JPH03228912A - Ground improving construction method and ground improving device for the same method - Google Patents

Abstract

PURPOSE:To prevent the sedimentation of a filling agent on the upper part of a packer by inserting a filling tube into the inside of a drilling pipe for closely bringing the packer into contact with the inner surface of a boring hole, and by discharging a washing fluid from the lower part of the drilling pipe, and also by injecting a filling agent through the filling tube. CONSTITUTION:A drilling pipe 33 in which a filling tube 37 has been housed is inserted into a boring hole 31. And at the lower end of a rigid pipe 38, a packer 45 is arranged, and at the lower end of a discharge pipe 46, the discharge port of a filling agent is formed. Then, a fluid is supplied through a fluid-supply tube 53 for expanding the packer 45 so as to be closely brought into contact with the hole 31. And a washing fluid is forcibly fed into a fluid passage 79 through the inflow port 67 of the pipe 33, and passing through the upper part of the packer 45, it is circulated through the gap between the pipe 33 and the inner surface of the hole 31, while the filling agent is injected into a filling space 55 through a pipe 46, and the filling agent leaked onto the upper part of the packer 45 is discharged to the ground surface. Thus, sedimentation of the filling agent on the upper part of the packer can be prevented, and the withdrawal of the pipe 38 or the like to the ground surface can be facilitated.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a soil improvement method and a soil improvement device used in this method, and particularly relates to a soil improvement method that uses a packer in a bore hole drilled in the ground. The present invention relates to a ground improvement method for improving the ground of dam foundations, etc. by injecting injection material, and to a ground improvement device used in this method.

[Conventional technology]

Conventionally, when constructing dams, buildings, etc. on soft ground,
BACKGROUND OF THE INVENTION The ground is strengthened by a construction method that creates compacted soil by press-fitting injection material into a borehole drilled into the ground.

Among these construction methods, a ground improvement method is known in which a packer is used to inject an injection material into a borehole drilled underground.

Figures 17 and 18 show the ground improvement device used in such a ground improvement method inserted into a borehole. The borehole is shown.

A drilling pipe 13 is inserted into the borehole 11, and the drilling pipe 13 is formed by connecting a plurality of pipes.

An injection tube 15 for press-fitting the injection material is housed in the borehole tube 13. A rigid tube 17 having rigidity is connected to the distal end of the injection tube 15, and the injection tube 15 and the rigid tube 17 An injection pipe 18 is configured. A wire 19 from the ground is connected to the rigid tube 17.

A fixing packer 21 is disposed in a portion of the rigid tube 17 that is located inside the borehole tube 13, and a sealing packer 23 is disposed in a portion located below the borehole tube 13.

These packers 21.23 can be accessed from the ground, e.g.
Fluid supply tube 25 that supplies fluid consisting of compressed air
The borehole 11 below the sealing packer 23 is an injection space 27 into which the injection material is press-fitted.
It is said that

The lower end of the rigid tube 17 protrudes below the sealing packer 23, and the injection material is press-fitted into the injection space 27 from the tip of the rigid tube 17.

The upper end of the sealing packer 23 is fixed to the rigid tube 17, and the lower end is fixed to a sliding part 29 disposed at the lower end of the rigid tube 17 so as to be slidable in the vertical direction.

In such a ground improvement device, as shown in FIG. 19 and FIG. Drill the hole to the planned depth. After drilling is completed, the packer 21.
Insert 23.

Then, the packers 21 and 23 are expanded by the fluid supplied from the fluid supply tube 25, and the fixing packer 2
1 is brought into close contact with the inside of the borehole 13 and fixed, and a sealing packer 23 is brought into close contact with the inner surface of the borehole 11.

After that, from the tip of the injection pipe 18, the sealing packer 23
The injection material 30 is press-fitted into the injection space 27 below, and the injection material 30 is press-fitted into the ground near the borehole 11.

