JPH08134887A - Soil improving equipment - Google Patents

Abstract

PURPOSE: To provide a soil improving device efficiently stabilize the ground at a low cost. CONSTITUTION: A soil improving device is provided with first agitation blades 27, 27, agitation rods 15, 15 equipped with second agitation blades 28, 28, and a solidifying agent feeder. Blade bodies 31, 31 constituting respective second agitation blades 28, 28 are freely rotated in a certain angle range in a horizontal plane. The rotary direction of the agitation rods 15, 15 is changed over in accordance with the scope of the ground to be improved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is to solidify earth and sand by mixing the solidifying material while stirring the earth and sand in the ground.
The present invention relates to a ground improvement device suitable for improving soft ground.

[0002]

2. Description of the Related Art As is well known, solidifying materials such as lime and cement are prepared in the form of slurry, and the slurry is stirred and mixed with the soil in the ground to hydrate the solidifying material slurry. Ion exchange between hydration products of clay reaction and clay minerals, or chemical solidification reaction mainly consisting of pozzolanic reaction is used to chemically solidify the soil and create improved piles in the ground. There is a construction method to improve the ground.

Conventionally, in such a ground improvement method, as shown in FIG.
Ground improvement device 1 based on a pile driver as shown in
Is used. In the ground improvement device 1, a stirring rod 4 is rotatably supported by a supporting column 3 provided on the main body 2 around its axis, and the lower end of the stirring rod 4 stirs the soil in the ground G. The schematic structure is provided with a blade 5, an earth auger 6 for scraping through the soil in the ground G, and a discharge port 7 for supplying the solidifying material slurry into the ground G from a solidifying material supply mechanism (not shown). ing.

In order to improve the ground G by using the ground improving apparatus 1 as described above, first, the stirring rod 4 is attached to the ground G.
While rotating, penetrates into the ground G with the earth auger 6 to a predetermined depth. Next, the solidified material slurry is supplied to the solidified material slurry by the solidified material supply mechanism.
To squirt from. Then, while pulling up the stirring rod 4, the jetted solidified material slurry and the soil of the ground G are stirred by the earth auger 6 and the stirring blades 5 to solidify the soil and form a columnar improved pile in the ground G. Create.

According to the purpose of using the structure built on the ground G or the ground G, such an improved pile is
The ground G was improved by forming it alone or in a block shape, a grid shape, a continuous wall shape, or the like.

[0006]

However, the conventional ground improvement device as described above has the following problems. That is, since the earth auger 6 that advances in the ground G is provided only at the lower end portion of the stirring rod 4, the improved pile formed in the ground G has an outer shape of
There was no choice but to have a cylindrical shape having a diameter equal to the rotating diameter of the earth auger 6. Therefore, when it is desired to improve the ground G over a wide area, many improved piles are formed, or improved piles are formed at appropriate intervals, and only the surface layer portion between the pile heads of these improved piles is separately improved. Therefore, there is a problem that the construction period is prolonged and the construction cost is increased. The present invention has been made in view of the above points, and an object of the present invention is to provide a ground improvement device capable of efficiently improving the ground at low cost.

[0007]

DISCLOSURE OF THE INVENTION The present invention is a ground improvement apparatus for improving the ground by mixing a solidifying material with the soil in the ground, which is rotatable about an axis and movable in the direction of the axis. A stirring rod and a solidifying material supply mechanism for supplying a solidifying material into the ground, the lower end of the stirring rod, a first stirring blade fixed to the stirring rod,
A second stirring blade composed of one or more blade bodies is provided, and each blade body of the second stirring blade is pivotally supported by the stirring rod at a base end portion thereof and is rotated in a horizontal plane within a certain angle range. The distal end portion of the second stirring blade is spaced apart from and close to the stirring rod, and the turning radius of the second stirring blade in a state where the distal end portion of each blade body is separated from the stirring rod, It is characterized in that the radius of rotation of the first stirring blade is larger by a certain size.

