JPH09268554A - Construction method of basic pile and device thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make it possible to mold a soil cement column and bury a core material at the same time by pulling up a rotary shaft where the core material is preliminarily inserted in the rotary shaft. SOLUTION: A basic pile construction device 1 is provided with an agitation blade 2 on the outer periphery near the tip and provided with a rotary shaft 4 where an outlet 3 of an improved material is formed and a core material 5 which is removably inserted in the axial direction inside the rotary shaft 4 from the rotary shaft 4. At first, the rotary shaft 4 is set at the position of a pile and then the rotary shaft 4 is turned in one direction integrally with the agitation blade 2 so that they may be penetrated while a weak ground is being agitated. While an improvement material (a curing material slurry) is being ejected from the outlet, they are mixed. Then, when the rotary shaft 4 reaches a specified depth, the rotary shaft is pulled slowly while it is being turned normally and reversely. At this time, the core material 5 is separated from the rotary shaft 4 and remains in a buried state in the soil cement column 7, which makes it possible to produce a core material-included basic pile.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for constructing a foundation pile for constructing a foundation pile on the ground to improve the ground and an apparatus therefor.

[0002]

2. Description of the Related Art Pile for ground improvement when there is soft ground such as sludge layer and support ground such as rock below this soft ground is roughly classified into support piles that are driven to reach the support ground. There are friction piles that are driven to the depth of soft ground without reaching the support ground. Here, the friction pile is supported by friction between the outer surface of the pile and the soft ground, and there is a soil cement column made of columnar soil cement, and further, a steel pipe is provided inside the soil cement column to increase strength. There is a core material-containing friction pile in which a core material made of, for example, is embedded.

As a method of constructing this core material-containing friction pile, conventional methods have been used, for example, JP-A-57-112513 and JP-A-6-116513.
The structure is known as disclosed in JP-A-2-148714 and JP-A-61-261516. That is, in the method disclosed in Japanese Patent Laid-Open No. 57-112513, as shown in FIG. 6, first, the rotating shaft 104 with the stirring blade 102 is rotated, and the rotating shaft 104 is stirred while stirring the ground by the stirring blade 102. (See FIG. 6A). At this time, the improving material is ejected from the discharge port formed on the rotary shaft 104, and the rotary shaft 104 is pulled out to remove the soil cement column 1
07 is formed. Next, soil cement column 107
The core material 105 is inserted before the solidification (see FIG. 6B). In this way, the core material 105 and the soil cement column 107 constitute the core material-containing friction pile 108 (see FIG. 6C). In this method, first, the soil cement column 107 is formed, and then the core material 105 is inserted into the soil cement column 107. The formation of the soil cement column 107 and the insertion of the core material 105 are performed in tandem. Therefore, there is a problem that the process becomes complicated.

Next, in Japanese Patent Laid-Open No. 62-148714, a core material is first driven into the ground. The rotary shaft is fitted into the driven core material from the outside, the core material is fitted into the hollow inside of the rotary shaft, and the rotary shaft is inserted while stirring the ground by the stirring blades. Then, the rotary shaft is raised while being reversely rotated, and along with this, the improving material is ejected to form a soil cement column. In this method, first, a core material is driven in, and then a soil cement column is formed around the core material, so that the core material is driven and the soil cement column is formed in succession. Therefore, there is a problem that the process is complicated.

Therefore, in the method disclosed in Japanese Patent Laid-Open No. 61-261516, first, the rotary shaft is rotated and the ground is agitated while stirring the ground by stirring blades, and at the same time, a hollow tubular member is inserted into the outer periphery of the rotary shaft. The core material is pressed down into the soil, and the improving material is ejected from the rotating shaft to form a soil cement column. Next, the stirring blade is folded to make it smaller than the hollow inner diameter of the core material, and the rotary shaft is pulled out from the core material. According to this construction method, unlike the above-mentioned two examples, the core material can be embedded simultaneously with the formation of the soil cement column.
However, in order to be able to pull out the rotary shaft, it is necessary to fold the stirring blade to make it smaller than the inner diameter of the hollow tubular core material, which complicates the structure of the construction device, and makes the core material a folded stirring blade. There is a problem that it becomes large because it becomes a size that can pass through. The above-mentioned problems are not limited to friction piles, and are the same not only in support piles but also in other foundation piles in general, and their solution has been desired.

[0006]

The present invention has been made in view of the above problems. That is,
The main object of this invention is to insert the core material into the rotary shaft, and to extract the rotary shaft that penetrates into the soft ground to form a soil cement column and at the same time, to embed the core material in the core material-containing foundation pile. It is to provide a construction method and an apparatus thereof.