When the injection is completed, the packer 21.23 is pulled out together with the injection pipe 18 from the drilling pipe 13, and the drilling pipe 13 is rotated to drill a hole to a predetermined depth. This process is repeated until the final planned depth is reached.

In the ground improvement device configured as described above, the packer 2
1.23 is inflated, the sealing packer 23 is brought into close contact with the inner surface of the borehole 11, and the ground around the borehole 11 can be improved by injecting the sealing packer 23 into the injection space 27 below the sealing packer 23. can.

Moreover, since the ground can be improved without pulling out the borehole pipe 13, workability can be improved. In particular, work efficiency can be greatly improved in ground improvement at a depth of 100 m or more, for example.

[Problems to be Solved by the Invention] However, in such a conventional ground improvement device, the injection material 3 is placed in the injection space 27 below the sealing packer 23.
0, the injection material 30 in the injection space 27 may leak upward into the sealing bunker 23 through cracks or the like that occur in the bore hole 11.

For this reason, the injection material 30 leaked above the sealing backer 23 is leaked to the upper part of the sealing packer 23 and the hole drilling pipe 13.
There was a problem in that the tip of the borehole 13, the sealing backer 23, etc. could not be recovered to the ground due to the precipitation between the surface of the borehole 11 and the inner surface of the borehole 11. In particular, when the injection material 30 is injected over a long period of time, the injection material 30 may be injected into the sealing packer 2.
3, there was a great risk of leakage upwards, and it was often impossible to recover the sealing packer 23 and the like.

In addition, in order to release the pressure inside the expanded packer 21.23, it is necessary to release the fluid inside the packer 21.23 to the outside, but if it is released using a long fluid supply tube 25 with a small inner diameter, it will take time and work. There was a problem with bad sex.

Furthermore, when the sealing packer 23 expands, the first
As shown in FIG. 8, since the sliding part 29 moves upward and the side surface of the lower end of the rigid tube 17 is exposed, there is a risk that the injection material 30 will stick to this part. There was a problem in that the sealing packer 29 could not be moved downward and the sealing packer 23 could not be completely deflated. For this reason, there was a problem that the seal packer 23 and the like could not be recovered to the ground.

The present invention has been made to solve the above-mentioned problems, and the ground improvement method according to claim 1 provides a ground improvement method that can discharge the injection material leaking above the packer to the ground. The purpose of the soil improvement device according to claim 2 is to provide a soil improvement device capable of discharging the injection material leaked above the packer to the ground, and the soil improvement device according to claim 3 is The purpose of the device is to provide a ground improvement device that can release the fluid in the packer all at once, and the ground improvement device according to claim 4 provides a ground improvement device that can reliably shrink the packer. The purpose is to provide.

[Means to solve the problem]

In the ground improvement method according to claim 1, an injection pipe having a packer disposed at its lower end is inserted into a borehole pipe in a borehole, and after the packer is expanded and brought into close contact with the inner surface of the borehole, A cleaning fluid is force-fed to a fluid passage in the borehole pipe, flows out from below the borehole pipe, rises between the inner surface of the borehole and the borehole pipe, and while cleaning the space therebetween, the cleaning fluid is The injection material is injected from the injection tube that protrudes downward.

In the ground improvement device according to the second aspect, an injection pipe whose lower end protrudes below the lower end of the borehole pipe and supplies the injection material from the ground is inserted into the borehole pipe in the borehole, and the lower end of the injection pipe A packer that expands and comes into close contact with the inner surface of the borehole is disposed in the part, and a fluid supply tube in the borehole pipe that supplies fluid from the ground is connected to the packer,
In a ground improvement device in which, after the packer is inflated and brought into close contact with the inner surface of the borehole, an injection material is press-fitted into the borehole from the injection pipe protruding below the packer, into the borehole pipe, A fluid passage is formed through which cleaning fluid pumped from the ground flows below the borehole pipe.

A soil improvement device according to a third aspect of the present invention is the ground improvement device according to a second aspect, in which a fluid pressure release valve that opens only when the packer is deflated is disposed in the fluid supply tube.

