JPH04347206A - Land improvement method - Google Patents

Abstract

PURPOSE:To enable the formation of a consolidated body and to prevent the generation of the looseness or a hollow defect of the land by providing a sludge pipe on a developing path of the consolidated body forming land, and providing a control device to control sludge withdrawal pressure and an earth moving amount thereto. CONSTITUTION:An excavator 6 is constituted of an injection pipe 4 injecting a grout through a hole excavated in a horizontal direction, a compressor 7 and a high-pressure pump 8. A sludge pipe 12 is provided on a developing path of the consolidated body 10 formed with an excavation bead 5 on the front end of the injection pipe 4, and a pressure gauge 14, a controlling valve 15, an earth moving flow meter, etc., are provided to the sludge pipe to make continuity of removed earth to a sedimentation tank 18 through a sludge withdrawal and water supply pipe 16. After that, the land is excavated by the excavator 6, and high-pressure grout is injected to the land from the injection pipe 4 through the high-pressure pump 7. At that time, the discharge of sludge and muddy water of excavated earth is controlled with the pressure gauge 14, the controlling valve 15 and the flow meter 17. According to the constitution, land improvement work as scheduled can be easily carried out.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a ground improvement method in which the ground is cut to form a solid body using grout, water, air, or other high-pressure jetting force.

0002

[Prior art] In recent years, grout such as cement milk is injected at high pressure from near the tip of the injection pipe, the ground is cut with that pressure, and at the same time, the cut soil and grout are stirred and mixed to form a solid in the ground. A ground improvement method that utilizes high-pressure injection force, an improved method that increases the cutting force by applying compressed air to high-pressure grout, and enlarges the diameter of the solid body, or a method that uses compressed air from a discharge port installed in the upper stage of the injection pipe. Construction methods are being implemented, such as cutting the ground by injecting high-pressure water along the grout and discharging the muddy ground, while injecting grout from the outlet provided at the bottom of the injection pipe to form a solid mass. . In addition, the upper section,
There is also a construction method in which high-pressure grout is injected with compressed air from a discharge port installed in the lower stage, and the grout is cut, stirred, and mixed to create a solid body and improve the ground.

[0003] When these methods are used to perform construction vertically from the ground, compressed air is used in combination to prevent the jetting force of high-pressure water or high-pressure grout from attenuating in the ground.
At the same time, the ability to discharge cutting mud to the ground can be increased. Although some of the injected or injected grout is discharged to the ground together with the mud, the majority is stirred and mixed into the ground.
Alternatively, after the mud has been discharged, it is filled into a cavity and becomes a solid, which effectively functions for ground improvement.

0004

[Problems to be Solved by the Invention] However, when using these construction methods that utilize high-pressure injection force to horizontally cut ground with a high groundwater level, especially when the depth is large and the pressure is high, Most of the injected or sprayed grout is discharged toward the front. Furthermore, due to underground water gushing out from around the injection pipe, almost all of the filled grout is discharged, making it impossible to form the desired solid.

Furthermore, depending on the ground conditions, the injected compressed air cannot be fully discharged and remains in the upper part of the cut ground, making it even more difficult to fill with grout. It was not put into practical use because of the problems of loosening and leaving cavities.

[0006] The present invention has been made in view of the above-mentioned problems. The purpose is to suppress the discharge of filled grout and cutting mud by using a horizontal construction method that utilizes high-pressure injection power, even if the ground is deep or has a high groundwater level and high water pressure. This purpose is to propose a method for improving the ground that can form a solid body while ensuring that the soil is solid and does not leave any looseness or cavities in the ground.

[0007]

[Means for Solving the Problems] This invention aims to inject high-pressure grout or high-pressure water and grout from an injection pipe, or inject compressed air in combination with this to cut the ground in a substantially horizontal direction while grouting. A soil improvement method in which a solid body having a diameter centered around a drilling rod is formed by stirring and mixing, and a sludge drainage pipe that communicates between the inside and outside of the ground along the upper end position of the diameter of the solid body to be formed. The above-mentioned problem was solved by constructing a ground improvement method characterized by installing a sludge pipe and controlling the volume of sludge by setting the sludge pressure discharged from the sludge pipe to an appropriate value. It is something.

[0008]

[Operation] In this ground improvement method, a sludge pipe is installed in advance along the upper end of the diameter of the compact to be formed to communicate between the inside and outside of the ground, and a pressure regulating device and a flow rate are installed near the discharge port outside the ground. Attach a meter, etc. to detect the pressure of sludge discharged from the sludge pipe. The pressure regulating device can arbitrarily set an appropriate mud discharge pressure, and controls and discharges the discharge amount of mud, muddy water, etc. of cutting earth and sand by maintaining the set appropriate mud discharge pressure. . Thereby, the grout injected from the injection pipe located at the center of the construction diameter can be suppressed from being discharged along with the mud, and the spouting of pressurized water in the ground can also be prevented. It also prevents mud and grout from being discharged from around the injection pipe due to extremely high pressure in the ground, making it possible to keep the required amount of grout in the cutting ground, and ensuring solidification of the specified diameter. can be created. In addition, since the mud drain pipe is arranged at the upper part of the cutting diameter, there is no residual air trapped in the upper part, and it is possible to prevent the loosening of the ground and the occurrence of defects due to cavities.

