JP3974936B2 - Soil drilling tool, construction machine with soil drilling tool, ground improvement method and soil purification method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The injection material discharge nozzle, the soil excavation tool, the swivel, the soil improvement method and the soil purification method according to the present invention relate to improvement of soft ground and purification of contaminated soil.
[0002]
[Prior art]
Conventional methods for improving soft ground include a method of jetting and stirring an injection material at ultra-high pressure and a method of mechanically jetting and stirring using a large machine.
[0003]
The conventional ground improvement method mainly consists of an agitation agitation method using ultra-high pressure injection and an auger agitation method using a large machine. In addition, since it is a method of making a pile by pressure by injecting from the tip of the nozzle, there is a disadvantage that a lot of mud is discharged, and the mechanical stirring method by a large machine is a very large machine, so the construction site is restricted, etc. was there.
[0004]
The ultra-high pressure jet agitation method allows construction with a relatively compact machine, but a large amount of mud (discharged slime) is generated, which is undesirable from the environment, and it is expensive to treat this mud. There is a problem that it takes.
[0005]
On the other hand, in the mechanical agitation method using a large machine, the construction machine is large and the place where it can be constructed is limited, and a large plant must be transported and installed for construction. There is a problem that the cost is high.
[0006]
In recent years, as a result of industrial activities, harmful substances leak into the ground and soil has become a problem. Although it is important to limit the emission of harmful substances, there was no effective solution once it was discharged. Even if spraying chemicals that decompose or neutralize harmful substances, the effect is limited to the soil on the surface, and it is difficult to treat deeply into the ground, and mechanical excavation increases costs. , It can also bring out underground harmful substances.
[Problems to be solved by the invention]
[0007]
The ultra-high pressure jet agitation method is effective for strengthening soft ground, but it has already been mentioned that the generated waste mud causes environmental problems and cost problems for treatment. As a promising technique for solving this problem, Japanese Patent Laid-Open No. 2001-159130 discloses “Mechanical stirring air cement milk mixed pressure feeding method and device” as a compressor and a grout pump connected to a cutting bit and digging while spouting air. A technique for advancing and excavating the cement milk after completion of the drilling to agitate the excavated soil and the cement milk to create an underground pile is described. According to this technique, since the mud is not discharged to the ground, it is possible to construct the soil strengthening work easily and inexpensively without causing environmental problems. Furthermore, the inventor of the present application has been intensively studied to improve the technology, and has proposed an invention according to Japanese Patent Application No. 2001-365491. The present invention relates to these inventions, and provides an injecting material discharge nozzle, a soil excavation tool, a swivel, a soil improvement method and a soil purification method for further developing the invention, and waste mud associated with a conventional method. The purpose is to solve the problems of environmental problems caused by the occurrence of large-scale facilities and large expenses caused by large-scale facilities.
[0009]
[Means for Solving the Problems]
To achieve the above object, soil excavation tool of the present invention is a soil excavation tool having a rotating blade provided around the shaft body and the shaft body, the shaft is rotary vane is provided The central part is thick and the both end parts are narrow along the axial direction, and the rotating blade has a shape in which the diameter increases from the tip toward the central part, and the diameter decreases toward the upper part. An injection material discharge nozzle is provided near the injection material discharge nozzle. The injection material discharge nozzle has a first tube for discharging the injection material and a second tube for discharging air provided outside the injection tube. The spiral grooves in the same rotational direction are provided on the inner surfaces of the first tube and the second tube. In order to stir the soil on the upper and lower surfaces of the rotating blades, a tip conduit having an air discharge port at the tip can be provided, and compressed air, water, or a mixture of compressed air and water can be ejected from the air discharge port A plurality of claws can be provided to stir the soil more effectively.