The ground improvement device according to claim 4 is the ground improvement device according to claim 2, wherein the upper end of the packer is fixed to the injection pipe,
A lower end portion is fixed to the injection tube so as to be slidable in the vertical direction, an upper end portion of a retractable protective cylinder covering the injection tube is fixed to the packer, and a lower end portion is fixed to the tip portion of the injection tube. That's what happens.

[For production]

In the ground improvement method according to claim 1, an injection pipe with a packer disposed at the lower end is inserted into a borehole pipe in a borehole, and the packer at the lower end of the injection pipe is expanded to tightly contact the inner surface of the borehole. Ru. After this, the cleaning fluid is pumped into the fluid passage inside the borehole pipe and flows out from the bottom of the borehole pipe, and the cleaning fluid that flows out of the borehole pipe rises between the inner surface of the borehole and the borehole pipe. During this time and while cleaning the upper part of the packer, the injection material is injected from the injection pipe that protrudes below the packer.

In the ground improvement device according to claim 2, a fluid passage is formed in the borehole pipe through which the cleaning fluid pumped from the ground flows below the borehole pipe. The packed packer is expanded and brought into close contact with the inner surface of the borehole. After this, the cleaning fluid is forced into the fluid passage inside the borehole pipe and flows out from the bottom of the borehole pipe.
The cleaning fluid that has passed through the fluid passage rises between the inner surface of the borehole and the borehole tube, and while cleaning the gap and the upper part of the packer, the injection material is injected from the injection tube that protrudes below the bunker.

In the ground improvement apparatus according to claim 3, in the ground improvement apparatus according to claim 2, one fluid pressure release valve that opens only when deflating the packer is disposed in the fluid supply tube, so that in order to deflate the packer, The fluid filled in the bunker is removed from the fluid supply tube (in this case, the fluid pressure release valve is opened, and the fluid is released from the fluid pressure release valve all at once).

In the ground improvement device according to claim 4, in the ground improvement device according to claim 2, the upper end of the packer is fixed to the injection pipe, the lower end is fixed so as to be slidable in the vertical direction of the injection pipe, and the injection pipe is fixed to the injection pipe. The upper end of the covering extendable protective tube is fixed to the packer, and the lower end is fixed to the tip of the injection tube, so when the packer is inflated or deflated, the lower end of the packer moves vertically. However, as the lower end of the packer moves, the protective tube expands and contracts, and the portion of the injection tube on which the lower end of the packer slides is always covered by the protective tube.

〔Example〕

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, details of the present invention will be described with reference to an embodiment shown in the drawings.

Figures 1 and 2 show a second embodiment of the ground improvement device of the present invention, and in the figures, reference numeral 31 indicates a bore hole of about 100 m in length, for example, formed by boring underground. ing.

A drilling pipe 33 is inserted into the borehole 31, and the drilling pipe 33 is formed by connecting a plurality of pipes. A drilling bit 35 is arranged at the lower end of the drilling tube 33.

An injection tube 37 for press-fitting the injection material is housed in the borehole tube 33, and a rigid tube 38 is connected to the lower end of the injection tube 37. 39 are configured.

Further, the rigid tube 38 is formed with an enlarged diameter portion 41,
The enlarged diameter portion 41 is formed in the borehole tube 33 and is locked to the reduced diameter portion 43, thereby fixing the rigid tube 38 to the borehole tube 33.

Further, the rigid tube 38 extends below the lower end of the borehole tube 33, and a packer 45 is disposed at the lower end of the rigid tube 38. This packer 45 is connected to the rigid tube 3
A discharge port 47 is formed at the lower end of the discharge pipe 46 below the packer 45, through which the injection material is discharged.

The upper end of the packer 45 is fixed to the rigid tube 38, and the lower end is fixed to a sliding part 49 disposed at the lower end of the discharge pipe 46 so as to be slidable in the vertical direction.

