JP2000073354A - Preparating method of ground improving body and preparating method of continuous walls - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent cement-mixed discharge mud from flowing out to the ground. SOLUTION: An outlet 6U for cement-mixed mud MG is provided on a top end part, and an agitating rod 2 having agitating impellers in at least the vicinity of the outlet is used. After the object ground is excavated and forced to a predetermined depth while loosening the ground by the agitating rod 2, the cement-mixed mud is discharged from the outlet in a process drawn up while rotating the agitating rod 2. Ground soil of an original position and the cement mixed mud MG from the outlet 6U are then agitatedly mixed by the agitating impellers 4, 4. After adding cement in discharge mud discharged to the ground in the drawing up process, the cement-mixed mud MG is discharged from the outlet 6U, and a cement column is formed by the drawing up process.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a ground improvement body construction method and a continuous wall construction method, and more particularly, to mixing cement-mixed mud and in-situ ground soil in a lifting process using a stirring rod. A soil cement column is formed so as to replace a loose hole.

[0002]

2. Description of the Related Art In a so-called deep mixing method or a soil-cement wall method, a stirring blade is provided with a stirring rod protruding outside of a shaft member, while rotating and penetrating into a target ground, or after the penetration. 2. Description of the Related Art Cement milk is supplied in the process of being pulled up while rotating, and is stirred and mixed with an in situ ground soil to form a soil cement column.

[0003]

However, in the construction method of a soil cement column in which cement milk is supplied when the stirring rod penetrates or when the stirring rod is pulled up, since the cement milk has a high fluidity, in principle, the cement cement is poured. The same amount of sludge as milk is discharged to the ground.

[0004] In recent years, from the viewpoint of location, waste disposal of this waste soil mixed with cement has become a major social problem.

[0005] On the other hand, the kneading property or the stirring and mixing property of the cement milk and the soil at the site are not sufficient, and it is difficult to form a high strength and uniform soil cement column.

[0006] Therefore, a main object of the present invention is to form a soil cement column having a very small amount of waste mud mixed with cement and excellent in kneading properties, and having a uniform strength, or a continuous wall formed by connecting these columns.

[0007]

According to a first aspect of the present invention, there is provided a stirrer rod having a discharge port for cement-mixed mud at a tip end thereof and having a stirring blade at least in the vicinity of the discharge port. Using, the target ground to a predetermined depth, excavation penetrating while loosening the ground by the stirring rod, or by inserting the stirring rod into a drilling hole excavated while loosening the ground to a predetermined depth by another drilling device,
In the process of pulling up while rotating the stirring rod, the cement-mixed mud is discharged from the discharge port, and the in-situ ground soil and the cement-mixed mud from the discharge port are stirred and mixed by the stirring blades. It is a ground improvement body forming method characterized in that the cement mixed mud is discharged from the discharge port after adding cement to the discharged mud discharged to the ground, and a soil cement column is formed by this lifting process. .

According to a second aspect of the present invention, a water injection port is provided at a front end portion, and a discharge port for cement-mixed mud is provided at a front end portion closer to the base side than the water injection port, and a stirring blade is provided at least near the discharge port. Using a stirring rod, the target ground to a predetermined depth, while pouring water from the water inlet, while digging and penetrating while loosening the ground by the stirring rod, in the process of pulling up while rotating the stirring rod, from the discharge port Discharge the cement-mixed mud, stir-mix the original ground soil and the cement-mixed mud from the discharge port with the stirring blade, and add the cement to the discharged mud discharged to the ground in the lifting process, and then add the cement. By discharging the cement-mixed mud from the discharge port, a soil-improved body forming method characterized by forming a soil cement column by this lifting process. That.

According to a third aspect of the present invention, a water injection port is provided at a distal end portion, and a discharge port for cement-mixed mud is provided at a front end portion closer to the base side than the water injection port, and a stirring blade is provided at least near the discharge port. Using a stirring rod, the target ground is digged into the target ground to a predetermined depth while water is being injected from the water injection port while the ground is loosened by the stirring rod, and then the water injection port of the stirring rod is positioned substantially at the discharge port. Once, the cement-mixed mud is discharged from the water inlet to penetrate to the original deepest position, and then, while rotating the stirring rod from the deepest position or from the level, the discharging is performed. The cement-mixed mud is discharged from the outlet, and the original ground soil and the cement-mixed mud from the discharge port are stirred and mixed by the stirring blade. Soil is discharged from the discharge port after the cement is added to the mud discharged to the ground in the evacuation process, and the cement-mixed mud is discharged from the discharge port. It is a construction method.

