction. A flow path 13 is formed inside the rotating rod 11 to feed the solidified material toward a discharge port described later.

  On the lower end side of the rotating rod 11, excavation blades 21 are provided that protrude in the horizontal direction at intervals of 180 °. A plurality of excavating blades 22 for excavating the ground are integrally provided below the excavating blade 21. The rotating rod 11 is rotated (forward rotation) in a direction in which the excavating blade 22 of the excavating blade 21 bites into the excavated soil during excavation. At this time, the stirring blade 21 bites into the excavated soil.

  Above the excavating blades 21, stirring blades 31 and 41 for stirring and mixing the excavated soil and the solidified material are provided. The upper and lower stirring blades 31 and 41 are provided so as to protrude in the horizontal direction at intervals of 180 °. The lower stirring blade 31 is integrally formed with a plurality of comb-like stirring claws 32 protruding in the direction of a free blade 61 described later.

  The excavating blade 21 and the lower stirring blade 31 are fixed to the rotating rod 11 and rotate integrally with the rotating rod. The upper stirring blade 41 is fixed to a cylindrical member that forms the flow path switching valve 42. The cylindrical flow path switching valve 42 is provided so as to surround the rotary rod 11 and is relatively rotatable in the circumferential direction of the rod within a predetermined angle range.

  At the time of construction, the flow path switching valve 42 is rotated by the resistance of the earth and sand received by the upper stirring blade 41. As a result, the flow path switching valve 42 is moved to the "upper discharge position" and "lower" according to the rotation direction of the rotating rod 11. It slides (rotates) in the circumferential direction between two positions of “discharge position”. Note that, within the rotatable range, the flow path switching valve 42 freely rotates with respect to the rotating rod 11, but when displaced to the full rotation limit, the flow path switching valve 42 rotates integrally with the rotating rod 11.

  On the outer wall side of the flow path switching valve 42, an upper discharge port 51 that communicates with the flow path 13 in the rotating rod through a through hole is provided (see FIGS. 2 and 3). Further, a lower discharge port 52 that communicates with the flow path 13 via a bypass passage 43 formed in the flow path switching valve 42 is provided on the tip side of the rotating rod below the lower stirring blade 31. In the present invention, the configuration of the rotating rod is not particularly limited. For example, the rotating rod is configured by a double pipe configured to have two flow paths, and one path is connected to the upper discharge port. Another path may be connected to the lower discharge port.

  In the state where the flow path switching valve 42 is in the “lower discharge position” shown in FIG. 3A, the lower flow path 15 communicating with the lower discharge port 52 is changed to the flow path 13 by the bypass passage 43 as shown in FIG. The upper discharge port 51 is blocked from the flow path 13 while being connected. On the other hand, when the flow path switching valve 42 is in the “upper discharge position” shown in FIG. 3B, the upper discharge port 51 is connected to the flow path 13 through the through hole as shown in FIG. 2B. In addition, the lower flow path 15 communicating with the lower discharge port 52 is blocked from the flow path 13. At the time of construction, the flow path switching valve 42 is displaced to a predetermined position in accordance with the advancing / retreating direction of the rotating rod 11, and the solidified material fed through the flow path 13 is discharged from either one of the upper and lower discharge ports 51 and 52. Let

  Between the upper and lower stirring blades 31 and 41, a boss 70 loosely fitted to the rotating rod 11 is provided as shown in FIG. Although the boss 70 is restricted from moving in the vertical direction by the ring-shaped movement restricting members 17, 17 of the rotating rod 11, the boss 70 has an inner diameter slightly larger than the outer diameter of the rod, so that it can freely rotate. The boss 70 is integrally provided with a free blade 61 (rotary wing) that projects in the horizontal direction.

  The free blade 61 has a blade body 71 composed of vertical wings. A plurality of comb-like stirring claws 73 protruding in the direction of the lower stirring blade 31 are integrally provided below the blade body 71.

  The stirring claw 73 of the free blade 61 does not interfere with or contact the stirring claw 32 of the rotating lower stirring blade 31, and one stirring claw of the lower stirring blade 31 and the free blade 61 is between the other stirring claws. It is possible to pass through the gap (or just beside the stirring claw) (see FIG. 1). With such a configuration, the solidification material can be reliably dispersed in the excavated soil in the stirring and mixing operation, and as a result, a uniform improved body can be obtained throughout.

