JP2001131954A - High-pressure injection stirring and mixing method and high-pressure injection stirring and mixing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress the discharge of sludge and a hardener mixed therein onto the ground and to enhance the construction speed. SOLUTION: In this construction method for pulling up a rod 1 inserted into the ground while at a high-pressure injecting a hardener H from the lower discharge port 3 of the rod 1 and injecting high-pressure water HW together with air Ai from an upper discharge port 4 on the base end side to construct a consolidated-body by the hardener in the ground, a substantially continued upper spiral blade 5 protruded from the circumferential surface of the rod 1 and positionally changed from the upper part to the lower part along the rotating directional advance of the rod 1 in a plan view is provided on at least the upper part of the upper discharge port 4 to promote the discharge of cut slime S onto the ground side. A discharge suppressing member 6 protruded from the circumferential surface of the rod 1 to suppress the discharge of the mixed material of the hardener with the soil onto the ground side is provided on at least the upper part of the lower discharge port 3.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high-pressure injection / stirring / mixing method and a high-pressure injection / stirring / mixing apparatus for ground improvement.

[0002]

2. Description of the Related Art A typical example of this type of high-pressure injection stirring mixing or replacement method is a so-called "JSG method" using a double tube and a "column jet grout method" using a triple tube.

[0003] The present invention will be described below in the context of the "column jet method". In this method, a hardening material such as cement milk is poured from a lower discharge port of a rod inserted into the ground.
The discharge is performed at a pressure of about 5 MPa, and the liquid is ejected with high pressure water while entraining air from the upper discharge port on the base end side of the lower discharge port. is there.

[0004]

In this method, the ground is cut by high-pressure water injected together with air from an upper discharge port, the cut slime is discharged to the ground side, and a hardening material is discharged from a lower discharge port. The basic idea is to mix and replace the ground and the hardening material, and to form a mixture of the ground and the hardening material as a consolidated body.

[0005] However, in order to discharge the cutting slime to the ground side, a gap for discharging the cutting slime must always be provided between the rod and the hole wall of the ground. It has been found that the gap may be reduced or clogged by discharged slime, which makes it difficult to discharge the cutting slime.

[0006] Smooth discharge of cutting slime is important in reducing resistance in the ground and increasing cutting efficiency. vice versa,
If the cutting slime is not smoothly discharged, the cutting efficiency will decrease, and cutting will take a long time. The long time required for cutting means that a large amount of mud is discharged in the meantime. Further, in order to obtain the target consolidation strength, a required amount of hardening material is required, but in the conventional example, the amount of sludge discharged to the ground is large, and the ratio of hardened material mixed in the sludge increases. Therefore, it is necessary to set the amount of the hardening material in anticipation of the mixing ratio of the hardening material into the sludge in advance, and therefore, the cost associated with the increase in the amount of the hardening material used is remarkable, and the disposal cost is increased. Had become.

[0007] Accordingly, a main object of the present invention is to suppress the amount of sludge discharged to the ground and the amount of hardened material that migrates to the ground, thereby reducing the amount of sludge and the amount of hardened material contained in the sludge. An object of the present invention is to reduce the amount of hardening material used, reduce the cost of sludge treatment, and increase the work efficiency.

[0008]

The present invention which has solved the above-mentioned problems is as follows.

<Invention according to claim 1> A high-pressure water is injected from a lower discharge port of a rod inserted into the ground while a high-pressure jet of a hardening material is performed, and air is entrained from an upper discharge port proximal to the lower discharge port. Raise while spraying,
In a method of forming a consolidated body by the hardening material on the ground, in a range including the upper position or the upper position of the upper discharge port, a discharge promoting member projecting from the outer peripheral surface of the rod at least during ground improvement work. A high-pressure jet-stirring / mixing method characterized by promoting discharge of cutting slime to the ground side by the high-pressure water.

