WO2018101627A1

WO2018101627A1 - Pile shoe for open lower end type intrusion concrete pile and open lower end type intrusion concrete pile including pile shoe

Info

Publication number: WO2018101627A1
Application number: PCT/KR2017/012547
Authority: WO
Inventors: 임성대
Original assignee: (주)삼일이엔씨
Priority date: 2016-11-30
Filing date: 2017-11-07
Publication date: 2018-06-07
Also published as: KR101793693B1

Abstract

The present invention relates to: a pile shoe for an open lower end type intrusion concrete pile, in which the pile shoe manufactured by welding an upper shoe and a lower shoe to each other in a state where a plurality of fastening bolts are arranged between the upper shoe and the lower shoe is bolt-assembled to the lower end of a concrete pile body, thereby enabling omission of on-site welding work; and an open lower end type intrusion concrete pile including the pile shoe.

Description

Bottom open penetration concrete pile with tip shoe and tip shoe for bottom open penetration concrete pile

The present invention bolts the tip shoe manufactured by welding the upper shoe and the lower shoe in the state of having a plurality of fastening bolts between the upper shoe and the lower shoe to the lower portion of the concrete pile body, so that the site welding operation can be omitted. It relates to a bottom open penetration concrete pile equipped with a tip shoe and a tip shoe for an open penetration concrete pile.

Piles installed in the ground for foundations of various construction and civil engineering structures are designed to receive mainly compressive force at the tip.

In order to use the pile efficiently, the pile body penetrates into the lower base plate through the remaining slime layer rather than the remaining slime layer at the bottom of the hole, so that the tip of the pile is directly supported on the base plate, so that the extreme load acts on the pile. The pile support ground should not be allowed to yield or break.

Accordingly, in order to secure a sufficient bearing capacity of the pile, a number of techniques for increasing the tip bearing capacity through penetration of the pile tip have been proposed.

One of them, Patent No. 10-1515347, "tip reinforcement pile" is coupled to the tip body reinforcing plate of the upper and lower strait cross-sectional form larger diameter than the diameter of the pile body to the bottom of the pile body.

The tip reinforcement pile is convenient in the inlet side because it increases the tip support force and prevents the enlarged tip portion from being caught in the inner wall of the hole when the pile is indented.

However, because the lower end of the reinforcing plate is difficult to penetrate the slime layer, there is a limit in the bearing capacity because it is not supported in the lower base plate of the drilling hole. In addition, it is hard to expect the slime compression effect because it is entered by the rotational penetration, not the slugging, and the tip bearing capacity is more likely to be lower than the piles due to the normal striking, and there is also a fear of long-term settlement.

To this end, the tip shoe of the upper and lower narrow cross-sectional shape having a diameter smaller than the diameter of the pile body is coupled to the bottom of the concrete pile body. Penetrated concrete piles have been developed that can be directly penetrated to improve bearing capacity.

In the above technology, the tip shoe is brought into the site with the upper shoe and the lower shoe separated, and the upper shoe is first bolted to the bottom of the concrete pile body, and then the lower shoe is coupled to the lower part of the upper shoe by field welding.

However, in the field welding process, it is difficult to maintain a constant welding quality according to the site conditions, the skill of the operator, etc., and in the case of rainy weather or high humidity, the welding work itself is difficult and greatly depends on the influence of outside air.

In addition, the welding wire must be used to pull the welding wire, in this case there is a problem that the equipment is stepped on the wire during the process of moving the heavy machinery machine is damaged or the wire is difficult to secure the heavy equipment movement copper wire .

The present invention combines the tip shoe to the bottom of the concrete pile body without on-site welding process, the lower open penetration concrete with the tip opening shoe and the tip shoe for the lower open penetration concrete pile that can improve workability and safety, ensure uniform quality and shorten the air To provide a stake.