[0008]

In the ground improvement device of the present invention, the stirring rod having the first stirring blade and the second stirring blade and the solidifying material supply mechanism are provided, and each blade body of the second stirring blade is provided within a certain angle range. It is configured to be rotatable. As a result, the stirring rod is rotated to penetrate into the ground, and the solidifying material supplied into the ground by the solidifying material supply mechanism is stirred and mixed with the earth and sand in the ground by stirring blades to solidify and improve the ground. can do. At this time, since the base end portion of the blade body of the second stirring blade is pivotally supported by the stirring rod, when the stirring rod is rotated in one direction, the tip end portion of each blade body should contact the surrounding ground. The reaction force caused by the force, that is, the earth pressure causes the blade body to rotate in the direction in which the tip portion is separated from the stirring rod. In this way, the radius of gyration of the second stirring blade becomes larger than that of the first stirring blade by a certain size. On the other hand, when the stirring rod is rotated in the opposite direction to the above, earth pressure from the surrounding ground causes the blade body to rotate in the direction in which the tip approaches the stirring rod, which reduces the radius of rotation of the second stirring blade. It is designed to be diameter.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to an embodiment shown in the drawings. Here, the ground improvement device according to the present invention,
For example, description will be made using an embodiment in the case of being applied to a biaxial ground improvement device having two drilling rods. As shown in FIG. 1, the ground improvement device 10 includes an endless caterpillar 1 for movement.
A support pillar 12 is hung vertically in front of a main body 11 having 1a,
This support pillar 12 is used for drilling and stirring the ground G.
The stirring mechanism 13 is provided, and a solidifying material supply mechanism (not shown) for supplying the solidifying material to the ground G is further provided.

As shown in FIG. 2, the drilling / agitation mechanism 13
Is provided with two stirring rods 15, 15. As shown in FIG. 1, the stirring rods 15 and 15 are
The upper end of each is connected to the drive motor 16. When the drive motor 16 is driven, the stirring rods 15 and 15 are rotationally driven in directions opposite to each other around their respective axes. The intermediate portions of the stirring rods 15 and 15 are rotatably supported around the axis by a guide member 18 that is vertically movable along the support 12.

The drive motor 16 is provided so as to be vertically movable along the support column 12, whereby the stirring rod 1 is provided.
The motors 5 and 15 are vertically movable together with the drive motor 16.

Behind the main body 11, there is a pull-out winch 20.
The pull-out winch 20 has one end of a wire 21 fixed thereto. And wire 21
The other end of the support member 2 is provided at the upper end of the support column 12.
2, a sheave 23 and 24 rotatably supported by a shaft 2, and a sheave 25 rotatably supported on the upper surface of the drive motor 16.
It is fixed to the lower surface of the support member 22 via. As a result, when the wire 21 is taken up by the pull-out winch 20, the drive motor 16, that is, the stirring rods 15 and 15 is raised along the support column 12. Also,
If the wire 21 is unwound from the pull-out winch 20, the stirring rods 15 and 15 are moved by the self-weight of the boring and stirring mechanism 13.
Are lowered along the support columns 12.

As shown in FIG. 2, each stirring rod 1
At the lower end of 5, a first stirring blade 27 and a second stirring blade 28 are provided so as to be vertically separated from each other by a certain size and are orthogonal to each other in a plan view. And the stirring rods 15, 1
An interference band 29 is provided at the lower end portion of 5 to keep these intervals.

The first stirring blade 27 is formed integrally with the stirring rod 15, and at its tip, bits 30, 30, ... For efficiently stirring the ground G are provided.

On the other hand, the second agitating blade 28 is configured to include blade bodies 31, 31 which are substantially J-shaped in a plan view. Each wing body 3
1 has a configuration in which it is sandwiched between an upper member 32a and a lower member 32b of a pedestal 32 formed integrally with the stirring rod 15. As shown in FIGS. 3 and 4, the pedestal 32 is provided with a pin 33 extending parallel to the axial direction of the stirring rod 15. The base end portion 31a of each wing body 31 is rotatably supported by the pin 33, whereby each wing body 31 is rotatable in a horizontal plane.

Further, each pedestal 32 is integrally formed with a stopper 34 for restricting the rotation angle of the wing body 31. With this stopper 34, as shown in FIG. 3, the blade body 31 hits the stopper 34 when the tip end portion 31 b of the blade body 31 rotates in a direction away from the stirring rod 15. Further, as shown in FIG. 4, when the blade body 31 rotates in a direction in which the tip end portion 31b approaches the stirring rod 15, the tip end portion 3 of the blade body 31 is rotated.
1b corresponds to a stopper 34 provided on the pedestal 32 of the other wing body 31. In this way, the blade bodies 31, 31 that constitute the second stirring blade 28 are
It is configured such that it can rotate about 33 in the range of a certain angle in a horizontal plane.

