JP2022038759A - Sludge discharge promotion mechanism - Google Patents

Abstract

To provide a technique for effectively preventing blocking of a path in an injection rod by sludge generated during execution of a high pressure injection agitation method.SOLUTION: During execution of a high pressure injection agitation method for inserting an injection rod 16 into a vertical hole 15, jetting a solidification material liquid and air from nozzles 35 and 36 of a first monitor 30 at high pressure when gradually pulling up the injection rod 16 by a predetermined distance while rotating the injection rod 16, and preparing an improvement body 17 in the ground 14, a plurality of inversion flow channels 37 are provided in the first monitor 30, the inversion flow channel 37 is arranged parallel to the injection rod 16, thereby an air discharge port 38 on its tip is turned to the upper part, a lower end 37a of the inversion flow channel 37 is communicated with a flow channel 41 of compression air, and ascent of sludge 70 existing in a gap between the vertical hole 15 and the injection rod 16 is promoted by addition of air 69 jetted upward from the air discharge port 38.SELECTED DRAWING: Figure 5

Description

The present invention relates to a mud discharge promoting mechanism, and more particularly to a technique for more effectively discharging the mud generated during the implementation of the high-pressure injection stirring method to the ground.

The high-pressure injection stirring method is known as one of the ground improvement methods.
In this construction method, a ground improvement device is first installed on the ground, and a hole is drilled with a casing almost vertically toward the ground below the ground to a predetermined depth to form a vertical hole.
When the casing reaches a predetermined depth, an injection rod such as a double pipe injection rod is inserted into the vertical hole instead of the casing, and the cement-based solidifying material liquid is discharged from the nozzle of the monitor attached to the tip of the casing in the radial direction together with air. Inject at high pressure toward the direction and rotate the injection rod.
As a result, the soil cut by the high-pressure jet of the solidifying material liquid is stirred and mixed with the solidifying material liquid.
By pulling up this injection rod at a predetermined speed, a cylindrical improved body is created in the soil in the vertical direction.

In the construction process of this high-pressure injection stirring method, mud (slime), which is a mixture of soil and solidifying material liquid, is generated, but basically the mud passes through the gap between the inner surface of the vertical hole and the outer surface of the injection rod. It is pumped to the ground and stored in the slime pit.
However, if the viscosity of the mud is relatively high, or if a large amount of foreign matter such as clay lumps or wood chips is mixed in the mud, the above gap will be clogged and the mud will not be discharged to the ground. Occurs.
If the construction is continued in this state, problems such as the surrounding ground rising due to the injection pressure from the injection rod will occur. Therefore, when clogging occurs, the construction is interrupted, the injection rod is pulled up, and water is sprayed. There is no choice but to clear the blockage, which is a big loss in terms of time and labor.

Therefore, various measures for preventing clogging of waste mud have been proposed so far.
For example, in the following Patent Document 1, an air pipe separate from the injection rod is inserted into the vertical hole, and compressed air or the like is injected diagonally upward from the injection port at the tip thereof and added to the mud. , A technique for preventing clogging of waste mud is disclosed.
Further, Patent Document 2 below discloses a technique for enhancing the effect of discharging mud by discharging air from a plurality of air discharge holes provided on the side surface of the injection rod.
Patent No. 6304730 JP 2000-017649

However, in the case of the technique of Patent Document 1, it is necessary to insert a plurality of air pipes different from the injection rod into the narrow vertical hole, which requires time and effort to install and the flow path of the mud drainage. As a result of being narrowed, there was a problem that the expected emission promoting effect could not be obtained.

On the other hand, in the case of the technique of Patent Document 2, since the injection rod itself is provided with the air discharge hole, the problem as in Patent Document 1 does not occur, but the air is discharged from the air discharge hole in the horizontal direction. , The air will hit the inner wall surface of the vertical hole once and then start to rise.
That is, in the method of Patent Document 2, the pressure of air cannot be directly applied to the mud drainage, and it mainly depends on the effect of improving the buoyancy by increasing the amount of air, so that the discharge efficiency is also dramatic. No improvement could be expected.

