JP2001040662A - Concrete pile and embedding method therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To give a large bearing power to a pile by installing a pipe jacking body having screw blades on the outer periphery to the tip of concrete pile in a freely rotatable manner with the same shaft center as that of the concrete pile. SOLUTION: When a rotation shaft 10 is rotated by an electric motor, a propulsion body 4 rotates with the same shaft center as that of the concrete pile 1 in the same direction as that of the rotation shaft 10. Then, screw blades 5 advances while excavating through the ground, and a concrete pile 1 fixed to the pipe jacking body 4 is embedded in the ground together with the pipe jacking body 4. During excavation and pipe jacking, the screw blades 5 are provided only on the pipe jacking body 4, so that the excavated sediment or the like remains in the ground as it is without being carried to the ground surface and removed. Because of this, the earth to be removed hardly occurs, and the sediment pushed by the volume of the concrete pile 1 is compressed accordingly and this gives a sufficient bearing power to the concrete pile 1. Thus, the concrete pile can be embedded in the ground without vibration and noise.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a concrete pile and a method of burying the same, and more particularly to a concrete pile and a method of burying the same suitable for use on soft ground.

[0002]

2. Description of the Related Art Conventionally, a method of burial by impact has been used for installing a ready-made concrete pile. Although this method is a preferable construction method because the ground is compacted, it cannot be used particularly in an urban suburb where there are densely populated houses because it causes noise pollution. Therefore, a method has been used in which a hollow hole is formed using an auger screw, and then the auger screw is pulled out and a ready-made concrete pile is embedded in the inner hole.

[0003] In this middle boring method, an auger screw larger than a pile diameter is used, and a hole is drilled in the ground while a benite solution or the like is jetted from the tip of the screw. Then, when the auger screw reaches a predetermined position, a cement mill is injected into the ground in place of the benite solution, a ready-made pile is inserted therein, and the pile tip is rooted and buried by the cement mill. Things.

[0004]

However, the method of embedding concrete piles using the auger screw is vibration-free and noise-free, but requires earth removal. In addition, the stratum around the concrete pile is disturbed, so that there is a problem that a large supporting force cannot be obtained around the pile.

[0005]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned conventional problems, and can be applied to ready-made concrete piles. The purpose of the present invention is to provide a pile having a large bearing capacity without the need for earth removal treatment.
A concrete pile and a method of burying the concrete pile, wherein a propulsion body having a spiral wing on an outer periphery is mounted on a tip of the concrete pile so as to be rotatable around the same axis as the concrete pile.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to an embodiment shown in the drawings. In the drawings, reference numeral 1 denotes a hollow ready-made concrete pile, as shown in FIG. 2, a plurality of through holes 3 are formed at predetermined intervals on a concentric circle. The through hole 3 is used for fixing a head such as a longitudinal bar buried under tension in the concrete pile 1 and has a large diameter hole 3A and a small diameter hole 3B.
The large-diameter hole 3A
Is provided with a female screw into which a bolt is screwed.

Reference numeral 4 denotes a propulsion body which is rotatably mounted on the tip of the concrete pile 1 and which is formed by integrally connecting an inverted conical portion 4B having a top portion to a lower portion of a short and long cylindrical portion 4A. A spiral blade 5 is provided on the outer peripheral surface of the cylindrical portion 4A and the inverted conical portion 4B. Reference numeral 6 denotes a flange formed on the outer periphery of the upper portion of the cylindrical portion 4A. The flange 6 is positioned at a predetermined distance along the circumference (4 in the drawing).
2), two insertion holes 7 for bolts B (see FIG. 6) are provided separately from each other.

Reference numeral 8 denotes a power transmission prism protruding from the center of the upper surface of the cylindrical portion 4A, and is vertically erected at a predetermined height. The injection hole 9 extends vertically to almost the lower portion of 4A, and further branches into four from the lower end, each of which is opened on the outer peripheral surface of the inverted conical portion 4B. Reference numeral 10 denotes a rotary shaft, and at its lower end, a rectangular cylindrical cap 1 which can be fitted in a watertight manner with the prism 8.
0A, and an injection hole 11 communicating with the injection hole 9 penetrates the center of the rotating shaft 10. The upper end of the rotating shaft 10 is connected to a motor (not shown).

