JP2756870B2 - Soft ground improvement equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for improving soft ground, and more particularly to an improvement in a stirring rod provided with a co-rotating blade.

[0002]

2. Description of the Related Art Conventionally, in a ground improvement method using a uniaxial rotating rod, a drilling wing is provided at the tip and a stirring rod provided with a stirring blade above the rotating body, and a hardening material mainly composed of cement milk is injected from the tip. There is known a method of making a hole while drilling, mixing and stirring excavated earth and sand with a stirring blade, and hardening the mixture into a columnar shape.

[0003] In order to stir excavated earth and sand with stirring blades, it is necessary to make the sand finer and homogenized as much as possible. However, in the case of clay ground, the block-shaped soil mass rotates together with the stirring blades. However, there is a problem that the particles remain without being refined and the stirring effect becomes insufficient.

Conventionally, a co-rotation prevention blade having an outer diameter larger than the drill hole diameter is rotatably loosely fitted around the stirring rod on the stirring blade, and is bitten into the drill hole ground to be stopped. There is also known a method in which earth and sand are finely divided and stirred by a blade cutting motion with a stirring blade.

[0005] However, since the co-rotation prevention wing is stopped by the earth pressure reaction force of the drilling ground, in a soft ground, the earth pressure reaction force varies depending on the soil quality, and the bite length at the tip depends on the soil quality. There was a problem that the selection had to be made and the production management became complicated.

Further, when the adjacent improved earth pillar is uncured immediately after the formation, the locking of the co-rotation prevention wing becomes uncertain, and if the tip is deeply digged in to ensure this, There was a problem that the resistance in the excavation direction was increased and the construction efficiency was reduced.

Further, since the conventional counter-rotating blade has a fixed upper and lower distance from the stirring blade, the area of the stirring blade in the axial direction is large, and when the soil mass is large or the sand is hard, the excavated soil can be removed. If the resistance is large and an unreasonable load acts on the shaft, and the axial area of the stirring blade is small and the sand is soft,
There has been a problem that the agitating blade simply idles by dividing the soil up and down between the co-rotation preventing blade and the agitating effect is reduced.

Further, there is another problem that the excavated earth and sand is scattered around the drilled hole due to the rotation of the stirring blade, and the unimproved earth and sand is mixed into the adjacent improved ground.

[0009]

SUMMARY OF THE INVENTION The present invention relates to the above-described conventional counter-rotating wings, in which it is difficult to change the spacing, the uncertainty of locking,
An object of the present invention is to solve the problems of increased excavation resistance, uncertainty of agitating action due to soil quality, and mixing of unimproved soil into adjacent improved ground.

[0010]

According to the present invention, a rotary stirring blade is attached to the tip of an inner tube rotatably inserted into an outer tube non-rotatably mounted on a lift table, and a rotating stirring blade is mounted on the outer periphery of the rotating stirring blade. The present invention proposes a means in which a raised cylindrical wall is attached, and a co-rotation prevention blade located above the stirring blade is attached to a lower outer periphery of the outer tube surrounded by the cylindrical wall.

[0011]

[Function] When the stirring blade is rotated by the rotation of the inner tube, the outer tube is non-rotatably mounted on the lifting platform, so the stirring blade at the tip of the outer tube stops without fail and cuts into the drilling ground. No need.

[0012] Since the stirring and mixing by the stirring blade is performed inside the cylindrical wall, the escape of unimproved earth and sand to the periphery is prevented,
It is possible to prevent troubles such as mixing of unimproved earth and sand into the adjacent improved part and collapse and intrusion of earth and sand from the adjacent improved part.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In FIG. 1, a lift 2 is mounted on a leader 1 mounted on a moving vehicle such as a crawler so as to be able to drive up and down.
The outer tube 3 is fixed so as not to rotate, and the lift 2
An inner tube 5 whose upper end is supported is rotatably inserted into a rotation support table 4 which is attached to the reader 1 so as to be able to move up and down.

The elevating table 2 and the rotary support table 4 are connected together by adjusting the vertical distance between them via a vertical operating mechanism such as a hydraulic cylinder 6.

The inner tube 5 is rotatably supported by a rotation drive device by a motor provided in the rotation support base 4.

Upper and lower co-rotation preventing blades 7 and 7 'are attached to the outer periphery of the tip of the outer tube 3, and a rotary stirring blade 8 is attached to the tip of the inner tube 5 protruding from the tip of the outer tube 3. An excavating blade 9 is attached to the lower surface of the rotary stirring blade 8, and a cylindrical wall 10 having an outer diameter slightly smaller than the outer diameter of the excavating blade 9 rises up on the outer periphery of the rotary stirring blade 8 to form an outer tube 3. Are installed so as to surround the periphery of the co-rotation prevention wings 7, 7 '. In addition, this excavating blade 9 is provided on the inner pipe 5 below the rotary stirring blade 8.
May be provided on the lower surface of a digging arm radially mounted on the outer periphery of the digging arm.