According to a fourth aspect of the present invention, there is provided the soil improvement method according to any one of the first to third aspects, wherein a slump value of the cement-mixed mud discharged from the discharge port is 8 cm or more.

According to a fifth aspect of the present invention, the stirring blade below the discharge port is inclined so as to act in a direction of pushing down the stirred and mixed treated soil downward during rotation during lifting. The construction method of a ground improvement body according to any one of the above.

According to a sixth aspect of the present invention, a stirring blade is provided also above the discharge port, and the stirring blade above is inclined so as to act in a direction to push up mud when rotating at the time of lifting. Item 6. A method for forming a ground improvement body according to any one of Items 1 to 3.

According to a seventh aspect of the present invention, coarse particles are removed from the mud discharged to the ground side to obtain mud comprising fine particles and water, and cement is added to the mud. The ground improvement body construction method according to any one of claims 1 to 3, wherein the soil is a cement-mixed mud.

The invention according to claim 8 has a water injection port at a tip end, a discharge port for cement-mixed mud at a base portion side from the water injection port, and a stirring blade at least near the discharge port. Using a multi-axis stirring mixer in which a plurality of stirring rods are arranged in parallel and parallel to the target ground to a predetermined depth,
After pouring water from the water inlet, while digging and penetrating while loosening the ground with the stirring rod, in the process of pulling up while rotating the stirring rod, the cement mixed mud is discharged from the discharge port, and the original ground and The cement-mixed mud from the discharge port is stirred and mixed by the stirring blades, and the cement-mixed mud is discharged from the discharge port after adding cement to the discharged mud discharged to the ground in the lifting process. A continuous wall forming method is characterized in that continuous soil cement columns for the number of shafts are formed by a lifting process, and continuous wall is formed by making the soil cement columns continuous.

[0015]

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings.

First, an example of a single-axis stirring rod according to the present invention used in the present embodiment will be described with reference to FIGS. The stirring rod 1 has lower stirring blades 4, 4,... Having a function of pushing down (pressing) treated soils having different inclination directions on the shaft member 2, and an upper stirring having a function of pushing up (decomposing and lifting mud). The blades 5, 5,... The lower stirring blade 3 at the tip is provided with excavation bits 3a.

A water inlet 6L is provided at the tip of the tip.
Thus, a discharge port 6U is formed on the base side. The discharge port 6U is formed above the lower stirring blades 4, 4,... And below the upper stirring blades 5, 5,.

Further, the shaft member 2 of the stirring rod 1 in the illustrated example
Although not shown in detail, has a double pipe structure, and is rotated by a rotary drive device 7 including a speed reducer. A double structure hose 9 for supplying water and cement mixed mud is connected to the shaft member 2 via a swivel joint 8.

As shown in FIG. 2, when the shaft member 2 is pulled up and rotated in the rotation direction, the lower stirring blades 4, 4,... Physically push down (press) the treated soil as shown in the left explanatory view. ), And the upper stirring blades 5, 5,... Exhibit a function of pushing up the discharged mud (performing de-mudging / lifting).

Next, a method of forming a ground improvement body according to the present invention using such a stirring rod will be described. <Preparation Step> FIG. 3 shows a preparation state in which the stirring rod 1 according to the present invention is mounted on a base machine (not shown) and the tip thereof is set to face the target ground.

Preferably, in order to reuse the discharged mud discharged to the ground side due to the excavation penetration and stirring and mixing, the stirring mud is settled by communicating with a portion serving as a mouth when the excavation penetrates. A pond 10 is provided, and a cement mixed mud production plant 20 is installed near the settling pond 10.

The mud in the sedimentation basin 10 is pumped up by a backhoe BH (may be pumped up by a pump not shown) and supplied to a hopper 21 of a manufacturing plant 20. The hopper 21 is separately provided with cement (“cement” in the present invention includes not only cement but also all materials mainly composed of cement such as cement mortar, cement clay, cement lime, etc.) Accordingly, water W1 and additive AD (other inorganic materials such as fine particle slag and bentonite, a foaming agent, a foaming agent, a separation preventing agent, a water reducing agent, etc.) are supplied at a predetermined compounding ratio. The discharged mud and the compound such as cement G supplied to the hopper 21 are supplied to the mixing drum 22 in a fixed amount and kneaded. The kneaded material is supplied into the stirring rod 1 as a cement-mixed mud by a pressure pump (a commercially available concrete pump is used) 23. The cement-mixed mud from the pressure pump 23 is configured to be discharged from the discharge port 6U through the double pipe hose 9.