[0011]
And the construction machine of this invention attaches the above-mentioned soil excavation tool to a work trolley with a swivel , and rotates a soil excavation tool via a connection apparatus. The swivel is a swivel for rotatably supporting the soil excavation tool, and the non-rotating portion is provided with a first air inlet, a second air inlet, and an injection material inlet, and the non-rotating portion A rotating shaft is rotatably provided, the rotating shaft is a triple tube composed of an outer tube and a double inner tube, and a connecting device for connecting an intermediate rod is provided at the end of the rotating shaft. The connecting device is a triple tube composed of an outer tube and a double inner tube, and is provided with a rotation preventing means for preventing relative rotation with the intermediate rod.
[0012]
In order to achieve the above-mentioned object, the soil improvement method of the present invention is provided in the vicinity of the tip conduit having the air discharge port at the tip, the shaft body, the rotary blade provided around the shaft body, and the rotary blade. have a injection material discharge nozzle, the shaft body is thinner at both ends portions thicker central portion along the axial direction in the portion where the rotary blade is provided, rotating blade the radial toward the center portion from the front end Rotate a soil excavation tool that expands and decreases in diameter toward the top , and excavates the soil while jetting either compressed air, water, or a mixture of compressed air and water from the tip conduit, When the soil excavation tool is rotated backwards and the soil is agitated, the ground reinforcement material such as cement milk is removed from the pipe by the injection material discharge nozzle provided with the spiral groove on the inner surface of the first pipe. While rotating around the axis The air is discharged into the inner surface of the first pipe, and has the same spiral groove in the rotational direction as the spiral groove provided on the inner surface of the first pipe, and the air is the same as the ground reinforcement material from the second pipe provided outside the first pipe. The ground reinforcement material is injected while being discharged around the ground reinforcement material while rotating in the direction, and the soil and the ground reinforcement material are mixed to create an improved body in the soil. A soil purification method can also be realized by using a chemical that purifies contaminants in the soil instead of the ground reinforcement as the injection material. In the soil purification method, as an agent for purifying contaminants in the soil, oxygen, oxygen-containing substances selected from air, oxygen peroxide, ozone, decomposing microorganisms, phosphorus, nitrogen, potassium for activating the decomposing microorganisms, Nutrients selected from silicon can be used.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below. FIG. 1 is a perspective view showing an example of a soil excavation tool according to the present invention, and FIG. 2 is a front view thereof. The soil excavation tool 1 according to the present invention has a spiral blade around a shaft body. A tip conduit 2 is provided at the tip, and a cutting tip 3 is provided. While cutting the ground with the cutting tip 3, the leading conduit 2 enters the ground. A shaft body 4 is provided following the leading conduit 2, and a spiral blade 5 which is a rotating blade is provided around the shaft body 4. Although the shaft body 4 is hollow, as shown in FIG. 2, the portion where the spiral blade 5 is provided is configured such that the central portion is thick and the both end portions are narrow along the axial direction. Here, as shown in FIG. 2, the shape is such that a cone is connected to both sides of the cylinder, and the diameter increases from both ends toward the center. And even if it sees with the whole shape containing the helical blade | wing 5, the diameter becomes large as a whole toward both ends from the center part.
[0014]
Although the shaft body 4 is hollow, a first inner tube 15a and a second inner tube 15b are provided inside, and the inner tubes 15a and 15b are injection material discharge nozzles 7 (injection material discharge ports). Connected to. The injection material discharge nozzle 7 is provided outward at a position where the diameter of the shaft body 4 is the largest. In this example, two injection material discharge nozzles 7 are provided, but three or more injection material discharge nozzles 7 may be provided. Details of the injection material discharge nozzle 7 are shown in FIGS. The injection material discharge nozzle 7 has a first tube 7a and a second tube 7c, and spiral grooves 7b and 7d are provided on the inner surface of each tube. The rotational directions of the spiral grooves 7b and 7d are the same. The second tube 7c may be provided with a plurality of tubes around the first tube 7a as shown in FIG. 4, or concentrically as the outer tube of the first tube 7a as shown in FIG. Good. As the first tube, one having an inner diameter of 5 to 8 mm is mainly used, but the diameter may be increased or decreased in accordance with the discharge amount of the injection material. In addition to providing the shaft body 4 completely perpendicularly, it may be tilted to some extent. As an example, the length of the first tube may be about 30 cm, a spiral of about one and a half rounds may be provided inside, and the outlet at the tip may be about 2.8 mm. A gap between the shaft body and the inner tube serves as a passage for compressed air, and compressed air, water, or a mixture of compressed air and water can be ejected from the tip of the front conduit 2.