[0007]

In order to solve this problem, in the invention of claim 1, it is possible to disengage from the rotary shaft provided with a stirring blade on the outer peripheral portion and the rotary shaft in the axial direction inside the rotary shaft. In the method of constructing a foundation pile using a foundation pile construction device having a core material inserted into a rotary shaft and a discharge port of a improving material such as a solidifying material slurry formed in the vicinity of the tip of the rotating shaft or in the stirring blade, While stirring the ground by stirring blades by the rotation of the rotating shaft, the improvement material is jetted from the discharge port and mixed into the ground to form a soil cement column in the ground, and the soil cement column is reached to a predetermined depth. After the formation, the technical means is taken such that only the rotating shaft is pulled out while the core material is embedded in the soil cement column.

Further, in the invention of claim 3, a rotating shaft having an agitating blade provided on an outer peripheral portion thereof, a core member which is detachably inserted from the rotating shaft in an axial direction inside the rotating shaft, and the rotating shaft. In a foundation pile construction device having a discharge port for improving material such as solidified material slurry formed near the tip of the stirring blade or on the stirring blade, when the rotary shaft penetrates while stirring the ground with the stirring blade by the rotation. To form a soil cement column in the ground by mixing the ground into the soil by ejecting the improving material from the discharge port, after forming the soil cement column to a predetermined depth, remove the core material from the rotating shaft into the soil cement column. The technical measure is that only the rotating shaft can be pulled out while it is buried.

Further, in the invention of claim 2 or 4, a technical means is provided in which a tooth portion for excavation is provided at the tip of the core material.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION Preferred embodiments of a foundation pile construction device of the present invention will be described below with reference to the drawings. FIG.
1 shows an example of a foundation pile construction device 1 for carrying out the core pile foundation method of the present invention. This foundation pile construction device 1 includes a rotating shaft 4 provided with a stirring blade 2 in the outer peripheral portion near the tip end thereof, and a discharge port 3 of the improving material, and a rotating shaft in the axial direction inside the rotating shaft 4. 4 and a core member 5 which is detachably inserted.

The rotary shaft 4 is provided so as to be rotated by a drive unit 6 such as a hydraulic motor connected to the upper end. The rotating unit 4 and the driving unit 6 are held by a column-shaped reader or the like equipped on a work vehicle (not shown). Then, the rotating shaft 4 is adapted to penetrate into the ground while agitating the soft ground by the screw-shaped stirring blades 2 provided integrally while rotating.

The discharge port 3 for the solidifying material slurry, which is the chemical improving material, is formed near the tip of the rotary shaft 4 or the stirring blade 2
Are formed in an appropriate number. In this embodiment, a nozzle serving as the discharge port 3 is formed on the lower stirring blade 2. Therefore,
Agitate the solidifying material slurry from the discharge port 3 with stirring,
The solidifying material slurry is mixed into the agitated soft ground, whereby a pillar body made of earth and sand mixed cement, that is, a soil cement column 7 is formed.

Next, the core material 5 is made of, for example, a steel pipe. The core material 5 is embedded in the center of the soil cement column 7 to increase the resistance to the shear load applied to the soil cement column 7 and reinforce the strength. In this embodiment, a tooth portion 5A for punching is integrally formed at the lower end of the core material 5, the tooth portion 5A is projected from the tip of the rotary shaft 4, and the tooth portion 5A is formed by the rotary shaft 4A. It has a larger diameter than the hollow. Since this tooth portion 5A is formed at the lowermost end, it always digs into the ground at the tip that is not stirred.

Since the core material 5 is removably inserted into the rotary shaft 4, when the rotary shaft 4 is pulled out after the soil cement column 7 is formed, the core material 5 is separated from the rotary shaft 4 and remains as it is. Remain in 7. When the rotary shaft 4 is pulled out, the stirring blade 2 is gradually pulled up while rotating in the forward and reverse directions. The core material 5 and the rotating shaft 4 may not be constrained, but the core material 5 may be detachable within the rotating shaft 4 (not shown). That is, a means for fixing the core material 5 to the rotating shaft 4 by sandwiching or releasing the core material 5 is provided, or one of the engaging / disengaging means is provided for the core material 5 and the other is formed for the rotating shaft 4. Thus, the core material 5 and the rotary shaft 4 may be maintained integrally during excavation, and the core material 5 may be left when the rotary shaft 4 is pulled out by separating the two.