The present invention according to a preferred embodiment relates to a tip shoe for the bottom open type penetration concrete pile coupled to the bottom of the concrete pile body, the bottom is open, the tip shoe is a ring for the top surface is coupled to the bottom of the concrete pile body Upper shoe of shape; A ring-shaped lower shoe coupled to be in close contact with an upper surface of the upper shoe; And a plurality of fastening bolts coupled to the upper shoe to fasten the upper shoe to the fastening nut provided at the lower end of the concrete pile body. Consists of, the upper shoe is formed with a coupling hole through which the bolt body of the fastening bolt is inserted, the lower portion of the coupling hole is formed with a bolt head receiving portion is inserted into the bolt head of the fastening bolt, the fastening bolt The bolt head is accommodated in the bolt head receiving portion and coupled to the upper end of the bolt body through the coupling hole to protrude a certain length to the upper portion of the upper shoe, the lower shoe is formed through the fastening hole narrower than the bolt head of the fastening bolt And, the bolt head of the fastening bolt provides a tip shoe for the bottom open type penetration concrete pile, characterized in that the tool insertion groove is formed.

According to another exemplary embodiment of the present invention, the upper shoe has a cross section of an upper and lower narrow shape, and the lower shoe has a top end shoe for a lower open penetration concrete pile, wherein a width of an upper end of the upper shoe is less than a lower end width of the upper shoe. do.

According to another preferred embodiment of the present invention, the lower shoe provides a tip shoe for a bottom open penetration concrete pile, characterized in that it is divided into a plurality of arc-shaped lower shoe units.

According to another preferred embodiment of the present invention, the fastening hole provides a tip shoe for a bottom open penetration concrete pile, characterized in that formed between the adjacent lower shoe unit.

The present invention according to another preferred embodiment provides a tip shoe for a bottom open penetration concrete pile, characterized in that any one of the coupling hole is fitted in place of the fastening bolt is fitted to the fastening nut.

The present invention according to another preferred embodiment provides a tip shoe for the lower open penetration concrete pile, characterized in that the fastening bolt is omitted in any one of the coupling holes.

According to another preferred embodiment of the present invention, there is provided a concrete pile body having a plurality of fastening nuts at a lower end thereof with an open portion; And the tip shoe coupled to the lower end of the concrete pile body; Consisting of, the fastening bolt of the tip shoe is screwed to the fastening nut of the concrete pile body provides a lower open-type penetration concrete pile with a tip shoe characterized in that the tip shoe is coupled to the concrete pile body.

According to another exemplary embodiment of the present invention, any one of the coupling holes may include a fastening bolt, and the end of the fitting rod may be fitted into the coupling hole corresponding to the coupling hole and the coupling hole, the coupling bolt being omitted. It provides a bottom open penetration concrete pile with a tip shoe.

According to the present invention has the following effects.

First, in the state having a plurality of fastening bolts between the upper shoe and the lower shoe, the upper shoe and the lower shoe may be welded in advance in a factory to produce a tip shoe. Since the tip shoe produced as described above is brought into the site and bolted to the bottom of the concrete pile body, the site welding work can be omitted during the production of the penetration concrete pile, so the work is simple and there is no fear of air delay.

Second, since the tip shoe is manufactured by factory welding, the welding quality is uniform and reliability can be secured.

Third, since the site welding work is omitted, there is no fear of safety accident because there is no interference between the field welding wire and various heavy equipment.

Fourth, since the fastening bolt is located between the upper shoe and the lower shoe does not fall off, there is no fear of losing the fastening bolt.

Fifth, in the case of using the fitting rod, the worker does not have to hold the tip shoe directly when tightening the fastening bolt can reduce the work force, it is easy to position the fastening bolt, the workability is improved.

1 is a perspective view of a concrete pile coupled to the tip shoe for the present invention lower open penetration concrete pile.

Figure 2 is an exploded perspective view of the tip shoe for the present invention open lower penetration concrete pile.

Figure 3 is a perspective view showing a coupling relationship between the tip shoe for the lower open penetration concrete pile of the present invention and the concrete pile body.

Figure 4 is a cross-sectional view of the tip shoe for the present invention lower open penetration concrete pile.

Figure 5 is a perspective view of the tip shoe for the present invention lower open penetration concrete pile including a lower shoe unit.

Figure 6 is a bottom view of the tip shoe for the present invention lower open penetration concrete piles showing embodiments of fastening holes.

7 is a cross-sectional view of the concrete pile equipped with the fitting rod according to an embodiment.

8 is a cross-sectional view of the concrete pile equipped with the fitting rod according to another embodiment.