Reference numeral 12 denotes a tip fitting fixed to the end plate 2 of the concrete pile 1 having an outer diameter of 1 mm.
A short cylindrical shape having the same diameter as
Is provided with a circumferential groove 13 along the circumference. 1
Reference numeral 4 denotes an end plate 2 of the concrete pile 1
There are provided a plurality of insertion holes for fixing with bolts b, and each insertion hole 14 is provided at a position corresponding to the large diameter hole 3A of the through hole 3 formed in the end plate 2.

Reference numeral 15 denotes four fitting members which can be inserted into the peripheral groove 13 of the tip fitting 12 and are formed in a sector plate shape. The outer diameter of the fitting member is equal to the outer diameter of the flange 6 of the propulsion body 4. The inner diameter is the same as the outer diameter of the peripheral groove 13 formed in the tip fitting 12. Then, each of the fitting members 15
Are formed with two insertion holes 16 at positions corresponding to the insertion holes 7 of the flange 6. 17 is a retaining cover,
A cylindrical portion 19 having a diameter slightly larger than the outer diameter of the concrete pile 1 is integrally connected to the inner periphery of the disk portion 18 having the same outer diameter as the flange 6 provided on the propulsion body 4; Two insertion holes 20 are formed in the disk portion 18 at positions corresponding to the insertion holes 7 of the flange 6.

Next, a method of mounting the propulsion body 4 on the tip of the ready-made concrete pile 1 will be described. First, the tip fitting 12 is brought into contact with the end plate 2 of the concrete pile 1 at a burial site or a factory. , Its insertion hole 1
4 through the through hole 3 formed in the end plate 2
The tip fitting 12 is fixed to the tip of the concrete pile 1 by screwing the bolt b into the large diameter hole 3A.

Then, the earth retaining cover 17 and the propulsion body 4 are sequentially inserted into the tip of the concrete pile 1, and the tip fitting 12 fixed to the end plate 2 of the concrete pile 1 is inserted into the upper surface recess of the propulsion body 4. When the fitting is performed and the lower surface thereof abuts, the respective insertion holes 7 and 20 are overlapped between the upper surface of the flange 6 of the propulsion body 4 and the lower surface of the disk portion 18 of the retaining cover 17. The fitting member 15 is provided at the joined portion.

The inner diameter side 15a of the fitting member 15
Is inserted into the circumferential groove 13 of the tip fitting 12,
The insertion hole 16 formed in the fitting member 15 and the insertion hole 7,
By inserting the bolt B into the bolt 20 and tightening the screwed nut N, the propulsion body 4, the sector plate 15, the retaining cover 1
7 is fixed integrally. Thereby, the propulsion body 4 is rotatably mounted on the lower end of the concrete pile 1. The number of the fitting members 15 is not particularly limited, but is preferably about four to six.

When the concrete pile formed in this way is buried in the ground, the rotating shaft 10 is inserted into the hollow of the concrete pile 1 when the concrete pile 1 is suspended by a leader (not shown). A cap 10 </ b> A provided at the lower end of the rotating shaft 10 is fitted to the prism 8 of the propulsion body 4. When the rotating shaft 10 is rotated by an electric motor, the propulsion body 4 is moved to the inner diameter side 15 a of the fitting member 15.
Is inserted into the peripheral groove 13, and
The propulsion body 4 has the same axis as the concrete pile 1 and the rotation axis 1
Rotate in the same direction as 0.

As the propulsion body 4 rotates, the spiral wings 5 advance while excavating in the ground, and the concrete pile 1 fixed to the propulsion body 4 is embedded in the ground together with the propulsion body 4. Also, during this excavation propulsion, water, bentonite and the like are appropriately pumped from the injection hole 11 of the rotating shaft 10 and the propellant 4
The soil is softened and fluidized by being ejected from the tip through the injection hole 9 formed therein, and excavation and propulsion are performed while reducing the friction between the propulsion body 4 and the soil. Alternatively, simultaneously with the excavation and propulsion by the propulsion body 4, the propulsion speed can be further increased by pressing the upper end of the concrete pile 1 with a hydraulic jack or rotating the concrete pile 1.