The lower end of the discharge pipe 46 is provided with a bellows-shaped protection tube 51 that can be expanded and contracted.
The upper end of this protective cylinder 51 is fixed to the sliding part 49, and the lower end is fixed to the lower end of the discharge pipe 46.

Further, a fluid supply tube 53 is connected to the packer 45 from the ground to supply a fluid such as compressed air to the borehole 31 below the packer 45.
is an injection space 55 into which an injection material is injected.

A fluid pressure release valve 57 that opens only when the packer 45 is deflated is disposed at the lower end of the fluid supply tube 53.

As shown in FIG. 3, this fluid pressure release valve 57 includes a valve body 59 disposed between four fluid supply tubes 53;
A ring member 6 is movably housed within this valve body 59.
1 and a spherical check valve 63 housed within the valve body 59.

A discharge port 65 that opens into the borehole pipe 33 is formed in the valve body 59 .

Further, the ring member 61 is housed in the valve body 59 so as to be movable in the direction of fluid flow, and as the ring member 61 moves, the fluid passage is changed.

That is, when fluid is supplied to the packer 45, the ring member 61 moves toward the packer 45 to close the discharge port 65, and when fluid is discharged from the packer 45, the ring member 61 moves toward the ground side. In order to move and open the discharge port 65,
The compressed fluid inside the packer 45 is discharged all at once from this discharge port 65.

At the upper end of the borehole tube 33, as shown in FIGS. 1 and 4, there is a lid member 69 formed with an inlet 67 for pumping a cleaning fluid made of water into the borehole tube 33. is screwed on.

5 The injection tube 37 and the fluid supply tube 53 are inserted through the hole 73 of the lid 71 as shown in FIGS. 5 and 6, which is screwed onto the lid member 69. Extended injection tube 37 and fluid supply tube 5
3 is connected to a pump (not shown) or the like.

In addition, the lid 71 is provided with a gasket 75 as shown in FIGS. 7 and 8 in order to improve the sealing performance within the borehole tube 33.
Packing holder 77 as shown in FIGS. 9 and 10
It is screwed onto the lid member 69 via.

Inside the borehole pipe 33, as shown in FIG.
A fluid passage 79 is formed through which cleaning fluid pumped from the borehole tube 33 flows below.

The cleaning fluid is configured to flow between the borehole tube 33 and the enlarged diameter portion 41 of the rigid tube 38.

In such a ground improvement device, as shown in FIGS. 11 and 12, after the injection material 81 in the borehole 31 bored in the ground has hardened,
A hole is drilled in the ground below to a predetermined depth using a drilling bit 35 placed at the lower end of the drilling pipe 363. When the hole drilling is completed, the packer 45 is inserted into the hole drilling tube 33 together with the injection tube 39, as shown in FIG.

Then, fluid is supplied from the fluid supply tube 53 to inflate the packer 45, and the packer 45 is inserted into the borehole 31.
Stick it to the inside. Thereafter, a cleaning fluid such as water is introduced into the fluid passage 79 from the inlet 67 formed in the borehole pipe 33.
The packer 45 is press-fitted from the tip of the discharge pipe 46 while flowing between the borehole pipe 33 and the inner surface of the borehole 31.
The injection material 81 is press-fitted into the injection space 55 below.

When the injection is completed, the fluid pressure release valve 57 is opened, and the fluid inside the packer 45 flows out from the outlet 65 of the fluid pressure release valve 57, causing the packer 45 to deflate, as shown in FIG. Packer 45 with rigid pipe 38 from drilling pipe 33
is pulled out, the drilling tube 33 is rotated, and the hole is drilled to the scheduled depth. This process is repeated until the final planned depth is reached.

In the ground improvement device configured as described above, the puff □7 and the hook 45 are expanded, and the packer 45 is moved to the borehole 3.
1 inner surface and inject the injection material 81 into the injection space 55 below this packer 45.
The ground around the borehole 31 can be improved without having to pull it out.

