JP2007262699A - Injection structure of high-pressure injection stirring apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an injection structure of a high-pressure injection stirring apparatus, injecting solidified material slurry as a more converged jet to make the solidified material slurry reach further to a distance, having a simple structure, easily manufactured at low cost, and further applicable even to a small-diameter rod. <P>SOLUTION: In this injection structure of the high-pressure injection stirring apparatus 1, the solidified material slurry 10 is injected into the ground 6 to cut the ground 6, and also the solidified material slurry 10 and soil to be improved are mixed and stirred to make a cylindrical soil improvement body 8. The injection structure of the high-pressure injection stirring apparatus includes: a nozzle 9 forming an injection port for the solidified material slurry 10; and a streamline part formed extending from the rear end of the nozzle 9 toward the upstream side, 70 mm or more long and having a circular sectional shape with the same diameter. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

The present invention relates to an injection structure of a high-pressure jet agitator for injecting solidifying material slurry into soft ground to solidify and improve the ground, and in particular, to allow the solidifying material slurry to reach a wider area. The present invention relates to an injection structure of a high-pressure injection agitator that can be used.

In the high-pressure jet agitation method, the ground to be improved is drilled with a rod to a predetermined depth, and solidified slurry is injected from the rod at a high pressure, and the ground is solidified in the surrounding ground while cutting the ground by the breaking force at that time. It is a method of injecting material slurry to solidify and improve the ground. In the high-pressure jet agitation method, if the ground cutting force by the solidifying material slurry is increased, the solidifying material slurry can reach a wider area and the construction efficiency can be increased. For this purpose, it is important to suppress the energy decay rate of the injected solidifying material slurry by injecting the solidifying material slurry as a more convergent jet. Under such circumstances, various improvements have been made on the flow path structure and nozzle structure of the solidified material slurry injection portion of the high-pressure jet agitator.

For example, an apparatus has been proposed in which a pressure reservoir portion having a larger cross-sectional area than the upstream portion and the downstream portion is provided in the middle of the supply channel of the solidifying material slurry (Patent Document 1). By this pressure reservoir, rectification and pressure stabilization of the solidified slurry supplied from the upstream side can be achieved, and the fluid ejection capability can be increased by 1.5 times or more compared to the case without the pressure reservoir. it can.
In addition, there has been proposed an injection head including a duct that connects a lower end of a rod to a nozzle and has a duct having a curvature radius that regularly changes while maintaining a constant sine curve (Patent Document 2).
JP 2004-76530 A JP 2004-76573 A

In the technique of Patent Document 1 described above, there is a problem that since it is necessary to provide a pressure reservoir portion having a large cross-sectional area in the middle of the flow path, it can be applied only to a rod having a relatively large diameter.
Moreover, in the technique of patent document 2, there exists a problem that the shape of a duct part is complicated and processing is difficult.
Therefore, the present invention is capable of injecting the solidified material slurry as a more convergent jet to reach the farther solidified material slurry, having a simple structure, and can be easily produced at low cost. Furthermore, it aims at providing the injection structure of the high pressure injection stirring apparatus which can be applied even if it is a small diameter rod.

The present invention provides the following jet structure of a high-pressure jet agitator to achieve the above object.
[1] A jet structure of a high-pressure jet agitating device for injecting a solidifying material slurry into the ground to cut the ground and mixing and stirring the solidifying material slurry and the soil to be improved to form a cylindrical ground improvement body , The nozzle that forms the injection port of the solidified material slurry, and the length that is formed from the rear end (the end opposite to the injection port) of the nozzle toward the upstream side and has the same length of 70 mm or more An injection structure for a high-pressure injection agitator comprising a rectifying unit having a circular cross-sectional shape with a diameter.
[2] The injection of the high-pressure jet agitator according to [1], further including a rod slurry passage having a diameter larger than that of the rectifying unit from the upstream end of the rectifying unit toward the upstream side. Construction.
[3] The high pressure according to [2], wherein an air flow passage for ejecting compressed air around the solidified material slurry injected from the nozzle is provided around the slurry flow passage of the rod and the rectification unit. The jet structure of the jet agitator.