The sedimentation basin 1 is composed of a first sedimentation basin 10A communicating with the mouth of the penetrating part as shown in FIG.
The first sedimentation basin 10A, which is separated from the coarse sediment in the first sedimentation basin 10A, is provided separately from the second sedimentation basin 10C communicating with the second sedimentation basin.
It is preferable to guide the sedimentation basin 10C and supply it to a cement-mixed mud production plant.

<Excavation Penetration Step> When the preparation is completed, the process proceeds to the excavation penetration step of the stirring rod 1. That is, as shown in FIG. 4, the excavation auxiliary water such as the water W2 is supplied from the water inlet 6L at the distal end portion through the double pipe hose 9, and the stirring rod 1 is rotated and lowered to rotate the excavating blade 3 at the distal end. The stirring rod 1 penetrates into the target ground to a predetermined depth while performing the excavation. As a result, mud columns are formed in the area to be improved. In some cases, such as when the target ground is loose, excavation can be performed without using the excavation water W2. Further, the stirring rod 1 may be inserted into a ground drilling hole which has been excavated and loosened to a predetermined depth by another excavator.

As the excavation penetrates, the discharged mud M overflows from the mouth of the penetrating portion. The overflowing mud M overflows to the sedimentation basin 10
, Coarse particles R are settled and separated. The supernatant mud MW composed of fine particles and water is pumped up by the backhoe BH and supplied to the cement-mixed mud production plant 20. In the production plant 20, cement G or the like is added to the mud MW from the sedimentation basin to produce cement mixed mud. This cement-mixed mud is supplied into the double-pipe hose 9 by the pressure pump 23 in the subsequent stirring and mixing process.

In particular, it is preferable that the cement-mixed mud is kneaded as much as possible by a pumping means such as a pressure pump 23 or a conveying path. It is desirable to determine the composition of the kneaded material so that the slump value of the kneaded material is 6 cm or more, particularly 8 cm or more, from the viewpoint of the pumpability by the concrete pump 23 and the reliability of replacement in the excavation penetration hole. Since this kneaded material (cement-mixed mud) is stirred and mixed with the original ground in the stirring and mixing step described later, it is preferable to determine the cement addition ratio in consideration of the stirring and mixing ratio.

<Stirring and Mixing Step> After the excavation and penetration of the stirring rod 1 is completed, stirring and mixing are preferably performed as follows. That is, as shown in FIG. 5, the stirring rod 1 is pulled up so that the water inlet 6L is located near the depth position of the discharge port 6U in a state where the stirring rod 1 has penetrated to a predetermined depth.

Thereafter, as shown in FIG.
In the process of penetrating to the deepest part while rotating in a predetermined direction,
The cement-mixed mud MG from the cement-mixed mud manufacturing plant 20 is supplied to the stirring rod 1 and discharged from only the water injection port 6L, and the discharged cement-mixed mud MG and the mud at the original position are stirred and mixed.

Next, when the stirring rod 1 reaches a predetermined deepest portion, as shown in FIG. 7, while the stirring rod 1 is pulled up while rotating in a predetermined direction (opposite to the stirring at the time of penetration), the cement mixed mud is removed. The cement-mixed mud MG from the manufacturing plant 20 is discharged only from the discharge port 6U, and the discharged cement-mixed mud MG and the in-situ ground soil are stirred and mixed.

Also in this pulling process, the rising of the stirred and mixed treated soil MB2 to the ground is suppressed by the pressing action of the lower stirring blades 4, 4,..., And the discharged mud M above the pressing action area is moved upward. Stirring blades 5,5 ...
, And is positively raised by the pushing-up action of the water. And the local board and discharge port 6
An improved mixture with cement mixed mud MG from U is created. The mud discharged into the sedimentation basin 10 in the stirring and mixing step is used for the production of the cement mixed mud in the cement mixed mud manufacturing plant 20 described above, and the produced cement mixed mud is sequentially supplied to the stirring rod 1. . By such a stirring and mixing process, a soil cement column is formed over the entire lifting area of the stirring rod 1.

In particular, in the stirring and mixing step, the cement-mixed mud discharged from the water injection port 6L at the time of intrusion and the cement-mixed mud supplied from the discharge port 6U at the time of pulling up go through the corresponding areas to be improved. The improved body is created while preferentially filling and taking in the in-situ ground soil in an amount insufficient to tightly fill the area to be improved. Therefore, a soil cement column having a desired compounding ratio can be formed in the improvement target region.