In the ground improvement device configured as described above, the packer 45 disposed at the lower end of the rigid pipe 38 in the borehole pipe 33 is expanded, and the packer 45 is inserted into the borehole 31.
It is said to be in close contact with the inner surface. After that, the cleaning fluid is forced into the fluid passage 79 in the borehole 33 and flows out from below, and the cleaning fluid that has passed through the fluid passage 79 rises between the inner surface of the borehole 31 and the borehole 33, During this time and while cleaning the upper part of the packer 45, the injection material 81 is injected from the discharge pipe 46 that protrudes below the packer 45.

Further, in order to deflate the packer 45, the fluid pressure release valve 57 is opened when the fluid filled in the packer 45 is removed from the fluid supply tube 53, and the fluid is released from the fluid pressure release valve 57. released all at once.

Furthermore, when inflating or deflating the packer 45,
The lower end of the bunker 45 moves in the vertical direction, and as the lower end of the packer 45 moves, the protection cylinder 51 expands and contracts, and the lower end of the packer 45 slides on the part of the injection pipe 39;
That is, the lower end of the discharge pipe 46 is always covered by the protective tube 51.

However, in the ground improvement device configured as above,
Since a fluid passage 79 is formed in the borehole tube 33 through which the cleaning fluid pumped from the ground flows below the borehole tube 33, a packer 45 disposed at the lower end of the rigid tube 38 in the borehole tube 33 is formed. is expanded, and this packer 45 fills the borehole 31.
After the cleaning fluid is in close contact with the inner surface of the borehole 31 , the cleaning fluid is forced into the fluid passage 79 in the borehole tube 33 and flows out from below. While cleaning the upper part of the packer 45 and the upper part of the packer 45, the injection material 81 is injected from the discharge pipe 46 which protrudes below the packer 45, and the injection material 81 leaked above the packer 45 is removed from the ground. can be discharged.

Therefore, the injection material 81 leaked above the packer 45.
However, the upper part of the packer 45, the drilling pipe 33 and the borehole 3
1, and the rigid pipe 38, packer 45, borehole pipe 33, etc. can be easily recovered on the ground.

In addition, in the ground improvement device configured as described above, the fluid pressure release valve 57 that opens only when the packer 45 is deflated is disposed in the fluid supply tube 53. When removing the fluid filled in the packer 45 from the fluid supply tube 53, the fluid pressure release valve 57 is opened, and the fluid is released from the fluid pressure release valve 57 all at once, thereby releasing the fluid in the packer 45 all at once. As a result, the working time associated with the contraction of the packer 45 can be significantly shortened, and the workability can be significantly improved compared to the conventional method.

Furthermore, in the ground improvement device 0 configured as described above, the upper end of the packer 45 is fixed to the injection pipe 39, the lower end is fixed to the discharge pipe 46 so as to be slidable in the vertical direction, and the discharge pipe 46 is covered. The upper end of the expandable protective cylinder 51 is fixed to the packer 45, and the lower end is fixed to the tip of the discharge pipe 46, so when the packer 45 is inflated or deflated, the lower end of the packer 45 is However, as the lower end of the packer 45 moves, the protective tube 51 expands and contracts, and the portion of the discharge pipe 46 on which the lower end of the packer 45 slides is always covered by the protective tube 51. Since the injection material 81 does not adhere to the tank, the packer 45 can be reliably contracted, and the rigid tube 38, the backer 45, etc. can be easily recovered on the ground.

In addition, in the ground improvement method described above, the borehole 3
A rigid tube 38 with a packer 45 disposed at its lower end is inserted into the borehole tube 33 in the borehole 1, and the packer 45 disposed in the rigid tube 38 is expanded, causing the packer 45 to tightly contact the inner surface of the borehole 31. The cleaning fluid is forced into the borehole 33 and flows out from the bottom of the borehole 33.
1, the injection material 81 is injected from the discharge pipe 46 that protrudes below the packer 45 while flowing upward between the inner surface of the hole and the drilling pipe 33 to clean the space, and the injection material leaked above the packer 45. 81 can be discharged to the ground, and the rigid pipe 38, packer 45, etc. can be easily recovered to the ground.

