JP3168918B2 - Ground improvement apparatus and method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a soil improvement apparatus and method for discharging a solidified material into a ground excavated downward and stirring to form a columnar consolidated portion in the ground. is there.

[0002]

2. Description of the Related Art Conventionally, as a ground improvement device, a drilling blade having a predetermined diameter is attached to a lower end of a rotating vertical pipe-shaped drive shaft, and a stirring blade having a predetermined diameter is mounted on the outer periphery of the drive shaft above the drive shaft. A device provided with a solidified material discharge port for discharging a solidified material such as lime or cement on the side of the drive shaft near the mounting and excavation wing has been used.

[0003] Then, after the drive shaft, excavating wings and the like are lowered in the soft ground while rotating, the part of the ground is excavated in a columnar shape without discharging the soil, and then the solidified material is discharged from a solidified material discharge port provided in the drive shaft. While discharging the water, the drive shaft was rotated and moved up and down. At that time, the soil and the solidified material were thoroughly mixed with the stirring blade, and the solidified material was solidified to form a columnar solidified portion in the ground.

[0004]

If the above method and apparatus are used, excavation of the ground is not particularly problematic. However, the solidified material is discharged, the drive shaft is rotated, and the soil and the solidified material are raised while being stirred. Sometimes, when the soil around the drive shaft is soft, such as a clay layer, the so-called co-rotation phenomenon has occurred, in which the soil around the drive shaft and the stirring blades is not stirred by just turning together.

In addition, when the apparatus is lowered for excavation, the drive shaft is misaligned, and the excavation hole is bent or the diameter of the excavation hole does not become the same. And a great power was needed when digging.

[0006]

In order to solve these problems, according to the present invention, a lower end of a vertical pipe-shaped drive shaft which is rotatable and movable up and down and whose lower end is sealed is extended laterally. Fixed on the side of the drive shaft above the excavation wing, and a solidified material jet is provided on the side of the drive shaft above the solidified material jet, and a stirring blade of approximately the same radius as the excavation wing is laterally mounted on the side of the drive shaft above the solidified material jet. In the ground improvement device fixed to the ground, a lever mounting bracket is mounted on a part of the outer periphery of the drive shaft so as to be rotatable relative to the drive shaft. A plurality of levers, which can be located outside the tip of the excavation wing, are mounted so as to be vertically swingable between a lateral position and a position inclined upward by a predetermined angle.

[0007] Two or more levers are used, each of which is mounted on a lever mounting bracket so as to be vertically rotatable between a substantially horizontal position and a position inclined upward by 20 to 40 degrees. Also,
A lever mounting bracket with a lever rotatably mounted on a part of the outer periphery of the drive shaft between the excavating wing and the stirring wing so as to be relatively rotatable while restricting the relative movement in the vertical direction. .

When the ground is improved using this device,
When lowering while rotating the drive shaft in the soft ground, the lever is made to descend with the slope inclined upward due to the resistance of the soil, and after excavating to the predetermined depth by the action of the excavating wing, from the solidified material ejection port When the solidified material is discharged and the drive shaft is rotated in the opposite direction to the excavation and moved up and down to stir and mix the soil in the soft ground with the solidified material, and the drive shaft is raised while rotating in the soft ground , The tip of the lever receives the pressure of the surrounding soil from above and digs into the surrounding soil, the lever rises in a state that it is almost horizontal and does not rotate, and the soil around the drive shaft in the soft ground is driven An attempt was made to prevent an attempt to rotate with the shaft.

[0009]

1 and 2 show an embodiment of an apparatus for carrying out the method of the present invention. FIG. 1 is a front view, and FIG. 2 is a sectional view taken along line AA of FIG. It is. Reference numeral 1 denotes a vertical pipe-shaped drive shaft which can rotate and move up and down and has a sealed lower end. The upper end of the drive shaft 1 is connected to a drive device (not shown). Further, a solidifying material supply device for supplying a solidifying material such as lime or cement into the drive shaft 1 is also connected.