According to the present invention, since the cutting slime is reliably discharged to the ground side by the discharge promoting member for promoting the discharge of the cutting slime to the ground side, the cutting efficiency is increased,
The construction speed can be increased. Therefore, it is possible to suppress the amount of sludge and the discharge of the hardening material mixed therewith, and the cost of sludge treatment is greatly reduced. In addition, due to the reliable discharge of the cutting slime, the specific gravity of the cutting soil in the ground is reduced and the stirring efficiency of the hardened material is increased, and in combination with the effect of the discharge suppressing member described below,
Since the amount of the hardening material used per consolidated body can be reduced, and even if the pulling speed is increased as compared with the conventional example, the consolidated body having the desired strength can be reliably formed, so that the construction efficiency can be improved.

<Invention according to claim 2> [0011] A high-pressure water is injected from a lower discharge port of a rod inserted into the ground while high-pressure jetting of a hardening material is performed and air is entrained from an upper discharge port proximal to the lower discharge port. Raise while spraying,
In the construction method of forming a consolidated body by the hardening material on the ground, in a range including the upper position or the upper position of the lower discharge port, at least at the time of ground improvement work, the discharge suppressing member protruding from the outer peripheral surface of the rod. A high-pressure injection-stirring / mixing method, wherein the mixed material of the hardener and the ground is prevented from being discharged to the ground side.

[0012] According to the present invention, it is presumed that, at the lower part of the rod, the mixed material of the hardened material and the ground is discharged to the ground side so as to be drawn into the discharge flow of the cutting slime to the ground side. However, at least at the upper portion of the lower discharge port, by providing a discharge suppressing member that protrudes from the outer peripheral surface of the rod and that suppresses discharge of the mixed material of the hardened material and the ground to the ground side, the hardened material and the ground It was considered that the generation of the discharge flow of the mixed material to the ground side could be prevented, and the effect was actually confirmed. Therefore, the ratio of the hardening material mixed into the cutting slime is reduced, and as a result, the hardening material is prevented from being discharged to the ground.

Here, when the hardening material is ejected from the lower discharge port of the rod at a high pressure, for example, at a high pressure of 10 to 40 MPa, the stirring and mixing efficiency of the ground is increased as compared with the conventional case of a relatively low pressure (2 to 5 MPa). Thus, the consolidated body has a uniform strength, and the use amount of the hardening material can be reduced from this point as well. In addition, it has been found that at a low-pressure discharge, the hardened material tends to be attracted to the upper cutting slime.

<Invention of Claims 3 and 4> A hardening material is ejected from a lower discharge port of a rod inserted into the ground at a high pressure, and air is entrained from an upper discharge port on the base end side of the lower discharge port. In a device used for a method of forming a consolidated body of the hardening material on the ground by injecting high-pressure water while injecting the high-pressure water, at least the ground improvement work is performed at an upper position of the upper discharge port or a range including the upper position. A high-pressure jet-stirring / mixing device provided with a discharge-promoting member that protrudes from the outer peripheral surface of the rod at the time and that promotes discharge of the cutting slime to the ground side by the high-pressure water.

The discharge promoting member may be, for example, a substantially continuous spiral blade or a plate-like member formed along the circumferential direction of the rod while being inclined from the upper side to the lower side along the progress of the rod rotation direction. The blades or the expandable / contractible member which is housed so as not to substantially protrude from the outer peripheral surface of the rod when the ground is inserted, and is protruded from the outer peripheral surface of the rod during the ground improvement work can be provided.

The discharge promoting member is inclined from the upper side to the lower side along the rotation direction of the rod,
By forming the slime by a substantially continuous spiral blade, the discharge of the cutting slime to the ground side can be promoted with a simple configuration.