[0015]
Although the claw is omitted in FIG. 2, a plurality of rectangular plate-like claws 6 are attached to the upper and lower surfaces of the spiral blade 6. The claw 6 is provided in a direction in contact with the circumference centered on the shaft body 4, that is, so that the thickness direction of the claw 6 is a radial direction. Of the rectangular shape of the nail 6, one corner is chamfered. In this chamfering, the corners may be cut off with a straight line or rounded. By directing in this way, the nail 6 provided on the lower surface of the spiral blade 5 when digging up, while the raised surface of the nail 6 provided on the upper surface of the spiral blade 5 when it is pulled up, is difficult to soil Stir the soil effectively.
[0016]
Next, an example of a swivel according to the present invention is shown in FIG. The upper part of the swivel 9 is a non-rotating part 10 and does not rotate. The non-rotating portion 10 is provided with an injection material introduction port 11, a first air introduction port 12a, and a second air introduction port 12b on the side surface. A rotating shaft 14 is attached to a non-rotating portion 10 through a bearing or the like so as to be rotatable. The rotating shaft 14 has a triple tube structure including a double inner tube 15 and an outer tube 16. The first inner tube 15 a is hollow, and this hollow portion constitutes the injection material passage 17. The injection material passage 17 is connected so that the injection material introduced from the injection material introduction port 11 can pass through. A second inner pipe 15b is provided outside the first inner pipe 15a, and a gap is provided between the two inner pipes to form a first air passage 18a. A gap is also provided between the second inner pipe 15b and the outer pipe 16, and this gap constitutes the second air passage 18b. The first air passage 18a is connected so that air introduced from the first air introduction port 12a can pass therethrough, and the second air passage 18b is connected so that air introduced from the second air introduction port 12b can pass therethrough. . A connecting device (not shown) for connecting the intermediate rod is provided at the end of the rotating shaft . This connecting device is also a triple tube composed of an outer tube and a double inner tube. This connecting device is for connecting the intermediate rod . The mating surfaces of the connection devices of both the swivel and the intermediate rod are formed in a flat shape, and are configured so that relative rotation cannot be performed between the connection devices. The swivel and the intermediate rod can be easily attached and detached by advancing and retracting in the axial direction. When connected, bolts (not shown) are tightened to prevent axial movement. The swivel according to the present invention needs to transmit a sufficient torque in both forward and reverse rotations, but the connection mechanism does not loosen the connection in either direction. A similar connecting device is also provided at the upper and lower ends of the intermediate rod and the upper end of the soil excavating device, so that the connection and separation can be easily performed, and the passage of the injection material and air is made easy by the internal triple pipe. It is formed.
[0017]
FIG. 7 shows the intermediate rod. The intermediate rod 22 has a triple-pipe structure similar to the swivel, and the hollow portion of the first inner tube 15a constitutes the injection material passage 17, and is interposed between the first inner tube 15a and the second inner tube 15b. The gap constitutes the first air passage 18a, and the gap between the second inner tube 15b and the outer tube 16 constitutes the second air passage 18b.