  In this embodiment, the stirring claws are provided only on the upper side of the lower stirring blade 31 and the lower side of the free blade 61, but such stirring claws are provided on the upper and lower stirring blades 31, 41 and the free blade 61. You may provide in both upper and lower sides and both front and back. In addition, a plurality of stirring claws may be provided above the excavating blade 21 at the lower end of the rod.

  The blade body 71 of the free blade 61 is designed to have a size that exceeds the stirring diameter of the stirring blades 31 and 41 (the rotation trajectory of the tip of the stirring blade). At the time of construction, since the tip of the blade body 71 bites into the soil outside the stirring diameter, even if the stirring blades 31 and 41 rotate together with the rotating rod 11, the free blade 61 is relative to the rotating rod in the excavated soil. The rotation becomes stationary (see FIG. 5). Therefore, the so-called “co-rotation phenomenon” in which the excavated soil adheres to the stirring blades 31 and 41 in a dumpling shape and the excavated soil rotates in synchronization with the stirring blades 31 and 41 can be prevented.

  However, when the adhesive strength of the excavated soil is relatively large, the excavated soil may adhere to the stirring blades 31 and 41 in a dumpling shape and rotate together with the free blade 61. The function cannot be performed at all and a “co-rotation phenomenon” may occur. When such a co-rotation phenomenon occurs, the quality of the improved body cannot be ensured, and some repair or reinforcement is required.

  Therefore, in the present invention, from the viewpoint of surely preventing the “co-rotation phenomenon”, the inclined blades 74 having inclined surfaces inclined with respect to the rod axis direction are integrally formed on the free blade 61 (see FIGS. 4 and 5). Since the earth pressure acts on the lower side and the upper side slope of the inclined blades 74 (that is, the back side and the front side of the inclined blades) when the stirring and mixing device is excavated and pulled up, the direction of rotation reverse to that of the stirring blades 31 and 41. The free blade 61 can be biased. As a result, at least the agitating blades 31 and 41 and the free blade 61 are prevented from rotating integrally (the free blade 61 rotates in the opposite direction with respect to the agitating blades 31 and 41 depending on the ground properties and soil quality of excavated soil. )

  In the example shown in FIG. 4, the inclined blades 74 are provided on the upper end side of the blade body 71, but such inclined blades may be provided on the lower end side of the free blade 61. Alternatively, such inclined blades may be provided on both upper and lower sides of the free blade 61 as shown in FIG. FIG. 6A is a perspective view showing a modification of the free blade, and FIG. 6B is a side view showing the free blade of FIG. (Not shown).

According to the stirring and mixing apparatus according to the first embodiment described above, the discharge ports are provided above and below the stirring blades, and in the process of digging the rotating rod 11, the solidified material (solidifying material slurry such as cement milk) is discharged from the lower discharge port 52. On the other hand, the solidification material is discharged from the upper discharge port 51 in the process of pulling out the rotating rod 11. Therefore, in the excavation process, the discharged solidified material and the excavated soil are stirred and mixed by the upper stirring blade 41 that follows the lower discharge port 52. Further, in the drawing process, the discharged solidified material and the excavated soil are stirred and mixed by the lower stirring blade 31 that follows the upper discharge port 51.
With such a configuration, the solidified material discharged in both the digging and drawing processes is always stirred and mixed by the stirring blade, so that the digging process and the drawing process need not be repeated two cycles as in the prior art. Also, the solidified material and excavated soil can be sufficiently stirred and mixed in one cycle. As a result, since the stirring efficiency is improved, it is possible to complete the construction in a shorter time than before without reducing the construction quality, and the construction cost can be reduced.