Foundation pile construction apparatus 1 constructed as described above
According to the above, the core material 5 is buried at the same time when the soil cement column 7 is constructed as follows. First, as shown in FIG. 1, the rotary shaft 4 is set at the pile position. Next, as shown in FIG. 2, the rotating shaft 4 is rotated integrally with the stirring blade 2 in one direction,
The stirring blade 2 penetrates the ground while stirring. With this stirring, the solidifying material slurry is jetted from the discharge port 3 of the rotating shaft 4 to mix the solidifying material slurry into the stirred soil. In this way, the stirring / mixing process proceeds.

Next, as shown in FIG. 3, when the rotary shaft 4 reaches a desired depth, that is, when the soil cement column 7 is formed to a predetermined depth, as shown in FIG. Gradually pull out while reversing. When the rotary shaft 4 is pulled out, the core material 5 is separated from the rotary shaft 4 and remains as it is embedded in the soil cement column 7 as shown in FIG. Since the core material 5 is inserted into the rotary shaft 4, the stirring blade 2 does not hit the core material 5 when the rotary shaft 4 is pulled out. Therefore, it is not necessary to fold the stirring blade 2 unlike the conventional configuration. In this way, the core material-containing foundation pile 8 including the soil cement column 7 having the core material 5 embedded therein is constructed.

In the present invention, the agitating blade may be one that only agitates earth and sand, and may be one that includes a blade for excavating. A configuration provided with only a stirring blade that performs only stirring, or a configuration that combines only stirring and excavation can be appropriately used. In addition, in the case of the stirring blade having the excavating function, it is preferable to dispose at least at the lowermost end.

[0018]

As described above, according to the method and apparatus for constructing a foundation pile of the present invention, the core material is inserted inside the rotary shaft with the stirring blades so as to be detachable from the rotary shaft. Improving the ground by constructing a foundation pile by injecting the solidifying material slurry to form a soil cement column by injecting while stirring with a blade and then pulling out the rotating shaft and leaving the core material embedded in the soil cement column. It can be performed. And since the core material can be embedded at the same time when the soil cement column is formed, the process can be simplified, and
Since the core material is inserted into the rotary shaft, a core material having a small diameter can be used. Further, the core material does not interfere with excavation and mixing by the stirring blade.

[Brief description of drawings]

FIG. 1 is a schematic view showing a state in which a rotary shaft is set at a pile position.

FIG. 2 is a schematic view showing a state where a rotary cement is penetrated to form a soil cement column.

FIG. 3 is a schematic diagram showing a state in which a rotating shaft has reached a predetermined depth.

FIG. 4 is a schematic diagram showing a state in which a rotary shaft is pulled out.

FIG. 5 is a schematic view showing a state after completion of pulling out a rotary shaft.

FIG. 6 is a process explanatory view for explaining an example of a conventional core material-containing foundation pile construction method, (a) shows a state in which a rotary cement is penetrated to form a soil cement column, and (b) shows a core material. The state of being inserted, (c) shows the state in which the core material is embedded in the soil cement column.

[Explanation of symbols]

 1 Foundation pile construction device 2 Stirring blade 3 Discharge port for solidifying material slurry 4 Rotating shaft 5 Core material 5a Teeth 7 Soil cement column 8 Core material containing foundation pile

Claims (4)

[Claims] 1. A rotating shaft having a stirring blade on its outer periphery,
A base having a core material that is detachably inserted from the rotary shaft in the axial direction inside the rotary shaft, and a discharge port for improving material such as solidifying material slurry formed near the tip of the rotary shaft or on the stirring blade. In the method of constructing a foundation pile using a pile construction device, while stirring the ground while stirring the ground by the rotation of the rotary shaft, the improvement material is ejected from the discharge port and mixed into the ground to mix it in the ground. A method for constructing a foundation pile, characterized in that a soil cement column is formed on the base, the soil cement column is formed to a predetermined depth, and then only the rotating shaft is pulled out while the core material is embedded in the soil cement column. 2. The method for constructing a foundation pile according to claim 1, wherein a tooth portion for excavation is provided at the tip of the core material. 3. A rotating shaft provided with a stirring blade on the outer periphery,
A base having a core material that is detachably inserted from the rotary shaft in the axial direction inside the rotary shaft, and a discharge port for improving material such as solidifying material slurry formed near the tip of the rotary shaft or on the stirring blade. In the pile construction device, when the rotating shaft penetrates the ground while stirring with stirring blades, the improving material is ejected from the discharge port and mixed into the ground to form a soil cement column in the ground. After forming the soil cement column to a predetermined depth, it is possible to pull out only the rotating shaft while the core material is separated from the rotating shaft and embedded in the soil cement column. . 4. The foundation pile construction device according to claim 3, wherein a tooth portion for excavation is provided at the tip of the core material.