JPH0516496B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an improvement in a ground improvement method for injecting a consolidation material into soft ground or the like.

[Conventional technology]

BACKGROUND ART In recent years, injection injection means have been frequently used as a soil improvement means in place of chemical injection means.

This injection injection means injects jet water mixed with consolidation material from a pipe buried in the ground, cuts the ground, and stirs the cut soil and consolidation material to solidify it in the ground. It forms an improved body.
In this method, the cutting of the ground and stirring of the earth and sand and consolidation material are performed using jet water, so depending on the soil quality of the ground, the cutting range may be narrow and it may not be possible to obtain a sufficient size of the consolidation improvement body. There is.

For this reason, various improvements have been made regarding the injection injection means, for example, one shown in FIG. 3 is known.

The injection injection means shown in Fig. 3 includes a jet water injection nozzle B and an air injection nozzle C installed in a pipe body A buried in the ground E, and jet water is injected in the air to cut the ground E. The aim is to improve one's abilities.

In addition, the present applicant has proposed, in Japanese Patent Application No. 113617/1983, a nozzle for cutting the ground and a nozzle for injecting solidifying material, which are provided in separate locations. Efforts are being made to expand the range of cement injection.

[Problem that the invention seeks to solve]

However, with the above-mentioned conventional technology, it is difficult to change the type, concentration, etc. of the consolidation material in accordance with the soil quality of the cutting ground, and there is a problem that the strength of the consolidated improved body that is formed becomes uneven. There is. In addition, the cut earth and sand may coexist with the differential that has become a consolidated improved body and the muddy water, and to resolve this, measures such as slowing down the cutting speed of the ground must be taken. However, there is a problem that the construction time is long.

[Purpose of the invention]

The present invention was made to solve these problems, and its purpose is to shorten the construction time for soil improvement and to equalize the strength of the consolidated improved body formed.

[Means for solving problems]

The ground improvement method according to the present invention cuts the ground by injecting jet water from a pipe body buried in the ground, and at the same time discharges compressed air from the pipe body, thereby creating an air area and a muddy water area in the ground. and sucking up muddy water from the muddy water region through the pipe body with an air lift using compressed air in the air region,
Consolidating agent-added mud, which is obtained by adding a consolidating agent to the sucked up muddy water, is injected into the lower part of the muddy water area through the pipe body.

[Action of the invention]

The ground improvement method according to the present invention sucks up cut earth and sand as muddy water and adds a consolidating material on the ground.
This makes it possible to freely change the concentration of the caking agent and to equalize the strength of the consolidated improved body that is formed.Also, by injecting the caking agent-added mud below the muddy water area, This prevents muddy water from mixing with the consolidated improved body and shortens construction time.

[Embodiments of the invention]

Embodiments of the ground improvement method according to the present invention will be described below with reference to FIGS. 1 and 2.

The method of the present invention utilizes a pipe A buried in the ground E in the same way as conventional injection injection means,
Pipe body A includes an outer pipe 1 fixed to the ground E, and an inner pipe 2 slidably fitted to the outer pipe 1 via a sealing material 3.
It consists of. A chuck portion 4 is provided at the upper portion of the inner tube 2, and the inner tube 2 is configured to move up and down, swing, and rotate via the chuck portion 4 by a predetermined device.

A high-pressure water pipe 5 and an air pipe 6 are disposed in the inner pipe 2. A jet water injection nozzle 7 is attached to the tip of the high-pressure water pipe 5, and an air suction port is attached to the tip of the air pipe 6. 8 is attached. High-pressure water is supplied to the high-pressure water pipe 5 from a pump (not shown) installed on the ground E, and the jet water injected from the nozzle 7 cuts the ground E. The air pipe 6 is equipped with a compressor (not shown) installed on the ground E.
Compressed air is supplied from the air suction port 8, and the cutting gap formed by the jet water is filled with the compressed air. Therefore, an air region D and a muddy water region I are defined in the ground E. For this reason, jet water is injected into the air with almost no resistance.
Its range becomes longer and the improvement range of Ground E can be expanded. Further, by attaching the ultrasonic distance measuring sensor 15 to the inner pipe 2 located in the air region D and controlling the position of the nozzle 7, the improvement range of the ground E can be changed freely.

Further, the inner pipe 2 is provided with an earth removal pipe 11 having a muddy water suction port 9 that opens into the muddy water area 1 and an air inlet 10 that opens into the air area D. A so-called air lift effect occurs due to the suction pressure of the compressed air flowing into the drain pipe 11, and muddy water is also sucked into the earth discharge pipe 11 and sucked upward.

As shown in FIG. 2, a dehydration tank 12 and a mixing tank 13 are provided above the earth removal pipe 11. The sucked mud water is dehydrated in the dehydration tank 12, and then mixed with cement, mortar, or other solidifying material in the mixing tank 13. G is added and mixed. By adding the consolidating material G on the ground E in this way, it is possible to change the mixing amount, type, etc. of the consolidating material G in accordance with the soil quality of the muddy water (ground E), and Dehydration tank 1 if dehydration is not required
It is also possible to directly introduce the muddy water into the mixing tank 13 without passing through the mixing tank 2.

The solidifying material-added mud H formed in the mixing tank 13 is sent to the injection pipe 14 via a pump (not shown) or the like. The injection pipe 14 is disposed within the inner pipe 2 and extends to the lower end of the inner pipe 2, and the caking agent-added mud H is injected into the lower part of the muddy water area I, and the caking improvement body F is placed below the muddy water area I. will be formed. This consolidated improved body F is gradually expanded upward by gradually raising the inner tube 2.

That is, during construction in the ground E, the air area D, muddy water area E, and consolidated improvement body F will be divided into three layers, so that there will be no hindrance to cutting with jet water or sucking up muddy water. The construction time can be shortened by increasing the rising speed of the inner pipe 2.

〔Effect of the invention〕

As described above, in the ground improvement method according to the present invention,
Since the amount of the consolidation material added can be freely changed depending on the soil quality of the cutting ground, the strength of the consolidated improved body formed can be made uniform.
In addition, since the ground is divided into three layers: an air region, a muddy water region, and a consolidated improvement body, there is no problem such as cutting of jet water, and the construction time can be shortened.

Furthermore, since muddy water is sucked up by an air lift, it is possible to reduce the power required for construction work, which has the effect of reducing construction costs.

[Brief explanation of the drawing]

Fig. 1 is a longitudinal sectional view showing the main parts of the equipment used in one embodiment of the ground improvement method according to the present invention, Fig. 2 is an explanatory diagram showing a dewatering tank and a mixing tank, and Fig. 3 shows a conventional example. FIG. 5... High pressure water pipe, 6... Air pipe, 7... Nozzle, 8... Air suction port, 11... Earth discharge pipe, 14...
...Injection tube, A...Tube body, D...Air area, E...
Ground, F... Consolidation improvement, I... Mud area.

Claims (1)

[Claims] 1. By injecting jet water from a pipe buried in the ground to cut the ground and discharging compressed air from the pipe, an air region and a muddy water region are formed in the ground, and the air region is The muddy water is sucked up from the muddy water area through the pipe body by an air lift using compressed air, and the mud added with the caking agent is injected into the muddy water area below the muddy water area through the pipe body. Ground improvement method.