Then, as shown in FIG. 3, when the stirring rods 15 and 15 are rotationally driven in the direction of the arrow in the drawing, the reaction force generated between the stirring rods 15 and 15 and the surrounding ground, that is, the earth pressure, causes the tip portions 31b and 31b. The blades 31, 31 of each second stirring blade 28 rotate in a direction in which
1a and 31a are in a state of hitting the stoppers 34 and 34 (hereinafter, this state is referred to as a "diameter expansion state"). As shown in FIG. 2, when this state is reached, the wing body 3
The turning radii of 1 and 31, that is, the turning radius of the second stirring blade 28 is larger than the turning radius of the first stirring blade 27 by a certain size. Further, as shown in FIG. 4, when the stirring rods 15 and 15 are rotationally driven in the direction of the arrow in the figure, the tip portions 31b and 31 are caused by earth pressure from the surrounding ground.
The blade bodies 31, 31 of the respective second stirring blades 28 rotate in the direction in which b approaches the stirring rod 15, and the tip portions 31b, 3
1b is in a state of hitting the stoppers 34, 34 (hereinafter, this state is referred to as a "reduced diameter state"). In this state, the radius of gyration of the second stirring blade 28 is the same as the radius of gyration of the first stirring blade 27 (see FIG. 2).

As shown in FIG. 2, the discharge ports 36, 3 are provided at the bases of the first stirring blade 27 and the second stirring blade 28 as described above.
7 are provided. One end of a slurry hose (not shown) that passes through the stirring rod 15 is connected to the discharge port 36 of the first stirring blade 27. Further, the discharge port 37 of the second stirring blade 28 has the inside of the interference band 29 and the stirring rod 15
One end of a slurry hose (not shown) that passes inside is connected. The other end of this slurry hose is connected to a slurry pressure feed pipe 38 arranged between the stirring rods 15 and 15.

On the other hand, a slurry manufacturing apparatus (not shown) for kneading the solidifying material slurry in a predetermined composition is installed on the ground. The slurry manufacturing apparatus is provided with a solidifying material supply pump for feeding the solidifying material slurry toward the discharge ports 36 and 37. The solidification material supply pump includes the slurry hose connected to the discharge port 36,
The slurry pressure feed pipe 38 connected to the discharge port 37 is connected. Further, the slurry manufacturing apparatus is provided with a switching valve that switches between the discharge port 36 and the discharge port 37 for feeding the solidified material slurry.
In this way, the solidified material slurry kneaded in the slurry manufacturing apparatus is changed by switching the switching valve.
It is designed to be ejected into the ground G from the discharge port 36 or 37.

Next, the ground improvement method using the ground improvement device 10 having the above-mentioned structure will be described in detail. First, the ground G
The stirring rods 15 and 15 are positioned at predetermined positions. Next, the drive motor 16 rotationally drives the stirring rods 15 and 15 to rotate the first stirring blades 27 and 27 and the second stirring blades 28 and 28 in the directions of the arrows shown in FIG. Then, the pull-out winch 20 is operated to feed the wire 21. Then, the first stirring blades 27, 27 penetrate into the ground G while rotating due to the own weight of the drilling / stirring mechanism 13. At this time, as shown in FIG. 4, the blade bodies 31, 31 of each second stirring blade 28 are in a reduced diameter state by the earth pressure (reaction force) from the surrounding ground G. At the same time, the solidifying material slurry is jetted into the ground G from the discharge ports 36, 36 of the first stirring blades 27, 27. Then, the ejected solidifying material slurry is supplied to the respective first stirring blades 27 in the ground G by the first stirring blades 27, 27.
It is agitated and mixed with earth and sand in the range of the turning radius of

After that, when the first stirring blades 27, 27 reach a predetermined depth, the feeding of the wire 21 by the extraction winch 20 is stopped, and the stirring rods 15, 1 are stopped.
Stop the descent of 5. And the stirring rods 15 and 15
While continuing to rotate, the solidified material slurry is continuously ejected from the discharge ports 36, 36 into the ground G for a certain period of time to perform the tip treatment of the improved pile.

Next, while the stirring rods 15 and 15 are rotated in the above-described rotation direction, the wire 21 is wound by the pull-out winch 20 and the stirring rods 15 and 15 are pulled up.

