KR100773110B1 - Combination pile of phc pile and steel pipe attached concrete pile, constructing method therefor and temporary pile used therein - Google Patents

Abstract

A composite pile of a prestressed high strength concrete(PHC) pile and an outer steel pipe attached concrete pile, a constructing method thereof, and an intrusion auxiliary pile used to the same are provided to determine a pile type, and to construct the pile effectively by integrating the PHC pile and the concrete pile using concrete. A composite pile has a lower part formed with a prestressed high strength concrete(PHC) pile(10) having a hollow(12), and an upper part formed with a concrete(21) and a steel beam hollow pipe(22). The steel beam hollow pipe is placed on the PHC pile and connected with the PHC pile integrally. Lower reinforcing bars(13) are inserted in the hollow of the PHC pile and installed with a floor plate(40) closing the hollow. An adhesion plate is closely contacted with the inner surface of the hollow of the PHC pile. Upper reinforcing bars(23) are inserted in the steel beam hollow pipe. The PHC pile and the concrete pile are integrated by pouring the concrete in the hollow of the PHC pile and the steel beam hollow pipe which are connected. Coupling plates(50) are integrally coupled with the reinforcing bars by combining the upper ends of the lower reinforcing bars with the lower ends of the upper reinforcing bars.

Description

Combination Pile of PHC Pile and Steel Pipe Attached Concrete Pile, Constructing Method therefor and Temporary Pile used therein}

1 is a schematic bending moment diagram when an external force acts on a pile installed on the ground.

2 is a schematic vertical cross-sectional view showing a state in which the composite pile according to the present invention is constructed on the ground.

Figure 3 is a schematic vertical cross-sectional view showing a state in which the composite pile is constructed on the ground according to another embodiment of the present invention using a binding plate.

Figure 4 is a schematic perspective view showing that the lower reinforcing bar and the upper reinforcing bar is connected to each other by using the coupling plate in the embodiment shown in FIG.

 Figure 5a is a schematic view from below of the bottom plate is coupled to the end of the lower reinforcing bar in the present invention.

Figure 5b is a cross-sectional view according to the line A-A of Figure 2 showing a state in which the bottom plate is installed in the hollow of the PHC pile in accordance with the present invention.

FIG. 5C is a partial cross-sectional view taken along the line B-B of FIG. 5B.

Figure 6 is a vertical cross-sectional view showing a state in which the penetration of the pile of the state synthesized using the penetration auxiliary pile in the state PHC pile and concrete pile is synthesized in accordance with the present invention.

FIG. 7 is a cross-sectional view taken along the line C-C of FIG. 6.

8 is a cross-sectional view showing a vertical cross-sectional structure of the lower pressure plate provided in the present invention.

Figure 9 is a schematic diagram showing the shape of the insertion guide member installed in the upper inlet of the steel hollow tube in the present invention.

FIG. 10 is a detailed view of circle D of FIG. 7 for showing the spacer installation structure of the penetration aid pile employed in the present invention in detail.

<Description of the symbols for the main parts of the drawings>

10 PHC stake

12 hollow

20 concrete piles

21 concrete

22 steel hollow tube

The present invention relates to a composite pile formed by synthesizing a prestressed high strength concrete pile and a cast-in-place concrete pile, a construction method thereof, and a penetration auxiliary pile used therein. Prestressed High Strength Concrete Pile (hereinafter abbreviated as "PHC pile") and on-site cast concrete piles are integrated to form a pile that efficiently fits the size of the applied stress on the piles that vary with depth to the ground. The present invention relates to a composite pile having a new structure, a construction method thereof, and a penetration assisting pile used therein, which enable economical construction of piles.

Figure 1 shows a schematic diagram of the bending moment when the external force acts on the pile installed on the ground, the dotted line is the case where the pile head is composed of a hinge, the dashed line is a case where the pile head is fixed. As shown in Figure 1, when the external force acts on the pile, the upper section is governed by the bending moment and the compression force, the lower section is mainly dominated by the compressive force.

PHC piles generally have high strength and high compressive resistance. However, the resistance to bending moments and shear forces is relatively weak. For this reason, when constructing using a PHC pile, a larger number of piles are used than other piles, or a large diameter pile is used in accordance with a design bending moment and shear force, and as a result, there is a problem in that economic efficiency is reduced.