The spiral blade or the plate-like blade is provided as a fixed blade on the outer surface of the rod. In this case, the drilling diameter must be equal to or larger than the outer diameter including the fixed blade. When the range is deep, collapse of the hole wall is likely to occur, and it is difficult to raise the hole. Further, there was a concern that a problem such as a long time would be required for drilling. Therefore, these problems can be solved all at once if the discharge promoting member is constituted by an expanding / contracting member and the hole diameter is reduced.

According to a fifth aspect of the present invention, the high-pressure water is injected from the lower discharge port of the rod inserted into the ground, and the high-pressure water is blown from the upper discharge port on the base end side of the lower discharge port. Raise while spraying,
In an apparatus used for a method of forming a consolidated body of the hardened material on the ground, in a range including the upper position or the upper position of the lower discharge port, at least at the time of ground improvement work, protruding from the outer peripheral surface of the rod. And a discharge suppressing member for suppressing discharge of the mixed material of the hardening material and the ground to the ground side.

<Embodiments of Claims 6 and 7> The discharge suppressing member is, for example, inclined from the lower side to the upper side along the progression of the rod rotation direction, and is substantially continuous. Alternatively, a disk-shaped blade formed along the circumferential direction of the rod, or is accommodated in a state where it does not substantially protrude from the outer peripheral surface of the rod when the ground is inserted, and is protruded from the outer peripheral surface of the rod during ground improvement work. It can be a free member.

The discharge suppressing member is inclined from the lower side to the upper side along the rotation direction of the rod,
By being formed by a substantially continuous spiral blade or a disk-shaped blade formed along the rod circumferential direction,
With a simple configuration, it is possible to suppress the discharge of the hardened material to the ground side. Further, the drilling diameter can be reduced by forming the discharge suppressing member by the expansion and contraction member.

[0021]

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

[First Embodiment] <High Pressure Injection Stirrer / Mixer>
First, as the apparatus of the present invention, it is possible to perform high-pressure ejection of the hardening material from the lower discharge port and pull up while injecting high-pressure water while entraining air from the upper discharge port proximal to the lower discharge port. As long as the structure is not limited, the high pressure injection stirring / mixing apparatus shown in FIG. 1 will be specifically described. The high pressure injection stirring / mixing apparatus has a drill bit 2 at the tip of a triple pipe rod 1. is there.

The distal end of the rod 1 has a lower discharge port 3 and an upper discharge port 4 on the base end side. Also, upper discharge port 4
In order to promote the discharge of the cutting slime S to the ground side by the high-pressure water HW, an upper portion protruding from the outer peripheral surface of the rod 1 and substantially continuous within a predetermined length range along the circumferential direction. The spiral blade 5 is provided integrally. Also,
At the upper position of the lower discharge port, in order to suppress the discharge of the mixed material of the hardening material H and the ground to the ground side, it protrudes from the outer peripheral surface of the rod 1 and substantially extends within a predetermined length range along the circumferential direction. The lower spiral blade 6 which is continuous with the lower spiral blade is integrally provided.

Here, the upper spiral blade 5 provided as a discharge promoting member is a substantially continuous spiral blade inclined from the upper side to the lower side along the rotation direction of the rod 1. On the contrary, the lower spiral blade 6 provided as a discharge suppressing member is inclined along the rotation direction of the rod 1 from the lower side to the upper side along the rod rotation direction, and is substantially continuous. Alternatively, it is a disk-shaped blade formed along the circumferential direction of the rod.

The drill bit 2 is, as shown in FIG.
A cylindrical portion 2B having an outer diameter larger than the outer diameter of the rod 1 and equal to or larger than the outer diameters of the spiral blades 5 and 6;
Are connected to each other by connecting ribs 2C. The tip of the main body 2A and the cylindrical portion 2B has a drilling tip.

As described above, the rod 1 composed of a triple tube is
The inside of the inner pipe 11 is used as a flow path of the drilling water W heading toward the lower end opening or the hardening material H heading toward the inner nozzle 3A forming the lower discharge port 3. This is performed by closing the drilling water W flow path by throwing in balls from the base end of No. 1. In addition, as shown in FIG. 6, only the hardening material H is ejected from the lower discharge port 3.

