JP2002038461A - Ground stabilizing device and its method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a ground stabilizing device and its method capable of sufficiently agitating soil and a paste by securely rotating an agitating rotor for the soil and the paste. SOLUTION: An excavation hole H is excavated by a lower cutter 4 of a shaft 1 while rotating the shaft. A rotary body 9 at the side of the shaft 1 rotates around an axial part 8 while revolving around the shaft 1a mixing soil with paste. Even if it becomes hard to rotate owing to the soil stuck to the rotary body 9, the front end of the rotary body bites in the internal wall face of the excavation hole H and connects to a joint 13 of a forcible rotation means 10 to be forcibly rotated to mix the soil and the paste.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a ground improvement apparatus and a ground improvement method for strengthening the ground by digging a drill hole in the ground.

[0002]

2. Description of the Related Art When a building is constructed on soft ground such as clay ground, the ground is strengthened. As a method of strengthening and improving the ground, a method of excavating an excavation hole in the ground and injecting a ground improvement paste such as mortar into the excavation hole has been widely practiced. The excavation hole is excavated by an excavator mounted on a lower portion of the shaft while rotating the shaft.

[0003] In order to improve soft ground, it is desirable to sufficiently mix the paste and soil in the excavation hole. The reason is that if the stirring and mixing of the paste and the soil are insufficient and the lump of the soil remains, the ground strength at that portion is significantly reduced locally. In particular, since the soft ground has a lot of clayey soil, if a lump of clay remains in the excavation hole, the ground strength at that portion is significantly reduced.

Therefore, the present inventor has previously proposed means for stirring soil and mortar in a borehole (JP-A-11-33).
No. 6069). In this method, a rotating body is attached to the side of the shaft, and while rotating the rotating body around the shaft, the rotating body rotates by the reaction force received from the soil and the paste in the drilling hole, and the soil and the paste are stirred and mixed. It is something to do.

[0005]

However, the rotating body of the above-mentioned conventional apparatus cannot rotate sufficiently or reliably in the soil if the clay soil adheres to it, and cannot sufficiently agitate the soil and the paste. There was a problem.

Accordingly, an object of the present invention is to provide a ground improvement apparatus and a ground improvement method that can sufficiently stir the soil and the paste by rotating the rotating body for stirring the soil and the paste while reliably revolving.

[0007]

A ground improvement apparatus according to the present invention comprises a shaft which is driven by a driving unit and rotates, an excavator mounted on a lower portion of the shaft, and a shaft which is located on a side of the shaft. While revolving around the periphery, the rotating body that rotates around the shaft part and stirs the soil, and on the side of the shaft, the relative revolution speed difference is given to the rotating body, And a forced rotation means for joining a rotating body which revolves around the shaft and forcibly rotates the rotating body.

[0008] Preferably, the forced rotation means has an outer end portion that cuts into an inner wall surface of the excavation hole, thereby imparting the revolution speed difference.

Further, according to the present invention, a drill hole is excavated in the ground by an excavator attached to a lower portion of a shaft while rotating a vertical shaft by a driving portion and pouring out a ground improvement paste. A ground improvement method in which the rotating body provided on the side of the shaft revolves around the shaft while rotating around the shaft to mix and mix the soil and the paste, wherein the forcibly attached to the shaft is provided. There is a rotating means, and by giving a relative revolution speed difference between the forced rotating means and the rotating body, the rotating body revolving around the shaft is joined to the forced rotating means, and the rotating body is The soil and the paste were stirred and mixed by forcibly rotating.

[0010] In the above configuration, the drilling hole is excavated by the drill while rotating the shaft. At this time, the rotating body revolves around the shaft while revolving around the shaft to remove the soil and paste. Stir. On the other hand, there is a relative rotation speed difference between the forced rotation means and the rotating body.Therefore, even if the clay cannot adhere to the rotating body and the rotating body cannot rotate, the circumference of the shaft is The revolving rotator is joined to the forcible rotating means, and is forcibly rotated by the forcible rotating means to agitate the soil and the paste.

[0011]

(Embodiment 1) Hereinafter, Embodiment 1 of the present invention will be described with reference to the drawings. FIG. 1 is a side view of the ground improvement device, and FIG. 2 is a plan view of a lower portion of the ground improvement device.

In FIG. 1, reference numeral 1 denotes a shaft, and a long plate-shaped stirrer 2 is provided at a pitch so as to protrude laterally.
The stirrer 2 stirs the soil, and the stirrer 2 is provided with an inclination angle θ with respect to the horizontal plane in order to enhance the stirring effect. The shaft 1 is driven by a driving unit 3 provided in a working machine (not shown) such as a crane truck in an upright posture, and rotates around its axis.

An excavator 4 is mounted below the shaft 1. The excavator 4 is provided with a plurality of excavating claws 5. In the lower part of the shaft 1, an outlet 6 for a paste for ground improvement is opened. The paste is pumped through the central hole 7 (FIG. 2) of the shaft 1 and supplied from the spout 6 into the drill hole H.

