JPS594006B2 - Ground improvement method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a ground improvement method, in which a curing agent is jetted out at high pressure from the core of a double nozzle provided at the tip of a blade extending from an injection pipe, and at the same time compressed air is injected from an enveloping part. This invention relates to a method of improving the cutting of the ground at a position protruding from an injection pipe by injecting it, and also improving the ground by using the protruding nozzle as a stirring blade to stir and mix the soil.

Conventionally, the method of improving the ground has been to inject a hardening agent into the ground at high pressure and high speed from a nozzle installed on the side wall of the injection pipe, and then mix and stir this hardening agent with a jet or a separate stirring blade. However, with this method, there is a limit to the distance that the curing agent jet can reach, and it was only possible to improve a small area around the injection tube.

In order to increase the diameter of the improved soil, the stirring head is equipped with a blade with two flow paths, and a double nozzle consisting of a core nozzle and an surrounding nozzle is installed at the tip of this blade, and the core nozzle hardens from the core nozzle. At the same time as the curing agent is injected at high pressure, compressed air is injected at high pressure from the surrounding nozzle to surround the curing agent to prevent the dispersion and attenuation of the jet stream, improving cutting efficiency. This provides an improvement method for the purpose of creating cylindrical improved ground.

An embodiment of the ground improvement method according to the present invention will be described in detail below with reference to the accompanying drawings.

1 includes an outer tube 2 and a plurality of inner tubes 3a, 3 inside the outer tube 2.
It is an injection pipe in which a plurality of stirring blades 5 and 6 are arranged side by side in a row, and a plurality of stirring blades 5 and 6 are provided on the head 4 at the top end thereof at intervals vertically and projecting in the lateral direction.

Each of the stirring blades 5 and 6 is provided with a core nozzle 7 for injecting a curing agent, and an enveloping nozzle 8 for injecting air so as to surround the nozzle 7 on the outside.
It communicates with the passages 9 and 10 provided in the.

The passages 9 and 10 provided in the head 4 are inner tubes 3a.

3b and communicates with the outer tube and inner tube 3c.

The upper end of the injection tube 1 is provided with a swivel device 11 .

The upper ends of the outer tube 2 and the inner tubes 3a, 3b, 3c are connected, and the swivel device 11 is connected to each hose 12a, 12.
b, 12c, 12d to a high pressure pump for pumping the curing agent and to a source of compressed air (none of which is shown).

Further, the injection tube 1 is driven by a driving device 13 so as to be able to rotate and move up and down.

The injection pipe 1 configured as above is lowered into the ground,
When a predetermined depth is reached, the inner pipe 3b corresponding to the surrounding nozzle 8 is connected via the hose 12 from the curing agent tank and the compressed air source.
, 3c is air, and the inner pipe 3a corresponding to the core nozzle 7 is fed a curing agent under high pressure and is injected at high speed.
3, the injection tube 1 is rotated up or down to inject the curing agent.

By injecting the curing agent in this way, the curing agent jet is guided to the tips of the stirring blades 5 and 6 and is injected from the overhanging position, and is further included in the air jet to prevent diffusion and extend the reach. Ru.

In addition, the hardening agent is supplied to the inner pipes 3, 3, . . . by separate independent hoses 12, 12, . Unlike branching into the spout, a large amount of curing agent is injected in a short time and thoroughly stirred and mixed by a plurality of stirring blades, making it possible to create an extremely dense and strong structure.

In particular, increasing the amount of curing agent discharged is extremely effective for improving ultra-soft ground that exceeds the liquid limit, and in combination with the action of multiple stirring blades, rapid and effective ground improvement can be achieved.

In addition, in non-flowable ground, a hardening agent can be supplied to the protruding part of the stirring blade by a method such as installing a hardening agent supply nozzle on the side wall of the outer tube to form a cylindrical shape, or it can be hardened into a donut shape without supplying the hardening agent. may be created.

As is clear from the above-mentioned configuration, the present invention involves inserting the injection pipe 1 consisting of the outer pipe 2 and a plurality of inner pipes 3a and 3b into the ground, rotating it with the drive device 13, and passing it through the swivel device 11. By feeding the curing agent and compressed air into the inner and outer tubes at high pressure, the curing agent is further transferred from the core nozzle 7 of the double tip nozzle of the stirring blades 5 and 6 protruding from the injection tube, and further from the enclosing nozzle 8 that surrounds this nozzle 7. Compressed air is injected at high speed and mixed by forced stirring using stirring blades 5 and 6 installed at the same time, and each of the double nozzles communicates with each inner tube built into the outer tube. Therefore, the amount of curing agent discharged can be dramatically increased.

Moreover, the curing agent injected from the core nozzle 7.8 at the tip of the stirring blades 5, 6 travels straight while cutting the earth and sand on the ground due to the injection force due to the pressure and flow velocity of the compressed air, and the radius becomes a dog, increasing the diameter of the constructed body. While increasing the size, a complete improved body can be created by stirring and mixing.

[Brief explanation of drawings]

The drawings show an embodiment of the ground improvement method according to the present invention, in which Fig. 1 is a front view of the injection pipe, Fig. 2 is an enlarged sectional view of the head, and Fig. 3 is an enlarged sectional view of the swivel device. . 1...Injection tube, 2...Outer tube, 3a,
3b, 3c...Inner tube, 4...Head, 5, 6...Stirring blade, 7...Curing agent injection core nozzle, 8... ... Air injection surrounding nozzle, 9, 10 ... Passage, 11 ... Swivel device, 12a to 12d ... Hose, 13 ...
...Drive device.

Claims (1)

[Claims] 1 At the tip of the injection tube, which has a plurality of inner tubes arranged side by side inside the outer tube, there are two flow paths and a plurality of stirring blades with double nozzles at the tip are provided extending from the injection tube. , an injection pipe provided with a swivel device at the upper end connected to each inner pipe and outer pipe and connected to a hardening agent high-pressure pump and a compressed air source via a hose is inserted to a predetermined depth in the target ground, and the above-mentioned stirring blade is While injecting compressed air from the core nozzle of the double tip nozzle to the surrounding nozzle surrounding the curing agent, the injection tube is rotated by the driving device and raised or lowered. A ground improvement method characterized by stirring and mixing the hardening agent and earth and sand while cutting the surrounding earth and sand by high-pressure jetting of the hardening agent and compressed air from a nozzle to create a dog-like structure with a radius.