JP2807418B2 - Ground improvement 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 ground improvement method capable of improving a ground by drilling holes in the ground.

[0002]

2. Description of the Related Art In order to improve soft ground, a method has been used in which a hole is excavated in the ground, excavated soil and a hardening agent are stirred and kneaded in the hole, and the ground is improved by hardening. .

Conventionally, a base machine or the like has been used for excavation of the hole, and a plurality of stirring bodies such as a stirring rod are vertically provided on a single rotating shaft so as to project in a direction perpendicular to the shaft. As described above, while rotating the stirring rod integrally (with) with the rotation of the rotating shaft and injecting the curing agent,
A method of stirring and kneading excavated soil and a hardening agent to improve the ground by hardening is used.

[0004] In addition, a rotating shaft for stirring is constituted by a double shaft of an outer shaft and an inner shaft rotating in mutually opposite directions, and large and small stirring blades each having a semicircular arc shape are respectively provided at lower ends of the inner and outer shafts. There has also been proposed a stirring blade structure in a ground improvement apparatus which is provided continuously and configured such that the small stirring blade body is positioned inside the large stirring blade body and is rotated inside and outside in opposite directions. Japanese Patent Publication No. Hei 3-40166).

[0005] In addition, as another example of a patent describing the related ground improvement device, see Japanese Patent Application Laid-Open No. 1-191717.
JP, JP-A-6-193047, JP-A-6-16-147
No. 93059.

[0006]

However, a plurality of stirring rods are provided vertically above and below the conventional single-shaft rotating shaft so as to project perpendicularly to the shaft, and the plurality of stirring bars are connected to the rotating shaft. In the ground improvement method by the ground improvement device that rotates integrally with the rotation, since all of the plurality of stirring rods rotate integrally with the rotation shaft, the so-called co-rotation phenomenon that the excavated soil rotates integrally with the coaxial. If the hardening agent is difficult to knead, such as the ground made of viscous soil, the excavated soil will be in a dumpling state wrapping the stirring rod. There is a disadvantage that kneading cannot be performed.

The rotary shaft for stirring is constituted by a double shaft of an outer shaft and an inner shaft rotating in opposite directions to each other, and large and small stirring blades having a semicircular arc shape are respectively connected to lower ends of the inner and outer shafts. In addition, the ground improvement method using the ground improvement device in which the small stirring blades are positioned inside the large stirring blades and rotated in the opposite directions on the inner and outer sides is more co-rotating than the conventional example. Although it has the effect of preventing the phenomenon and the formation of dumpling soil as a dumpling, in this device, since only small and large stirring blades rotating in opposite directions are continuously connected to the tips of the lower ends of the inner and outer shafts, the shearing force is weak, Excavation speed was slow, stirring and kneading tended to be insufficient, and the effect of preventing the above-mentioned co-rotation phenomenon and formation of dumped soil was still insufficient.

An object of the present invention is to provide a technique capable of solving the above-mentioned disadvantages of the prior art.

[0009]

SUMMARY OF THE INVENTION According to the present invention, an upper stirring blade portion is formed by an arcuate outer blade connected to an outer shaft and a middle blade positioned inside the arcuate outer blade and connected to the inner shaft. While forming, below the upper stirring blade portion, an arc-shaped outer blade connected to the inner shaft,
A lower stirring blade is formed by the middle blade located in the arc-shaped outer blade and connected to the outer blade of the upper stirring blade via a stirring blade body mounting portion, and further below the lower stirring blade at the lower end of the inner shaft. By drilling a circular column-shaped drilling hole perpendicular to the ground by rotating the outer and inner shafts in opposite directions, and when the drilling blade reaches a predetermined depth, the inner shaft The hardener is injected from the hardener injection nozzle below the hardener through the hardener passage provided in the above, and the hardener and the excavated soil are agitated and kneaded to improve the ground by forming a ground improvement portion in the excavation hole. The present invention relates to a ground improvement method characterized by the following.

[0010]

Next, embodiments of the present invention will be described with reference to the drawings. As shown in FIG. 4, a ground improvement device 1 used in the ground improvement method of the present invention includes a base machine 2 and a hardener supply pump 3.