A shaft portion 8 is provided upright on the upper surface of the excavator 4, and a rotating body 9 is mounted on the shaft portion 8 so as to be freely rotatable (rotated). The rotating body 9 of the first embodiment has a cross shape in plan view as shown in FIG. 2, and has a tapered shape. When the shaft 1 rotates, the rotating body 9 revolves around the shaft 1 and rotates around the shaft 8 by a reaction force received from soil or paste in the excavation hole H. In the first embodiment, the excavator 4 is used as a member for disposing the shaft 8.
The shaft 8 may be provided on a member other than the excavator 4.

Next, the forced rotation means 10 provided above the excavator 4 will be described. The forced rotation means 10 includes a tubular mounting body 11 rotatably mounted on the shaft 1,
A plurality of arm-shaped extending portions 12 extending horizontally from the mounting body 11 to the side, and a substantially long plate-shaped joining portion 13 projecting downward from the distal end portion of the extending portion 12 toward the rotating body 9. Made up of

In the first embodiment, as shown in FIG. 2, four extending portions 12 extend in a cross shape in plan view. The cross-sectional shape of the distal end portion of the joining portion 13 is tapered inward and is joined to the distal end portion of the rotating body 9 having a tapered shape. In this way, by forming at least one of the rotating body 9 and the joining portion 13 to be joined to each other into a tapered shape, the joining and separation of both are smoothly performed.

As shown in FIG. 1, the extension 12 and the joint 1
3 protrudes slightly (distance D) outward from the outer end b of the rotating body 9 and the excavator 4, and therefore the outer end a of the extension 12 and the joint 13 is As shown in the figure, the excavator 4 slightly bites into the inner wall surface of the underground hole H excavated. Therefore, when excavating the excavation hole H while the shaft 1 rotates, the rotating body 9 rotates (revolves) around the shaft 1, but the forcible rotating means 10 does not rotate (revolve) around the shaft 1, or Smooth rotation (revolution) becomes difficult, and the revolving speed becomes slower than the revolving speed of the rotating body 9, thereby giving a relative revolving speed difference between the rotating body 9 and the forcible rotating means 10, and Body 9 is forced rotation means 1
0 is joined to the joint 13. The outer end of the rotating body 9 is located substantially at the same position as the outer end b of the excavator 4 and is located inside the outer end a of the extension 12 and the joint 13.

This ground improvement apparatus has the above-described configuration, and its operation will be described below. The shaft 1 is held vertically, and is lowered while being rotated about its axis by the drive unit 3. Then, the excavator 4 also rotates together with the shaft 1 and excavates the excavation hole H in the ground.

During excavation, the paste is poured out from the spout 6, and the soil and the paste in the excavation hole H are stirred and mixed by the stirrer 2. When the shaft 1 rotates, the rotating body 9 rotates (revolves) around the shaft 1.
Rotates around the shaft 8 by the reaction force received from the soil and the paste in the excavation hole H, and stirs and mixes the soil and the paste.

In the case where the soil is particularly clayey, the soil tends to stick to the rotating body 9, and as a result, the rotating body 9 becomes difficult to rotate around the shaft portion 8. Not enough. On the other hand, forced rotation means 1
0 is freely rotatably attached to the shaft 1, but as described above, the outer end a of the extension 12 or the joint 13
Is cut into the inner wall of the borehole H, so the shaft 1
, The forced rotation means 10 stops rotating (revolution) or becomes difficult to rotate (revolve), and the rotating body 9 and the forced rotation means 10 have a relative revolution speed difference as described above. Therefore, the tip of the rotating body 9 revolving around the shaft 1 is connected to the joint 1 as shown by a broken line in FIG.
3 and is forcibly rotated (rotated) about the shaft portion 8. Therefore, even if the clay-like soil sticks to the rotating body 9, the rotating body 9 surely rotates (rotates) and stirs and mixes the soil and the paste.

(Embodiment 2) FIG. 3 is a side view of a ground improvement apparatus according to Embodiment 2 of the present invention. The joint 15 of the forcible rotation means 10 ′ is substantially rod-shaped and includes a coil spring 16 as an elastic member, and the upper end thereof is detachably attached to the hole 19 of the extension 14 by a bolt 18. I have. As in the first embodiment, the extension 14
Is cut into the inner wall surface of the excavation hole H. The configuration other than the joining portion 15 is the same as that of the first embodiment.

The holes 19 are formed at upper and lower portions at a plurality of locations (in this example, two locations on the outside and inside) in the longitudinal direction of the extension portion 14. Therefore, the joint 15 is connected to any of the holes 19.
Can be installed selectively. In FIG. 3, the joint 15 shown by a solid line shows a case where the joint 15 is attached to the outer hole 19.
In addition, the joining portion 15 indicated by a dashed line shows a case where it is attached to the inner hole portion 19. Therefore, the mounting position of the joint 15 can be changed according to excavation conditions or the like, or the joint 15 indicated by a solid line and the joint 15 indicated by a chain line may be mounted together.