The injection structure of the high-pressure jet agitating device of the present invention includes a rectifying unit that is formed from the rear end of the nozzle toward the upstream side and has a circular cross-sectional shape with a length of 70 mm or more and the same diameter. The solidified material slurry can be injected as a more converged jet (in other words, a jet having a small spread in the direction perpendicular to the injection direction), and the energy decay rate of the solidified material slurry after injection can Can also be suppressed. Thereby, the solidification material slurry can reach a wider area, and a ground improvement body having a larger improved diameter can be obtained. And since the diameter of a ground improvement body is large, in the predetermined area used as the object of ground improvement, the number of construction required in order to improve this area can be reduced, and work efficiency can be improved.
In addition, the injection structure of the high-pressure jet agitating apparatus of the present invention only needs to include a rectifying unit having a specific length and cross-sectional shape, and does not require any other complicated structure. Moreover, it can be applied to a small-diameter rod.

Hereinafter, an embodiment of a high-pressure jet agitator including the jet structure of the present invention will be described based on the drawings. FIG. 1 is a diagram showing a state in which ground improvement work is being performed using a high-pressure jet agitator including the jet structure of the present invention, and FIG. 2 is an example of the jet structure of the present invention (without an air flow passage). FIG. 3 is a cross-sectional view showing another example of the injection structure of the present invention (having an air flow passage), and FIGS. 4 to 7 are embodiments of the injection structure of the present invention used in experiments. FIG. 8 is a diagram showing the configuration of an impact load test apparatus, FIGS. 9 to 11 are diagrams showing the test results of the impact load, and FIGS. 12 to 15. Fig. 16 is a cross-sectional view showing an embodiment of the injection structure of the present invention (having an air flow passage) used in the experiment, Fig. 16 is a diagram showing the configuration of an experimental apparatus for impact load, and Figs. It is a figure which shows the experimental result of a load.

As shown in FIG. 1, a high-pressure jet agitating apparatus 1 according to the present invention includes a hollow rod 4 that can penetrate into the ground 6 and a tip monitor 5 (hereinafter abbreviated as “monitor 5”) connected to the lower end of the rod 4. .) The monitor 5 includes a nozzle 9 for injecting the solidified material slurry. The solidified material slurry 10 pumped from the plant (not shown) through the swivel 3 and the hose 7 passes through the slurry flow passage in the rod 4 and the monitor 5 and is injected from the nozzle 9 into the ground 6.
The rod 4 can rotate 360 degrees in the horizontal direction and can move in the vertical direction (vertical direction). After drilling the ground with the rod 4 to the lower end of the design depth in the area to be improved, the rod 4 is rotated at a predetermined rotational speed while the solidified slurry 10 is injected from the nozzle 9 at this point. The cylindrical ground improvement body is formed by pulling up continuously intermittently. Thereafter, by repeating the same operation, a cylindrical ground improvement body 8 having a predetermined length in the vertical direction is finally created.
Improvement work of the ground 6 in the area to be improved by repeating the creation of the ground improvement body 8 while moving the high-pressure jet agitator 1 on the rail 2 laid on the ground 6 to be improved. Can be completed.

The injection structure of the high-pressure injection agitator 1 is shown in FIG. In FIG. 2, a monitor 5 having a nozzle 9 is attached to the lower end of the rod 4 of the high-pressure jet agitator 1.
The rod 4 is a cylindrical tube having a rod slurry flow passage 11. The rod slurry flow passage 11 is formed in a cylindrical shape having a constant diameter.
The lower end portion of the rod 4 and the upper end portion of the monitor 5 are each provided with a threaded portion (not shown) that can be screwed together. The monitor 5 is fastened to the rod 4 by these threaded portions.
The monitor 5 includes a rectifying unit 12 having a smaller diameter than the rod slurry flow passage 11. The rectifying unit 12 has a first rectifying unit 12a extending from the lower end of the rod slurry flow passage 11 in the same direction as the rod slurry flow passage 11 (vertical direction) when the monitor 5 is connected to the rod 4, and The second rectification unit 12b is bent vertically at the lower end of the first rectification unit and extends in the horizontal direction.
A nozzle 9 is disposed at the end of the second rectifying unit 12b. The nozzle 9 is attached to the monitor 5 so that the solidified material slurry can be sprayed in the horizontal direction. The nozzle 9 includes a flow passage having a smaller diameter than the second rectifying unit 12b.