On the other hand, since the PHC pile is manufactured in advance and transported to the site, it is generally used to select and use a PHC pile having strength and size corresponding to the maximum working stress applied to the pile. In addition to PHC piles, conventional pile designs will utilize ready-made piles of single material having the same cross-section and performance. However, in the pile, the upper section is dominated by the bending moment (bending stress) and compression force (compression stress), whereas the lower section is mainly dominated by the compressive force, so if you use a ready-made pile in accordance with the working stress of the upper section In the section unnecessarily the pile size and strength are unnecessarily large. That is, although there are some differences depending on the coupling structure and condition of the foundation of the upper part of the pile and the pile head, the ground state of the pile upper section, the length of the pile, etc., as described above, when the external force acts on the pile, the depth is about 2 m to 5 m In this section (upper section), the maximum bending moment and the compressive stress act in this section (upper section), whereas the bending moment decreases rapidly in the section below (lower section). In the past, the piles were excessively used in the lower sections of the piles with small bending stress. It has a cross section, which leads to very inefficient and inefficient construction. There is a problem that the rain increased. In particular, when constructing the steel pipe pile of the same size in the longitudinal direction of the ground, there is a problem that the expensive steel pipe is wasted and the construction cost greatly increases.

The present invention was developed to solve the problems of the prior art as described above, while using the advantages of the PHC pile, such as high compressive strength, and efficiently pile type according to the working stress size for the pile that changes depending on the depth of the ground It is an object of the present invention to provide a composite pile having a new structure and a construction method thereof, which enables economical construction of piles by determining the structure and its cross section.

It is also an object of the present invention to provide an auxiliary penetration pile that can be constructed economically and efficiently such a composite pile.

In the present invention, in order to achieve the above object, the upper section of the pile dominated by bending stress and compressive stress is to be made of a pile consisting of cast-in-place concrete and steel hollow tube with a large stiffness for this, the pile predominantly compressive stress The lower section of provides a synthetic pile configured to consist of PHC piles.

Hereinafter, with reference to the accompanying drawings will be described the configuration and effect of the composite pile 1 according to an embodiment of the present invention, and its construction method.

2 is a schematic vertical cross-sectional view showing a state in which the composite pile 1 according to the present invention is constructed on the ground. As shown in the figure, the section of the pile that is mainly dominated by the compressive stress, that is, the lower portion is composed of the PHC pile 10, the section of the large bending stress and compressive stress, that is, the upper portion of the cast concrete 21 and the steel hollow tube ( 22 is composed of a cast-in-place pile 20, the PHC pile 10 and the cast-in-place pile 20, the connection between the steel hollow pipe 22 and the head of the PHC pile 10, and reinforcing bars (13, 23) by the continuous placement of the continuous reinforcement and in-situ concrete 21 to form a composite pile (1) of the present invention. The bending stress and the compressive stress dominates the section consisting of the cast-in-place pile 20 is a section of about 2 to 5m from the ground, it may vary depending on the conditions of the ground.

Specifically, as shown in FIG. 2, a circular steel hollow tube 22 is placed at the head of the PHC pile 10 having a hollow 12, and a lower end portion of the steel hollow tube 22 and a PHC pile ( The joint steel plate 11 of the head of 10) is integrally joined by welding.

As described above, in the state in which the steel hollow tube 22 and the PHC pile 10 are connected, the interior of the steel hollow tube 22 and the hollow 12 of the PHC pile 10 are connected to each other in the present invention. Reinforcing bars 13 and 23 are continuously inserted into the inside of the hollow steel pipe 22 and the hollow 12 of the PHC pile 10 which are subsequently passed through. That is, as shown in the figure, the lower reinforcing bar 13 is inserted into the hollow 12 of the PHC pile 10, and the upper reinforcing bar 23 is inserted into the steel hollow tube 22, In the present invention, as shown in the drawing, the lower reinforcing bar 13 extends to the inside of the steel hollow tube 22 or although not shown in the drawing, the upper reinforcing bar 23 is hollowed out of the PHC pile 10 ( 12) arranged to extend inside. The joints of the PHC pile 10 and the steel hollow tube 22 are further reinforced by the continuous reinforcement of the reinforcing bars 13 and 23, thereby increasing the reliability of the joint and driving the PHC pile 10 and the steel hollow tube by driving. Even if a crack occurs in the concrete between the joints of (22), it is possible to maintain a firm joint.

In arranging the lower reinforcing bar 13 and the upper reinforcing bar 23, it is preferable that the reinforcing bar 13 and 23 are installed to overlap each other. The upper part of the lower reinforcing bar 13 and the lower part of the upper reinforcing bar 23 may be completely connected and integrated. However, the upper part of the lower reinforcing bar 13 may not be completely coupled and may be simply overlapped as shown in the drawings. In the drawings, reference numerals 15 and 25 denote transverse rebars 15 and 25 provided in the reinforcing bars 13 and 23, respectively.