Then, when the second stirring blades 28, 28 rise to a predetermined depth, the rotation direction of the drive motor 16 is switched and the stirring rods 15, 15 are reversed. Then, as shown in FIG. 3, the blade body 3 of each second stirring blade 28 is
Due to earth pressure from the surrounding ground G, the tips 1 and 31 rotate in a direction in which their tip portions 31b and 31b are separated from the stirring rods 15 and 15 and are in a diameter expanded state. Along with this, a switching valve (not shown) of the slurry manufacturing apparatus is switched to eject the solidifying material slurry from the discharge ports 37, 37 of the second stirring blades 28, 28. And stirring rod 1
Continue raising 5,15. Then, the discharge port 37,
The solidifying material slurry ejected from 37 is the second stirring blade 2
8, 28, the ground G is agitated and mixed with the earth and sand in the range of the radius of gyration of each second agitation blade 28.

As described above, the first stirring blades 27, 27
The solidifying material slurry discharged from the discharge ports 36, 36 of No. 2 and the discharge ports 37, 37 of the second stirring blades 28, 28 by the first stirring blades 27, 27 and the second stirring blades 28, 28, respectively. It is agitated and mixed with the soil of ground G. Then, the hydration reaction of the solidifying material slurry mixed with the earth and sand, the ion exchange action between the hydration product of this hydration reaction and the clay mineral, or the chemical consolidation reaction mainly consisting of the pozzolanic reaction etc. It is chemically solidified, and as a result, the improved pile A is formed in the ground G as shown in FIG.

In the improved pile A thus constructed, the deep layer portion has a small diameter portion A1 having the same diameter as the rotation radius of the first stirring blade 27, and the surface layer portion has the same diameter as the rotation radius of the second stirring blade 28. Has a large diameter portion A2.

After that, the above steps are repeated to form a predetermined number of the improved piles A at predetermined positions.
The improvement of the ground G is completed. At this time, if a plurality of improved piles A having such a shape are formed so that the surface layer portions A2 are adjacent to each other, the ground G can be improved over a wide range.

The above-mentioned ground improvement device 10 is provided with the stirring rods 15 and 15 having the first stirring blades 27 and 27 and the second stirring blades 28 and 28, and the solidifying material supply mechanism, and each second stirring blade. The wing bodies 31, 31 forming the wing 28 are rotatable in a horizontal plane within a certain angle range. Thereby, the stirring rods 15 and 15 are rotated to penetrate into the ground G, and the solidifying material slurry supplied into the ground G by the solidifying material supply mechanism is supplied to the first stirring blades 27 and 27 and the second stirring blades 28 and 28. By stirring and mixing with the earth and sand in the ground G at 28, the improved pile A having a shape having a small diameter in the deep layer and a large diameter in the surface layer can be formed in a single step. Then, even when a wide ground improvement is required only in the surface layer portion, the ground G can be improved with a smaller number of improved piles A than the conventional one by forming a plurality of improved piles A having such a shape. . As a result, it becomes possible to efficiently improve the ground G at low cost and in a short period of time.

Moreover, the blade body 3 constituting the second stirring blade 28
1, 31 are rotatably supported by pins 33, 33,
It is configured to be rotatable within a fixed angle range. Accordingly, when the stirring rods 15 and 15 are driven to rotate in one direction, the blade bodies 31 and 31 are automatically expanded by the earth pressure from the surrounding ground G, and the stirring rods 15 and 1 are also expanded.
If 5 is reversed, the diameter is automatically reduced by the earth pressure from the surrounding ground G. Therefore, the stirring rods 15, 1
The radius of rotation of the second stirring blade 28, that is, the pile diameter of the improved pile A can be easily changed only by switching the rotation direction of No. 5. Moreover, since no drive source is required to expand / reduce the diameter of the second stirring blade 28, it becomes possible to manufacture the ground improvement device 10 that can achieve the above effects at low cost. It is possible to suppress the occurrence of failures and the like. As a result, also by this, the cost for improving the ground G can be reduced.

Further, the solidifying material slurry discharged from the discharge port 36 of the first stirring blade 27 and the discharge port 37 of the second stirring blade 28.
The pile strength of the small diameter portion A1 and the large diameter portion A2 of the improved pile A can be easily changed by changing the composition with the solidifying material slurry discharged from. Therefore, even when the improved strength of the ground G is changed depending on the location, it can be easily installed.