In order to achieve the above object, the lower end of the open type penetration concrete pile tip shoe of the present invention relates to the front end shoe of the lower open type penetration concrete pile coupled to the bottom of the open concrete pile body, the tip shoe, the top surface Ring-shaped upper shoe for coupling to the lower end of the concrete pile body; A ring-shaped lower shoe coupled to be in close contact with an upper surface of the upper shoe; And a plurality of fastening bolts coupled to the upper shoe to fasten the upper shoe to the fastening nut provided at the lower end of the concrete pile body. Consists of, the upper shoe is formed with a coupling hole through which the bolt body of the fastening bolt is inserted, the lower portion of the coupling hole is formed with a bolt head receiving portion is inserted into the bolt head of the fastening bolt, the fastening bolt The bolt head is accommodated in the bolt head receiving portion and coupled to the upper end of the bolt body through the coupling hole to protrude a certain length to the upper portion of the upper shoe, the lower shoe is formed through the fastening hole narrower than the bolt head of the fastening bolt And, the bolt head of the fastening bolt is characterized in that the tool insertion groove is formed.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings and preferred embodiments.

1 is a perspective view of a concrete pile coupled with the tip shoe for the lower open penetration concrete pile of the present invention, Figure 2 is an exploded perspective view of the tip shoe for the lower opening penetration concrete pile of the present invention, Figure 3 is a lower opening for penetration concrete pile It is a perspective view which shows the coupling relationship of a tip shoe and a concrete pile main body.

As shown in Figures 1 to 3, the tip shoe for the lower open penetration concrete pile according to the present invention is to be coupled to the lower end of the concrete pile body (2) with the lower side, the upper surface of the lower end of the concrete pile body (2) Ring-shaped upper shoe 31 to be coupled to; A lower shoe 32 having an upper surface coupled to be in close contact with the lower surface of the upper shoe 31; And a plurality of fastening bolts 33 coupled to the upper shoe 31 to fasten the upper shoe 31 to the fastening nut 21 provided at the lower end of the concrete pile body 2. Consists of, the upper shoe 31 is formed with a coupling hole 311 through which the bolt body 332 of the fastening bolt 33 is inserted, the lower portion of the coupling hole 311 fastening bolt 33 The bolt head 331 of the bolt head 331 is inserted is received is formed, the bolt head 331 of the fastening bolt 33 is stored in the bolt head housing 312 and the bolt body 332 The upper end of the coupling hole 311 is characterized in that it is coupled to protrude a predetermined length to the upper portion of the upper shoe 31.

The tip shoe for the lower open penetration concrete pile of the present invention comprises an upper shoe 31, a lower shoe 32 and a fastening bolt 33.

The upper shoe 31 and the lower shoe 32 are coupled in a ring shape along the lower outer peripheral surface of the concrete pile body 2 so as to communicate with the inside of the concrete pile body 2 whose lower portion is open.

The upper shoe 31 is formed with a plurality of coupling holes 311 and the bolt head receiving portion 312 below the coupling hole 311, the bolt body 332 and the bolt head of the fastening bolt 33 to be described later ( 331 are inserted and received respectively.

The diameter of the bolt head receiving portion 312 is configured to be larger than the diameter of the coupling hole (311).

The fastening bolt 33 is coupled to the upper shoe 31 and is not dropped out by the lower shoe 32 coupled to the upper shoe 31.

Accordingly, the fastening bolt 33 may be welded to the upper shoe 31 and the lower shoe 32 in a state in which the fastening bolt 33 is coupled to the coupling hole 311 of the upper shoe 31. Since the tip shoe 3 is brought into the site while the shoe 32 is welded, only the bolt is assembled to the concrete pile body 2, so that the site welding process can be omitted.

The fastening bolt 33 is for fastening the upper shoe 31 to the fastening nut 21 provided at the lower end of the concrete pile body 2, and a plurality of fastening bolts 33 are provided to be spaced apart along the circumference of the upper shoe 31. .

The fastening bolt 33 is protruded a predetermined length to the upper end of the upper shoe 31 through the upper end of the bolt body 332 through the coupling hole 311.

The bolt body 332 portion of the protruding fastening bolt 33 is screwed to the fastening nut 21 provided at the bottom of the concrete pile body (2), the front end shoe (3) is coupled to the concrete pile body (2) do.

The fastening nut 21 is coupled to each lower end of the steel rods 22 provided in the concrete pile body 2 along the longitudinal direction of the concrete pile body 2.

The fastening nut 21 has a female thread formed on the inner circumferential surface of the lower fastening nut so as to correspond to the thread of the fastening bolt 33.