The length of the rectifying unit 12 (the sum of the length of the first rectifying unit 12a and the length of the second rectifying unit 12b; L _{1 in} FIG. 2) is 70 mm or more, preferably 80 mm or more, more preferably 90 mm or more. More preferably, it is 100 mm or more, and particularly preferably 120 mm or more. If the length is less than 70 mm, the solidified material slurry sprayed from the nozzle 9 tends to diffuse, and the cutting force cannot be improved. When the length is 120 mm or more, it converges to the upper limit value of the cutting force and does not contribute to the improvement of the cutting force even if it is extended further.
The upper limit of the length of the rectifying section 12 (L ₁₎ is not particularly limited, be increased to said length, the effect of the present invention tends to be leveled off, and the rectifying section 12 is formed In consideration of avoiding an increase in the size of the monitor 5, it is preferably 600 mm or less, more preferably 500 mm or less, and particularly preferably 200 mm or less.
Note that the length (L ₁ ) of the rectifying unit 12 is the length of the axial line of the flow path, that is, the length of the first rectifying unit 12a and the second rectifying unit, as shown by a one-dot chain line in FIG. The sum of the length of 12b (not including the length of the nozzle).
The stirring blade 13 refers to a portion that protrudes in the horizontal direction from the circumferential surface portion of the rod 4 in which the vertical slurry flow path is disposed, and normally, a horizontal rectification portion that protrudes in the horizontal direction from the vertical slurry flow path and This is a part including the nozzle part.
The rectifying unit 12 has a circular cross-sectional shape having the same diameter. When the diameter changes or has a cross-sectional shape other than a circle, the solidifying material slurry sprayed from the nozzle is insufficiently converged, making it difficult to reach the solidifying material slurry jet far away. Or a complicated shape makes it difficult to produce a monitor.

The boundary between the rod slurry flow passage 11 and the rectifying unit 12 does not necessarily coincide with the connection surface between the rod 4 and the monitor 5, and may be located in the rod 4 above the rod 4 by a predetermined distance. Alternatively, it may be positioned in the monitor 5 below a predetermined distance from the upper end of the monitor 5. For example, the monitor 41 in FIG. 5 includes a portion of the rod slurry flow passage 43.
That is, the term “rod slurry flow passage” is named for the sake of convenience as meaning a flow passage located upstream of the rectifying unit, and is limited to the flow passage formed in the rod. It is not a thing.
Further, the “rectifying unit” is usually formed in the monitor, but a part thereof may be formed in the rod.

The material forming the peripheral surface of the rectifying unit 12 may be any material that can withstand the pressure of the circulating solidifying material slurry and can form a smooth peripheral surface, such as steel or a hardened reinforcing layer. Examples thereof include synthetic rubber reinforced with steel wire (material for ultra-high pressure hose). As the material, either a non-flexible material (for example, steel) or a flexible material (for example, a synthetic rubber reinforced with a hard steel wire as a reinforcing layer) can be used.
The degree of smoothness of the peripheral surface of the rectifying unit 12 is preferably at least about 200-S or more as the surface roughness defined by JIS B 0601. Further, the surface roughness is preferably smoother, but considering the processing effort and cost increase by increasing the degree of smoothness, even the smoothest is as smooth as about 1.5-S. I just need it. Therefore, a practical range of the surface roughness is about 1.5-S to 200-S.

The jet structure of the high-pressure jet agitating apparatus of the present invention can have a structure (double pipe structure) having an air flow passage for jetting compressed air so as to surround the solidified material slurry jet jetted from the nozzle. .
An example of an injection structure having an air flow passage is shown in FIG. In FIG. 3, a rod 20 having an air flow passage 25 and a monitor 21 having an air flow passage 26 are connected. The air flow passage 25 is formed in a cylindrical shape having the same axis as the slurry flow passage 23 of the rod. The air flow passage 26 is formed in an L-shaped cylindrical shape having the same axis as that of the rectifying unit 24. The air flow passage 25 and the air flow passage 26 form an integral air flow passage by connecting the rod 20 and the monitor 21. The air flow passage guides compressed air from an air supply device (compressor; not shown) disposed on the ground through an air cap around the nozzle 22. The air flow passage 26 of the monitor 21 forms an air outlet 27 having an annular air cap having the same center point as the center point of the nozzle 22 on the same plane as the front end of the nozzle 22.

Compressed air sent into the air flow passages 25 and 26 by the air supply device is jetted into the ground from an air outlet 27 provided around the nozzle 22. Thereby, the solidification material slurry can be injected into the ground in such a form that the compressed air surrounds the solidification material slurry injected from the nozzle 22. In this case, the compressed air has a function of reducing the energy decay rate of the solidified slurry after injection. As a result, the solidified material slurry can reach farther.
2 regarding the length of the rectifying unit, the smoothness of the peripheral surface of the rectifying unit, and the like in the above-described injection structure of FIG. 2 are different in the form of the rod and the monitor (for example, FIGS. 3 to 7 and FIGS. 12 to 15). ) Regardless.