[0010] At the lower end of the drive shaft 1, several excavating wings 2 extending in the lateral direction are fixed and provided.
The solidified material ejection port 3 is provided on the side surface of the. On the side surface of the drive shaft 1 above the solidified material ejection port 3, the agitating blade 4 having the same radius as the excavating blade 2 is slightly twisted, for example, 3
And several were fixed and provided. As shown, the stirring blades 4 were arranged at different positions in the vertical and circumferential directions.

A drive shaft 1 between the solidified material ejection port 3 and the stirring blade 4
Two ring-shaped collars 5 are fixedly provided at a certain interval in the vertical direction on a part of the outer periphery of the bracket, and the mounting bracket 7 for the lever 6 is connected between the two collars 5 by the drive shaft 1. It was mounted so as to be relatively rotatable with respect to. A bush can be attached to the rotating part. The mounting bracket 7 is divided into two pipe sections 7a.
A flange portion 7b for mounting the lever 6 so as to be swingable in the vertical direction is mounted near the back portion and the connecting portion. 8
Is a connecting tool consisting of a bolt and a nut.

The lever 6 is tilted upward by a predetermined angle such as 20 to 40 degrees with respect to a lateral position by a pin 9 or a bolt 8 serving also as a pin on a flange portion 7b on the side surface of the mounting bracket 7. It was mounted so that it could swing up and down between these positions. The length of the lever 6 is such that, when the lever 6 is in a horizontal state, the position of the tip of the lever 6 is located outside the position of the tip of the excavating wing 2 by a predetermined dimension t, for example, 5 to 20 mm. I made it. The lever 6 can be freely rotated upward, but is restricted so as not to rotate downward below the horizontal direction. For this purpose, a stopper is provided below the flange portion 7b. The tip of the lever 6 may be square or round. However, in this embodiment, the tip is rounded in order to reduce the resistance in the direction perpendicular to the wall surface.

In FIGS. 1 and 2, four levers 6 are provided at substantially equal intervals. However, the number of levers 6 may be two or more, such as three or two symmetrically arranged levers. You can choose. In order to prevent misalignment during excavation, which will be described later, three or four levers 6 are more preferable. The lever 6 can be provided on the stirring blade 4 in addition to being provided between the solidified material ejection port 3 and the stirring blade 4. In FIG. 1, reference numeral 10 denotes soft ground, and reference numeral 11 denotes soil in the excavated portion.

Next, the operation of the above device will be described. When the rotating drive shaft 1 is lowered vertically into the soft ground 10, a part of the ground 10 is excavated by the action of the excavating wing 2. At this time, the excavated soil 11 remains in the excavation hole without being discharged outside. At the time of excavation by the excavation wing 2, the lever 6 receives the pressure of the soil from below, so that the lever 6 descends while the tip is lifted upward by a certain angle and does not rotate or hardly rotates. Then, a centripetal force as a reaction force acts on each lever 6.

[0015] Since it descends in this state, a part of the vertical force is dispersed in the horizontal direction and thus contributes to stability, and the core of the drive shaft 1 can be stabilized during excavation and descent, thereby preventing misalignment. be able to. At the same time, the contact resistance of the tip of the lever 6 to the wall surface of the excavation hole is reduced. Further, since the soil 11 is shredded in the vertical direction by the lever 6, the stirring is promoted.

When the drive shaft 1 and the excavation wing 2 are lowered to a predetermined depth and excavated, they are raised once while rotating in the same direction. While discharging the solidified material such as cement, the drive shaft 1 is rotated in the direction opposite to the direction of excavation, lowered to the excavated position, and then pulled up. The solidified material is mixed and stirred. The stir step by the vertical movement may be performed not only in one cycle of descending and rising but also in two or more cycles.