In the present invention as described above in the state having a plurality of fastening bolts 33 between the upper shoe 31 and the lower shoe 32, the upper shoe 31 and the lower shoe 32 by welding in advance in the factory, etc. (3) to produce. The tip shoe 3 thus manufactured is brought into the site and bolted to the bottom of the concrete pile body 2 to increase the allowable tip bearing capacity of the pile after the construction of the pile is completed.

Accordingly, since the site welding operation can be omitted, the front end shoe 3 can be coupled to the bottom of the concrete pile body 2 only by the bolting operation, so that the operation is simple and there is no fear of air delay.

In addition, since the tip shoe 3 is manufactured by factory welding, the welding quality is uniform and reliability can be ensured, and there is no interference between the field welding wire and various heavy equipments, and the fastening bolt 33 may be lost. There is no stable supply of materials.

4 is a cross-sectional view of the tip shoe for the lower open penetration concrete pile according to the present invention.

As shown in FIG. 4, the upper shoe 31 has a cross section of an upper and lower narrow shape, and the lower shoe 32 may be configured such that the width of the upper end of the upper shoe 31 is less than or equal to the lower end width of the upper shoe 31. .

In this way, the upper shoe 31 is configured in the cross-sectional shape of the upper and lower straits in which the inclined surface is formed on the inner and outer sides so that the width becomes narrower from the upper side to the lower side, while the cross-sectional width of the lower shoe 32 is less than the lower end width of the upper shoe 31. When configured as, a part or all of the pointed tip shoe 3 to the bottom can be easily penetrated and supported through the remaining slime layer of the bottom of the drilled hole to the base side of the weathered rock or more.

The lower shoe 32 is formed with a through hole 321 narrower than the bolt head 331 of the fastening bolt 33, the tool insertion groove 333 in the bolt head 331 of the fastening bolt 33. ) Is formed.

Accordingly, a tool such as a wrench can be inserted into the tool insertion groove 333 formed in the bolt head 331 of the fastening bolt 33 by passing through the fastening hole 321 in the field.

Accordingly, by rotating the tool inserted into the tool insertion groove 333 to rotate the fastening bolt 33, it is possible to easily fasten the fastening bolt 33 to the fastening nut 21.

In particular, the width of the fastening hole 321 is formed to be narrower than the width of the bolt head 331 is configured so that the fastening bolt 33 is not dropped out.

The tool insertion groove 333 may be formed in a polygonal shape, such as a square, hexagon, etc., the end of the tool for rotating the fastening bolt 33 is the shape of the tool insertion groove 333 to be connected to the tool insertion groove 333. It is preferable to configure in a shape corresponding to.

5 is a perspective view of the tip shoe for the present invention lower open penetration concrete pile including a lower shoe unit.

As shown in FIG. 5, the lower shoe 32 may be divided into a plurality of arc-shaped lower shoe units 32 ′.

Since the upper shoe 31 has a relatively large area of the upper surface and the lower surface, the flat plate may be cut and the bottom surface of the plate may be chamfered to be manufactured in the upper and lower narrow shapes.

However, the lower shoe 32, which is narrower than the upper shoe 31, should be manufactured in a ring shape or by casting by bending a steel bar to produce a ring shape.

At this time, bending the lower shoe 32 may deteriorate the strength and ductility of the lower shoe 32 due to deformation of the steel bar, and in the case of casting, excessive manufacturing cost is uneconomical.

Therefore, if the lower shoe 32 is divided into a plurality of arc-shaped lower shoe units 32 'having a gentle curvature, the forging can be forged, thereby reducing the manufacturing cost and preventing the reduction of strength and ductility.

In addition, by arranging the spaces of the adjacent lower shoe units 32 ′ slightly apart from each other, heat deformation due to heat effects generated when the lower shoe 32 is welded to the upper shoe 31 may be absorbed.

As shown in (a) and (b) of Figure 6, the fastening hole 321 may be formed between the neighboring lower shoe unit 32 '.

The fastening hole 321 formed through the lower shoe 32 described above with reference to FIG. 4 may be formed between neighboring lower shoe units 32 '.

That is, as shown in (a) of FIG. 6, the fastening holes 321 may be formed by spaced apart from neighboring lower shoe units 32 ′, and the lower shoe units 32 as shown in FIG. 6 (b). It is also possible to form a fastening hole 321 between the adjacent lower shoe unit 32 'by forming both ends of the semicircular shape.