The base machine 2 is configured to be movable.

The base machine 2 supports the rotating shaft 5 vertically by the leader 4, and the excavating blade attached to the rotating shaft 5 and its tip by the drive motor 6 interposed between the reader 4 and the rotating shaft 5. The rotary shaft 5 is lowered along the leader 4 while rotating the rotary shaft 7 to excavate a circular column-shaped excavation hole 9 perpendicular to the ground 8.

The hardener supply pump 3 and the swivel joint 10 are connected to each other via a hose 11.
During the ground improvement work, the hardener is supplied from the pump 3 to the swivel joint 10 via the hose 11, and is further injected from the hardener injection nozzle via the inner shaft as described later.

FIG. 3 shows a technical example in the course of reaching the present invention. FIG. 3 (A) is a partial cross-sectional view of a principal part of a ground improvement apparatus showing a technical example. FIG. 2B is a side view of the same, and FIG. 2C is a plan view of the digging blade portion viewed from below the digging blade portion attached to the tip of the rotating shaft in the device.

As shown in FIG. 3A, a plurality of propeller-like middle wings 13 are vertically connected at appropriate intervals so as to rotate together with the rotation of the inner shaft 12 in the axial direction of the inner shaft 12. Set up. The plurality of middle wings 13 are provided so as to project in a direction perpendicular to the axis.

Two (one pair) middle wings 13 on both sides of each shaft
Project radially.

On the other hand, a plurality of arc-shaped outer wings 15 are arranged vertically so as to rotate together with the rotation of the outer shaft 14. As shown in the figure, the plurality of outer wings 15 are, as shown in FIG. 3A, in a technical example having three outer wings 15 on one side, the outermost outer wings 15 of the outer wings 15 that are vertically adjacent to each other. One lower end of the blade 15 is connected to the upper end of the lower second outer blade 15 therethrough via a common stirring blade mounting portion 16, and the second lower outer blade 1
5 is connected to the upper end of the third-stage outer blade 15 via a stirring blade body attaching portion 16 which is common to the lower end.

As shown, each of the plurality of middle wings 13 connected to the inner shaft 12 is positioned inside each outer wing 15 of the outer shaft 14. Although not shown, these inner shafts 1
The two and outer shafts 14 are rotated in opposite directions by a contra-rotating gear mechanism 17 interposed between the inner and outer shafts 12 and 14 and the hydraulic motor 6 as shown in FIG. .

The inventor of the present invention has been studying the agitating blade structure of the above-mentioned technical example more intensely. It rotates together with the forward and reverse rotation of 12, 14. That is, a plurality of outer wings 15 are vertically connected by an outer wing, while a plurality of middle wings 13 on the inner side of the outer wing are vertically connected by a middle wing, and these are rotated biaxially forward and backward. In this case, we examined what would happen if the outer wing and the inner middle wing were connected.By doing so, the stirring effect between the hardener and the excavated soil was further improved, and a strong It was found that a ground improvement part was obtained. Hereinafter, the stirring blade structure used in the ground improvement method of the present invention will be described in detail with reference to the drawings.

That is, as shown in FIG. 1, each of the stirring blades including the middle blade 13 and the outer blade 15 is connected in two stages. The middle wing 13 and the outer wing 15 are connected.

That is, as shown in the embodiment of FIG. 1, the lower end of the arcuate outer wing 15 is not connected to the lower outer wing 15 on the outer shaft 14, but the middle wing 13 and the stirring blade body are attached. The inner shaft 12 is connected to the outer wing 15 without connecting the lower end of the middle wing 13 to the inner wing 13 at the lower end of the inner shaft 12.

In other words, in this case, the forward and reverse rotation of the inner and outer shafts 12 and 14 causes the connected one of the middle wings 13 and the outer wing 1 to rotate.
5 and the connecting body B of the other middle wing 13 and outer wing 15 in the other direction. When this configuration is viewed as upper and lower stirring blades, the upper stirring blade is constituted by the upper outer blade 15 and the upper middle blade 13, and the lower stirring blade is constituted by the lower outer blade 15 and the lower middle blade 13. Are formed respectively.