The passage between the inner pipe 11 and the middle pipe 12 is a flow path of the high-pressure water HW communicating with the inner nozzle 4A constituting the upper discharge port 4, and the gap between the middle pipe 12 and the outer pipe 13 is outside. The air Ai communicates with the nozzle 4B.

<Construction Example> In order to improve the ground using such an apparatus, first, as shown in FIG. 1, a mud discharging pit 21 is formed on the surface of the ground, and a hole is drilled by the rod 1 to a predetermined depth. At the time of drilling by the rod 1, drilling water W is supplied through the inner pipe 11, and the lower end of the rod 1 and the lower discharge port 3
This is performed by rotating the rod 1 while discharging from the nozzle. Instead of drilling with the rod 1, after drilling the casing, the rod 1 may be inserted into the drilled hole, and the casing 1 may be pulled out to insert the rod 1 to a predetermined depth in the ground. In this case, the drill bit is unnecessary.

Next, in the process of pulling up while rotating the rod 1 clockwise in plan view, the hardener H is ejected from the lower discharge port 3 at a high pressure and the upper discharge port 4 on the base end side.
The high-pressure water HW is jetted while entraining the air Ai to form a consolidated body of the hardening material H on the ground. Here, in the initial stage of the start of the pulling, in order to inject the hardening material into the cutting area by the high-pressure water, the high-pressure water HW alone is jetted and pulled up. Therefore, it is desirable to adopt a mode of injecting the hardening material H under high pressure.

Here, the hardening material H is supplied from the lower discharge port 3 by one.
Injection is performed at a pressure of 0 to ³⁰ MPa at a rate of ³⁰ to 200 liters / minute, and air Ai is injected from an outer nozzle 4B of the upper discharge port 4 at a rate of 1 to 5 m ³ / minute at a pressure of 0.3 to 1.5 MPa. High pressure water HW from nozzle 3A 20 ~ 60MP
A preferred form is that the jetting is performed under the condition of 50 to 180 liters / minute at a.

When the high-pressure water HW is injected from the upper discharge port 4 while entraining the air Ai, the ground can be cut and the ground can be loosened. As described above, the slime S generated by this cutting is applied to the upper spiral blade (discharge promoting member) 5.
The rotation accompanying the rotation of the rod 1 promotes discharge to the ground side (mud pit 21). Thus, in addition to the air lift effect due to the entrainment of the air Ai, by performing the mechanical forcible discharge by the upper spiral blade 5, the cutting slime S is smoothly discharged to the ground side. In an ultra-soft ground, a gap is likely to be blocked near the upper part of the upper outlet 4 of the rod 1, and the blockage of the gap can be prevented by the upper spiral blade 5, so that a discharge path for the cutting slime S can be always secured. .

As described above, when the hardening material H is injected at a high pressure from the lower discharge port 3 to the already loosened ground while smoothly discharging the cutting slime S, the ground particles and the hardening material H are mixed and stirred. And the hardened material H in the target ground area
To form a consolidated body. At this time, the hardening material H to be sprayed is such that the lower discharge port 3 and the upper discharge port 4 are separated from each other (the distance is preferably 20 to 100 cm), and the lower spiral blade 6 exists on the upper side. Therefore, the generation of the discharge flow is prevented, and the ratio of entering the upper cutting area is extremely reduced.

<Others> In addition to the discharge promoting member and the discharge suppressing member, as shown in FIG. 7, a discharge promoting member 5A and a discharge suppressing member in which spiral blades are arranged stepwise while changing the circumferential position. 6A can also be used.

Further, as shown in FIG. 8 as an example of the form of the discharge promoting member 5B, a plurality of spiral blades may have different circumferential positions at the same height position.