  Further, according to the above-described stirring and mixing apparatus, earth pressure acts on the inclined blades 74 of the free blade 61 while rotating (or pulling up) while rotating the rod, so that the free blade rotates in the reverse direction. Can be biased in the direction. As a result, at least the stirring blades 31 and 41 and the free blade 61 are prevented from rotating integrally even if affected by the excavated soil that rotates together with the stirring blades 31 and 41 (the soil quality of the surrounding ground and Depending on the nature of the excavated soil, etc., the free blade rotates in the opposite direction with respect to the stirring blade). Accordingly, since the relationship in which the stirring blades 31 and 41 rotate relative to the free blade 61 is always maintained, the rotation of the stirring blades and the excavated soil is reliably prevented, and the solidified material and the excavated soil are reliably and efficiently supplied. It becomes possible to stir and mix.

(Second Embodiment)
Next, based on FIG. 7 thru | or FIG. 9, the stirring mixing apparatus which concerns on 2nd Embodiment is demonstrated.
FIG. 7 shows a stirring and mixing apparatus according to the second embodiment of the present invention.
8A is a perspective view showing a free blade 62 included in the stirring and mixing apparatus of FIG. 7, and FIG. 8B is a side view showing the free blade of FIG. (The illustration of the stirring claw is omitted).
FIG. 9 is a top view showing the free blade 62 shown in FIG. 8, and shows the positional relationship between the stirring diameter and the free blade during construction.

  The stirring and mixing apparatus according to the second embodiment has a free blade 62 having a configuration different from that of the free blade 61 in the first embodiment. Since the configuration other than the free blade is the same as that of the first embodiment, the description thereof is omitted.

  Similar to the free blade 61 of the first embodiment, the free blade 62 is rotatably provided to the rotating rod 11. This free blade has a blade body (vertical blade) 71 extending in the radial direction of the rotating rod 11 and a detent member 77 for preventing rotation of the free blade 62 during stirring and mixing.

  The two blade bodies 71 are fixed to the boss 70 at intervals of 180 °. Each blade body is formed to have a length exceeding the stirring diameter of the stirring blades 31 and 41, and at the time of construction, a part of the tip side thereof bites into the ground outside the stirring diameter (see FIG. 9). .

  As shown in FIGS. 8 and 9, the anti-rotation member 77 is fixed to the blade body 71 in a state of projecting in a substantially “<” shape along the outer periphery of the stirring diameter. The anti-rotation members 77 are provided on both surfaces of each blade main body 71, respectively, and a total of four anti-rotation members are provided in this embodiment.

  According to the stirring and mixing apparatus according to the second embodiment described above, the rotation preventing member 77 has a side surface in contact with the side wall (hole wall) of the surrounding ground outside the stirring diameter (see FIG. 9). Friction resistance acts between the side wall and the anti-rotation member during stirring and mixing. Therefore, since the brake effect due to the frictional resistance acts on the anti-rotation member 77, it is possible to maintain the free blade 62 in a stationary state (non-rotating state) in the soil regardless of the nature and behavior of the excavated soil. Become. As a result, it becomes possible to more reliably prevent the stirring blade and the excavated soil from co-rotating.

  Further, according to the above-described stirring and mixing apparatus, the rotation preventing member 77 is provided on the blade body 71 in a state of projecting in a substantially U shape (mountain shape). With such a shape, since the top and bottom are both inclined (see FIG. 8B), the resistance acting on the rotation preventing member at the time of excavation and extraction can be reduced as much as possible. As a result, it is possible to prevent the stirring blade and the excavated soil from co-rotating without hindering the advancing and drawing of the stirring and mixing device.

(Third embodiment)
Next, based on FIG.10 and FIG.11, the stirring and mixing apparatus which concerns on 3rd Embodiment is demonstrated.
FIG. 10A is a perspective view showing the free blade 63 included in the stirring and mixing apparatus according to the third embodiment, and FIG. 10B shows the free blade of FIG. 10A viewed from the direction of arrow C. FIG.
FIG. 11 is a top view showing the free blade 63 shown in FIG. 10, and shows the positional relationship between the stirring diameter and the free blade during construction.

  The stirring and mixing apparatus according to the third embodiment has a free blade 63 having a configuration different from that of the free blade 61 of the first embodiment. Since the configuration other than the free blade is the same as that of the first embodiment, illustration and description thereof are omitted.

  Similar to the free blade 61 of the first embodiment, the free blade 63 is rotatably provided to the rotating rod 11. The free blade 63 includes a blade body (vertical blade) 72 extending in the radial direction of the rotating rod 11, and a guide blade 81 for guiding the free blade 63 in a direction opposite to the rod rotating direction during stirring and mixing. have.