Each of the agitated and mixed treated soils MB1, MB
2 is pushed down by the lower stirring blades 4, 4,.
Cement-mixed mud MG does not mix into the discharged mud M discharged to the ground side by the upper stirring blades 5, 5,. Therefore, the discharged mud M discharged to the ground side can be reused in the production of the cement-mixed mud in the above-described plant 20 or for other uses.

On the other hand, changes in the contents of the improvement area in the above-described example of the improvement body construction method will be described in detail with reference to FIG. First, it is assumed that the composition of the ground before the excavation of the stirring rod 1 is as shown in the figure as an initial state. When the stirring rod 1 is excavated and penetrated while supplying the excavated water W2 to the target ground, the excavated water W
The discharged mud M is discharged into the sedimentation basin 10 by the supply amount of 2, the volume of the stirring rod 1, and the amount of the discharged mud M due to the pushing-up action of the upper stirring blade at the time of excavation. Instead, the stirring rod 1 and the drilling water W2 are added as contents of the penetration area. on the other hand,
The discharged mud M generated due to the excavation and penetration is removed by sedimentation and separation in a sedimentation basin to obtain a muddy water composed of fine particles and water, and cement is added to the muddy water to produce a cement-mixed mud MG. The amount of cement to be added is determined in consideration of the amount of in-situ mud taken in during stirring and mixing.
If necessary, for example, when the water content of the muddy water is low, water is added in consideration of the pumpability to the stirring rod. When stirring and mixing is performed using the cement-mixed mud MG, the stirring rod 1 is pulled out, and further, the discharged mud M in an amount corresponding to the supply amount of the cement-mixed mud MG is discharged to the sedimentation basin 10, and the amount of the decrease In a state where the amount of the cement-mixed mud MG corresponding to the amount is added. Therefore, an improved body corresponding to a desired compounding ratio is formed. In addition, although a small amount of sludge will eventually be generated, the cement-mixed mud will not be mixed with the mud generated by stirring and mixing due to the pushing-up action of the upper stirring blade and the pushing-down action of the lower stirring blade. It can be used for producing cement-mixed mud at the time of building a body. Therefore, in the present construction method, the mixed waste of the cement-mixed mud and the mud is not generated, and the generated mud can be reused.

<Example of Application to Deep Mixing Method> As is apparent from the above example, the present invention relates to a method of individually forming a single soil cement column in a target ground by mechanical stirring and mixing. In addition, it can be applied to soil cement deep mixing process or continuous wall method.

For example, in the case of performing the deep mixing process on two axes, as shown in FIG. 9, two stirring rods 100A and 100B similar to the stirring rod 1 shown in FIG. 1 and the like are connected in a parallel arrangement. Two-axis stirring rod 100
, An improved body can be formed in the same manner as in the case of the single shaft described above. In FIG. 9, 102A and 102B indicate shaft members of each rod, 103A..., 103B... Indicate excavation stirring blades of each stirring rod, 104A. , 105B
... indicate the upper stirring blade of each stirring rod, and 106U, 1
06L indicates a discharge port and a water injection port, respectively, and 107L
Denotes a biaxial rotation driving device that rotates the stirring rods 100A and 100B in opposite directions, and 110 denotes a biaxial connecting member that connects the lower portions of both rods. FIG. 10 is a plan view of an improved body formed by using the stirring rod 100.

When the present invention is applied to a soil cement continuous wall method, a three-axis stirring rod shown in FIG. 11 can be used. That is, three stirring rods 200A to 200C similar to the stirring rod 1 shown in FIG.
A three-axis stirring rod 200 connected and connected in a parallel arrangement is used. In FIG. 11, 202A to 202C indicate shaft members of each rod, 203A to 203C indicate excavation stirring blades of each stirring rod, 204A to 204C indicate lower stirring blades of each stirring rod, and 205A to 205C indicate respective stirring members. The upper stirring blade of the rod is shown.
L indicates a discharge port and a water injection port, respectively, and 207 indicates adjacent stirring rods 200A, 200B and 200B, 2B.
A triaxial rotation driving device that rotates 00C in the reverse direction is shown, and 210 indicates a triaxial connecting member that connects the lower portions of both rods.