At the upper end of the cylindrical wall 10, there is provided a lid plate 11 which is a circular plate which rotatably surrounds the outer tube 3 and has a plurality of openings on its annular surface. An upper stirring blade 8 'located below the co-rotation prevention blade 7 is attached to the surface.

The distal end of the inner pipe 5 is provided with a discharge port 12 for discharging a soil hardening material such as cement milk which has been pumped through the inside from above.

Next, a method of performing ground improvement work using the construction apparatus having the above-described configuration will be described. The rotary drive device rotates the inner pipe 5 while drilling with the excavating blade 9 while hardening from the discharge hole 12 at the tip. Discharge the material.

The earth and sand excavated by the excavation blade 9 is lifted up as a mass of earth and is stirred by the upper and lower rotary stirring blades 8 and 8 ′. While the co-rotation is prevented by the blocking blades 7 and 7 ′, the blades are successively made finer by the blade cutting action of the rotary stirring blades 8 and 8 ′ and the co-rotation preventing blades 7 and 7 ′ and are stirred and mixed with the hardener.

In this case, the harder the soil of the excavated earth and sand, the greater the resistance of the blade cutting action. Therefore, according to the hardness or resistance of the soil, the hydraulic cylinder 6 reduces the distance between the lifting platform 2 and the rotary support platform 4. And the rotating stirring blades 8, 8 '
And the counter-rotating wings 7, 7 'are widened, and conversely, the softer the soil, the more the rotary stirring blades 8, 8' and the counter-rotating wings 7, 7 '.
An operation of narrowing the vertical interval with 7 ′ is performed.

By adjusting the vertical spacing between the rotary stirring blades 8, 8 'and the co-rotation preventing blades 7, 7' according to the hardness or resistance of the soil, the blade cutting action is smoothed and the soil mass is narrowed. Granulation and its homogenization can be reliably achieved.

In this way, the above-described stirring and mixing is repeatedly performed while drilling to the planned depth, and the excavated earth and sand are uniformly stirred and mixed as a whole. It is raised and pulled up, and then the earth pillar is formed by hardening of the hardening material.

The above construction is sequentially performed adjacent to the periphery to improve the entire ground.

In the illustrated embodiment, two sets of upper and lower counter-rotating blades and rotary stirring blades are provided, but these may be one set.

[0026]

As described above, according to the present invention, when the stirring blade is rotated by the rotation of the inner tube, the outer tube is non-rotatably mounted on the elevating table. Can be reliably stopped without cutting into the drilling ground, making it possible to carry out improvement work smoothly and reliably without resistance to excavation regardless of the soil quality or the adjacent improved ground. Production management can be simplified.

Further, since such a stirring and mixing is performed inside the cylindrical wall, the escape of the unimproved earth and sand to the surroundings is prevented, and the unimproved earth and sand is mixed into the adjacent improved portion and the earth and sand from the adjacent improved portion are mixed. Troubles such as collapse intrusion can be prevented.

The upper end of the inner pipe is rotatably supported by a rotating support table which is connected to the elevating table via an up-down operating mechanism so as to adjust the vertical distance, so that the inner pipe rotates according to the hardness or resistance of the soil. By adjusting the vertical distance between the agitating blade and the co-rotation preventing blade, the blade cutting action can be smoothed, and the fineness of the earth mass can be reliably achieved.

[0029]

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional side view showing a construction state by an apparatus of the present invention.

FIG. 2 is a cross-sectional plan view of a co-rotation prevention wing portion in a construction state by the apparatus of the present invention.

FIG. 3 is a cross-sectional plan view of a lower rotary stirring blade portion in a working state by the apparatus of the present invention.

FIG. 4 is a cross-sectional plan view of an upper rotary stirring blade portion in a working state by the apparatus of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Leader 2 Elevating stand 3 Outer tube 4 Rotation support stand 5 Inner tube 6 Hydraulic cylinder 7 Co-rotation prevention blade 7 'Co-rotation prevention blade 8 Rotary stirring blade 8' Rotary stirring blade 9 Drilling blade 10 Cylindrical wall 11 Cover plate 12 Discharge port

Claims (2)

(57) [Claims] 1. A rotary stirring blade is attached to a tip of an inner pipe rotatably inserted into an outer pipe non-rotatably mounted on a lift table,
A cylindrical wall rising upward is attached to the outer periphery of the rotary stirring blade, and a co-rotation prevention blade located above the stirring blade is attached to a lower outer periphery of the outer tube surrounded by the cylindrical wall. Soft ground improvement equipment to do. 2. The soft ground improvement according to claim 1, wherein the inner pipe is rotatably supported at its upper end by a rotary support table which is connected to the lift table via a vertical operation mechanism so as to adjust the vertical distance. apparatus.