  The two blade bodies 72 are fixed to the boss 70 at intervals of 180 ° and extend in the radial direction of the rotating rod 11. Each blade body 72 is formed slightly shorter than the upper and lower stirring blades 31 and 41.

  The guide blade 81 is fixed to the tip side of each blade body via a bowl-shaped base plate 85 so as to extend beyond the stirring diameter of the stirring blade. Each guide blade 81 extends so as to be inclined at the same angle with respect to the rod axis direction (see FIG. 10B).

  According to the stirring and mixing apparatus according to the third embodiment described above, the guide blade 81 bites into the surrounding ground outside the stirring diameter during construction (see FIG. 11), and the side surface of the guide blade that is inclined during the excavation process and the pulling process. The free blade 63 can be rotated in the direction opposite to the rod rotation direction by the earth pressure (the resistance of the earth and sand of the surrounding ground) acting on the rod. Therefore, in the stirring and mixing process, the free blade 63 always maintains the reverse rotation state (the reverse rotation state with respect to the stirring blade) even when affected by the excavated soil to rotate with the stirring blade. As a result, as compared with the case where the free blade is simply stopped (rotation prevention), the rotation of the stirring blade and the excavated soil is more reliably prevented, and the solidified material and the excavated soil are more efficiently stirred and mixed. It becomes possible.

(Fourth embodiment)
Next, based on FIG.12 and FIG.13, the stirring and mixing apparatus which concerns on 4th Embodiment is demonstrated.
FIG. 12A is a perspective view showing a free blade 64 included in the stirring and mixing device according to the fourth embodiment, and FIG. 12B is a view of the free blade of FIG. FIG.
FIG. 13 is a top view showing the free blade 64 shown in FIG. 12, and shows the positional relationship between the stirring diameter and the free blade during construction.

  The stirring and mixing apparatus according to the fourth embodiment has a free blade 64 having a configuration different from that of the free blade 61 of the first embodiment. Since the configuration other than the free blade is the same as that of the first embodiment, illustration and description thereof are omitted.

  The free blade 64 is provided so as to be rotatable with respect to the rotating rod 11 as in the free blade 61 of the first embodiment. The free blade 64 has a blade body (vertical blade) 72 extending in the radial direction of the rotating rod 11 and a guide roller 83 that can be rotated as the stirring and mixing device is dug and pulled out.

  The two blade bodies 72 are fixed to the boss 70 at intervals of 180 ° and extend in the radial direction of the rotating rod 11. Each blade body 72 is formed slightly shorter than the upper and lower stirring blades 31 and 41.

  The guide roller 83 is rotatably supported on the tip side of each blade body via a bowl-shaped base plate 85 so as to extend beyond the stirring diameter of the stirring blades 31 and 41. Each guide roller 85 is pivotally supported by an extended bracket 87 in a state parallel to the rod axis direction.

According to the stirring and mixing apparatus according to the fourth embodiment described above, since the guide roller 83 bites into the surrounding ground outside the stirring diameter during construction (see FIG. 13), the excavated soil to be rotated together with the stirring blades 31 and 41 is used. Even if influenced, the free blade 64 is maintained in a stationary state (non-rotating state) in the earth and sand.
In addition, since the guide roller 83 is rotatably provided and rotates as the stirring and mixing device digs and pulls out, the penetration resistance and the drawing resistance acting on the free blades during digging and drawing can be reduced. Therefore, by extending such a guide roller, the digging resistance and the pulling resistance are greatly reduced as compared with the case where the dimensions of the blade body are simply increased, and the construction can be efficiently performed.

(Fifth embodiment)
Next, based on FIG.14 and FIG.15, the stirring and mixing apparatus which concerns on 5th Embodiment is demonstrated.
FIG. 14A is a perspective view showing a free blade 65 included in the stirring and mixing apparatus according to the fifth embodiment, and FIG. 14B is a view of the free blade of FIG. FIG.
FIG. 15 is a top view showing the free blade 65 shown in FIG. 14, and shows the positional relationship between the stirring diameter and the free blade during construction.