[0018]
FIG. 8 shows an example of a civil engineering machine according to the present invention. The work carriage 23 is self-propelled with an endless track 24 and can easily move the entire apparatus at a construction site. A leader 26 is attached to the work carriage 23 via an arm 25 that can move up and down. The leader 26 is a sliding attachment device that attaches the chuck 27 so as to be movable up and down. When the work carriage 23 is moved to the construction site, the angle of the arm 25 is adjusted and the leader 26 is set up vertically. The uppermost intermediate rod is passed through the chuck 27, and the intermediate rod is grasped by the chuck 27. A swivel 9 is connected to the uppermost intermediate rod, and the soil excavation tool 1 is connected to the lowermost intermediate rod. The chuck 27 can rotate the intermediate rod 22 in both forward and reverse directions by hydraulic drive. That is, the intermediate rod 22 functions as a drive shaft that transmits the rotation of the chuck 27 to the soil excavation tool 1 at the tip. An injection material hose 28 and two air hoses 29a and 29b are connected to the swivel 9, and each hose is connected to a trout pump and a compressor of a plant (not shown). The swivel 9, the intermediate rod 22 and the soil excavation tool 1 each have a triple pipe structure, but are connected so that the passages of the air and the injection material are connected.
[0019]
When digging with the soil excavation tool 1, air is sent by a compressor and ejected from the tip of the soil excavation tool 1, and the spiral blades of the soil excavation tool 1 are rotated so as to advance downward. There are (1) a method of sending air, (2) a method of sending water, and (3) a method of sending air and water. In places where there are roads etc., using air and water will reduce water usage and will not flood the road, but in places where water does not pose a problem, drill only with water. May be. When drilling holes with air and water, a compressor and a water supply pipe are connected to the ejector, and water and air are mixed and then pumped through the air hose 29. After digging to some extent, the intermediate rod 22 is added to dig deeper. Since the claw 6a on the lower surface of the spiral blade is cut off on the side opposite to the traveling direction side, it effectively cuts and agitates the earth and sand and smoothly feeds the earth and sand that has been cut back. In order to smoothly feed the cut earth and sand, the spiral blade loop has a shape in which the diameter increases from the tip toward the center, and the diameter decreases toward the top. In the soil excavation tool 1, the portion of the shaft body 4 to which the spiral blade 5 is attached has a thick central portion and narrow both end portions along the axial direction. Therefore, the spiral blade and the shaft body are strong even in the central part, and the soil excavation tool 1 is less likely to break in the ground during construction because the earth and sand are smoothly fed while digging, and the ground is relatively hard. Construction can also be performed in clayey places.
[0020]
When digging to the final depth, the soil excavation tool 1 is pulled up while rotating the spiral blades so that the rotation direction of the chucks 27 is reversed. At this time, the injection material is introduced from the injection material hose 28, and the injection material is injected into the ground from the injection material discharge port of the soil excavation tool 1. Furthermore, high-pressure compressed air is sent from the air hose. Since the spiral groove is provided on the inner surface of the first tube of the injection material discharge nozzle, the injection material is discharged while rotating with respect to the length direction of the tube and flies far away. Further, air that travels while rotating in the same direction as that of the injection material is accompanied around the injection material, and the injection material can fly far by being carried by this air. In addition, the direction of the spiral groove of the 1st pipe | tube and 2nd pipe | tube of an injection material discharge nozzle is determined according to the rotation direction of the soil excavation tool 1 at the time of raising. In this example, since the soil excavation tool 1 rotates counterclockwise when it is pulled up, the spiral grooves of the first pipe and the second pipe of the injection material discharge nozzle are also provided so as to rotate counterclockwise. When pulling up, the nail on the upper surface of the spiral blade stirs the earth and sand. Since the nail | claw on the upper surface of a spiral blade | wing is cut off in the advancing direction side at the time of reverse rotation, it is similarly hard to be smooth in soil and agitates earth and sand effectively. In the civil engineering machine and method according to the present invention, the mechanical stirring of the earth and sand and the stirring of the earth and sand by the injection of the injection material are simultaneously performed, and the cut earth and sand and the injection material are mixed efficiently, and the spiral blade Therefore, the cut earth and sand are not discharged to the ground as waste mud. Here, as a method of rotating the soil excavation tool 1 in a reverse direction, an operation of rotating the soil excavation tool 1 in a reverse direction while keeping the soil excavation tool 1 at a constant depth and an operation of pulling up the soil excavation tool 1 by a predetermined interval without rotating are alternately repeated. It is preferable to return it because it effectively prevents the generation of waste mud. When pulling up, the work proceeds while removing the intermediate rods sequentially, contrary to when digging. If it raises to predetermined | prescribed height, injection | pouring of an injection material will be stopped and the soil excavation tool 1 will be pulled up. When the construction of one hole is completed in this way, the work carriage 23 is moved to the next position and the same construction is repeated.