[A. Experimental example using an injection structure without an air flow passage]
As the form of the injection structure having no air flow passage, the structure shown in FIGS. 4 to 7 is adopted, and the diameter and length of the rectifying unit are changed, so that the fluid injected from the nozzle in each of these cases An experiment was conducted to measure the impact load.
In each case, the diameter of the slurry flow path of the rod was 65 mm.
The material of the peripheral surface of the rectifying unit was steel. The surface roughness of the peripheral surface of the rectifying unit was 12-S.
As the nozzle, a nozzle having a total length of 20 mm, a taper angle of 20 degrees, a linear portion length of 10 mm, and an opening diameter of 5.45 mm was used.

(1) Form of injection structure (a) Type 1 (FIG. 4)
The injection structure shown in FIG. 4 is formed by connecting a monitor 31 having a nozzle 32 and a rectifying unit 34 to a rod 30 having a slurry flow passage 33 for the rod.
In FIG. 4, the rectifying unit 34 has a portion that extends horizontally and a portion that extends vertically.
Note that the monitor 31 shown in FIG. 4 is formed so as to give a continuous extension portion downward with respect to the outer peripheral surface of the rod 30 when connected to the lower end of the rod 30. 30 is a substantially columnar member having an outer peripheral surface that is concentric with and has the same outer diameter.
The form shown in FIG. 4 has an advantage that the cutting force of the solidifying material slurry can be increased while the structure is within the range of the diameter of the rod 30.
(B) Type 2 (Fig. 5)
The injection structure shown in FIG. 5 is formed by connecting a monitor 41 having a nozzle 42 and a rectifying unit 44 to a rod 40 having a rod slurry flow passage 43.
The rectification part 44 consists only of the part extended horizontally.
(C) Type 3 (Fig. 6)
The injection structure shown in FIG. 6 is formed by connecting a monitor 51 having a nozzle 52 and a rectifying unit 54 to a rod 50 having a rod slurry flow passage 53.
In the rectifying unit 54, the length of the vertically extending portion and the length of the horizontally extending portion are substantially equal.
(D) Type 4 (Fig. 7)
The injection structure shown in FIG. 7 is formed by connecting a monitor 61 having a nozzle 62 and a rectifying unit 64 to a rod 60 having a rod slurry flow passage 63.
The rectifying unit 64 is formed by bending a part extending vertically downward, a part extending obliquely downward, a part extending vertically downward, and a part extending horizontally from the lower end of the slurry flow passage 63 of the rod. Has been.

(2) Length (L ₁ ) and diameter (D1) of the rectifying unit
Jet water (solidified material slurry) ejected from the nozzle by changing the diameter (D1) of the rectifying unit to 9 mm, 12 mm, and 15 mm and changing the length (L ₁ ) of the rectifying unit in the range of ₁ mm to 300 mm. The impact load at a predetermined flight distance point was measured.
FIG. 8 shows a schematic diagram of an experimental apparatus used for measuring the impact load. The experimental apparatus includes an impact load generation unit 70 and an impact load measurement unit 71. The impact load generator 70 includes a storage tank 72, a flow meter 73, a super high pressure pump 74, a pressure gauge 75, a rod 77, a monitor 78, a nozzle 79, and a pipe 76 for guiding water from the storage tank 72 to the rod 77. It has.
The water in the storage tank 72 is circulated through the pipe line 76 at a flow rate of 300 liters per minute by the ultrahigh pressure pump 74, further flows down through the rod 77, and is injected from the nozzle 79. The water path 84 is indicated by a dotted line. The injection pressure at that time was 28 MPa.
On the other hand, the impact load measuring unit 71 includes a load cell 81 having a steel plate 80 (having a disk shape with a diameter of 30 mm), a booster 82 electrically connected to the load cell 81, and an electrical connection to the booster 82. The recorder 83 is provided. The water sprayed from the nozzle 79 collides with a plate 80 disposed at a distance of 2.0 m (shown as “L” in the figure). The impact load received by the plate 80 is measured by the load cell 81 and recorded in the recorder 83 via the booster 82.
The results are shown as graphs in FIGS.