In particular, in the triaxial stirring rod 200 shown in FIG. 11, the stirring blade 204 of the stirring rod 200C at the end is used.
The rotation trajectories of C and 205C are smaller in diameter than the other stirring blades and intersect at one point without overlapping with the rotation trajectories of the stirring blades of the adjacent center stirring rod 200B, and the stirring rod 2 at the other end.
The rotation trajectory of 00A overlaps with the rotation trajectory of the stirring blade of the adjacent center stirring rod 200B. In this case, the shape of the improved body constructed by one formation is as shown in FIG.

At the time of construction, one improved body is formed in the same manner as in the case of the single shaft. By performing such formation according to a so-called continuous method (standard method or single-push method) or a so-called advance drilling method using a single-axis stirring rod together, a completely wrapped soil cement continuous wall 300 as shown in FIG. 13 is obtained. Can be created.

<Others> (A) In the present invention, all the stirring blades of the stirring rod can be formed as lower stirring blades.

(B) The discharge port for the cement-mixed mud according to the present invention may be provided not only on the shaft member but also on the stirring blade as long as it is within the area where the lower stirring blade pushes down the agitated material. When the discharge port is provided on the stirring blade, a discharge port is provided on the lower surface of the blade, and the cement-mixed mud can be discharged from the discharge port below the blade through the shaft member and the stirring blade.

(C) In the present invention, the cement-mixed mud can be discharged continuously during pulling up or intrusion, or can be discharged intermittently.

(D) In the stirring rod of the present invention, it is preferable that the volume of the rod portion corresponding to the depressing action area is made larger than the other portions by, for example, increasing the diameter of the shaft member. This makes it possible to reduce the amount of ground soil taken in situ during stirring and mixing, and to more reliably form an improved body having a desired mixing ratio with respect to the improved area.

(E) The present invention does not require that the stirring blades are inclined, but it is mentioned above that the inclined stirring blades are effective.

(F) On the other hand, in the above embodiment,
When the upper stirring blades 5, 5,... Are intended for a ground having a large resistance at the time of excavation penetration, as shown in FIG. 14, the stirring rod has a double pipe structure of an upper rod 2A and a lower rod 2B, and an upper rod 2A. , And the lower stirring blades 4, 4,... Are attached to the lower rod 2B, and when they are rotated as shown, the resistance to the ground is reduced.

Further, for the purpose of reducing the resistance, FIG.
As shown in FIG. As shown in FIG. 16, it is also possible to form a movable cross-section wing 52 that automatically rotates when rotating about a central axis 52a.

[0046]

As described above, according to the present invention, it is possible to form a soil cement column having an extremely small amount of sludge mixed with cement and having excellent kneading properties and a uniform strength, or a continuous wall formed by connecting these columns. Can be.

That is, since the cement-based material is added to the mud discharged to the ground and returned to the penetration hole to be discharged from the discharge port, the amount of discharged cement-mixed mud is extremely reduced.

[0048] Since the cement-mixed mud discharged from the discharge port is forcibly stirred and mixed by the stirring blade, the kneadability is extremely excellent. Therefore, a uniform soil cement column can be created.

In this case, in particular, by setting the slump value of the cement-mixed mud rich in the presence of the down stirring blades and / or the rich blended cement to 8 cm or more, it is possible to form an improved body which is always replaced below the discharge port.

[Brief description of the drawings]

FIG. 1 is a front view showing a stirring rod according to the present invention.

FIG. 2 is a longitudinal sectional view thereof.

FIG. 3 is a schematic view showing a preparation step in an improved body creation method according to the present invention.

FIG. 4 is a schematic view showing an excavation and penetration step in the improved body creation method according to the present invention.

FIG. 5 is a schematic diagram showing a preparation stage of a stirring and mixing step in the improved body creation method according to the present invention.

FIG. 6 is a schematic view showing an initial stage of a stirring and mixing step in the improved body forming method according to the present invention.

FIG. 7 is a schematic view showing a later stage of the stirring and mixing step in the improved body forming method according to the present invention.

FIG. 8 is an explanatory view showing a change in the contents of a stirring rod penetration area in the improved body creation method according to the present invention.

FIG. 9 is a front view showing a biaxial stirring rod according to the present invention.

FIG. 10 is a plan view showing an improved body formed using the biaxial stirring rod according to the present invention.

FIG. 11 is a front view showing a three-axis stirring rod according to the present invention.

FIG. 12 is a plan view showing an improved body obtained by one-time formation using the triaxial stirring rod according to the present invention.