Furthermore, by checking the color of the cleaning fluid that has passed through the fluid passage 79 and is discharged to the ground from the borehole 31, it is possible to check whether the injection material 81 has leaked.

In the above embodiment, an example was described in which the distal end of the discharge pipe 46 disposed at the distal end of the injection pipe 39 was covered with a bellows-shaped protective tube 51, but the present invention is not limited to the above embodiment. (As shown in FIG. 15, the injection tube 85
Even if the distal end of the discharge tube 86 is not covered with a bellows-shaped protective tube, the adverse effects caused by leakage of the injection material can be eliminated.

Further, in the above embodiment, an example was explained in which the inside of the borehole pipe 33 was simply made into a fluid passage 79, but the second invention is not limited to the above embodiment, and for example, as shown in FIG. Furthermore, by housing a hose 89 through which cleaning fluid flows in the borehole tube 87 and using the space inside the hose 89 as a fluid passage, substantially the same effect as in the above embodiment can be obtained.

Further, in the above embodiment, an example was explained in which a fluid made of compressed air was supplied to the packer 45, but the present invention is not limited to the above embodiment, and for example, a fluid made of water was supplied to the packer. Also, almost the same effects as in the above embodiment can be obtained.

Further, in the above embodiment, an example was explained in which a cleaning fluid consisting of water was pumped into the fluid passage 79 in the borehole pipe 33, but the present invention is not limited to the above embodiment. Almost the same effect as in the above-mentioned embodiment can be obtained by force-feeding the cleaning fluid into the fluid passage in the borehole pipe.

Further, in the above embodiment, an example was explained in which the present invention was applied to a ground improvement device in which one packer 45 was attached to a rigid pipe 38, but the present invention 3 is not limited to the above embodiment, and for example, Even when the present invention is applied to a double backer in which two packers are attached to an injection pipe, substantially the same effects as in the above embodiment can be obtained.

〔Effect of the invention〕

In the ground improvement method according to claim 1, an injection pipe with a packer disposed at the lower end is inserted into a borehole pipe in a borehole, and the packer at the lower end of the injection pipe is expanded to tightly contact the inner surface of the borehole. Ru. After this, the cleaning fluid is forced into the fluid passage inside the borehole pipe and flows out from the bottom of the borehole pipe, and the cleaning fluid that flows out of the borehole pipe rises between the inner surface of the borehole and the borehole pipe. During this time and while cleaning the upper part of the packer, the injection material is injected from the injection pipe that protrudes below the packer, and the injection material that has leaked above the packer can be discharged to the ground.

In the ground improvement device according to claim 2, a fluid passage is formed in the borehole pipe through which the cleaning fluid pumped from the ground flows downwardly of the borehole pipe. The packed packer is expanded and brought into close contact with the inner surface of the borehole. After this, the cleaning fluid is forced into the fluid passage in the borehole pipe and flows out from the bottom of the borehole pipe, and the cleaning fluid that has passed through the fluid passage rises between the inner surface of the borehole and the borehole pipe. While cleaning the upper part of the backer, the injection material is injected from the injection pipe that protrudes below the packer, and the injection material that has leaked above the packer can be discharged to the ground.

In the ground improvement apparatus according to claim 3, in the ground improvement apparatus according to claim 2, a fluid pressure release valve that opens only when deflating the packer is disposed in the fluid supply tube. When removing the fluid filled in the packer from the fluid supply tube, the fluid pressure release valve is opened, and the fluid is released from the fluid pressure release valve all at once, allowing the fluid inside the packer to be released all at once.