  The stirring and mixing apparatus according to the fifth embodiment has a free blade 65 having a configuration different from that of the free blade 61 of the first embodiment. Since the configuration other than the free blade is the same as that of the first embodiment, illustration and description thereof are omitted.

  The free blade 65 is provided so as to be rotatable with respect to the rotating rod 11 as in the free blade 61 of the first embodiment. The free blade 65 includes a blade body (vertical blade) 72 extending in the radial direction of the rotating rod 11 and a guide roller 83 that can be rotated as the stirring and mixing device is dug and pulled out.

  The two blade bodies 72 are fixed to the boss 70 at intervals of 180 ° and extend in the radial direction of the rotating rod 11. Each blade body 72 is formed slightly shorter than the upper and lower stirring blades 31 and 41.

  The guide roller 83 is rotatably supported on the tip side of each blade body via a bowl-shaped base plate 85 so as to extend beyond the stirring diameter of the stirring blades 31 and 41. Each guide roller 83 is pivotally supported by an extended bracket 87 while being inclined at the same angle with respect to the rod axis direction.

According to the agitating and mixing apparatus according to the fifth embodiment described above, the guide roller 83 bites into the surrounding ground outside the agitating diameter during construction (see FIG. 15), and in addition, the earth is applied to the inclined guide roller during the excavation process and the lifting process. The free blade can be rotated in the direction opposite to the rod rotation direction by the action of the pressure (the resistance of the surrounding earth and sand). Therefore, in the stirring and mixing process, the free blade 65 always maintains the reverse rotation state (the reverse rotation state with respect to the stirring blades) even if it is affected by the excavated soil that rotates together with the stirring blades 31 and 41. As a result, as compared with the case where the free blade is simply stopped (rotation prevention), the rotation of the stirring blade and the excavated soil is more reliably prevented, and the solidified material and the excavated soil are more efficiently stirred and mixed. It becomes possible.
Moreover, since the guide roller 83 is rotatably provided and rotates as the stirring and mixing device digs and pulls out, the penetration resistance and the drawing resistance acting on the free blade 65 during digging and drawing can be reduced. . In addition, the free blade 65 can be smoothly reversely rotated during excavation and extraction.

(Construction procedure for ground improvement method)
Next, based on FIG. 16, the construction procedure of the ground improvement construction method using the stirring and mixing apparatus 1 shown in FIG. 1 will be described.

  First, the stirring and mixing device 1 is provided in a base machine (not shown) so as to be capable of rotating excavation, and positioned at a place where ground improvement work is required (FIG. 16 (a)). Next, the front end side of the stirring and mixing device 1 is pushed toward the ground while the rotating rod 11 is rotated forward via a motor. Then, the ground is excavated by the excavating blades 21 and the excavated earth and sand are stirred together with the stirring blades 31 and 41 to excavate the ground (FIG. 16B).

  And if the front-end | tip of the stirring and mixing apparatus 1 reaches | attains the setting depth position, a slurry-like solidification material (cement milk etc.) will begin pumping to the flow path 13 of the rotating rod 11 via a pump. At this time, the cylindrical flow path switching valve 42 is in the “lower discharge position” shown in FIGS. 2 (A) and 3 (A). Accordingly, the solidified material flowing in the flow path 13 passes through the bypass passage 43 of the flow path switching valve 42 and is discharged from the lower discharge port 52 at the tip of the rod (not discharged from the upper discharge port 51).

  Then, the solidified material is pumped, and the excavating soil and the solidified material are mixed and stirred by the stirring blades 31 and 41 by continuing the excavation while the rotating rod 11 is rotated forward (FIG. 16 (c)). In the process of excavation, since the agitating blades 31 and 41 are in a positional relationship to follow the lower discharge port 52, the solidified material discharged from the preceding lower discharge port 52 is agitated and mixed with the excavated soil by the agitating blades 31 and 41. .