[B. Experimental example using an injection structure having an air flow passage]
As the form of the injection structure having the air flow passage, the one shown in FIGS. 12 to 15 is adopted, and the diameter and length of the rectifying unit are changed, and the impact of the fluid injected from the nozzle in each of these cases An experiment was conducted to measure the load.
In each case, the diameter of the slurry flow path of the rod was 65 mm.
The material of the peripheral surface of the rectifying unit was steel. The surface roughness of the peripheral surface of the rectifying unit was 12-S.
As the nozzle, a nozzle having a total length of 20 mm, a taper angle of 20 degrees, a straight portion having a length of 10 mm, and an opening diameter of 5.45 mm was used.

(1) Form of injection structure (a) Type 1 (FIG. 12)
The injection structure shown in FIG. 12 is formed by connecting a nozzle 91, an air flow passage 96, and a monitor 91 having a rectifying unit 94 to a rod 90 having an air flow passage 95 and a rod slurry flow passage 93.
In FIG. 12, the rectifying unit 94 has a portion that extends horizontally and a portion that extends vertically.
Note that the monitor 91 shown in FIG. 12 is formed so as to give a continuous extension portion downward with respect to the outer peripheral surface of the rod 90 when connected to the lower end of the rod 90. And a substantially columnar member having an outer peripheral surface having the same outer diameter as the concentric.
(B) Type 2 (Fig. 13)
The injection structure shown in FIG. 13 is formed by connecting a monitor 101 having a nozzle 102, an air flow passage 106 and a rectifying unit 104 to a rod 100 having an air flow passage 105 and a rod slurry flow passage 103.
The rectifying unit 104 includes only a portion extending horizontally.
(C) Type 3 (Fig. 14)
The injection structure shown in FIG. 14 is formed by connecting a nozzle 111 having an air flow passage 115 and a rod slurry flow passage 113 to a monitor 111 having a nozzle 112, an air flow passage 116 and a rectifying unit 114.
The length of the vertically extending portion is substantially equal to the length of the horizontally extending portion.
(D) Type 4 (FIG. 15)
The injection structure shown in FIG. 15 is formed by connecting a nozzle 121, an air flow passage 126, and a monitor 121 having a rectifying unit 124 to a rod 120 having an air flow passage 125 and a rod slurry flow passage 123.
The rectifying unit 124 is formed by bending a portion extending vertically downward, a portion extending obliquely downward, a portion extending vertically downward, and a portion extending horizontally from the lower end of the slurry flow passage 123 of the rod. Has been.

(2) Length (L ₁ ) and diameter (D1) of the rectifying unit
9mm caliber (D1) of the rectification section, 12 mm, 15 mm and varied, and the length of the rectifying portion _{(L 1)} is varied in a range of 1Mm～300mm, water jets ejected from the nozzle (consolidated materials slurry The impact load at a predetermined flight distance point was measured.
FIG. 16 shows a schematic diagram of an experimental apparatus used for measuring the impact load. The experimental apparatus includes an impact load generation unit 130 and an impact load measurement unit 131. The impact load generator 130 includes a storage tank 132, a flow meter 133, a super high pressure pump 134, a pressure gauge 135, a rod 137, a monitor 138, a nozzle 139, and a pipe 136 for guiding water from the storage tank 132 to the rod 137. (The above configuration is the same as that in FIG. 8). In addition, an air flow passage 146 and a compressor 145 for feeding compressed air into the air flow passage 146 are provided.
An air flow passage is provided inside the rod 137 and the monitor 138 for flowing compressed air and injecting it around the nozzle 139.
The water in the storage tank 132 is circulated through the pipe 136 at a flow rate of 300 liters per minute by the ultrahigh pressure pump 134, further flows down in the rod 137, and is injected from the nozzle 139. The water path 144 is indicated by a dotted line. The injection pressure at that time was 28 MPa.
The compressor was operated to deliver compressed air at a pressure of 1.05 MPa and a flow rate of 6 m ³ / min.
On the other hand, the impact load measurement unit 131 includes a load cell 141 having a steel plate 140 (having a disk shape with a diameter of 30 mm), a booster 142 electrically connected to the load cell 141, and an electrical connection to the booster 142. The recorded recorder 143 is provided. The water sprayed from the nozzle 139 collides with the plate 140 arranged at a point of a flight distance of 2.0 m (indicated by “L” in the figure). The impact load received by the plate 140 is measured by the load cell 141 and recorded in the recorder 143 via the booster 142.
The results are shown as graphs in FIGS.

From FIG. 9 to FIG. 11 (when the air flow passage is not provided) and FIGS. 17 to 19 (when the air flow passage is provided), the magnitude of the impact load is determined by the shape of the rectifying unit and the size of the inner diameter D1. regardless, it shows the same behavior, and, if the length L ₁ of the rectification section is at 70mm or more, it can be seen that substantially constant impact load (maximum load) is obtained.