Here, during the excavation and propulsion, the spiral wing 5 is provided not on the entire length of the concrete pile 1 but on the propulsion body 4 alone. It remains in the ground without being excavated. Accordingly, when almost no waste soil is generated, the soil and soil pushed away by the volume of the concrete pile 1 is compressed, so that the concrete pile 1 is given a sufficient supporting force. In addition, since the spiral wing 5 is only slightly larger than the diameter of the concrete pile 1, the soil is not disturbed without excavating extra soil. Further, the length of the propulsion body 4, the size of the spiral wing 5, and the like are appropriately changed according to the soil properties. For example, when the soil is very hard, the propulsion body 4 is made vertically long and the tip of the inverted conical portion 4B is made an acute angle.

When the concrete pile 1 reaches a predetermined depth, the rotation of the rotating shaft 10 is stopped, and the concrete shaft 1 is pulled out from the hollow of the concrete pile 1. At this time, since the cap 10A of the rotating shaft 10 and the prism 8 of the propulsion body 4 are connected by fitting, the cap 10A is easily detached from the prism 8 by pulling the rotating shaft 10 upward. In addition, the propulsion body 4 attached to the tip of the concrete pile 1 has a spiral wing 5
The concrete pile 1 is buried together with the concrete pile 1 so that the concrete pile 1 has a strong supporting force. After this,
A cement mill can be injected from the injection holes 11 and 9 to further solidify the periphery of the concrete pile 1.

[0018]

According to the present invention having the above-described structure, a concrete pile can be buried underground without vibration and without noise. Also, since the drilling hole diameter of the spiral wing formed on the propelling body at the tip of the concrete pile is only slightly larger than that of the concrete pile, it can be buried without disturbing the stratum around the concrete pile. Sediment remains in the ground and is compressed around the concrete pile, and the propulsion body at the tip of the pile is buried while being fixed to the tip of the concrete pile. Therefore, while a large bearing capacity can be obtained, the earth removal process is not necessary, and the amount of earth and sand to be buried around after the burial is small. Therefore, there are various effects such as a significant reduction in cost.

[Brief description of the drawings]

FIG. 1 is a front view of a tip portion of a concrete pile according to the present invention.

FIG. 2 is a bottom view of the same.

FIG. 3 is a longitudinal sectional view of FIG.

FIG. 4 is a sectional view taken along line II-II of FIG.

FIG. 5 is a sectional view taken along line III-III in FIG. 3;

FIG. 6 is an exploded perspective view of a pile tip.

FIG. 7 is a perspective view of the ready-made concrete pile as viewed from the bottom side.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Concrete pile 2 End plate 3 Through-hole 3A Large-diameter hole 4 Propulsion body 5 Spiral wing 8 Square column part 9 Injection hole 10 Rotating shaft 10A Cap 12 Tip fitting 13 Peripheral groove 15 Fitting member

Claims (8)

[Claims] 1. A concrete pile, wherein a propulsion body having a spiral wing on an outer periphery is mounted on a tip of the concrete pile so as to be rotatable about the same axis as the concrete pile. 2. A tip fitting having a circumferential groove is fixed to the tip of a concrete pile, and a fitting member which can be assembled to a propulsion body having a spiral wing on the outer periphery is fitted to the circumferential groove of the tip fitting. A concrete pile, wherein the propulsion body is mounted so as to be rotatable around the same axis as the concrete pile using the circumferential groove as a guide. 3. The concrete pile according to claim 2, wherein the tip metal fitting is fixed to a large diameter hole of a darma hole formed in an end plate of the concrete pile by bolting. 4. A concrete pile according to claim 1, wherein a square column for power transmission is provided at the center of the upper surface of the propulsion body so as to cover a cap provided at the lower end of the rotating shaft. . 5. The concrete pile according to claim 4, wherein an injection hole having an upper end opening in the center of the upper surface of the prism portion and a lower end opening in the lower surface of the propulsion body is formed inside the propulsion body. 6. A method for burying a concrete pile according to any one of claims 1 to 5 in the ground, wherein a propulsion body mounted on a tip of the concrete pile is rotated about the same axis as the concrete pile, A method for burying a concrete pile, wherein the concrete pile is buried underground while excavating and propelling the ground with the propulsion body. 7. When excavating and propelling the underground with a propulsion body, water or the like is sprayed from the lower end of the propulsion body, and a concrete pile is buried underground while assisting the propulsion of the propulsion body with the spraying force. The method of burying a concrete pile according to claim 6, wherein the concrete pile is buried. 8. The method according to claim 6, wherein the concrete pile is rotated or pressed when the concrete pile is buried.