KR100760888B1 - An extended head pile with inside and outside reinforcement - Google Patents

Abstract

The present invention relates to a head extension pile having an internal and external reinforcement for supporting a load of a structure, the front end of the pile having an internal and external reinforcement of the same length or the same area extending from side to side based on the diameter of the pile at the embedded end of the pile. It is an object of the present invention to provide a head extension pile having internal and external reinforcement portions that can secure stability, constructability and economy by increasing the bearing capacity and driving the pile to increase the strength of the pile.

Pile, driving, first support wall, first head, driving surface, inclined surface, internal reinforcement, external reinforcement

Description

An extended head pile with inside and outside reinforcement}

1 is a conceptual diagram showing the file history showing the relationship between the internal strength of the pile and the construction history of the constructed pile;

2 is a view showing a change in the moment according to the position of the force applied to the axis when the structure is loaded;

Figure 3 is a plan view and a partial cross-sectional view of the head extension pile having an internal and external reinforcement which is an embodiment of the present invention;

Figure 4 is a partial cross-sectional view showing the difference that occurs when driving the head expansion file having a reinforcement portion and the general expansion file which is an embodiment of the present invention.

5 is a partial cross-sectional view showing a case of driving in the head extension pile having an internal and external reinforcement portion of another embodiment of the present invention,

Figure 6 is a partial cross-sectional view of the head extension pile configured in a stacking form of the inner and outer reinforcement portion of another embodiment of the present invention.

-Explanation of symbols for the main parts of the drawing-

1: first support wall 2: second support wall

3: first head portion 4: second head portion

5, 12: file (cylindrical expansion file) 6:

7: center hole 10: slope

11: Structure

R1: Internal reinforcement part R2: External reinforcement part

The present invention relates to a head extension pile, and more particularly, to provide a pile structure that improves the bearing capacity of the pile supporting the load of the structure, piles that can ensure the stability, construction and economical efficiency of pile strength during pile construction A head extension pile having internal and external reinforcement parts for providing a construction method.

In general, when a building or a structure is erected, a foundation work is performed to reinforce the ground to support the upper structure according to the condition of the ground or the load of the structure. A shallow foundation or a deep foundation is performed according to various conditions such as the load of the structure. The case where the root entrance width ratio is 1 or less is called the shallow foundation, and the case where the root entrance width ratio is 1 or more is defined as the deep foundation. In the case of shallow foundations, structures are supported directly on the ground without using piles, and piles are used to reinforce the bearing capacity when the ground below the structures cannot support the load of the upper structure.

The pile foundation is a foundation method that connects the head to the structure. If the pile is classified according to the material, it can be classified into steel pile, concrete pile, composite pile, etc. It can be divided into pour method.

The type method (anti-taking method) is to force the pile into the ground by striking the pile from the top after the pile is put up. When the pile is forced into the ground by the driving energy, the pile shaft pushes the soil around and closes the pile. It has good external support and easy to install.

However, the type method is difficult to vertically approach when the pile is to be installed deeply, excessive vibration and noise are generated, and construction in the city is limited.

On the other hand, the embedding method solves various problems of the type construction method by forming a hole in the ground in advance, injecting an adhesive about half of the hole, and then inserting and fixing the file into the hole. As a result, the embedding method is mainly used for the pile foundation in the city center now.

In addition, the proportion of foundation work in building construction is very large, and in the case of pile construction, various pile construction methods are applied due to the different ground conditions and conditions for each site, lack of accurate understanding of driving equipment and construction based on the experience of the contractor. It is used and feels difficulty every time.

1 is a conceptual diagram of the file strength showing the relationship between the internal strength of the pile and the construction history of the constructed pile. As shown in FIG. 1, the load PF of the structure 11 is supported by the construction strength of a plurality of piles 12 adjoining the bottom of the structure 11. The construction strength of the pile 12 is the sum of the tip bearing force TF of the pile tip and the peripheral frictional force SF of the pile side. By the way, in most cases, the strength of the pile itself is high, but the construction strength (supporting force) of the pile is lowered due to workability.

For example, in the case of a high strength concrete pile (PHC, hereinafter referred to as PHC) of Φ 400, the pile itself is 112 tf but the construction strength is about 60 to 80 tf, consequently 32 to 52 tf of the pile strength is wasted. In particular, in the case of the embedding method, after the ground is drilled larger than the diameter of the pile, the fabricated pile is installed in the perforation and the cement is injected between the pile and the ground to increase the peripheral frictional force. Subsequent tests showed that the peripheral friction was very minimal and most construction strength was dependent on the tip bearing capacity. Therefore, in the embedding method, it was necessary to make the construction history close to the pile itself, thereby improving the use efficiency of the pile.