When the lever 6 is lifted, the lever 6
It receives a pressure of 1 from above and becomes horizontal. The end portion of the lever 6 in the horizontal state protrudes outside the inner diameter of the excavation hole by t and cuts into the wall. As a result, the lever 6 is prevented from rotating with the drive shaft 1 and rises without rotating. This prevents the soil 11 around the excavation axis 1 from trying to rotate with the excavation axis 1
Together with the solidified material and remain in the wellbore with good mixing and agitation. After processing,
Over time, these solidify spontaneously, forming a solid columnar foundation.

[0018]

According to the present invention, since the construction as described in the claims is adopted, the lever can be prevented from rotating due to the resistance of the soil even when the drive shaft rotates, and at the time of descent. The tip of the lever is lifted by a predetermined angle, so that the tip of the lever can bite into the wall of the excavation hole during pulling.

[0019] Therefore, at the time of descending, misalignment is prevented, and the drive shaft descends straight, so that a desirable hole can be excavated. In addition, it is possible to prevent the co-rotation phenomenon of the soil or the like around the drive shaft at the time of lifting. In addition, power during excavation can be reduced as compared with the case where the wings are fixed horizontally.

[Brief description of the drawings]

FIG. 1 is a front view showing an embodiment of the apparatus of the present invention.

FIG. 2 is a sectional view taken along line AA of FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Drive shaft 2 Excavation wing 3 Solidified material ejection port 4 Stirring wing 6 Lever 7 Mounting bracket 9 Pin 10 Ground 11 Soil in digging hole

Claims (4)

(57) [Claims] An excavating wing extending in a lateral direction is fixed to a lower end of a vertical pipe-shaped driving shaft which is rotatable and vertically movable and has a lower end sealed, and a side surface of the driving shaft above the excavating wing. In the ground improvement device, a solidified material ejection port is provided, and a stirring blade of approximately the same radius as the excavation wing is fixed to the side of the drive shaft above the solidified material ejection port in the lateral direction. A lever mounting bracket is attached to a part of the lever mounting bracket so as to be rotatable relative to the drive shaft, and a plurality of levers whose tip positions are located outside the tip position of the excavation wing are provided on the side surface of the lever mounting bracket. ,
A ground improvement device mounted to be vertically swingable between a horizontal position and a position inclined upward by a predetermined angle. 2. The ground improvement according to claim 1, wherein two or more levers are respectively attached to the lever mounting brackets so as to be vertically rotatable between a substantially horizontal position and a position inclined upward by 20 to 40 degrees. apparatus. 3. A lever mounting bracket having a lever rotatably mounted on a part of an outer periphery of a drive shaft between a drilling blade and a stirring blade in a state where relative movement in a vertical direction is restricted. The ground improvement device according to claim 1 or 2, which is rotatably mounted. 4. A vertically extending excavation wing fixed to a lower end of a vertical pipe-shaped drive shaft which is rotatable and vertically movable and has a sealed lower end, and a side surface of the drive shaft above the excavation wing. A solidified material jet is provided on the side of the drive shaft above the solidified material jet, and a stirring blade of approximately the same radius as the excavation wing is fixed to the lateral direction, and a lever is attached to a part of the outer periphery of the drive shaft. A plurality of levers whose tip positions can be located outside the tip position of the excavator wings are mounted on the side of the lever mounting bracket so that the bracket can be rotated relative to the drive shaft. When the drive shaft is lowered while rotating in soft ground using a soil improvement device that is mounted so that it can swing up and down between the ground and a predetermined angle, the lever moves upward due to soil resistance. To the specified depth by the action of the excavation wing. After the excavation, the solidified material is discharged from the solidified material spout and the drive shaft is rotated in the opposite direction to the excavation and moved up and down to stir and mix the soil in the soft ground with the solidified material. When the lever is lifted while rotating in the soft ground, the tip of the lever receives the pressure of the surrounding soil from above and digs into the surrounding soil, and the lever rises in a state that the lever is almost horizontal and does not rotate, A ground improvement method capable of preventing soil around a drive shaft inside from trying to rotate together with the drive shaft.