As a result, the connected one of the middle wings 13
And the outer wing 15 rotate together, and the other middle wing 13 and outer wing 15 rotate together. In addition, in FIG. 1, the connection body A and the connection body B also indicate the rotation direction as they are.

Reference numeral 17 in FIG. 1 denotes a contra-rotating gear mechanism. FIG. 2 is a side view of the stirring blade structure.

In the reference numerals shown in FIGS. 1 and 2,
Since the same reference numerals as those in FIG. 3 indicate the same functions, other explanations are omitted.

In the ground improvement work according to the ground improvement method of the present invention, the inner shaft 1
The rotary shaft composed of the outer shaft 2 and the outer shaft 14 and the excavating blade 7 are lowered while rotating.

The rotation of the inner shaft 12 and the outer shaft 14 in opposite directions causes the plurality of middle wings 13 and the plurality of outer wings 15 connected to the shafts 12 and 14 to rotate in opposite directions, respectively. A circular column-shaped excavation hole 9 perpendicular to the ground 8 is excavated.

When the excavating blade 7 reaches a predetermined depth, the inner shaft 1
2, a curing agent is injected from a curing agent injection nozzle 19 below the passage 18 through a curing agent passage 18 provided inside
The hardening agent and the excavated soil are stirred and kneaded to form a ground improvement portion in the excavation hole 9 to improve the ground.

According to the method of the present invention, a plurality of stirring rods are vertically provided on a conventional one-axis rotating shaft so as to protrude in a direction perpendicular to the shaft, and the plurality of stirring bars are rotated with the rotation of the rotating shaft. The disadvantage of the ground improvement device that rotates integrally can be eliminated.

That is, in the conventional method, all the plurality of stirring rods rotate integrally with the rotating shaft, and the excavated soil rotates integrally with the coaxial shaft, so that a so-called co-rotation phenomenon occurs, and sufficient stirring and kneading cannot be performed. However, in the case where the hardening agent is difficult to knead like the ground made of viscous soil, there is a disadvantage that the excavated soil is in a dumpling state wrapping the stirring rod and cannot be stirred and kneaded at all, In the present invention, the upper stirring blade portion is formed by the arc-shaped outer blade connected to the outer shaft and the middle blade positioned inside the arc-shaped outer blade and connected to the inner shaft. At the lower part, the lower stirring blade is constituted by an arc-shaped outer blade connected to the inner shaft, and a middle blade positioned within the arc-shaped outer blade and connected to the outer blade of the upper stirring blade via a stirring blade body mounting portion. Part, and the excavation blade part is connected to the lower end of the inner shaft further below, and the outer shaft and the inner shaft are mutually connected. By drilling in the direction, a circular column-shaped excavation hole perpendicular to the ground is excavated, and when the excavation blade reaches a predetermined depth, through a curing agent passage provided inside the inner shaft, a curing agent injection nozzle at a lower portion thereof Spray hardener from
The hardening agent and the excavated soil were mixed and kneaded to improve the ground by forming a ground improvement portion in the excavation hole, so that even if the excavated soil becomes a dumpling state wrapping around the middle wing, A plurality of outer wings on the outer side can break the state of the dumplings, and can be sufficiently stirred and kneaded with the hardener to form a ground improvement portion in the borehole.

Further, since these two shafts rotate forward and backward with respect to each other and the middle wing and the outer wing connected to the two shafts rotate forward and backward,
The shearing force is greatly improved, the effect of preventing co-rotation phenomenon and the formation of dumpling soil is significantly improved, and good stirring and kneading can be performed even when the hardening agent is difficult to knead such as the ground made of viscous soil. In addition, the speed of excavation is increased, and ground improvement work can be completed in a short time.

Further, in the ground improvement method of the conventional apparatus in which the large and small stirring blades rotating in the opposite directions are continuously connected to the tips of the lower ends of the inner and outer shafts, the shearing force is weak and the excavation speed is low.
The stirring and kneading are also likely to be insufficient, and there is still an insufficient effect on the co-circumference phenomenon and the effect of preventing the excavated soil from being dumped.However, in the present invention, these drawbacks can be solved and compared with the ground improvement method using the conventional device. Therefore, the shearing force is significantly improved, the effect of preventing co-rotation phenomenon and the formation of dumped soil is significantly improved, and good agitation is possible even when the hardening agent is hard to knead as in the ground made of viscous soil. The kneading is performed, and the excavation speed is improved, so that the ground improvement work can be completed in a shorter time.