The present invention has been devised in view of the current situation, and an object of the present invention is to realize a technique capable of effectively preventing the path in the injection rod from being blocked by the mud generated during the implementation of the high-pressure injection stirring method. There is.

In order to achieve the above object, the wastewater discharge promoting mechanism according to claim 1 inserts an injection rod into a vertical hole formed in the ground, and rotates the injection rod step by step by a predetermined distance. When pulling up, the solidifying material liquid and air are injected at high pressure from the nozzle of the monitor provided at the tip of the injection rod, and the soil is cut by the high pressure jet of this solidifying material liquid, and the cut soil and the solidifying material liquid are separated. In carrying out the high-pressure jet stirring method of stirring and mixing to create an improved body in the ground, an inversion flow path is provided in at least one of the injection rod and the monitor, and the inversion flow path is set at 90 degrees (preferably) with respect to the injection rod. Is arranged at an angle smaller than 45 degrees) so that the upper end opening is directed upward and the lower end of the inverted flow path is communicated with the supplied compressed air flow path, and the upper end opening of the inverted flow path is connected. It is characterized in that it is configured to promote the rise of the waste mud existing in the gap between the vertical hole and the injection rod by adding the air jetted upward from the vertical hole.

The mud discharge promoting mechanism according to claim 2 includes a first flow path, a second flow path, and a third flow path in which the injection rod and the monitor according to claim 1 are arranged concentrically, respectively. It has a triple pipe structure, and the solidifying material liquid is supplied to the first flow path, high-pressure air for creating an improved body is supplied from the first air compressor to the second flow path, and the nozzle is used. Is communicated with the first flow path and the second flow path, and high-pressure air for promoting wastewater discharge is supplied from the second air compressor to the third flow path, and the lower end of the reversal flow path. Is characterized in that it communicates with the third flow path.

The mud discharge promotion mechanism according to claim 3 has a double pipe structure in which the injection rod and the monitor according to claim 1 have a first flow path and a second flow path arranged concentrically, respectively. A solidifying material liquid is supplied to the first flow path, and high-pressure air for creating an improved body and high-pressure air for promoting wastewater discharge are supplied to the second flow path via a common air compressor. Is supplied, the nozzle is in communication with the first flow path and the second flow path, and the lower end of the inversion flow path is in communication with the second flow path via the branch point. It is a feature.

The mud discharge promoting mechanism according to claim 4 has an outer peripheral surface of at least one of the injection rod and the monitor according to claims 1 to 3, the lower end thereof is connected to the upper end opening of the reversal flow path, and the upper end is on the ground side. A positioned guide groove is formed, and the air for promoting the discharge of mud discharged from the upper end opening of the reversal flow path is guided in the ground direction along the guide groove.

The mud discharge promoting mechanism according to claim 5 is provided with a plurality of reversing flow paths in claims 1 to 4 in the body of the monitor having a diameter larger than that of the injection rod, and the upper end openings thereof are provided. Is formed on the stepped portion of the body portion protruding from the outer peripheral surface of the injection rod, and each inversion flow path is arranged so as to be parallel to the second flow path, thereby promoting the discharge of mud. It is characterized in that the air for use is injected in the direction of the ground.

In the mud discharge promoting mechanism according to claim 6, the reversing flow path according to claims 1 to 5 is formed in the outer shell of the injection rod, and the upper end opening thereof is relative to the outer peripheral surface of the injection rod. It is characterized by being formed flush with each other.

According to the mud discharge promoting mechanism according to the present invention, there is a structure in which air is injected upward at high pressure from the upper end opening of the reversing flow path provided in the injection rod inserted into the vertical hole or the monitor. Therefore, the air pressure can be directly applied to the mud located above the upper end opening, and the accumulation of the mud in the vertical hole can be effectively suppressed.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.
First, a general procedure of the high-pressure injection stirring method will be described with reference to FIG.
First, as shown in FIG. 1 (a), the ground improvement device 12 is installed on the ground surface 10 and lowered into the ground 14 at a predetermined stroke speed while injecting high-pressure drilling water from the tip of the casing 13. , Drill a vertical hole 15 to the planned depth.