On the other hand, the discharge promoting member and the discharge suppressing member can extend below the upper discharge port 4 and the lower discharge port 3, respectively.

[Second Embodiment] Next, a rod 1A according to a second embodiment shown in FIGS. 9 to 11 is an umbrella-shaped wing 7 that can be housed along the rod direction as the discharge suppressing member.
This is an example in the case of using.

Since the lower spiral blade 6 (discharge suppressing member) shown in the first embodiment is a member fixedly provided on the outer peripheral surface of the rod, the drilling diameter necessarily includes the lower spiral blade 6. Drilling is performed with the outer diameter being equal to or larger than the outer diameter. However, especially in the case of a ground having a deep ground improvement and a high softness, it is difficult to pull up the rod if the collapse exceeds a predetermined amount, even if the discharge path is secured by the upper spiral blade 5. This causes a problem that the drilling takes a long time or the drilling takes a long time. Therefore, the above problem is solved at once by using a wing-spreading member as shown in the present embodiment as a hardening material discharge suppressing member.

The expanded wing 7 is accommodated in a state where it does not substantially protrude from the outer surface of the rod when the ground penetrates as shown in FIG.
Thereafter, at the time of the ground improvement work shown in FIG. 10, the umbrella is extended just to open the umbrella and functions as a hardening material discharge suppressing member.

The structure is such that the upper end is supported by a shaft 14 at the lower part of the middle tube 12 at a plurality of positions in the radial direction, in the example shown in FIG. An expandable membrane supporting material 8, 8 comprising an expanded bone 15 and a receiving bone 17 having one end connected to the middle of the expanded bone 15 by a shaft 18 and the other end connected to the inner tube 11 by a shaft 16. Are provided, and a rectangular film material 19 is stretched by using the developed bones 15, 15,.
As the film material 19, from the viewpoint of strength and abrasion,
Polyester-based, aromatic polyamide-based (para-based), ultra-high-strength polyethylene, carbon-based fiber cloth, canvas cloth, and the like are preferably used. The deployment amount of the wing expander 7 can be adjusted by the amount by which the inner pipe 11 is pulled up.

[Third Embodiment] Next, a rod 1B according to a third embodiment shown in FIGS. 12 to 14 is a radially expandable and contractible rubber ring 23 (hereinafter referred to as an expanded and contracted rubber ring) as the discharge suppressing member. ) Is used.

The expanded and contracted rubber ring 23 does not protrude from the outer surface of the rod due to contraction when the ground penetrates as shown in FIG. 12, and then, when the ground is improved as shown in FIG. Protruding into
It functions as a hardening material discharge suppressing member.

As shown in FIG. 14, the structure is such that the upper and lower parts of the rubber ring 23 are disposed on the same side as the outer surface of the rod with the ring-shaped opening facing the opposite side. Ring storage tubes 22A, 22B
When the ground penetrates, the expanding and contracting rubber ring 23
Is a rubber ring storage tube 2 so as not to protrude outside the rod.
2A and 22B. Specifically, inside the rubber ring storage tubes 22A and 22B, storage grooves 22a and 22b each having a ring-shaped opening facing the opposite side are formed, and the storage grooves 22a of one rubber ring storage tube 22A are formed.
The expansion / contraction rubber ring 23 is accommodated in a ring-shaped groove space extending from a to the accommodation groove 22b of the other rubber ring accommodation tube 22B.

In order to make the rubber ring 23 project outside the rod, air is supplied to the inside of the expansion / contraction rubber ring 23 from the air supply holes 25 formed in the middle tube 12. Then, as shown in FIG. 14, the expanding / contracting rubber ring 23 gradually protrudes from the intermediate portion and protrudes in a flange shape. The openings 22c and 22d are narrower than the width of the accommodation groove, and the enlarged portions 23a and 23b formed on the upper and lower edges of the expanding and contracting rubber ring 23 are engaged with the narrow portions, respectively. 23 is held so as not to come off. The expanding and contracting rubber ring 23 includes a large number of wires 23c and 23 to secure strength and a certain degree of rigidity.
It is preferable to use one enclosing c. Further, in order to reliably return to the original storage state by bleeding air, for example, the inner ends of the storage grooves 22a and 22b and the enlarged portion 23
It is desirable to provide restoring means such as a spring 24 connecting the a and 23b.