In the above embodiment, the diameter of the second stirring blade 28 is expanded only in the surface layer of the ground G. However, the diameter of the second stirring blade 28 may be expanded if necessary. Good. For example, as shown in FIG. 6, in the range indicated by reference numeral (a) in the drawing, the drive motor 16 is rotated in the forward direction to keep the second stirring blade 28 in a reduced diameter state, and indicated by reference numeral (b) in the drawing. Within the range, the drive motor 16 may be rotated in the reverse direction so that the second stirring blade 28 is expanded and the improved pile A ′ is formed. In the improved pile A ′ thus constructed, the small diameter portion A1 ′ formed by the first stirring blade 27 and the large diameter portion A2 ′ formed by the second stirring blade 28 are alternately continuous in the vertical direction. It has a multi-layer structure.
Then, by forming a plurality of such improved piles A ′ such that the large diameter portions A2 ′ are adjacent to each other, it is possible to improve the ground G into a rigid frame structure.

In the above embodiment, the number of stirring rods 15 provided in the ground improvement device 10 is not limited, and it goes without saying that one or three or more stirring rods may be provided. Further, the shape and number of blades 31 provided in the second stirring blade 28 are not limited. In addition to this, in order to prevent lateral displacement of the ground G,
A spiral blade may be formed on the stirring rod 15 to discharge the stirred soil in the ground G to the ground.

[0032]

As described above, according to the ground improvement device of the present invention, the second stirring blade includes the stirring rod having the first stirring blade and the second stirring blade, and the solidifying material supply mechanism. Each wing body is configured to be rotatable within a fixed angle range. With this, by rotating the stirring rod to penetrate into the ground, the solidifying material supplied into the ground by the solidifying material supply mechanism is stirred and mixed with the earth and sand in the ground by the first stirring blade and the second stirring blade. An improved pile having a shape having a large diameter portion and a small diameter portion can be formed in a single process. Therefore, the ground can be improved with a smaller number of improved piles than the conventional one, and as a result, the ground can be efficiently improved at low cost and in a short period of time. Moreover, the blade body that constitutes the second stirring blade is configured to be rotatable within a fixed angle range. By this, due to the earth pressure from the surrounding ground,
Since the turning radius of the second stirring blade, that is, the pile diameter of the improved pile can be automatically changed only by switching the rotating direction of the stirring rod, the improvement having the large diameter portion and the small diameter portion at arbitrary positions The pile can be easily constructed. Moreover, since no drive source is required to expand or reduce the diameter of the wing body, it becomes possible to manufacture a ground improvement device that can achieve the above effects at low cost, It is possible to suppress the occurrence of such as. As a result, this also makes it possible to reduce the cost required for ground improvement.

[Brief description of drawings]

FIG. 1 is a side view showing an example of a ground improvement device according to the present invention.

FIG. 2 is a front view showing a first stirring blade and a second stirring blade provided in the ground improvement device.

FIG. 3 is a plan cross-sectional view showing a diameter expanded state of the second stirring blade.

FIG. 4 is a plan cross-sectional view showing a reduced diameter state of the same.

FIG. 5 is a vertical cross-sectional view showing an example of ground improved by using the ground improving apparatus.

FIG. 6 is a vertical cross-sectional view showing another example of the ground improved by using the ground improvement device.

FIG. 7 is a side view showing an example of a conventional ground improvement device.

[Explanation of symbols]

 10 Ground Improvement Device 15 Stirring Rod 27 First Stirring Blade 28 Second Stirring Blade G Ground

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Junji Tanaka 1-13-23, Kashiidai, Higashi-ku, Fukuoka-shi, Fukuoka (72) Inventor Sumio Ito 4-76 Matsugaoka, Kasuga-shi, Fukuoka

Claims (1)

[Claims] 1. A ground improvement device for improving the ground by mixing a solidifying material with the soil in the ground, the stirring rod being rotatable about an axis and movable along the axis. A solidifying material supply mechanism for supplying a solidifying material into the ground is provided, and a first stirring blade fixed to the stirring rod and a second stirring blade including one or more blades are provided at a lower end portion of the stirring rod. And a base end portion of each blade body of the second stirring blade is pivotally supported by the stirring rod to be rotatable in a horizontal plane within a certain angle range, and a tip portion thereof is The radius of gyration of the second agitating blade in a state in which the agitating rod can be separated from and approaching the agitating rod and the tip end portion of each blade body is spaced from the agitating rod is more constant than that of the first agitating blade. A ground improvement device characterized by having a larger size.