As such, various methods have been proposed for the efficiency of files as follows.

That is, Japanese Laid-Open Utility Model Publication No. 55-50142 is disclosed as a conventionally known technique, in which a tip steel sheet having a through hole is attached to a tip of a steel pipe, and a tip support formed by reinforcing ribs is formed between the steel pipe and the tip steel sheet. Steel pipe piles are described.

 The known technology is composed of a method of inserting a pile into an exposed ground or an excavated hole and then simply seating it on the ground, but not having an economic ripple effect, and filling the soil without injecting cement. Because of this, there is a defect that the waste capacity is large, and the reinforcing difficulty (central reinforcement) is very difficult and excessively expensive.

On the other hand, Japanese Laid-Open Patent Publication No. 2003-138561 is known as a similar technique, but it discloses a multistage expansion port (blocking wall) proposed to improve the continuous underground wall. In the literature, there is a problem that the construction difficulty is large and the cost is excessively consumed as a general concrete site placing method using a longitudinal continuous excavation equipment directly in the field. In addition, the multi-level expansion port (blocking wall) in the form of a continuous underground wall is a technique that is not used in reality because it is a form of excavation of the ground, because the use of concrete curing cars and reinforcing bars is inconvenient.

The present invention is to solve the problems of the prior art made as described above,

An object of the present invention is to increase the construction strength of the pile without affecting the weight or volume of the pile used in the embedding method, to improve the use efficiency and economic efficiency of the pile, and to improve the bearing capacity of the pile supporting the load of the structure The present invention provides a head extension type pile having internal and external reinforcement parts suitable for pile construction method by providing stability of construction strength and construction efficiency while providing pile structure.

Another object is to provide a head extension pile having internal and external reinforcement parts which can be applied to the embedding method as it is and at the same time increase the construction strength of the higher pile by driving after the embedding method.

The present invention provides a head-expanded pile that allows the head to be formed larger than the diameter of the pile by internal and external reinforcement portions extending left and right with respect to the central axis at the tip portion of the pile in order to increase the supporting force of the pile.

Particularly, in the present invention, in the case of a general pile having a pile diameter of Φ300 to Φ500, the head portion of the pile is extended to the same length with respect to the central axis, so that the design and pile production can be easily executed. In the case of a large pile having a pile diameter of Φ500 or more In this case, the sum of the bearing capacity is the same as the center axis of the extended head part, so that a larger pile capacity can be obtained without error in the case of a large pile.

Head expansion file of the present invention for achieving the above object,

In constructing the pile for supporting the load of the structure, the first head portion having an inner and outer area and the central axis of the second support wall so that the sum of the inner and outer support forces extending left and right relative to the central axis of the first support wall is equal It is a circular structure having a second head portion having an inner and outer area so that the sum of the inner and outer bearing forces extending from side to side as the reference is the same, and the support stress of the first and second support walls and the first and second head portions is symmetrical. A central through hole is formed between the first and second head portions while having a driving surface on the upper portion of the circular structure, and an inclined surface is integrally formed over the entire circumference of the upper ends of the first and second head portions. At the same time, it is characterized in that the stack is sequentially formed in one piece.

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Hereinafter, with reference to the accompanying drawings an embodiment of the present invention will be described in detail.

2 is a view showing a change in the moment when the structure is loaded.

As shown in Figure (a) the structure is subjected to the load of its own structure to the center of the structure as shown by the arrow.

However, when a separate force such as arrow 9 is applied from the side of the structure as shown in (b), a moment of force to be turned on the load of the structure is generated separately.

Therefore, when a separate force is applied as shown by the arrow 9 in the state where the load of the structure is applied as shown in FIG. (C), the first moment to turn to the load of the structure is generated, the displacement is generated, and the displacement is stopped. Additional secondary moments are applied up to the point in time, thus adversely affecting the structure.

The same applies to the head-extended pile, so this should be taken into account when making a reinforcement plate.

3 is a plan view and a partial cross-sectional view of a head extension pile having internal and external reinforcement portions which is an embodiment of the present invention.

As shown in the plan view at the top, the pile 5 is formed at the center of the first support wall 1 and the second support wall 2, which is a cylindrical cylindrical structure, which is a cylindrical structure. An inner reinforcing portion R1 is formed inside the inner portion, an outer reinforcing portion R2 is formed outside the pile 5, and a central through hole 7 is formed at the center thereof.