Next, as shown in FIG. 1 (b), after the injection rod 16 is built up to the bottom of the vertical hole 15, solidification which is a mixture of solidifying material and water is performed from the nozzle of the monitor provided at the tip of the injection rod 16. The material liquid and air are rotated while being injected at high pressure, and the depth is raised to the planned depth at a predetermined stroke speed.

As a result, as shown in FIG. 1 (c), a columnar improved body (pile body) 17 which is a mixture of soil, water, and a solidifying material is formed.
Through this construction, the waste mud 18, which is a mixture of soil, water, and solidifying material, is pumped to the ground through the gap between the injection rod 16 and the vertical hole 15 and stored in the slime pit 19.

FIG. 2 is a vertical sectional view of the first monitor 30 according to the present invention mounted on the tip of the injection rod 16, in which the first tube 31 arranged in the center and the second tube 31 arranged outside the first tube 31 are arranged in the center. 32, a third tube 33 arranged outside the tube 32, a cylindrical body 34, a first nozzle 35, a second nozzle 36, and a plurality of reversing flow paths 37. An air discharge port 38 is provided as an upper end opening provided at the tip of each inversion flow path 37.
Since the diameter of the body portion 34 is larger than the diameter of the injection rod 16, it projects outward from the outer peripheral surface of the injection rod 16 and a step portion 34a is formed at the upper end.

The first tubular body 31 includes a wide-diameter portion 31a having a relatively large diameter, a narrow-diameter portion 31b having a relatively small diameter, and a funnel-shaped valve seat portion 31c formed at the boundary between the two.
By fitting a steel ball (not shown) into the valve seat portion 31c, the lower end opening 31d of the first pipe body 31 is closed (details will be described later).

As shown in FIG. 3, which is a cross-sectional view taken along the line AA of FIG. 2, the first tube body 31, the second tube body 32, and the third tube body 33 are arranged concentrically, respectively, and the first tube body 31 is arranged. A cylindrical first flow path 39 is formed in the tubular body 31 of the above.
Further, an annular second flow path 40 is formed between the first tube body 31 and the second tube body 32.
Further, an annular third flow path 41 is formed between the second tube body 32 and the third tube body 33.

The first nozzle 35 includes a central opening 35a and a peripheral opening 35b formed around the central opening 35a. The central opening 35a is communicated with the first flow path 39. Further, the peripheral opening 35b is communicated with the second flow path 40.
The second nozzle 36 also includes a central opening 36a and a peripheral opening 36b formed around the central opening 36a. The central opening 36a is communicated with the first flow path 39. Further, the peripheral opening portion 36b is communicated with the second flow path 40.

Four air discharge ports 38 are provided on the stepped portion 34a of the body portion 34, and the four reversing flow paths 37 connected to each air discharge port 38 have a connecting pipe (connecting path) at the lower end 37a of each. ) 42 is communicated with the third flow path 41.
Each inversion flow path 37 is arranged so as to be parallel to the third flow path 41, reverses the direction of the high-pressure air supplied from the ground through the third flow path 41, and is vertical toward the ground. It has a function of injecting.

The injection rod 16 connected to the first monitor 30 has a so-called triple tube structure including a first tube 50, a second tube 51, and a third tube 52 arranged concentrically, respectively. A first cylindrical flow path 53 is provided in the first tube body 50, and an annular second flow path is provided between the first tube body 50 and the second tube body 51. 54, an annular third flow path 55 is formed between the second tube 51 and the third tube 52, respectively.
Further, the first flow path 53, the second flow path 54, and the third flow path 55 on the injection rod 16 side are the first flow path 39 and the second flow path 40 on the first monitor 30 side, respectively. , It is communicated with the third flow path 41.

