JPS6062324A - Ground improvement work - Google Patents

Abstract

PURPOSE:To uniformly form stabilized ground by a method in which a powdery improving agent and compressed air which are joined at a nozzle port are jetted against a shield wall provided to the inner wall of a stirring blade, and compressed air is dissipated from an air vent holes provided in the stirring blade. CONSTITUTION:A rotary shaft 4 is actuated and penetrated to a given depth by means of a transmission mechanism 13. While pulling up the shaft 4, a powdery improving agent, e.g., cement, etc., in a hopper 17 and compressed air are sent through each supply tube 15 into the rotary shaft, 4 jetted integrally from a powdery improving agent outlet 7 and a compressed air outlet 8 through a powder discharge path 5 and an air discharge path 6, and sent under pressure to below the inclined stirring blade 3. The improving agent is partly collied against the shield wall 9 and dropped, and partly flied to the next shield wall 9 and gradually dropped into soft ground. The compressed air is discharged through air vent holes 10 into the ground.

Description

DETAILED DESCRIPTION OF THE INVENTION This invention uses a stirrer installed at the lower end of a rotary shaft to blow out an improving agent such as powder into soft ground using pressurized air, and distributes it evenly using inclined stirring blades. This relates to a ground improvement method that creates strong columnar solidified sections inside the ground.

In the past, various methods have been seen here and there for improving the ground by squirting this type of improving agent made of powder such as quicklime or cement onto soft ground and stirring and mixing it.

Particularly in recent years, improved construction methods have been seen here and there for soil improvement, in which a mixture of pressurized air and various powder improvers is injected into the ground from the base of an agitating blade through a spout and mixed by rotation. However, in these improved construction methods, various powdered chemical improvers are blown straight from the jet nozzle to the tip of the stirring blade during injection injection, and only the outer periphery of the tip of the stirring blade is mixed and hardened. The disadvantage is that the inside of the hardened column does not harden evenly, creating cavities inside.

Furthermore, with these devices that pump a mixture of powder improver and pressurized air from the spout, if the water pressure and earth pressure due to the condition of soft ground are strong, the water pressure and earth pressure may be applied to the spout. There is a drawback that pressure is applied and various powder improvers cannot be injected into the ground from inside.

This invention was made in view of the above drawbacks, and
The main structure is that the powder improver and pressurized air are separately supplied to the inside of the stirring shaft from the powder discharge passage and the air discharge passage inside the rotating shaft, and the tilted stirring blades The improver discharged from the powder outlet installed near the base is sprayed and dispersed using pressurized air from the air outlet located at the rear, and is sprayed onto several fast-cut walls installed on the inner wall of the inclined stirring blade. As the additive is dropped sequentially from the inside to the outside, pressurized air is diffused through an air vent hole provided above the inclined stirring blade. The main feature of this invention is that the improver such as powder is ejected by pressurized air from the tilted stirring blades of the tilted shaft of the stirring shaft and hits each blocking wall sequentially from the inside to the outside. Because it falls, it has the effect of improving uniform mixing on the outer and inner peripheries, and the blocking wall can completely prevent water pressure and soil buildup, and the powder discharge passage and air discharge passage are arranged side by side. Therefore, the injection action is reliable and the improvement agent is prevented from being ejected due to earth pressure, etc., which is a good thing. In other words, trf.

This invention is a ground improvement method that is completely different from conventional methods, and uses a stirring tool with an inclination angle in the ground to improve the axial compressive strength and create a stable ground by making the mixture of the improved area uniform. This has been confirmed by experiment.

The present invention will be described below based on embodiments shown in the accompanying drawings.

Figure 1 shows the entire apparatus for implementing this invention method (11 is a rotating shaft to which rotation is transmitted from the transmission mechanism 0).
4) shows the stirrer body detachably installed at the lower end,
This stirrer body (11 is the stirring shaft (2) which is the center)
The stirring shaft (2) has an inclined stirring '8131131 facing toward the outer periphery of the shaft (2). Stirring shaft (2
Inside the rotating shaft (4), there is a powder discharge passage (51) such as a pipe through which improving agents such as quicklime and cement powder are passed.

Air discharge passages (61) such as pipes for introducing high-pressure air are installed in parallel with each other. At the tips of the powder discharge passage +51 and the air discharge passage +61, there are powder jet ports (7). and an air outlet (8) are formed, and the tip of the air discharge passage (6) is connected to the rear position of the powder outlet (7). At least one on the inside wall.

A plurality of blocking walls (91+91...) are fixed to the hanging shape 111 at predetermined intervals.Furthermore, a plurality of blocking walls (91+91...) are fixed to the hanging shape 111 at appropriate intervals. One or several air vents (IQG) must be drilled.