[0021]
[Example 1]
It is an example in which the present invention is applied to ground improvement work. A high concentration cement milk is used as an injection material. The cement milk used in this construction method may have a higher cement ratio than in the ordinary construction method (for example, about 760 kg of cement in 1 m ³ of the infused infusion material) in order to make the improved body sufficiently strong. preferable. Here, if the amount of cement is increased, the specific gravity of the injection material is increased and the suction with the pump is liable to be worsened. Therefore, it is preferable to add a water reducing agent mainly composed of aromatic sulfone and specially modified lignin. The blending of the water reducing agent facilitates the flow of cement milk and facilitates feeding by the pump, and increases the strength of the improved body. Using the trade name as a main component an aromatic sulfone and special modified lignin San Flow SW-2000S (Nippon Paper Industries) as a water reducing agent in this embodiment, the cement 1000kg and sun during the injection member 1 m ³ of dough up 5 kg of Flow SW-2000S was blended to obtain a compression strength 1 MPa (design standard strength) of the improved body. Since cement milk with a higher concentration than the conventional method is used in this way, the amount to be injected is small, and the specific gravity is large, so it is difficult to go up. This also contributes to making it difficult to discharge mud. ing. There are a method of jetting cement milk mixed with air at a low pressure of 0.6 to 2.5 MPa and a method of jetting cement milk at an ultrahigh pressure of 18.0 to 29.0 MPa. The ultra high pressure jet stirring was used. Since the rotational force is given by the spiral groove provided on the inner surface of the pipe of the air and the cement milk injection material discharge nozzle, and the air rotating in the same direction around the injection material is discharged together, the cement milk is far away. It is possible to fly up to an underground pile with a diameter larger than that of the spiral blade. For example, when a spiral blade having a diameter of 1 m was used, an underground pile having a height of about 1.8 m was obtained by using an ultra-high pressure jet. By using the injection material discharge nozzle according to the present invention, cement milk The flying distance increases by about 30%, and an underground pile having a diameter of about 2.3 m can be formed. Since the cut earth and sand are mixed with cement milk and constitute an underground pile as an improved body, they are not discharged as waste mud on the ground. When pulling up, the spiral blade rotates counterclockwise in FIG. 2 and pulls the earth and sand from above and strongly presses the agitated and mixed earth and cement downward with the blade, so that a strong underground pile can be formed, Strongly suppresses the generation of mud. For this reason, it does not cause environmental problems due to waste mud, and it does not incur a large amount of cost for the treatment of waste mud. Therefore, it is an environment-friendly construction method with excellent workability, economy and safety. ing.
[0022]
In order to inject cement milk effectively in the lateral direction by high-pressure jet agitation using an injection material discharge nozzle equipped with a spiral groove, it is possible to create an improved body with a wider range than the diameter of the spiral blade. In addition, the construction period can be shortened and the economy can be improved, and the close construction and the mutual construction can be carried out, so that the construction can be integrated as a whole. It is necessary to pay attention to the injection amount per unit time, and if the excessive injection is performed, the effect of the present invention that no mud is generated may not be exhibited. It is preferable to know in advance about the injection amount per unit time at a limit where no mud is generated and to inject at about 70% of the limit injection amount in order to further ensure prevention of mud. In this example, it was 70 liters / min. The pulling speed (expressed in terms of time required for pulling up 1 m below) is 3.0 min / m, 0.01 N / mm ² ≦ C ≦ 0 for clay soil with C <0.01 N / mm ² (= MPa). It was set to 5.0 min / m for the soil of 03 N / mm ² (5 ≦ N ≦ 10), and 6.0 min / m for the sand of 10 ≦ N ≦ 15. In addition, a grout pump having a capacity of 70 to 150 liters / min was used so that it could cope with a spiral blade having a diameter of 1.5 m used mainly at an injection rate of about 140 liters / min.