That is, as shown in the partial cross-sectional view shown in the lower part of FIG. 3, the first head portion 3 having the same length extending left and right with respect to the central axis of the first support wall 1 is constituted, and the second head portion ( 4) has the same length extending from side to side with respect to the central axis of the second supporting wall 2.

The first and second support walls 1 and 2 and the first and second head portions 3 and 4 are piles 5 of circular structures which are symmetrical, and the piles are circular piles. The upper part of (5) has a driving surface (6).

In addition, a central through hole 7 is formed between the first and second head parts 3 and 4 to prevent buoyancy caused by slime or water pushed by the driving force generated at the lower support surface of the pile. It is constructed to be heeled, and it is a medium of hard ground and weak pile, which can induce smooth flow of force when navigating.

4 is a partial cross-sectional view showing the difference between the head extension pile having an internal and external reinforcement portion and the general extension pile in the embodiment of the present invention.

The left side shows a sectional view when hitting a general head extension file, and the right side shows a sectional view when hitting the file of FIG. 3 which is an embodiment of the present invention.

The upper portion of the cylindrical expansion pile (5) configured as described above has a driving surface (6) after being driven after the pile is embedded, the cylindrical pile (5) has a concrete pile, PHC, having a diameter of 350, 400, 450, 500 mm, etc. Steel pipe or the like.

The inner and outer reinforcements R1 and R2 are plate-shaped structures having a predetermined thickness that are coupled to the lower end of the cylindrical pile 5 by the cylindrical pile and the joining means. Here, the joining means may join the pile and the reinforcement plate by the general welding when the cylindrical pile 5 is a steel pipe. On the other hand, if the pile is a concrete pile or PHC, or the like may be further provided with an iron plate reinforcing strip to form integrally or wrap the lower end, at this time, the steel plate reinforcing strip and the inner and outer reinforcing parts are combined with the pile.

Table 1 illustrates the dimensions and dynamics of piles and reinforcements.

TABLE 1

Type of file Φ350 PHC Φ400 PHC Φ450 PHC Φ500 PHC File itself history (tf) 89 112 137 173 Peripheral frictional force (tf) 30.37 38.13 46.76 59.04 Tip bearing capacity (tf) 58.63 73.87 90.24 113.96 Diameter of existing pile (mm) 350 400 450 500 Existing pile cross section (㎠) 961.625 1256 1590 1963 Reinforcement Plate Proper Diameter (mm) 473 531 587 660 Reinforcement plate cross section (㎠) 1759 2216 2707 3419 Gusset plate diameter (mm) 123 131 137 160 Compressive stress (σc: tf / ㎠) 0.10 0.10 0.10 0.10 Thickness of Reinforcement Plate (mm) 10.8 11.1 11.3 12.2 Extrusion Length of Reinforcement Plate (a: mm) 62 66 69 80

Here, sigma c = 3 x tip bearing force / reinforcing plate cross section.

In the case of Φ350 PHC in Table 1, the tip bearing capacity requires 58 tf to obtain 89 tf pile capacity, but the tip bearing capacity of 58 tf is obtained by the cross section 961.625 ㎠ of the existing pile having a diameter of 350 mm. Can't get it. Therefore, the cross-sectional area of the tip of the pile must be widened to obtain 58 tf of tip bearing capacity. In Table 1, the cross-sectional area of the reinforcing plate is 1759 cm 2 and the diameter is 473 mm, and the thickness t of the reinforcing plate is selected to be 10.8 mm.

In Table 1, in the case of Φ400, Φ450, and Φ500 PHC, the cross-sectional area of the reinforcement plate is extended to 2216, 2707, 3419 cm2, respectively, in order to utilize all pile strengths corresponding to the diameter of each pile. The diameters are expanded to 531, 587 and 660 mm. As can be seen from Table 1, the thickness of the reinforcement plate is formed thicker as the protrusion length of the reinforcement plate is larger.

In this example, the size of the expansion may vary according to the stress at the tip end due to the change of the frictional force, which needs to be determined according to the condition of the ground.

In addition, the central through hole 7 formed between the first and second head portions 3 and 4 constituting the reinforcing portion prevents the head extension pile 5 from rising by underground leachate, and the leachate It is filled and filled in the circular structure.

The central through hole (7) introduces unnecessary slime into the pile when penetrating the pile by driving, and also introduces soil and cement paste pushed in by the driving into the inside, so that the slime and cement paste are mixed and hardened. do.