  In the excavation process of FIG. 16C, the stirring blades 31 and 41 are rotating forward, but earth pressure (sediment resistance) acts on the lower slope of the inclined blades 74 of the free blade 61, The free blade is urged in the reverse rotation direction (see FIG. 4A). As a result, even if the surrounding ground outside the stirring diameter is extremely loose, at least the stirring blades 31 and 41 and the free blade 61 are prevented from rotating in the same direction (depending on the inclination angle and the looseness of the ground) The blade 61 rotates in the opposite direction with respect to the stirring blades 31 and 41).

  When the above-described mixing and agitation work of the excavated soil and the solidified material is performed to a set arbitrary depth position, the solidified material is stopped from being pumped, and fixing agitation is performed as necessary (FIG. 16D). )). Subsequently, the rotating rod 11 is reversely rotated. At this time, since the upper stirring blade 41 receives the resistance of earth and sand, the cylindrical flow path switching valve 42 rotates from the “lower discharge position” to the “upper discharge position” along the outer peripheral surface of the rod. As a result, as shown in FIG. 2B and FIG. 3B, the upper discharge port 51 is connected to the flow path 13 of the rotating rod, and the lower flow path 15 leading to the lower discharge port 52 is connected to the flow path 13. Is cut off from.

  When the flow path switching valve 42 is rotated to the limit by the reverse rotation of the rotating rod 11 and the switching of the discharge port is completed, the pump is operated again, and the solidified material is pumped to the flow path 13 of the rotating rod. To do. Thereby, the solidified material flowing in the flow path 13 is discharged from the upper discharge port 51 (not discharged from the lower discharge port 52).

  Then, the solidified material and the solidified material are mixed and agitated by the stirring blades 31 and 41 by pumping the solidified material and pulling up the rotating rod 11 while being reversely rotated (FIG. 16 (e)). In the process of pulling up, since the stirring blades 31 and 41 follow the upper discharge port 51, the solidified material discharged from the preceding upper discharge port 51 is stirred and mixed against the excavated soil by the stirring blades 31 and 41. . At this time, although the stirring blades 31 and 41 are rotating in the reverse direction, earth pressure (sediment resistance) acts on the upper inclined surface of the inclined blade 74 of the free blade 61 to urge the free blade in the forward rotation direction. (See FIG. 4B).

  Finally, if the stirring and mixing device is pulled up, a cylindrical body in which earth and sand and a solidifying material are mixed can be formed in the ground (FIG. 16 (f)). A series of such operations are sequentially performed at a necessary number at different locations. When a certain period of time elapses after the improvement work is completed, a substantially columnar improvement body formed by solidifying the mixture of earth and sand and the solidifying material is formed.

  As described above, according to the present invention, the discharged solidified material and the excavated soil are stirred and mixed by the stirring blade that follows the lower discharge port in the excavation process, and the stirring blade that follows the upper discharge port in the drawing process. Thus, the discharged solidified material and the excavated soil are agitated and mixed. Therefore, since the solidified material discharged in both the excavation and drawing processes is always stirred and mixed by the stirring blades, it is solidified in one cycle without repeating the drilling process and the drawing process two cycles as in the prior art. The material and excavated soil can be thoroughly mixed. As a result, the construction can be completed in a shorter time than before without degrading the construction quality, and the construction cost can be reduced.