In the above-described second and third embodiments, the example in which the expandable / contractible member is applied to the discharge suppressing member has been described. Can be used.

[0045]

DESCRIPTION OF THE PREFERRED EMBODIMENTS At one site, a conventional C is used to create a shaft at a geological point P5 of corroded soil and organic soil and a point A2 of fine sand mixed with clay.
With the JG method (column jet grout method) and the method of the present invention, a compact was formed while changing the construction conditions. Table 1 shows the construction conditions.

[0046]

[Table 1]

Tables 2 and 3 show the results of examining the physical properties of the sludge during the formation of each compact.

[0048]

[Table 2]

[0049]

[Table 3]

Further, the results of examining how the cement in the hardened material (cement milk) used for forming each compact was transferred to the sludge and the improved product (compact) were determined.
Tables 4 and 5 show the results of the compressive strength of the consolidated body in each case at the target improved diameter of 2.0 m.
It was shown to.

[0051]

[Table 4]

[0052]

[Table 5]

[0053]

[Table 6]

On the other hand, in each case, the cement in the hardening material (cement milk) is discharged and the improved body (consolidated body)
FIG. 15 shows the results obtained by examining how the transition was made.

(Discussion) According to the above experimental results, the effects of the present invention were clarified for the following items. (1) A compact having a target strength can be obtained while reducing the amount of the hardening material used. (2) The construction speed can be shortened by increasing the lifting speed of the rod. (3) The amount of sludge itself can be reduced. (4) The ratio of the amount of cement contained in the amount of sludge to the amount of sludge can be significantly reduced. (5) The ratio of the amount of cement contained in the consolidated body to the amount of cement used in cement milk as a hardening material can be significantly increased.

[0056]

As described above, according to the present invention, it is possible to suppress the discharge of the mud and the hardening material mixed therein into the ground, thereby reducing the amount of the hardening material used, and further reduce the sludge treatment cost. In addition, advantages such as an increase in construction efficiency can be provided.

[Brief description of the drawings]

FIG. 1 is a diagram showing a rod 1 according to a first embodiment in a state of penetrating the ground.

FIG. 2 is a diagram showing a lifting state (at the time of ground improvement).

FIG. 3 is a perspective view of a rod tip.

FIG. 4 is a perspective view from the lower surface side.

FIG. 5 is a cross-sectional view of the upper discharge port portion (viewed along the line VV in FIG. 1).

FIG. 6 is a transverse sectional view of the lower discharge port portion (viewed along the line VI-VI in FIG. 1).

7 (A) is a plan view and FIG. 7 (B) is a side view showing another example of a rod.

8 (A) is a plan view and FIG. 8 (B) is a side view showing another rod example.

FIG. 9 is a diagram showing a ground penetration state of a rod 1A according to a second embodiment.

FIG. 10 is a diagram illustrating a lifting state (at the time of ground improvement).

FIG. 11 is a view taken along line XI-XI in FIG. 10;

FIG. 12 is a diagram showing a ground penetration state of a rod 1B according to a third embodiment.

FIG. 13 is a diagram showing a lifting state (at the time of ground improvement).

FIG. 14 is an enlarged vertical cross-sectional view of a portion 23 of an expanding / contracting rubber ring.

FIG. 15 is a summary result of examining how cement in a hardened material (cement milk) migrated to sludge and an improved body (consolidated body).