5 is a cross-sectional view illustrating a structure of a head extension pile having internal and external reinforcement portions at one end thereof. As shown in Fig. 5, the head extension pile 5 is composed of a cylindrical pile portion and lower and inner reinforcement portions R1 and R2 (see Fig. 3).

And the upper part has a post-driven surface (6) is driven after the pile embedded construction, the cylindrical pile (5) is a concrete pile, PHC, steel pipe, H-shaped steel having a diameter of 350, 400, 450, 500, 600 mm, etc. Outside composite pipe and wood pipe.

The inner and outer reinforcement formed at the bottom is a plate-shaped structure of a predetermined thickness that is integrally formed with the cylindrical pile portion or joined by the joining means at the lower end of the cylindrical pile portion.

5 is the same basic configuration as FIG. 3, wherein the first and second head portions 3 and 4 and the first and second support walls 1 and 2 are circularly symmetrical. The file 5 is shown.

Here, the first and second heads 3 and 4 have a predetermined thickness t, and both sides of the first and second heads 3 and 4 having the predetermined thickness are inclined. It has a sloped surface 10.

Table 2 illustrates the dimensions and dynamics of the pile.

TABLE 2

Type of file Φ350 PHC Φ400 PHC Φ450 PHC Φ500 PHC File itself history (tf) 89 112 137 173 Peripheral frictional force (tf) 30.37 38.13 46.76 59.04 Tip bearing capacity (tf) 58.63 73.87 90.24 113.96 Diameter of existing pile (mm) 350 400 450 500 Existing pile cross section (㎠) 961.625 1256 1590 1963 Reinforcement part proper diameter (mm) 473 531 587 660 Reinforcement section cross section (㎠) 1759 2216 2707 3419

In the case of Φ 350 PHC in Table 2, the tip bearing capacity must be 58 tf to obtain the pile capacity of 89 tf. By the way, by the cross-sectional area 961.625 cm 2 of the existing pile having a diameter of 350 mm, it is not possible to obtain a tip support force of 58 tf. Therefore, in order to obtain the tip bearing force 58 tf, the cross section of the tip of the pile must be 1759 cm 2. That is, the diameter of the reinforcement portion needs to be extended to 473 mm.

In Table 2, in the case of Φ400, Φ450, and Φ500 PHC, the cross-sectional area of the tip should be extended to 2216, 2707, 3419 ㎠, respectively, in order to utilize all the pile's own strengths corresponding to the diameter of each pile. The diameter needs to be extended to 531, 587, 660 mm.

In this example, the size of the expansion may vary according to the stress at the tip end due to the change of the frictional force, which needs to be determined according to the condition of the ground.

The present invention made as described above looks at the difference generated when driving the head extension file having a reinforcement part and the general extension file in Figure 4 as follows.

It should be noted here that the general extension file on the left side is a file used for a buried method, and is not compared with the method of navigating after landfilling as in the present invention, but in terms of navigating after landfilling, in fact, the present method Does not use the process of scouring after landfill.

When the file (5) is buried and driven, the file enters the depth (X).

At this time, when the soil is pushed toward the center hole (7) during driving, a moment of force for bending the reinforcement plate is generated (F2), and as described in (c) of FIG. 1, the additional moment is continuously generated until the displacement stops. It may adversely affect the structure installed on the pile.

On the other hand, the present invention has internal and external reinforcement portions R1 and R2 of the same length extending left and right when driving the pile after embedding the pile, thereby providing a central through hole (7). ) As the soil is pushed into the ground, an even distribution of force occurs, which minimizes the force of bending the steel plate of the reinforcement part, and receives the vertical force as the center of the first and second support walls (1) and (2). There is no need for additional reinforcement.

FIG. 5 is a partial cross-sectional view showing a case of driving in a head extension pile having internal and external reinforcement portions according to another embodiment of the present invention. Here, when the pile is driven after embedding the pile 5 in the same manner, the pile has a depth (X). The file will be inserted, increasing the file's history.

Even at this time, the soil is pushed into the central through hole (7) and has the same length internal and external reinforcement parts extending from side to side to the first head part and the second head part, so that evenly distributed force is generated by each internal and external reinforcement part. Since it receives only vertical force and no eccentricity is generated from the outside, stable internal load can be secured. Soil rising by the load on the pile can be prevented by the internal reinforcement on the inside of the pile. There is an effect that can minimize the force of the soil has the effect that can prevent the part weakened by the soil.