[0023]
[Example 2]
It is the example which applied this invention to soil purification construction. In this embodiment, a chemical that decomposes and neutralizes the pollutants in the soil is used as an injection material. Here, the agent for purifying pollutants in soil is selected from oxygen-containing substances selected from air, oxygen peroxide and ozone, decomposing microorganisms, phosphorus, nitrogen, potassium and silicon for activating the decomposing microorganisms It uses the nutrients that are produced and decomposes the pollutants with microorganisms. In particular, in the decomposition of organic matter, specific examples include methane-utilizing bacteria, toluene-utilizing bacteria, phenol-utilizing bacteria, nitrifying bacteria, propane-oxidizing bacteria, and isopropylene-oxidizing bacteria. By supplying the oxygen content and nutrients necessary for activating these microorganisms to the ground, the pollutants are effectively decomposed and the soil is purified. After digging to a depth necessary for decontamination, the chemical is injected into the soil while the soil excavating tool 1 is rotated in the reverse direction and pulled up. The drug is given a rotational force by the spiral groove of the injection material discharge nozzle, and can reach a wide range in the ground. Therefore, it is possible to purify the entire area with less work. The spiral blade 6 is effective because the chemical is injected while mechanically stirring the earth and sand. Even when the contamination has progressed to a deep location, the contamination can be removed as long as the soil excavation tool 1 reaches. Furthermore, since no mud is generated in this embodiment, the contaminated earth and sand do not appear on the ground surface, and the construction can be performed safely. In addition, the injection material discharge nozzle according to the present invention is suitable for use in the ground strengthening method and the soil purification method by being incorporated in the soil excavation tool as described above, but the application range is not limited to this, and water is injected. It can be used in all fields as a nozzle for cutting stones and as a nozzle for cleaning liquids, and when used in such a field, the injection material includes water and cleaning liquid. Means liquid in general.
[0024]
【The invention's effect】
According to the present invention, the injection material can be blown far away while being rotated by the groove provided on the inner surface of the tube of the injection material discharge nozzle, and the injection material can be injected over a wide range in the ground. In soil improvement and purification of contaminated soil, large-scale equipment is not required, and effective construction can be performed with a short construction period and low cost.
[Brief description of the drawings]
FIG. 1 is a perspective view of a soil excavation tool according to the present invention.
FIG. 2 is a longitudinal sectional view of the same.
FIG. 3 is a cross-sectional view showing a spiral groove inside an injection material discharge nozzle.
FIG. 4 is a transverse sectional view and a longitudinal sectional view of an example of an injection material discharge nozzle.
FIG. 5 is a cross-sectional view and a vertical cross-sectional view of another example of an injection material discharge nozzle. .
FIG. 6 is a cross-sectional view of a swivel.
FIG. 7 is a cross-sectional view of an intermediate rod.
FIG. 8 is a front view showing a civil engineering machine according to the present invention.