[0009]

[Example] Hereinafter, an example will be given and explained with reference to the drawings. FIG. 1 shows an example of improvement construction of the ground 3 performed from inside a shaft 2 blocked by a shaft wall 1.

The apparatus used in this embodiment is equipped with an injection pipe 4 that penetrates into the ground 3 in a horizontal direction and also serves as a drilling rod. The drilling rod 4 is made of a double pipe with a drilling bit 5 at its tip, has a boring device 6 at the base end of the injection pipe 4 located in the shaft 2, and has piping connected to a high-pressure pump 7 and a compressor 8. It is connected. Further, around the injection pipe 4 that penetrates the shaft wall 1, a double mouth packer 9 is attached to enable rotation of the pipe, and an airtight seal is provided.

The injection pipe 4 is rotated about an axis by a boring device 6 to dig into the ground.

After reaching the required depth, the compressor 8 supplies compressed air and the high-pressure pump 7 supplies high-pressure grout to the injection pipe 4, and these are injected into the ground from the tip.

In addition, as shown in FIG. 2, the apparatus of this embodiment has a structure in which a solid body 10 having a substantially circular cross section is formed along the upper end position of a diameter 11 centered around an injection pipe 4 formed by injecting grout. A mud removal pipe 12 is provided. The base end of the mud removal pipe 12 penetrates the shaft wall 1 and is located inside the shaft 2, communicating the inside and outside of the ground 3. The mud drainage pipe 12 in the ground 3 has a large number of water intake ports 13 perforated therein, and a mouth packer 9 is installed around the pipe that penetrates the shaft wall 1.
Sludge drainage water pipe 1 which is airtightly sealed and equipped with a pressure regulator equipped with a pressure gauge 14 and a regulating valve 15 at the base end.
6 are connected. Flowmeters 17 and 2 are installed in the sludge water pipe 16.
Two settling tanks 18 are arranged in series.

[0014] In this embodiment, the ground water level 19 is high and the ground under pressure water is improved, and high-pressure grout 20 is injected from the tip of the injection pipe 4, or compressed air is injected along it. At the same time, the boring device 6 is operated to stir and mix the grout 20 while pulling out the injection pipe. Groundwater pressure is applied in the ground 3, and at the same time high pressure grout 2
The pressure in the ground increases further due to the pressure of zero and compressed air, but when the injection force reaches the mud removal pipe 12 at the upper position of the construction diameter 11, the cut earth and sand including the grout flows through the mud removal pipe. It is discharged outside the atmospheric pressure, that is, into the shaft. Furthermore, as the injection pipe rotates, the direction of the injection moves away from the mud removal pipe, but the cut earth and sand is always guided and discharged toward the upper mud removal pipe where there is less resistance. The amount of sludge discharged is controlled based on the condition that the sludge discharge pressure is maintained at an appropriate pressure set in advance on the pressure gauge 14.

Therefore, although some of the injected grout is discharged together with the cut mud, by setting the valve pressure of the pressure regulator to an appropriate value based on the pore water pressure in the ground, unnecessary discharge can be avoided. , it is possible to create a desired solidified body 10 in which earth and sand and grout are stirred and mixed. In addition, since the air is discharged through the mud removal pipe, there is no risk of leaving loose ground or cavities.

[0016]

[Effects of the Invention] This invention is as described above, and according to this construction method, even in deep ground with a high groundwater level, construction can be performed in the horizontal direction using high-pressure jetting power to achieve the planned construction diameter. It is possible to secure and form solid bodies and improve the ground.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal cross-sectional view showing a ground improvement method according to an example.

FIG. 2 is a sectional view taken along the line AA in FIG. 1;

[Explanation of symbols]

1... Shaft wall, 2... Vertical shaft, 3... Ground, 4... Injection pipe, 5... Drilling bit, 6... Boring device, 7... Compressor,
8... High pressure pump, 9... Mouth packer, 10... Solid body, 1
1... Creation diameter, 12... Sludge drainage pipe, 13... Water intake, 14... Pressure gauge, 15... Control valve, 16... Sludge drainage water pipe, 17. ...flow meter, 18...settling tank, 19...groundwater level, 20...high pressure grout.

Claims (1)

[Claims] [Claim 1] High-pressure grout, high-pressure water and grout are injected from the injection pipe, or compressed air is injected in combination with this, and the ground is cut in a substantially horizontal direction while the grout is stirred and mixed to form the injection pipe. A soil improvement method that forms a consolidated body with a diameter centered around A ground improvement method characterized by controlling the amount of mud discharged by setting the pressure of mud discharged from the pipe to an appropriate value.