Therefore, by inserting and rotating a tool such as a wrench toward the tool insertion groove 333 formed in the bolt head 331 of the fastening bolt 33 through the fastening hole 321, the fastening bolt 33 is fastened to the fastening nut 21. Can be fastened to

At this time, the width of the fastening hole 321 formed between the adjacent lower shoe unit 32 'is formed to be narrower than the width of the bolt head 331 is configured so that the fastening bolt 33 is not dropped out.

As shown in FIG. 7, any one of the coupling holes 311 may be provided with a fitting rod 34 fitted to the fastening nut 21 instead of the fastening bolt 33.

The fitting rod 34 may be configured to be forcibly fitted to the fastening nut 21, and may be made of rubber or synthetic resin.

One end of the fitting rod 34 may be configured to be tapered so as to decrease in width toward the end so that it can be easily inserted into the fastening nut 21.

When the fitting rod 34 is provided in any one of the coupling holes 311 as described above, the concrete pile main body 2 is laid down, and then the fitting rod 34 is inserted into the fastening nut 21 located at the top thereof. In the state in which the position of (3) is temporarily fixed, the remaining fastening bolts 33 may be fastened with the fastening nuts 21.

Therefore, since the operator does not have to hold the tip shoe 3 directly during the fastening operation of the fastening bolt 33, the work force can be reduced, and the workability is improved because the fastening bolt 33 is easily positioned.

As shown in FIG. 8, any one of the coupling holes 311 may be configured to omit the fastening bolt 33.

In contrast to the embodiment illustrated in FIG. 7 described above, in the embodiment illustrated in FIG. 8, the fitting rod 34 is fixed to the top end fastening nut 21 while the fitting rod 34 is fixed to the fastening nut 21 positioned at the top. Of the coupling hole 311 of the coupling hole 311 is inserted into any one of the coupling hole (311) omitted, and then fastening the remaining fastening bolt 33 and the fastening nut 21 to the position of the tip shoe (3) Can be fixed.

Therefore, since the operator does not need to hold the tip shoe 3 during the fastening operation of the fastening bolt 33, the work force can be reduced, and the workability is improved because the fastening bolt 33 is easily positioned.

To this end, the fitting rod 34 is screwed to the fastening nut 21 or fixed by interference fit, and one end of the fitting rod 34 is configured to protrude a predetermined length to the outside of the fastening nut 21.

That is, the embodiment of FIG. 7 manufactures the tip shoe 3 while the fitting rod 34 is coupled to the upper shoe 31 in advance, and the embodiment of FIG. 8 has the tip without the fitting rod 34. The production of the shoe 3 is different from the point of assembly of the tip shoe 3 to the fitting rod 34 in the field, but as a result, it is the same in that there is an effect of reducing work force and improving workability.

In addition, the present invention includes a lower open penetration concrete pile provided with a tip shoe.

The bottom open-type penetration concrete pile provided with the front end shoe of the present invention has a lower portion of the concrete pile body (2) having a plurality of fastening nuts (21) at the bottom thereof; And the tip shoe (3) coupled to the lower end of the concrete pile body (2); Consists of, the fastening bolt 33 of the front end shoe (3) is screwed to the fastening nut 21 of the concrete pile body (2) is characterized in that the front end shoe (3) is coupled to the concrete pile body (2) It is done.

The concrete pile 1 can be supported by the front end shoe 3 is penetrated directly into the base plate through the remaining slime layer of the lower hole of the drilling hole.

In addition, the upper shoe 31 and the lower shoe 32 are welded in advance in a state in which the fastening bolt 33 coupled to the fastening nut 21 provided in the concrete pile body 2 is coupled to the upper shoe 31. Since (3) is manufactured, the tip shoe 3 can be easily coupled to the concrete pile body 2 without a field welding process, thereby improving workability and safety.

As shown in FIG. 4, the fastening nut 21 is coupled to a lower end of the steel rod 22 located inside the concrete pile body 2 along the length direction of the concrete pile body 2.

In addition, the fastening bolt 33 is omitted in any one of the coupling holes 311 in the lower open-type penetration concrete pile provided with the tip shoe of the present invention, the coupling hole 311 and the coupling hole in which the fastening bolt 33 is omitted. The end of the fitting rod 34 may be fitted to the fastening nut 21 corresponding to the 311.