As shown in FIG. 4, in the first flow path 53 of the injection rod 16, the solidifying material liquid obtained by kneading cement and water from the high-pressure pump 61 and the slurry plant 62 via the triple pipe swivel 60 of the ground improvement device 12. Is supplied at high pressure.
Further, air is supplied to the second flow path 54 from the first air compressor 63 at a high pressure, and air is supplied to the third flow path 55 from the second air compressor 64 at a high pressure.

Therefore, as shown in FIG. 5, if the steel ball 65 is previously fitted to the valve seat portion 31c of the first pipe body 31 to close the lower end opening 31d, the first nozzle 35 and the second nozzle 35 and the second The solidifying material liquid 66 is vigorously ejected from the nozzle 36 together with the air 67 to form a high-pressure jet 68.
At the same time, the air 69 for promoting the discharge of mud is injected at a high pressure upward (ground side) from the air discharge port 38 provided at the tip of each inversion flow path 37.

Here, the amount of the improved body-building air 67 injected from the first nozzle 35 and the second nozzle 36 per unit time, and the air 69 for promoting the discharge of mud ejected from each air discharge port 38. Although the amounts per unit time are set to be equal (eg 2.0 m ³ / min respectively), by controlling the outputs of the first air compressor 63 and the second air compressor 64 separately, they can be mutually controlled. It is also possible to make a difference in the ratio of.

FIG. 6 shows the function of the mud discharge promoting mechanism in the construction process of the high-pressure injection stirring method, in which the first monitor 30 is inserted into the vertical hole 15 and the first nozzle 35 and the second nozzle 36 are inserted. At the same time as injecting the solidifying material liquid 66 and air 67 from, the first monitor 30 is rotated at a predetermined speed, and the first monitor 30 is pulled up by one step (for example, 2.5 cm) at a predetermined timing. An improved body 17 is formed in the ground 14.

A large amount of mud 70 is generated in this process, and these are subjected to the pressure of the air 67 and the solidifying material liquid 66 discharged from the first nozzle 35 and the second nozzle 36 to enter the vertical hole 15. As it rises, it is energized by the upward air 69 injected at high pressure from the air discharge port 38 of the first monitor 30, and is discharged to the ground without staying in the vertical hole 15.

As shown in FIG. 7, the waste mud 70 may stay at a position below the air discharge port 38 and block the vertical hole 15, but in this case, as shown in FIG. 8, the injection rod is temporarily inserted. By lowering 16 and moving the air discharge port 38 of the first monitor 30 to a position below the stagnant portion, the mud 70 stagnated by the upward high-pressure air 69 can be loosened.

As shown in FIG. 9, when the improved body 17 is formed by injecting only the solidifying material liquid 66 at high pressure without injecting air 67 from the first nozzle 35 and the second nozzle 36, through the same construction. The generated mud 70 can be effectively discharged by the upward high-pressure air 69 injected from the air discharge port 38.
In this case, the operation of the first air compressor 63 is stopped to cut off the supply of air to the first nozzle 35 and the second nozzle 36, and the second air compressor 64 is operated to operate the reversing flow path 37. And air is supplied to the air discharge port 38.

As shown in FIG. 10, when the vertical hole 15 is formed in the ground 14 by using the drilling water 72 jetted from the lower end opening 31d of the first monitor 30, the mud drain 70 generated in this drilling process is also formed. Is discharged to the ground by the upward high-pressure air 69 ejected from the air discharge port 38.
Incidentally, at the time of this drilling, the steel ball 65 is removed from the valve seat portion 31c in the first monitor 30, the lower end opening 31d of the first pipe body 31 is opened, and the first nozzle 35 and the second nozzle 35 and the second After closing the nozzle 36, high-pressure drilling water 72 is supplied from the ground to the first flow path 39.

FIG. 11 shows an example in which a plurality of guide grooves 74 connected to each inversion flow path 37 and the air discharge port 38 are formed on the outer peripheral surface of the third pipe body 33 of the first monitor 30.
In this case, the air 69 injected from the air discharge port 38 travels along the guide groove 74 to increase the directivity, and it becomes possible to stimulate the mud drainage more effectively.

