JPS603577B2 - Ground improvement method using soil improvement chemical injection - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a ground improvement method for improving soft ground by injecting a soil improvement chemical into the ground.

In the conventional soft ground improvement method, water is injected to install the injection pipe, which tends to create voids around the outer circumference of the injection pipe. , the chemical liquid is ejected from the gap to the ground,
This causes a loss of hydraulic pressure and the effect of injecting chemical liquid into the ground is significantly reduced. Therefore, in sleeve construction methods such as the soletanche method, after the injection pipe is erected into the ground by injecting pressurized water, grout is applied to seal the outer circumference of the injection pipe, and then full-scale chemical injection is carried out. However, the problem is that the grout prevents the chemical solution from penetrating into the ground, making grout construction laborious.

In addition, in the instant setting double pipe construction method, the voids around the injection pipe are filled and sealed with a gel time chemical solution that is close to instant setting, but it is not very effective against sand deposits and has the same drawbacks as above. .
The present invention aims to solve the above-mentioned difficulties in the conventional ground improvement method by injection of soil improvement chemicals. The chemical solution injection pipe is penetrated into the ground to be improved to a required depth without using water using a shoe having a spiral digging blade, and the ground surface to be improved is directly exposed to the outer peripheral surface of the chemical solution injection pipe at a predetermined depth. After the chemical solution is brought into close contact with the chemical solution injection pipe, a soil improvement chemical solution is press-fitted from inside into the plurality of annular recesses provided on the outer periphery of the chemical solution injection pipe, and the chemical solution is embedded in the annular recessed port. The present invention provides a ground improvement method by injection of a soil improvement chemical, which is characterized in that the ground improvement chemical is forced into the outer peripheral ground by expanding an elastic annular body.

The construction method of the present invention has the above-mentioned configuration, and uses a shoe having a spiral excavation blade with a maximum diameter that is approximately the same as the outside diameter of the chemical injection pipe, to extremely efficiently excavate only the ground within a range that is approximately the same as the outside diameter of the injection pipe. The chemical injection pipe can be easily penetrated to a predetermined depth by digging, without using water, and according to the penetration method, the ground to be improved can be seen on the outer circumferential surface of the chemical injection pipe that has reached a predetermined depth. It is in a compacted state that it is directly in close contact with the chemical injection pipe, and not only does it not create a gap around the outer periphery of the chemical injection pipe, but also forms a consolidated layer of the ground itself to which no water is added. Eliminates the need for sealing processes such as grouting,
There is no loss of the chemical liquid or liquid pressure around the chemical liquid injection tube, and the transfer of the chemical liquid is moderately permitted.

Therefore, water injection and sealing processes around the chemical injection pipe are no longer necessary, making it possible to significantly shorten and simplify the process.In addition, the chemical injection pipe can be easily penetrated, improving the efficiency of chemical liquid penetration into the ground. The range can be expanded, and the ground improvement effect can be greatly improved.

Furthermore, according to the method of the present invention, since an injection tube is used in which elastic annular bodies are embedded and iron-bonded inside a large number of annular recesses arranged on the outer periphery of the chemical injection tube, penetration of the chemical injection tube is prevented. In some cases, the elastic annular body does not obstruct penetration and is not moved significantly, effectively preventing dirt from entering the annular recessed window, making injection of the chemical solution extremely smooth.

In addition, according to the method of the present invention, it is possible to penetrate the chemical liquid injection pipe without using water, so that the chemical liquid infiltrated in the previous process can be made uneven by the injection of pressure water, or the chemical liquid can penetrate due to the presence of pressure water. In addition, injection of pressurized water into wet ground is not preferable for chemical injection, and it has a high sensitivity ratio, which means that once disturbed, it will return to its original state. In the case of viscometers that are difficult to return to, the injection of pressurized water is particularly undesirable and inhibits the penetration of chemical solutions, but the method of the present invention does not have such drawbacks and can be used on flooded ground and viscous ground. It is possible to effectively inject chemicals into the area.

Hereinafter, one embodiment of the construction method of the present invention will be described with reference to the drawings. 1 to 3 show a chemical liquid injection pipe 1 used in the construction method of the present invention, and 1 in the figure is a hollow chemical liquid injection pipe, and the tip thereof has a spiral digging blade 2 on its outer periphery. A shoe 3 is attached to the shoe, and the maximum diameter of the shoe 3 is the same as that of the chemical injection tube 1.
It is approximately the same as the outer diameter of. In addition, a large number of annular grooves 4 are provided on the outer circumferential surface of the drug solution injection tube 1 at predetermined intervals, and drug solution injection holes 5 are formed radially between each annular groove 4 and the hollow part of the drug solution injection tube 1. It is arranged and operated quickly.