Further, an upper auxiliary stirring blade (111) having several vertical blades protruding from the upper stage of the inclined stirring blade (3) provided on the stirring shaft 121, and a vertical blade gJ (to) at the lower stage. A lower auxiliary agitating blade 0 with a protruding structure is formed respectively. Reference numeral I indicates a tower erected on various mounts α8, and 5 indicates an improvement agent for various powders etc. from the distributor feeder. Indicates a feed pipe for sending out , aη indicates various hoppers, and as indicates a support column of tower A4.

This invention has the above-mentioned configuration, and to explain this ground improvement method now, the construction equipment shown in Fig. 1 is set at a predetermined location on soft ground, and the rotation axis +41 is set from the transmission mechanism value jK.
Activate it and start penetrating.

Purchase to desired depth. Next, the rotating shaft (4) is rotated by K and pulled upward one by one, and then the various powder improvers such as -a'0 cement and raw stone and pressurized air are applied to each feed pipe. The powder is sent to the rotary shaft (4), and the powder discharge passage (5
) and an air discharge passage (6), each having a powder discharge port +71.
and one inclined stirring blade (3) by the air outlet (8).
is pumped to the bottom of the At this time.

The powder improver blown out by the pressurized air is stirred at an angle.
A part of the improver hits the front of the blocking wall +91191 installed on the inner wall of lK+31 and falls down, and the improver that does not fall scatters up to the next fast-cutting wall (91K) and sequentially falls from the front into a soft surface such as sludge, and the average It is possible to solidify the whole body uniformly by dispersing the air into the air. At this time, the ejected pressure air flows through the blocking wall (air vent hole no. (1 (1... ...is released into the ground in sequence.

In addition, when the downward inclination angle of the inclined stirring blade (3) in this invention was about 60 degrees, the highest result was obtained for the unconfined compressive strength.

As explained above, according to the present invention, the improvement agent discharged into the ground is spread evenly, and the entire mixing area is averaged and hardened and solidified.

Since the powder improver can be efficiently dispersed with a very simple structure, a stable supply is ensured, a homogeneous columnar shape can be efficiently obtained, and there is no problem with L7 that easily causes failures.

The powder discharge passage and the air discharge passage are arranged in parallel on the stirring shaft of the stirrer body, and the powder discharge port and the air discharge port are connected to each other near the tip of the stirring shaft, so that the improvement agent can be discharged easily. There are advantages in that it is extremely easy to adjust the injection amount of pressurized air and the flow rate ratio of both can be easily adjusted depending on the geology. Furthermore, inside the inclined stirring blade! l
Since several iK shear walls are hung down, the spraying of various improvers is not scattered only at the tips, but is ensured to fall down and mixed by the rapid shear walls in order. It has the effect of improving mixing evenly on the inside without scattering and mixing, and the excellent effect of securing the water pressure and soil pressure related to the powder spout and improving the discharge of the improving agent by the rapid shearing wall. be.

Furthermore, the air vent hole drilled above the inclined stirring blade ensures that the compressed air is dispersed into the ground through the air vent hole at the top after the improver is pumped, and the air is adjusted as appropriate depending on the number and size of the air vent hole. It has excellent effects and is convenient in that it can be released by hand.

[Brief explanation of drawings]

FIG. 1 is a front view of the entire apparatus showing an embodiment of the present invention, FIG. 2 is a front view of the stirring blade, FIG. 3 is a side view, FIG. 4 is a partially cutaway sectional view, and FIG. The figure is also a plan view,
FIG. 6 is an exploded perspective view of the main parts. (2) is the stirring shaft, (3) is the inclined stirring blade, (4) is the rotating shaft, +51 is the powder discharge passage, (61 is the air discharge passage,
(7) is a powder spout. (8) is an air outlet, (9) is a fast-cutting wall, and the frame is an air vent hole.

Claims (1)

[Claims] A powder improver and pressurized air are discharged while rotating from a downwardly inclined agitating blade provided on the agitator body located at the lower end of a rotating shaft suspended by a tower. In a ground improvement method in which powder is mixed with soft ground, the powder improver and pressurized air, which are pumped from the powder discharge passage and air discharge passage inside the rotating shaft, are separately supplied to the inside of the stirring shaft. The powder is sprayed integrally from a powder spout provided near the base of the inclined agitator and an air spout located behind it. Spray the tile improvement agent sequentially onto several blocking walls provided on the inner wall of the inclined agitator, l! A ground improvement method characterized by dispersing pressurized air from an air vent hole drilled above an inclined stirring blade.