[Explanation of symbols]
1. Soil excavation tool2. Tip conduit3. Cutting tip 4. 4. Shaft body 5. Spiral blade Nails 7. 7. Injection material discharge port Air outlet 9 Sibel 10 Non-rotating part 11. Injection material inlet 12. Air inlet 14. Rotating shaft 15. Inner tube 16. Outer tube 17. Injection material passage 18. Air passage 22. Intermediate rod 23. Work carriage 24. Endless track 25. Arm 26. Leader 27. Chuck 28. Injection material hose 29. Air hose

Claims (6)

A soil excavation tool having a shaft body and a rotary blade provided around the shaft body, wherein the shaft body has a thick central portion along the axial direction and a narrow end portion at a portion where the rotary blade is provided. The rotating blade has a shape in which the diameter increases from the tip toward the central portion and the diameter decreases toward the top, and an injection material discharge nozzle is provided near the rotation blade, and the injection material discharge nozzle Has a first tube for discharging the injection material and a second tube for discharging air provided outside thereof, and has the same rotational direction as the inner surfaces of the first tube and the second tube. A soil excavation tool characterized by a spiral groove. The soil excavation tool according to claim 1, wherein a tip conduit having an air discharge port is provided at a tip portion of the shaft body, and a plurality of claws for stirring the soil are provided on the upper and lower surfaces of the rotary blade. a) a work carriage; b) a non-rotating portion provided with a first air introducing port, a second air introducing port and an injection material introducing port; and a rotating shaft provided rotatably with respect to the non-rotating portion, The rotating shaft is a triple tube composed of an outer tube and a double inner tube, c) a tip conduit having an air discharge port at the tip, a shaft body, a rotating blade provided around the shaft body, and a rotating blade It is a soil excavation tool having an injection material discharge nozzle provided in the vicinity, and the shaft body has a thick central part along the axial direction in the part where the rotary blade is provided, and both ends are thin. The diameter increases from the tip toward the center and decreases toward the top, and the injection material discharge nozzle discharges the first pipe that discharges the injection material and the air provided outside thereof. And a second tube for the inner surface of the first tube and the second tube Construction machine comprising a soil excavation tool, wherein the spiral groove in the same rotational direction are those provided. Tip have a injection material discharge nozzle provided in the vicinity of the rotating blades and rotor blades disposed around the lead pipe and shaft and the shaft body having an air discharge port, the shaft is rotating blades are provided In the part, the central part is thick along the axial direction and both ends are thin, and the rotating blade rotates the soil excavation tool whose diameter increases from the tip toward the central part and the diameter decreases toward the top. And excavating the soil while jetting either compressed air, water or a mixture of compressed air and water from the leading conduit, and after reaching a predetermined depth, the soil excavating tool is rotated in reverse to stir the soil. However, the injection material discharge nozzle provided with a spiral groove on the inner surface of the first pipe discharges the ground reinforcing material into the ground while rotating it with respect to the axis of the pipe, and in the same rotational direction as the first pipe. Outside the first tube with a spiral groove The soil and ground reinforcement are mixed by injecting the ground reinforcement while causing the air to rotate in the same direction as the ground reinforcement from the second pipe provided in A ground improvement method to create an improved body in the soil. Tip have a injection material discharge nozzle provided in the vicinity of the rotating blades and rotor blades disposed around the lead pipe and shaft and the shaft body having an air discharge port, the shaft is rotating blades are provided In the part, the central part is thick along the axial direction and both ends are thin, and the rotating blade rotates the soil excavation tool whose diameter increases from the tip toward the central part and the diameter decreases toward the top. And excavating the soil while jetting either compressed air, water or a mixture of compressed air and water from the leading conduit, and after reaching a predetermined depth, the soil excavating tool is rotated in reverse to stir the soil. While discharging the chemical solution for purifying the pollutants in the soil with the injection material discharge nozzle provided with the spiral groove on the inner surface of the first tube while rotating it with respect to the axis of the tube, Helix in the same rotational direction as the tube The second pipe provided outside the first pipe has air injected in the same direction as the chemical liquid while being discharged around the chemical liquid while injecting the chemical liquid to mix the soil and the chemical liquid. , Soil purification method to remove pollution in the soil. The agent for purifying pollutants in the soil is selected from oxygen-containing substances selected from air, oxygen peroxide and ozone, decomposing microorganisms, phosphorus, nitrogen, potassium and silicon for activating the decomposing microorganisms. The soil purification method according to claim 5, which is a nutrient.

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