In the above, an example in which the reversing flow path 37 and the air discharge port 38 are provided on the first monitor 30 attached to the tip of the injection rod 16 is shown, but the reversing flow path and the air discharge port are provided in the middle of the injection rod 16. By providing it, it is possible to promote the discharge of waste mud.

FIG. 12 shows an example thereof, in which the third tube 52 constituting the outer shell of the injection rod 16 is relatively thick, and a plurality of inverted flow paths 37 extending diagonally upward from below are provided inside the third tube body 52. In addition to forming, it has a structure in which the lower end 37a of each inverted flow path 37 is communicated and connected to the third flow path 55 formed between the third tube body 52 and the second tube body 51.
The angle between each inverted flow path 37 and the third flow path 55 is set to, for example, 20 degrees or less.

The upper end of each inversion flow path 37 has an elliptical opening on the outer peripheral surface of the third pipe body 52, which functions as an air discharge port 38 for promoting mud discharge.
The air discharge port 38 is formed so as to be flush with the outer peripheral surface of the third pipe body 52, and since there is no protrusion on the outside, chucking is performed when the injection rod 16 is added and built. It does not get in the way.

Although not shown, in this case as well, the solidifying material liquid is supplied from the high-pressure pump 61 and the slurry plant 62 installed on the ground to the first flow path 53 in the first pipe body 50.
Further, high-pressure air for creating an improved body is supplied from the first air compressor 63 on the ground to the second flow path 54 formed between the first pipe body 50 and the second pipe body 51. To.
Further, high-pressure air for promoting wastewater discharge is supplied from the second air compressor 64 on the ground to the third flow path 55 formed between the second pipe body 51 and the third pipe body 52. Will be done.

As described above, since each inversion flow path 37 has a predetermined length secured from the lower side to the diagonally upper direction, the high-pressure air supplied from the ground through the third flow path 55 is the inversion flow path. The traveling direction is reversed via 37, and high-pressure air is injected from the air discharge port 38 toward the ground.
As a result, the mud existing above it can be effectively stimulated and discharged to the ground.

In this way, by providing the reversing flow path 37 and the air discharge port 38 in the middle of the injection rod 16, high-pressure air 69 is injected into the mud at a position closer to the ground than when it is provided in the first monitor 30. And the discharge can be promoted.
Although not shown, the third flow path 55 is branched at a plurality of upper and lower points in the injection rod 16 and the reversing flow path 37 is connected to each branch tube at a plurality of points having different depths. It is also possible to promote the discharge of mud.

FIG. 13 is a vertical cross-sectional view of the second monitor 80 mounted on the tip of the injection rod 16, in which the first tube 31 arranged in the center and the second tube 32 arranged outside the first tube 31 are shown. It is provided with a cylindrical body portion 34, a first nozzle 35, a second nozzle 36, a plurality of reversing flow paths 37, and an air discharge port 38 provided at the tip of each reversing flow path. ..

The first tubular body 31 includes a wide-diameter portion 31a having a relatively large diameter, a narrow-diameter portion 31b having a relatively small diameter, and a funnel-shaped valve seat portion 31c formed at the boundary between the two.
By fitting the steel ball 65 into the valve seat portion 31c, the lower end opening 31d of the first pipe body 31 is closed.

The first tube body 31 and the second tube body 32 are arranged concentrically, respectively, and a cylindrical first flow path 39 is formed in the first tube body 31.
Further, an annular second flow path 40 is formed between the first tube body 31 and the second tube body 32.

The first nozzle 35 includes a central opening 35a and a peripheral opening 35b formed around the central opening 35a. The central opening 35a is communicated with the first flow path 39. Further, the peripheral opening 35b is communicated with the second flow path 40.
The second nozzle 36 also includes a central opening 36a and a peripheral opening 36b formed around the central opening 36a. The central opening 36a is communicated with the first flow path 39. Further, the peripheral opening portion 36b is communicated with the second flow path 40.