In the ground improvement device according to claim 4, in the ground improvement device according to claim 2, the upper end of the packer is fixed to the injection pipe, the lower end is fixed so as to be slidable in the vertical direction of the injection pipe, and The upper end of the expandable protective tube that covers the packer is fixed to the packer, and the lower end is fixed to the tip of the injection tube, so when the packer is inflated or deflated, the lower end of the packer moves vertically. However, as the lower end of the packer moves, the protective tube expands and contracts, and the portion of the injection tube on which the lower end of the packer slides is always covered by the protective tube, ensuring that the packer is deflated.

[Brief explanation of drawings]

FIG. 1 and FIG. 2 are longitudinal sectional views showing one embodiment of the ground improvement device according to the present invention. FIG. 3 is a longitudinal sectional view showing the fluid pressure release valve of FIG. 2. FIG. 4 is a longitudinal cross-sectional view showing the lid member of FIG. 1 and a portion of its vicinity in a cutaway manner. FIG. 5 is a cross-sectional view of the lid of FIG. 4. FIG. 6 is a longitudinal sectional view taken along line VI-VI in FIG. 5. FIG. 7 is a cross-sectional view showing the packing shown in FIG. 4. FIG. 8 is a longitudinal sectional view taken along the line ■-■ in FIG. 7. FIG. 9 is a cross-sectional view showing the packing retainer of FIG. 4. FIG. 10 is a longitudinal sectional view taken along the line XX in FIG. 9. FIGS. 11 to 14 are vertical sectional views showing the ground improvement method step by step. FIG. 15 is a partially cutaway vertical cross-sectional view of the ground improvement device in a state where no bellows-shaped covering member is disposed on the injection pipe. FIG. 16 is a longitudinal cross-sectional view showing an example in which a hose is housed in a borehole tube and the inside of the hose is used as a fluid passage. FIG. 17 and FIG. 18 are longitudinal sectional views showing a conventional ground improvement device. FIG. 19 to FIG. 22 are vertical sectional views showing the conventional ground improvement method step by step. [Explanation of symbols of main parts] 31... Boring hole 7 33.87... Drilling pipe 39.85... Injection pipe 45... Backer 51... Protective tube 53... Fluid supply Tube 55...Injection space 57...Fluid pressure release valve 79...Fluid passage 81...Injection material. 8 6 Figure 83- -85- L-1 ” Procedural amendment document Amane case display 1990 Patent application No. 25754 Name of invention Ground improvement method and soil improvement device used in this method Case of person who amends Relationship with Applicant Address 6-22 Matsugaeda-cho, Kita-ku, Osaka Name Japan Basic Technology Co., Ltd.

Claims (4)

[Claims] (1) Insert an injection pipe with a packer at its lower end into a borehole pipe, inflate the packer and bring it into close contact with the inner surface of the borehole, and then insert the injection pipe into the borehole pipe. The cleaning fluid is forced to flow out from below the borehole pipe, rises between the inner surface of the borehole and the borehole pipe, and while cleaning the space therebetween, the injection pipe protrudes below the packer. A ground improvement method characterized by injecting an injection material. (2) Insert an injection tube whose lower end protrudes below the lower end of the borehole tube and supplies the injection material from the ground into the borehole tube in the borehole. A packer is placed in close contact with the inner surface of the borehole, and a fluid supply tube in the borehole pipe that supplies fluid from the ground is connected to this packer, and after the packer is expanded and brought into close contact with the inner surface of the borehole. , a ground improvement device in which injection material is pressurized into the borehole from the injection pipe protruding below the packer, in which cleaning fluid pumped from the ground into the borehole pipe is pumped below the borehole pipe; A ground improvement device characterized by forming a fluid passage for circulation. (3) The soil improvement device according to claim 2, wherein the fluid supply tube is provided with a fluid pressure release valve that opens only when the packer is deflated. (4) The upper end of the packer is fixed to the injection pipe, and the lower end is fixed so as to be slidable in the vertical direction of the injection pipe, and the upper end of the expandable protection cylinder covering the injection pipe is fixed to the packer. 3. The soil improvement device according to claim 2, wherein the soil improvement device has a lower end fixed to the tip of the injection pipe.