Further, by incorporating the coil spring 16, it is possible to reduce the impact when the joint 15 is joined (impacted) to the rotating body 9. In particular, when there are many pebbles in the soil, the pebbles are easily trapped between the joint 15 and the rotating body 9 to easily damage the rotating body 9 and the joint 15, but by using an elastic member such as a coil spring. The impact can be reduced by the cushioning action. There are various forms in which an elastic member is used as the joining member. For example, the joining member 13 itself shown in FIG. 1 may be formed of an elastic member such as rubber.

(Embodiment 3) FIG. 4 is a plan view of a lower portion of a ground improvement apparatus according to Embodiment 3 of the present invention. From the mounting body 11, a main extension portion 14A and a sub extension portion 14B which constitute compulsory rotation means extend laterally. Main extension 14A
Is the same length as the extending portion 12 of the first embodiment, and its outer end a bites into the inner wall surface of the excavation hole H. The sub-extension 14B is considerably shorter than the main extension 14A. The rotating body 9 similar to the joint 15 in the second embodiment is provided on the sub-extending portion 14B.
A joint 15 'protruding toward is mounted.

Therefore, also in this case, a revolution speed difference occurs between the rotating body 9 and the joint 15 ', and the rotating body 9 is connected to the joint 15'.
Are forced to rotate by joining, and stir the soil and paste. As is clear from the above embodiments, the forcible rotation means can be variously changed in design, and the difference is that a revolving speed difference is given between the forcible rotation means and the rotating body to forcibly rotate the rotating body. I just need.

The present invention can be modified in various ways. For example, in each of the above embodiments, the forced rotation means and the rotating body are formed by making the outer end portion of the forced rotation means bite into the inner wall surface of the excavation hole. In addition to this, forcible rotation means smoothly rotates around the shaft by giving friction / sliding contact resistance to the joint between the shaft 1 and the mounting body 11, for example. It is also possible to make the rotation speed difference between the rotor and the rotating body.

[0027]

As described above, the present invention is provided with the forced rotation means for generating a relative revolution speed difference between the rotating body and the rotating body, so that the drilling hole is excavated in the ground by the excavator while rotating the shaft. At this time, even if the rotating body cannot rotate due to sticking of clay soil to the rotating body, etc., the rotating body is forcibly rotated by joining the forced rotation means, so the rotating body is securely rotated Thus, the excavation hole can be excavated while reliably mixing and mixing the soil and the paste.

[Brief description of the drawings]

FIG. 1 is a side view of a ground improvement device according to a first embodiment of the present invention.

FIG. 2 is a plan view of a lower portion of the ground improvement device according to the first embodiment of the present invention.

FIG. 3 is a side view of a ground improvement device according to Embodiment 2 of the present invention.

FIG. 4 is a plan view of a lower portion of a ground improvement device according to Embodiment 3 of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Shaft 3 Drive part 4 Excavator 8 Shaft part 9 Rotating body 10, 10 'Forcible rotation means 11 Mounting body 12 Extension part 13, 15, 15' Joining part 14A Main extension part 14B Sub extension part 16 Coil spring ( Elastic member)

Claims (5)

[Claims] 1. A shaft driven by a drive unit to rotate, an excavator mounted on a lower portion of the shaft, and a shaft around the shaft while revolving around the shaft at a side of the shaft. A rotating body that rotates and stirs the soil, and a rotation speed difference that is provided on a side of the shaft and that is relative to the rotating body, whereby the joint portion revolves around the shaft. A ground improvement device comprising: forced rotation means for forcibly rotating the rotating body by being joined to a body. 2. The ground improvement device according to claim 1, wherein the forced rotation means has an outer end portion that bites into an inner wall surface of the excavation hole to impart the revolution speed difference. 3. The ground improvement device according to claim 1, wherein said joint is made of a flexible elastic member. 4. A drilling hole is excavated in the ground by an excavator mounted on a lower part of the shaft while rotating a vertical shaft by a driving part and pouring out a ground improvement paste. While revolving the rotating body provided around the shaft around the shaft, the ground and the paste are rotated around the shaft to mix and mix the soil and the paste, wherein the forced rotation means attached to the shaft is By providing a relative revolution speed difference between the forced rotating means and the rotating body, the forced rotating means is joined to the rotating body rotating around the shaft to forcibly rotate the rotating body. A ground improvement method characterized by rotating the soil and stirring and mixing the soil and the paste. 5. The ground improvement method according to claim 4, wherein the revolving speed difference is provided by an outer end of the forcible rotating means biting into an inner wall surface of the excavation hole.