Further, an elastic annular body 6 made of hard rubber or the like is embedded in each of the annular recessed windows 4, and the elastic annular body 6 normally closes the chemical injection hole 5, and The inside of the annular recess 4 is filled to prevent the intrusion of earth and sand, and the chemical injection pipe 1 is
When a soil improvement chemical is press-fitted into the bottom side of the annular concave window 4 from the chemical injection hole 5 in the hollow part, the elastic annular body 6 is pushed outward and the soil improvement chemical is poured from the side edge of the elastic annular body 6. It is designed to be ejected towards the ground.

In addition, 7 is a screw thread part for connecting an injection tube above the drug solution injection tube 1. The illustrated chemical injection pipe has the above-described configuration.Next, to explain the ground improvement method using this chemical injection pipe 1, first, the shoe 3 attached to the tip of the chemical injection pipe 1 described above , the chemical liquid injection pipe 1 is penetrated into the ground to be improved to a required depth without using water.

When penetrating, the spiral digging blade 2 of the shoe 3 effectively digs into the ground only within a range approximately the same as the outer diameter of the chemical injection pipe 1, making it easy to penetrate without using water. be able to. As described above, when the chemical liquid injection pipe 1 is penetrated to a predetermined depth, the ground surface to be improved comes into direct contact with the outer peripheral surface of the chemical liquid injection pipe 1. In other words, the shoe 3 having the spiral digging blade 2 digs through the ground within a limited minimum area and moves it to the surrounding area, and since the ground is minimized, the chemical solution is The soil on the outer circumferential surface of the injection tube 1 looks like the ground itself has been directly compacted, and the consolidated layer portion is in close contact with the outer circumferential surface of the chemical injection tube 1. Next, a soil improvement chemical is press-fitted from the hollow part of the chemical injection pipe 1 into the bottom side of each annular groove 4 through the chemical injection hole 5 .

By press-fitting the chemical liquid, each elastic annular body 6 embedded in the annular concave tube 4 is pushed outward and an appropriate amount of space is formed between the side edge portion of the elastic annular body 6 and the annular concave groove 4. To create a gap, soil improvement chemicals are forced into the surrounding ground. Since the above-mentioned consolidated layer of the ground is compressed and formed around the chemical injection pipe 1, the existence of the consolidated layer eliminates the loss of the soil improvement chemical and the loss of its hydraulic pressure, and the consolidated layer Since these are in a state where they have hardly been worshiped, the migration of the chemical solution is allowed to a certain extent, and the soil improvement chemical solution discharged from each annular recessed window is transferred into the surrounding ground with sufficient hydraulic pressure. Penetrates evenly and effectively and reaches deep inside. In addition, the elastic annular body 6 described above is embedded in the annular groove 4 at the time of initial penetration and does not protrude from the outer circumferential surface of the drug solution injection tube 1, making it easier for the drug solution injection tube 1 to penetrate. Furthermore, the infiltration of earth and sand into the annular recess 4 is effectively prevented, and the discharge of the ground improvement chemical solution in the next step becomes smooth.
Although the present invention has been described above with reference to embodiments, it goes without saying that the present invention is not limited to such embodiments, and that various design modifications can be made without departing from the spirit of the present invention. .

[Brief explanation of the drawing]

FIG. 1 is a vertical cross-sectional view showing an example of a chemical injection tube used in the construction method of the present invention, FIG. 2 is a partially enlarged vertical cross-sectional view of FIG. 1,
FIG. 3 is a partially enlarged cross-sectional view of FIG. 1. 1: Chemical injection tube, 2: Spiral drilling blade, 3: Shoe, 4: Annular recessed window, 5: Chemical injection hole, 6: Elastic annular body. Figure 1 Figure 2 Figure 3

Claims (1)

[Claims] 1. A shoe having a helical digging blade with a maximum diameter that is approximately the same as the outside diameter of the chemical injection tube is attached to the tip of the hollow chemical injection tube.
After penetrating the chemical injection pipe into the ground to be improved to a required depth without using water and bringing the improved ground surface into direct contact with the outer peripheral surface of the chemical injection pipe at a predetermined depth, A soil improving chemical solution is press-fitted from inside into a plurality of annular recesses arranged on the outer periphery of the chemical solution injection pipe, and the elastic annular body embedded in the annular recesses is pushed and expanded. A soil improvement method using soil improvement chemical injection, which is characterized by injecting soil improvement chemicals into the surrounding ground.