A plurality of air discharge ports 38 are provided on the stepped portion 34a of the body portion 34, and in the reversing flow path 37 connected to each air discharge port 38, each lower end 37a has a branch pipe (branch path) 81. It is communicated with the second flow path 40 via.
Each inversion flow path 37 is arranged so as to be parallel to the second flow path 40, reverses the traveling direction of the high-pressure air supplied from the ground through the second flow path 40, and is vertical toward the ground. It has a function of injecting.

The injection rod 16 connected to the second monitor 80 has a so-called double pipe structure having a first pipe body 50 and a second pipe body 51 arranged concentrically, respectively. A cylindrical first flow path 53 is formed in the tube body 50, and an annular second flow path 54 is formed between the first tube body 50 and the second tube body 51. There is.
Further, the first flow path 53 and the second flow path 54 on the injection rod 16 side are communicated with the first flow path 39 and the second flow path 40 on the second monitor 80 side, respectively.

As shown in FIG. 14, in the first flow path 53 of the injection rod 16, the solidifying material obtained by kneading cement and water from the high-pressure pump 61 and the slurry plant 62 via the double pipe swivel 83 of the ground improvement device 12. The liquid is supplied at high pressure.
Further, air is supplied from the first air compressor 63 to the second flow path 54 at a high pressure.

Therefore, when the high-pressure injection stirring method is applied using the second monitor 80, the mud generated in the process of forming the improved body 17 is discharged from the first nozzle 35 and the second nozzle 36. It rises in the vertical hole 15 under the pressure of the solidifying material liquid, is energized by the upward air 69 injected at high pressure from the air discharge port 38 of the second monitor 80, and stays in the vertical hole 15. It is discharged to the ground without.

In the case of the first monitor 30 described above, the air 67 for creating an improved body injected from the first nozzle 35 and the second nozzle 36, and the air for promoting the discharge of mud ejected from each air discharge port 38. Since 69 is supplied via a separate air compressor and flow path, when the flow path, nozzle, or discharge port is clogged, any system can be used by observing the operating status of each compressor. It has the merit of being able to determine whether it is blocked.
Further, in the case of the first monitor 30, by adjusting the output of each air compressor individually, the ratio of the supply amount of the air 67 for creating the improved body and the supply amount of the air 69 for promoting the wastewater discharge can be adjusted. There is also a merit that it can be adjusted freely.

On the other hand, in the case of the second monitor 80, the air 67 for creating an improved body injected from the first nozzle 35 and the second nozzle 36 and the mud discharge promotion injected from the air discharge port 38 are promoted. Since the air 69 for the purpose is supplied from the common air compressor and flow path, there is a demerit that it is not possible to determine in which system the clogging occurred, and the supply amount of the air 67 for the improvement body construction and the promotion of wastewater discharge. While there is a demerit that the ratio of the supply amount of air 69 is fixed, there is a merit that the configuration can be simplified and the weight of the entire mechanism can be reduced.

It is a schematic diagram explaining the general construction procedure of the high pressure injection stirring method. It is sectional drawing which shows the structure of the 1st monitor which concerns on this invention. FIG. 2 is a cross-sectional view taken along the line AA of FIG. It is a figure which shows the connection relationship between a ground improvement apparatus, a 1st air compressor, a 2nd air compressor, and a high pressure pump. It is sectional drawing which shows the structure at the time of operation of the 1st monitor. It is a figure explaining the function of this invention in the construction process of a high pressure injection stirring method. It is a figure explaining the function of this invention in the construction process of a high pressure injection stirring method. It is a figure explaining the function of this invention in the construction process of a high pressure injection stirring method. It is a figure explaining the function of this invention in the construction process of a high pressure injection stirring method. It is a figure explaining the function of this invention in a drilling process. It is sectional drawing which shows the modification of the 1st monitor. It is sectional drawing which shows the example which provided the reversal flow path and the air discharge port for promoting the discharge of mud in the middle of the injection rod. It is sectional drawing which shows the structure at the time of operation of the 2nd monitor which concerns on this invention. It is a figure which shows the connection relationship between a ground improvement apparatus, a 1st air compressor, and a high pressure pump.