1 is an overall view showing a stirring and mixing device according to a first embodiment of the present invention. 2A shows the stirring and mixing apparatus in the lower discharge state, and FIG. 2B shows the stirring and mixing apparatus in the upper discharge state. 3A shows the flow path switching valve in the lower discharge position, and FIG. 3B shows the flow path switching valve in the upper discharge position, which are shown in FIGS. 2A and 2B, respectively. It corresponds. It is a perspective view which shows the free blade provided in the rotating rod so that rotation was possible. It is a top view which shows the free blade shown in FIG. 4, Comprising: The positional relationship of the stirring diameter at the time of construction and a free blade is shown. 6A is a perspective view showing a modified example of the free blade shown in FIG. 4, and FIG. 6B is a side view showing the free blade of FIG. 6A viewed from the direction of arrow A. FIG. . FIG. 7 shows a stirring and mixing apparatus according to the second embodiment of the present invention. 8A is a perspective view showing a free blade of the stirring and mixing apparatus of FIG. 7, and FIG. 8B is a side view showing the free blade of FIG. 8A viewed from the direction of arrow B. is there. It is a top view which shows the free blade shown in FIG. 8, Comprising: The positional relationship of the stirring diameter at the time of construction and a free blade is shown. FIG. 10A is a perspective view showing a free blade of the stirring and mixing apparatus according to the third embodiment, and FIG. 10B shows a state where the free blade of FIG. 10A is viewed from the direction of arrow C. FIG. It is a top view which shows the free blade shown in FIG. 10, Comprising: The positional relationship of the stirring diameter at the time of construction and a free blade is shown. FIG. 12A is a perspective view showing a free blade of the stirring and mixing apparatus according to the fourth embodiment, and FIG. 12B is a view of the free blade of FIG. FIG. It is a top view which shows the free blade shown in FIG. 12, Comprising: The positional relationship of the stirring diameter at the time of construction and a free blade is shown. FIG. 14A is a perspective view showing a free blade included in the stirring and mixing device according to the fifth embodiment, and FIG. 14B shows a state where the free blade of FIG. FIG. FIG. 15 is a top view showing the free blade shown in FIG. 14 and shows the positional relationship between the stirring diameter and the free blade during construction. It is a figure which shows the construction procedure of the ground improvement construction method of this invention. It is a figure which shows the construction procedure of the conventional ground improvement construction method.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Stirring mixing apparatus 11 Rotating rod 13 Flow path 15 Lower flow path 17 Ring-shaped movement control member 21 Excavation blade 22 Excavation blade 31 Lower stirring blade 32 Stirring claw 41 Upper stirring blade 42 Cylindrical flow path switching valve (flow path switching means)
43 Bypass passage 51 Upper discharge port 52 Lower discharge port 61 Free blade (rotary blade)
62 Free blade
63 Free blade (Rotatable wing)
64 Free blade (rotary wing)
65 Free blade (rotary wing)
70 Boss 71 Blade body (vertical wing)
72 Blade body (vertical wing)
73 Stirring claw 74 Inclined blade 75 Blade body 77 Non-rotating member 81 Guide blade 83 Guide roller 85 Base plate 87 Bracket

Claims (16)