FIG. 13 is a plan view showing a soil cement wall formed using the triaxial stirring rod according to the present invention.

FIG. 14 is an explanatory diagram showing another embodiment of the present invention.

FIG. 15 is an explanatory view showing another embodiment of the stirring blade of the present invention.

FIG. 16 is an explanatory view showing another embodiment of the stirring blade of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... stirring rod, 2 ... shaft member, 3 ... excavation stirring blade, 4 ...
Lower stirring blade, 5: upper stirring blade, 6U: discharge port, 6L
... water inlet, 7 ... rotary drive, 8 ... swivel joint.

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2D040 AB05 AB07 BA08 BC01 BD03 BD05 CA01 DB07 EA12 EA16 EA18 EB04

Claims (8)

[Claims] 1. A discharge port for cement-mixed mud is provided at a tip portion, and a stirring rod having a stirring blade at least in the vicinity of the discharge port is used to excavate the target ground to a predetermined depth while loosening the ground with the stirring rod. Or, after inserting the stirring rod into a drilling hole excavated while loosening the ground to a predetermined depth by another drilling device, in the process of pulling up while rotating the stirring rod, the cement mixed mud is discharged from the discharge port. The in-situ ground soil and the cement-mixed mud from the discharge port were stirred and mixed by the stirring blade, and the discharged mud discharged to the ground in the lifting process was added with cement and then discharged from the discharge port. A soil improvement method, characterized by discharging cement-mixed mud and forming soil-cement columns by this lifting process . 2. A stirrer rod having a water inlet at a front end thereof, a discharge port for cement-mixed mud at a base part side from the water inlet, and a stirring blade at least near the discharge port. To the predetermined depth, while pouring water from the water inlet, while digging and penetrating while loosening the ground with the stirring rod, in the process of pulling up while rotating the stirring rod, the cement mixed mud is discharged from the discharge port. Mixing the original ground soil and the cement-mixed mud from the discharge port with the stirring blade, and adding the cement to the discharged mud discharged to the ground in the pulling process, and then mixing the cement from the discharge port. A soil improvement body construction method characterized by discharging mud and forming soil cement columns by this lifting process. 3. A stirring rod having a water inlet at a tip end thereof, a discharge port for cement-mixed mud at a base portion side from the water inlet, and a stirring blade at least near the discharge port. After digging and penetrating the ground to a predetermined depth while pouring water from the water inlet and loosening the ground with the stirring rod, the stirring rod is once pulled up to a level at which the water inlet is almost located at the discharge port. From the state, the cement-mixed mud penetrates to the original deepest position while discharging the cement-mixed mud from the water injection port, and then, from the deepest position or from the level, pulls up the cement-mixed mud from the discharge port while rotating the stirring rod. The raw soil and the cement-mixed mud from the discharge port are stirred and mixed by the stirring blades. A cement-improved soil is discharged from the discharge port after the cement is added to the discharged mud discharged into the soil, and a soil-cement column is formed by the pulling-up process. 4. The method for constructing a ground improvement body according to claim 1, wherein a slump value of the cement-mixed mud discharged from the discharge port is 8 cm or more. 5. The agitating blade below the discharge port is inclined so as to act in a direction of pushing down the agitated mixed soil during rotation during lifting. Construction method of ground improvement body. 6. A stirring blade is provided above the discharge port.
The method according to any one of claims 1 to 3, wherein the upper stirring blade is inclined so as to act in a direction to push up mud during rotation during lifting. 7. A method in which coarse particles are eliminated from the mud discharged to the ground side to obtain mud comprising fine particles and water, and cement is added to the mud to form a cement-mixed mud. Item 4. The ground improvement body creation method according to any one of Items 1 to 3. 8. A water injection port at a tip end, a discharge port for cement-mixed mud at a front end portion closer to the base side than the water injection port, and a plurality of stirring rods having stirring blades at least in the vicinity of the discharge port. Using a plurality of parallel stirring mixers arranged side by side, the target ground to a predetermined depth, while pouring water from the water inlet, while excavating and penetrating while loosening the ground by the stirring rod, rotating the stirring rod In the process of lifting, the cement-mixed mud is discharged from the discharge port, and the original ground soil and the cement-mixed mud from the discharge port are stirred and mixed by the stirring blades. On the other hand, after the cement is added, the cement-mixed mud is discharged from the discharge port, and by this pulling-up process, continuous soil cement columns for the number of shafts are formed, A continuous wall forming method characterized by forming a continuous wall by making the soil cement column continuous.