It is a figure which shows the state which is performing the ground improvement construction using the high voltage | pressure injection stirring apparatus containing the injection structure of this invention. It is sectional drawing which shows an example (thing which does not have an air flow path) of the injection structure of this invention. It is sectional drawing which shows the other example (those which has an airflow path) of the injection structure of this invention. It is sectional drawing which shows the form example (Type 1; what does not have an airflow path) of the injection structure of this invention used in experiment. It is sectional drawing which shows the example (Type 2; what does not have an airflow path) of the injection structure of this invention used in experiment. It is sectional drawing which shows the example (Type 3; what does not have an airflow path) of the injection structure of this invention used in experiment. It is sectional drawing which shows the example (Type 4; what does not have an airflow path) of the injection structure of this invention used in experiment. It is a figure which shows the structure of the experiment apparatus of an impact load. It is a figure which shows the experimental result (inner diameter of the slurry flow path for injection: 9 mm; what does not have an air flow path) of an impact load. It is a figure which shows the experimental result (inner diameter of the slurry flow path for injection: 12 mm; what does not have an air flow path) of an impact load. It is a figure which shows the experimental result (inner diameter of the slurry flow path for injection: 15 mm; what does not have an air flow path) of an impact load. It is sectional drawing which shows the structural example (type 1; what has an airflow path) of the injection structure of this invention used in experiment. It is sectional drawing which shows the structural example (type 2; what has an airflow path) of the injection structure of this invention used in experiment. It is sectional drawing which shows the form example (type 3; what has an airflow path) of the injection structure of this invention used in experiment. It is sectional drawing which shows the structural example (type 4; what has an airflow path) of the injection structure of this invention used in experiment. It is a figure which shows the structure of the experiment apparatus of an impact load. It is a figure which shows the experimental result (inner diameter of the slurry flow path for injection: 9 mm; what has an air flow path) of an impact load. It is a figure which shows the experimental result (Inner diameter of the slurry flow path for injection: 12 mm; what has an air flow path) of an impact load. It is a figure which shows the experimental result (Inner diameter of the slurry flow path for injection: 15 mm; what has an air flow path) of an impact load.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 High pressure jet stirring apparatus 2 Rail 3 Swivel 4, 20, 30, 40, 50, 60 Rod 5, 21, 31, 41, 51, 61 Tip monitor 6 Ground 7 Hose 8 Cylindrical ground improvement body 9, 22, 32 , 42, 52, 62 Nozzle 10 Solidified slurry 11, 23, 33, 43, 53, 63 Rod slurry flow passage 12, 24, 34, 44, 54, 64 Rectifier 12a First rectifier 12b Second Rectifier 13 Stirring blade 25, 26 Air flow passage 27 Air outlet 70, 130 Impact load generator 71, 131 Impact load measuring unit 72, 132 Storage tank 73, 133 Flow meter 74, 134 Super high pressure pump 75, 135 Pressure gauge 76,136 Pipe line 77,137 Rod 78,138 Tip monitor 79,139 Nozzle 80,140 Plate 81,141 Load cell 82,142 Booster 83, 143 Recorder 84, 144 Path 90, 100, 110, 120 Rod 91, 101, 111, 121 after injection of water (replacement of solidified material slurry) Tip monitor 92, 102, 112, 122 Nozzle 93, 103, 113, 123 Rod slurry flow path 94, 104, 114, 124 Rectifier 95, 96, 105, 106, 115, 116, 125, 126 Air flow path 145 Compressor 146 Air flow path

Claims (3)

In the injection structure of the high-pressure jet agitating device for creating a cylindrical ground improvement body by mixing and stirring the solidification material slurry and the soil to be improved while injecting the solidification material slurry into the ground,
A nozzle that forms the injection port for the solidified material slurry, and a rectifying unit that is formed from the rear end of the nozzle toward the upstream side and has a circular cross-sectional shape with a length of 70 mm or more and the same diameter. An injection structure of a high-pressure injection agitation device.   The injection structure of the high-pressure jet agitating device according to claim 1, further comprising a rod slurry passage having a diameter larger than that of the rectifying unit from an upstream end of the rectifying unit toward an upstream side. 3. The high-pressure jet agitating device according to claim 2, further comprising an air flow passage for ejecting compressed air around the solidified material slurry injected from the nozzle around the slurry flow passage and the rectifying unit of the rod. Injection structure.

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