Used when building a house on a site with poor ground conditions, while discharging the solidified material from the rotating rod having the excavating blade and the stirring blade, the rotating rod is rotated to mix and mix the excavated soil and the solidified material. In the stirring and mixing apparatus for creating a substantially columnar improvement body,
A rotating rod having a flow path for feeding the solidified material;
A drilling blade provided on the lower end side of the rotating rod;
A stirring blade for stirring and mixing the excavated soil and the solidified material;
An upper discharge port provided above the stirring blade and communicating with the flow path of the rotating rod;
A lower discharge port provided below the stirring blade and communicating with the flow path of the rotating rod;
An agitation and mixing apparatus configured to discharge a solidified material from the lower discharge port in a digging process and to discharge a solidified material from the upper discharge port in a drawing process.   It is configured to be able to selectively block between the flow path and the upper discharge port or between the flow path and the lower discharge port, and is fed through the flow path according to the advancing and retreating direction of the rotating rod. 2. The stirring and mixing apparatus according to claim 1, further comprising switching means for discharging the solidified material from either one of the upper and lower discharge ports.   The switching means includes a flow path switching valve provided so as to be displaceable between two positions with respect to the rotating rod. The flow path switching valve communicates the upper discharge port with the flow channel and the lower discharge port. 2. An upper discharge position for blocking the upper discharge port and a lower discharge position for blocking the upper discharge port with respect to the flow path and allowing the lower discharge port to communicate with each other. 2. The stirring and mixing apparatus according to 2.   The said flow-path switching valve consists of a substantially cylindrical member provided so that rotation between two positions was possible with respect to the said rotation rod, and has a stirring blade integrally. Stir and mixing device.   The rotating rod includes a double pipe configured to have two independent flow paths capable of feeding a solidified material, one path being connected to the upper discharge port, and the other path being the The stirring and mixing device according to any one of claims 1 to 4, wherein the stirring and mixing device is connected to a lower discharge port. The stirring and mixing device has a free blade provided so as to be rotatable with respect to the rotating rod,
The free blade has a slope inclined with respect to the rod axis direction,
The free blade is biased in a direction opposite to the rod rotation direction by earth pressure acting on the slope of the free blade during the excavation process and the pulling process. The stirring and mixing apparatus according to any one of claims 1 to 5. The stirring and mixing device has a free blade provided so as to be rotatable with respect to the rotating rod,
The free blade has a blade body extending in the radial direction of the rotating rod, and inclined blades provided on the upper end side and / or lower end side of the blade body and inclined with respect to the rod axis direction,
2. The free blade is urged in a direction opposite to a rod rotation direction by earth pressure acting on the inclined blades during a digging process and a pulling process. The stirring and mixing apparatus according to any one of 1 to 5. The stirring and mixing device has a free blade provided so as to be rotatable with respect to the rotating rod,
The free blade has a blade body extending in the radial direction of the rotating rod and having a length exceeding the stirring diameter of the stirring blade, and a detent member for preventing the rotation of the free blade during stirring and mixing. And
The anti-rotation member is provided in the blade body in a state of extending substantially along the outer periphery of the stirring diameter so that the side surface is in contact with the side wall of the surrounding ground outside the stirring diameter,
6. The rotation of a free blade is prevented by the resistance of earth and sand acting on the anti-rotation member during a digging process and a pulling process, according to any one of claims 1 to 5. Stir and mixing device.   9. The stirring and mixing device according to claim 8, wherein the anti-rotation member is fixed to the blade body in a state of protruding in a substantially U shape. The stirring and mixing device has a free blade provided so as to be rotatable with respect to the rotating rod,
The free blade has a blade body extending in the radial direction of the rotating rod, and a guide blade for guiding the free blade in a direction opposite to the rod rotating direction during stirring and mixing.
The guide blade is provided on the tip side of the blade body in an inclined state with respect to the rod axis direction so as to extend beyond the stirring diameter of the stirring blade,
The free blade is biased in the direction opposite to the rod rotation direction by earth pressure acting on the guide blade outside the stirring diameter during the excavation process and the pulling process. The stirring and mixing apparatus according to any one of claims 1 to 5. The stirring and mixing device has a free blade provided so as to be rotatable with respect to the rotating rod,
The free blade has a blade body that extends in the radial direction of the rotating rod, and a guide roller that can rotate as the stirring and mixing device digs and pulls out,
The guide roller is rotatably provided on the tip side of the blade body so as to extend beyond the stirring diameter of the stirring blade,
The rotation of the free blade is prevented by the guide roller biting into the ground outside the stirring diameter in the excavation process and the pulling process. Stirring and mixing device. The stirring and mixing device has a free blade provided so as to be rotatable with respect to the rotating rod,
The free blade is capable of rotating as the stirring and mixing device digs and pulls out while guiding the free blade in the direction opposite to the rod rotating direction during stirring and mixing, and the blade body extending in the radial direction of the rotating rod And a guide roller
The guide roller is rotatably provided at the tip side of the blade body in an inclined state with respect to the rod axis direction so as to extend beyond the stirring diameter of the stirring blade.
During the excavation process and the pulling process, earth pressure acts on the guide roller that has digged into the ground outside the stirring diameter, so that the free blade is biased in the direction opposite to the rod rotation direction. The stirring and mixing device according to any one of claims 1 to 5, wherein   The stirring and mixing device according to any one of claims 6 to 12, wherein each of the stirring blade and the free blade has a plurality of comb-shaped stirring claws. In the ground improvement construction method for residential ground using the apparatus according to any one of claims 1 to 13,
Discharging the solidification material from the lower discharge port of the stirring and mixing device, and digging up the stirring and mixing device so that the stirring blade follows the lower discharge port; and
A ground improvement method characterized by including a step of discharging the solidification material from the upper discharge port of the stirring and mixing device and pulling up the stirring and mixing device so that the stirring blade follows the upper discharge port. In the ground improvement construction method for residential ground using the apparatus according to any one of claims 6 to 13,
A ground improvement method characterized by digging up or pulling up a stirring and mixing device while rotating a rotating rod in a direction opposite to a rotating direction in which a free blade is energized. 15. The ground improvement method according to claim 14, wherein the construction of one improved body is completed in one cycle including the excavation process and the lifting process one step at a time.

Images