[0033]

As described above, according to the present invention, a plurality of agitating rods are provided vertically in the vertical direction of a conventional one-axis rotating shaft so as to project perpendicularly to the axis, and the plurality of agitating rods are attached to the rotating shaft. A conventional device that can eliminate the disadvantages of the soil improvement method using a soil improvement device that rotates together with the rotation, and also has a large and small stirring blade that rotates in the opposite direction connected to the tip of the lower end of the inner and outer shafts. In comparison with these conventional methods, the shearing force is significantly improved, the co-rotation phenomenon and the effect of preventing the excavated soil from being dumped are significantly improved, and the soil is hardened like the ground made of cohesive soil. Even when the agent is difficult to knead, good stirring and kneading are performed, furthermore, the excavation speed is improved, and the ground improvement work can be completed in a shorter time,
Good stirring and kneading can be performed even when a powdery curing agent is used in a ground having a high water content such as a tidal flat.

In particular, in the method of the present invention, by adopting the stirring structure for connecting the adjacent stepped middle blade and outer blade in each of the upper and lower stirring blade portions connected in two stages as described above, The shearing force is further improved, the co-rotation phenomenon and the effect of preventing the excavated soil from being clustered are improved, and good stirring and kneading are performed even when the hardening agent is hard to knead like the ground made of viscous soil, Further, the excavation speed is further improved, and the ground improvement work can be completed in a shorter time.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a main part of a ground improvement device used in an embodiment of a method of the present invention.

FIG. 2 is a side view of the device.

FIG. 3A is a partial cross-sectional main configuration diagram of a ground improvement device showing a technical example leading to an embodiment of the present invention. (B) is the same side view. (C) is a plan view of the digging blade portion viewed from below the digging blade portion attached to the tip of the rotating shaft in the same device.

FIG. 4 is an explanatory diagram of a ground improvement device showing an embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Ground improvement device 2 Base machine 3 Hardening agent supply pump 4 Leader 5 Rotating shaft 6 Hydraulic motor 7 Drilling blade 8 Ground 9 Drilling hole 10 Swivel joint 11 Hose 12 Inner shaft 13 Middle wing 14 Outer shaft 15 Outer wing 16 Stirrer blade Attachment part 17 Contra-rotating gear mechanism 18 Hardener passage 19 Hardener injection nozzle A Connected body (rotation direction) B Connected body (rotation direction)

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-61-165416 (JP, A) JP-A-3-8920 (JP, A) Jiko 5-45625 (JP, Y2) (58) Survey Field (Int.Cl. ⁶ , DB name) E02D 3/12

Claims (1)

(57) [Claims] An arcuate outer wing (1) connected to an outer shaft (14).
5) and an inner shaft (1) located in the arcuate outer wing (15).
An upper stirring blade is formed by the middle blade (13) connected to 2), and an inner shaft (12) is formed below the upper stirring blade.
Arcuate outer wing that is continuously provided to (15), arcuate outer wing (15)
Agitating wing body located on the outer wing (15) of the upper agitating wing portion
A lower stirring blade portion is formed by the middle blade (13) connected via the mounting portion (16) , and further below the inner shaft (1).
2) An excavation blade (7) is continuously provided at the lower end, and the outer shaft (14) and the inner shaft (12) are rotated in opposite directions to each other, so that a circular column-shaped excavation hole perpendicular to the ground (8). (9) is excavated, and when the excavation blade (7) reaches a predetermined depth, the inner shaft (1) is excavated.
A hardener is injected from a hardener injection nozzle (19) below the hardener through a hardener passage (18) provided inside 2), and the hardener and the excavated soil are stirred and kneaded to form a drilling hole (9). A ground improvement method comprising forming a ground improvement portion therein to improve the ground.