To this end, the fitting rod 34 is screwed to the fastening nut 21 or fixed with an interference fit, and configured to protrude a predetermined length to the outside of the fastening nut 21.

Therefore, as shown in FIG. 8 described above, after producing the tip shoe 3 in a state without the fitting rod 34, the coupling holes 311 and the fastening bolt 33 is omitted at both ends of the fitting rod 34 in the field. The insertion hole 21 may be inserted into the fastening nut 21 corresponding to the coupling hole 311, and the remaining fastening bolt 33 may be fastened to the fastening nut 21 to fix the position of the tip shoe 3.

Accordingly, it is possible to reduce workforce and improve workability.

The lower open penetration concrete pile provided with the tip shoe and the tip shoe for the lower open penetration concrete pile of the present invention is a tip shoe manufactured by welding the upper shoe and the lower shoe while having a plurality of fastening bolts between the upper shoe and the lower shoe. By assembling the bolt to the bottom of the concrete pile body, the field welding work can be omitted, the operation is simple and can prevent the air delay. In addition, since the tip shoe is manufactured by factory welding, there is an industrial applicability in that welding quality is uniform and reliability can be ensured.

Claims

Regarding the tip shoe (3) for the lower open type penetration concrete pile coupled to the lower end of the concrete pile body (2) of which the lower part is open,

The tip shoe 3,

An upper shoe 31 of a ring shape for an upper surface to be coupled to a lower end of the concrete pile body 2;

A lower shoe 32 having an upper surface coupled to be in close contact with the lower surface of the upper shoe 31; And

A plurality of fastening bolts 33 coupled to the upper shoe 31 for fastening the upper shoe 31 to the fastening nut 21 provided at the lower end of the concrete pile body 2; Consisting of

The upper shoe 31 has a coupling hole 311 through which the bolt body 332 of the fastening bolt 33 is inserted, and a bolt head of the fastening bolt 33 at the lower portion of the coupling hole 311. 331 is inserted into the bolt head receiving portion 312 is formed, the bolt head 331 of the fastening bolt 33 is accommodated in the bolt head receiving portion 312 and the upper end of the bolt body 332 is The coupling hole 311 is coupled to protrude a predetermined length to the upper portion of the upper shoe 31, the lower shoe 32 is fastening hole 321 narrower than the bolt head 331 of the fastening bolt 33 It is formed through, the bolt head 331 of the fastening bolt 33, the tip opening shoe for the lower open type penetration concrete pile, characterized in that the tool insertion groove 333 is formed.
In claim 1,

The upper shoe 31 has a cross section of the upper and lower narrowing shape, the lower shoe 32 is a top shoe for the lower open type penetration concrete pile, characterized in that the width of the upper end of the cross-section is less than the bottom width of the upper shoe (31).
In claim 1,

The lower shoe 32 is a tip shoe for a lower open penetration concrete pile, characterized in that divided into a plurality of arc-shaped lower shoe unit (32 ').
In claim 3,

The fastening hole 321 is the tip shoe for the bottom open-type penetration concrete pile, characterized in that formed between the adjacent lower shoe unit (32 ').
In claim 1,

Any one of the coupling hole 311, the end shoe for the lower open type penetration concrete pile, characterized in that the fitting rod 34 is fitted to the fastening nut 21 is provided in place of the fastening bolt (33).
In claim 1,

One end of the coupling hole 311, the end shoe for the bottom open-type penetration concrete pile, characterized in that the fastening bolt 33 is omitted.
A concrete pile body (2) having a plurality of fastening nuts (21) at a lower end thereof with an open portion; And a tip shoe 3 according to claim 1 coupled to a lower end of the concrete pile body 2. Consisting of

The tip shoe 3 is characterized in that the fastening bolt 33 of the tip shoe 3 is screwed to the fastening nut 21 of the concrete pile body 2 so that the tip shoe 3 is coupled to the concrete pile body 2. Lower open penetration concrete piles provided.
In claim 7,

The fastening bolt 33 is omitted in any one of the coupling holes 311, the coupling bolt 3 is omitted in the coupling hole 311 and the coupling nut 21 corresponding to the coupling hole 311 is fitted. Lower open type penetration concrete pile with a tip shoe, characterized in that the ends of the rods 34 are fitted.