[Explanation of symbols]

1 1A 1B ... rod, 2 ... drill bit, 3 ... lower discharge port, 4 ... upper discharge port, 5 ... upper spiral blade, 6 ... lower spiral blade, 7 ... wing spread, 19 ... film material, 23 ... Expandable rubber ring

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Hyoji Narusawa 4-20 Sendagaya, Shibuya-ku, Tokyo Inside Japan Sogo Water Co., Ltd. (72) Inventor Norio Takahashi 4-20 Sendagaya, Shibuya-ku, Tokyo Japan Sogo Stock Water Stock F term in the company (reference) 2D040 AA01 AB05 BA01 BA06 BA08 BB01 BD05 CA01 CB03

Claims (8)

[Claims] 1. A high-pressure jet of a hardening material from a lower discharge port of a rod inserted into the ground, and pulling up while jetting high-pressure water while entraining air from an upper discharge port proximal to the lower discharge port. And performing a method of forming a consolidated body of the hardened material on the ground, wherein at least an upper portion of the upper discharge port or a range including the upper position is protruded from the outer peripheral surface of the rod at least during ground improvement work. A high-pressure jet-stirring / mixing method comprising providing a member and promoting discharge of the cutting slime to the ground side by the high-pressure water. 2. A high-pressure jet of a hardening material from a lower discharge port of a rod inserted into the ground, and pulling up while jetting high-pressure water while entraining air from an upper discharge port proximal to the lower discharge port. And performing a method of forming a consolidated body of the hardened material on the ground, wherein at least an upper position of the lower discharge port or a range including the upper position, at least at the time of ground improvement work, a discharge suppression projecting from the outer peripheral surface of the rod. A high-pressure injection-stirring / mixing method comprising providing a member and suppressing discharge of the mixed material of the hardening material and the ground to the ground side. 3. A high-pressure jet of a hardening material from a lower discharge port of a rod inserted into the ground, and pulling up while jetting high-pressure water while entraining air from an upper discharge port proximal to the lower discharge port. An apparatus used in a method of forming a solidified body of the hardened material on the ground, wherein at least an upper position of the upper discharge port or a range including the upper position is protruded from the outer peripheral surface of the rod at the time of ground improvement work. A high-pressure jet stirring / mixing device, further comprising a discharge promoting member for promoting discharge of the cutting slime to the ground side by the high-pressure water. 4. The discharge facilitating member is inclined from the upper side to the lower side along the progression of the rod rotation direction, and is a substantially continuous spiral blade or a plate formed along the rod circumferential direction. The high-pressure jet stirring / mixing device according to claim 3, wherein the blade is a blade. 5. The discharge promoting member is an expandable / contractible member which is accommodated in a state where it does not substantially protrude from the rod outer peripheral surface when the ground is inserted, and is protruded from the rod outer peripheral surface during ground improvement work. Item 4. A high-pressure injection-stirring / mixing apparatus according to Item 3. 6. A high-pressure jet of a hardening material from a lower discharge port of a rod inserted into the ground, and pulling up while jetting high-pressure water while entraining air from an upper discharge port proximal to the lower discharge port. An apparatus used for a method of forming a solidified body of the hardened material on the ground, wherein at least an upper position of the lower discharge port or a range including the upper position is protruded from an outer peripheral surface of the rod at the time of ground improvement work. And a discharge suppressing member for suppressing discharge of the mixed material of the hardening material and the ground to the ground side is provided. 7. The discharge suppressing member is inclined from the lower side to the upper side along the progress of the rod rotation direction, and is a substantially continuous spiral blade or a plate formed along the rod circumferential direction. The high-pressure jet stirring / mixing device according to claim 6, wherein the blade is a blade. 8. The discharge suppressing member is an expandable / contractible member which is accommodated in a state where it does not substantially protrude from the outer peripheral surface of the rod when the ground is inserted, and which is protruded from the outer peripheral surface of the rod during ground improvement work. Item 7. A high-pressure injection-stirring / mixing device according to Item 6.