And in the present invention, the expansion of the internal and external reinforcement is determined by the following two.

First, it can be determined by the method by equal distribution of unit forces.

In other words, the moment and deflection caused by the bearing force are the same as the inner and outer reinforcement parts (Fig. 3: R1, R2) to minimize the eccentricity of the reinforcement part and transmit the upper force to the ground efficiently.

Determine the length of the internal and external reinforcements (Fig. 3: R1, R2) under the same conditions (when the moments are equal) and the square of the distance away from the unit stress is equal to the square of the distance away from the unit stress (when the deflection is the same). The moment can be satisfied by the design stress of the material of the reinforcement and the deflection constraints by the design standard.

This method is convenient to use in general piles with pile diameters of Φ300 to Φ500, and the design and pile manufacturing are simple because the head portion is extended to the same length with respect to the central axis.

Second, since the same unit stress acts on the internal reinforcement area and the external reinforcement area, the total stress acting on the internal reinforcement area and the total stress acting on the external reinforcement area are set equal so that the internal and external reinforcement parts (Fig. 3: R1, R2) The length is determined and the moment can be satisfied by the design stress of the material of the reinforcement and the deflection constraints by the design specification.

Therefore, since there is no moment added to reinforcement by expansion decision of reinforcement part, it is possible to effectively support and transmit the force of upper part to ground through pile.

This method can be applied to large piles with a file diameter of Φ500 or more.The expansion head of piles has the same area of support as the central axis, which makes the design and construction work difficult or difficult. In this case, a more accurate file history value can be obtained without errors.

In addition, the construction of such piles is usually carried out at a distance of 2.5 times the diameter of piles, and the test according to the same test is used as one book per 250 books, but the static test. In particular, the method used in the field is EOID (End of Initial Driving) before the surrounding filler (cement paste) is hardened, and waits for 1-3 weeks to test after the filler is hardened. have.

In the above two methods, the equipment with more than 100tf is used, so to carry out the pile construction, the internal load should be measured immediately by using the EOID method to continue the next construction.However, after the filler is hardened, the method of testing the filler is hardened. Because of time, it is difficult to carry out pile construction. In order to continue the construction of the pile, the pilot equipment has to pass over the pile again for testing, which is expensive and time-consuming to protect the pile.

For this reason, the construction of the E.O.I.D (initial test) method must be carried out with sufficient strength so that the construction can be performed with confidence. For example, the D400 PHC Class A pile has a construct with an outer diameter of 400 mm and an inner diameter of 270 mm. This is a ready-made pile with a hollow cylinder in the middle of the cross section for efficient use of the cross section. If the pile meets the support surface which is in contact with the soil, the area is 683.74㎠ and if the reinforcement plate has 25mm internal and external reinforcement due to the characteristics of the ground, it is reinforced with a construct having an outer diameter of 450mm and an inner diameter of 220mm. Accordingly, the area where the pile meets the support surface in contact with the soil may be increased by 177% to 1209.69㎠. Even if other effects are not taken into account, the area where the pile meets the support surface in contact with the soil in the EOID (Initial Test Method) test is increased by 177% compared to the existing area. Progress can be fast.

In addition, when the filler is hardened, it is increased to 1256.00㎠ when compared with only the outside area without considering the area of the through hole and 1589.63㎠ when reinforced, and the existing area when the outside area is not considered without considering the central hole area (closed effect). Compared to the area taking into account), an increase of 127% can be seen. In other words, the final file is a conventional file having an outer diameter of 400 mm and an inner diameter of 270 mm is converted into an efficient file having an outer diameter of 450 mm and an outer diameter of 220 mm.

As a result of the crushing after reclamation, 177% is increased in the side of the tip support (initial test method), and when the filler is hardened, the pile strength is increased by about 127%.

FIG. 6 is a partial cross-sectional view of a head extension pile including the internal and external reinforcement parts in a stacked form according to another embodiment of the present invention.

As shown in the plan view of FIG. 6A, the pile 5 has a first cylindrical wall 1 and a second supporting wall 2 formed at the center thereof as a single cylindrical cylindrical structure. Internal reinforcing portions R1 and R1 'are formed in a stack inside the in-pile 5, and external reinforcing portions R2 and R2' are formed in a stack in the outside of the pile 5. In the center, the central through hole 7 is formed.