10 Ground surface
12 Ground improvement equipment
13 Casing
14 Ground
15 vertical hole
16 Injection rod
17 Improved body
18 Mud drainage
19 slime pit
30 First monitor
31 The first tube of the monitor
32 Monitor second tube
33 The third tube of the monitor
34 Torso
35 1st nozzle
36 Second nozzle
37 Inverted flow path
38 Air outlet
39 Monitor first channel
40 Monitor second channel
41 Monitor third channel
42 Connecting pipe
50 First tube of injection rod
51 Second tube of injection rod
52 Third tube of injection rod
53 First flow path of injection rod
54 Second flow path of injection rod
55 Third flow path of injection rod
60 Triple tube swivel
61 High pressure pump
62 Slurry plant
63 First air compressor
64 Second air compressor
65 steel ball
66 Solidifying liquid
67 Air for building improved bodies
68 High pressure jet
69 Air for promoting wastewater discharge
70 Mud drainage
72 Drilling water
74 Guide groove
80 Second monitor
81 Branch pipe

Claims (6)

When the injection rod is inserted into the vertical hole formed in the ground and the injection rod is gradually pulled up by a predetermined distance while rotating, the solidifying material liquid and air are provided from the nozzle of the monitor provided at the tip of the injection rod. Is injected at high pressure, the soil is cut by the high-pressure jet of this solidifying material liquid, and the cut soil and the solidifying material liquid are stirred and mixed to create an improved body in the ground.
An inversion flow path is provided on at least one of the injection rod and the monitor.
By arranging this reversing flow path at an angle smaller than 90 degrees with respect to the injection rod, the upper end opening thereof is directed upward.
The lower end of this inverted flow path is communicated with the flow path of the supplied compressed air,
A mud discharge promotion mechanism configured to promote the rise of mud existing in the gap between the vertical hole and the injection rod by adding air injected upward from the upper end opening of the reversal flow path. The injection rod and the monitor have a triple tube structure having a first flow path, a second flow path, and a third flow path arranged concentrically, respectively.
The solidifying material liquid is supplied to the first flow path, and the solidifying material liquid is supplied.
High-pressure air for creating an improved body is supplied from the first air compressor to the second flow path.
The nozzle communicates with the first flow path and the second flow path, and is communicated with the first flow path and the second flow path.
High-pressure air for promoting wastewater discharge is supplied from the second air compressor to the third flow path.
The mud discharge promoting mechanism according to claim 1, wherein the lower end of the inverted flow path is communicated with the third flow path. The injection rod and the monitor have a double pipe structure having a first flow path and a second flow path arranged concentrically, respectively.
The solidifying material liquid is supplied to the first flow path, and the solidifying material liquid is supplied.
High-pressure air for creating an improved body and high-pressure air for promoting wastewater discharge are supplied to the second flow path via a common air compressor.
The nozzle communicates with the first flow path and the second flow path, and is communicated with the first flow path and the second flow path.
The mud discharge promoting mechanism according to claim 1, wherein the lower end of the inverted flow path is communicated with the second flow path via a branch portion. On the outer peripheral surface of at least one of the injection rod and the monitor, a guide groove is formed in which the lower end thereof is connected to the upper end opening of the reversing flow path and the upper end is located on the ground side.
The discharge according to any one of claims 1 to 3, wherein the air for promoting the discharge of mud discharged from the upper end opening of the reversal flow path is guided in the ground direction along the guide groove. Mud discharge promotion mechanism. A plurality of the inversion flow paths are provided in the body of the monitor having a diameter larger than that of the injection rod.
Each upper end opening is formed on the stepped portion of the body portion protruding from the outer peripheral surface of the injection rod.
Each inversion flow path is arranged so as to be parallel to the second flow path.
The mechanism for promoting mud discharge according to any one of claims 1 to 4, wherein the air for promoting mud discharge is injected toward the ground. The reversal flow path is formed in the outer shell of the injection rod.
The mud discharge promoting mechanism according to any one of claims 1 to 5, wherein the upper end opening is formed flush with the outer peripheral surface of the injection rod.

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