That is, in FIG. 3, the first head portion 3 having the same length extending left and right with respect to the central axis of the first supporting wall 1 is composed of R1 + R2, and the second head portion 4 is the second. Has the same length of R1 + R2 extending from side to side with respect to the central axis of the support wall (2),

In FIG. 6, the first head portion 3 forming one layer becomes R1 '+ R2', and the first head portion forming two layers has a length of R1 + R2, and the same length of the second head portion is the same. It consists of a first layer and a second layer having a, and sequentially stacked to form a first head portion and a second head portion.

In this case, in the case of using the metal pile as shown in (b), the metal pile is laminated by means of welding or the like, and in the case of using the concrete pile as shown in (d), it is used after hardening by integrally forming multiple stages.

When connecting the metal extension part to the concrete pile as shown in (C), the band-shaped metal is wound around the concrete pile with a steel plate reinforcing band, and the metal extension part (internal and external reinforcement part) is joined by means of welding or the like.

And in the piles the first and second support walls 1, 2 and the first and second head portions 3, 4 are piles 5 of circular structure which are symmetrical. The upper part of the pile (5) of the circular structure has a driving surface (6).

A central through hole 7 is formed between the first and second head portions 3 and 4 to prevent buoyancy caused by slime or water that is pushed by the driving force generated at the lower support surface of the pile. It is configured to be a medium of hard ground and weak pile and can induce smooth flow of force when navigating. In addition, since the stacking part is composed of both symmetry, the flow of force from the ground can be transferred from the upper lamination part to the lower lamination part, and the force can be induced evenly in the ground continuously. Ideally, the flow can be delivered.

In the case of stacking the head parts in this way, compared with the case of using the head parts having the same thickness (t), the strength of the piles per unit area is almost the same, but the area of the head parts can be reduced, which greatly reduces the material. There is.

As described above, according to the present invention, since the number of piles used in construction can be reduced by raising the construction strength of the pile to the pile itself without affecting the weight or volume of the pile used in the embedding method, Can greatly increase the efficiency and economics of use. In addition, by using the reinforcement unit or reinforcement plate in combination with the existing file, it is possible to greatly increase the utilization of the existing file.

In addition, the design strength is determined to be the smaller of the pile bearing capacity determined by the ground or workability compared to the pile itself, which is constructed from existing piles, resulting in a loss of 30-40% (LOSS) of pile strength. When the head extension pile with reinforcement is used, it is an effective method that can exhibit 100% of the strength of the current construction method, and the design can be used as the pile strength.

In addition, in the construction aspect, it is possible to carry out the construction quickly and safely by effectively improving the pile strength in the early stages, and increase the pile strength in terms of design, thereby reducing the number of piles and inducing cost reduction and shortening of air.

In addition, if the design is completed with a small load, the effect of reducing the length of the pile can be expected.

Compared to the projected pile construction in the original site, the head extension pile was installed and applied in the same way as before, and the pile construction was completed at about 50/20 ~ 50/10. It has an effect.

In other words, if the design strength is low in consideration of constructionability, the length of the pile can be reduced by about 20 to 40%, resulting in a reduction in construction costs.

In addition, the amount of tofu cleanup for connecting pile foundations and piles is also reduced, thus reducing waste and enabling eco-friendly construction.

Accordingly, it is a method that can secure economic feasibility, safety, constructability, and eco-friendliness compared to existing methods.

As a result, when the design strength is increased by using the head extension pile having internal and external reinforcement at the time of design, the number of piles can be reduced by about 30 to 40%, and the amount of concrete cement and rebar is reduced by about 10% ~ as the pile cap becomes smaller. In addition to the 20% reduction, in addition to the reduction in the number of files can significantly reduce the air, as well as the labor and labor costs, current costs, financial costs can be remarkably reduced in the civil engineering, construction industry Very useful.

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Claims (8)

delete delete delete delete delete In constructing piles for supporting the load of the structure, The first head part 3 having an inner and outer area and the second axis of the second support wall 2 are horizontally positioned so that the sum of the inner and outer support forces that extend from side to side with respect to the central axis of the first support wall 1 is the same. Has a second head portion 4 having an inner and outer area such that the sum of the inner and outer supporting forces extended is equal, The first and second supporting walls 1 and 2 and the first and second heads 3 and 4 have a circular structure in which the supporting stresses are symmetrical, and the driving surface 6 is disposed on the circular structure. At the same time, a central through hole 7 is formed between the first and second head portions 3 and 4, Head-increasing pile having internal and external reinforcement, characterized in that the inclined surface (10) is integrally formed over the entire circumference of the upper end of the first and second head portion (3,4) and sequentially stacked and integrally formed. delete delete

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