In some cases, the inner diameter of the steel hollow tube 22 and the inner diameter of the hollow 12 of the PHC pile 10 are different from each other to continuously arrange the lower reinforcing bar 13 and the upper reinforcing bar 23 as described above. Sometimes it is difficult. In this case, it can be modified by the embodiment shown in FIG. In the embodiment shown in Figure 3 is further provided with a coupling plate 50 for the continuous joint of the lower reinforcing bar 13 and the upper reinforcing bar (23). 4 is a schematic perspective view showing that the lower reinforcing bar 13 and the upper reinforcing bar 23 are connected to each other by using the coupling plate 50. The coupling plate 50 may be formed of a steel plate in which a through hole is formed in the center, and a plurality of coupling holes are provided, respectively, and an upper end of the lower reinforcing bar 13 and a lower end of the upper reinforcing bar 23 are respectively provided. By being coupled to the coupling hole is connected integrally up and down. The coupling plate 50 not only functions to maintain the spacing of the reinforcing bars 13 and 23 in addition to the connection function between the upper and lower reinforcing bars 13 and 23, and the coupling plate 50 itself is a steel hollow tube ( 22) to function as a reinforcing member in the interior to increase the resistance to the bending stress of the composite pile (1) according to the invention, and to further strengthen the joint between the PHC pile (10) and the steel hollow tube (22) Exert.

By performing tag welding or the like in the state where the ends of the reinforcing bars 13 and 23 are inserted into the coupling holes, the ends of the coupling plate 50 and the reinforcing bars 13 and 23 may be firmly coupled. Of course, in addition to welding, it is also possible to use a known coupling method such as screw coupling. In addition, in connecting the upper portion of the lower reinforcing bar 13 to the coupling plate 50, the upper end of the lower reinforcing bar 13 passes through the coupling plate 50 to the inside of the steel hollow tube 22 It can also be extended to. In FIG. 3 and FIG. 4, reference numeral 51 is a reinforcing rib 51 for reinforcing the coupling plate 50.

At the end of the lower reinforcing bars 13 inserted into the hollow 12 of the PHC pile 10, the hollow 12 of the PHC pile 10 is closed later to support the load of concrete to be poured and lower reinforcing bars ( The bottom plate 40 is provided to maintain the spacing and torsion of the 13). FIG. 5A shows a schematic view of the bottom plate 40 coupled to the end of the lower reinforcing bar 13 as viewed from below, and FIG. 5B shows the inside of the hollow 12 of the PHC pile 10. As a cross sectional view showing a state in which the bottom plate 40 is installed, a cross-sectional view along the line AA is shown in FIG. In the embodiment shown in Figure 5a and 5b, the bottom plate 40 has a coupling hole is formed so that the end of the lower reinforcing bar 13 is coupled to the coupling hole. In the embodiment shown in the drawing has an end portion of the lower reinforcing bar 13 has a structure that is fastened by the nut 42 through the coupling hole, but is not limited thereto, and the lower reinforcement through a method such as welding The bottom plate 40 may be coupled to the end of the reinforcing bar 13. In the embodiment shown in the drawings, reference numeral 43 is a reinforcing rib 43 for reinforcing the bottom plate (40).

On the other hand, in the present invention, in order to prevent the loss of concrete poured into the bottom plate 40 may be further provided with the following configuration. FIG. 5C shows a partial cross-sectional view along line BB of FIG. 5B, as shown in FIGS. 5A-5C, the inner surface of the hollow 12 of the PHC pile 10 at the top or bottom edge of the bottom plate 40. In close contact with the contact plate 44 may be provided. The contact plate 44 may be made of an elastic material. Such a circular band-shaped contact plate 44 is provided on the top surface of the bottom plate 40 using an adhesive or the like, as shown in Figure 5c or not shown in the figure, but the bottom surface of the bottom plate 40 It may be provided in. The contact plate 44 is in contact with the inner surface of the hollow 12 when the lower reinforcing bar 13 is inserted into the hollow 12 of the PHC pile 10, when the concrete is later poured, the concrete This function prevents leakage and loss.

As shown in FIGS. 2 and 3, the PHC pile 10 and the steel hollow tube 22 are connected to each other and the reinforcing bars 13 and 23 are continuously disposed therein. Inside the hollow 12 and the inside of the steel hollow tube 22, the concrete 21 is continuously poured and filled, so that the PHC pile 10 and the steel hollow tube 22 are completely integrated into one composite pile 1. . In the figure, the member number 60 is the foundation concrete 60 poured on the head of the composite pile (1).

Thus, in the synthetic pile 1 of the present invention having a structure in which the PHC pile 10, the concrete pile 20 consisting of the steel hollow tube 22 and the site-pouring concrete 21 is integrally synthesized, the compressive stress PHC pile 10 having a large compressive strength is located in the lower section of the ruling, and concrete pile 20 having a large bending strength is located in the upper section where the bending stress and the compressive stress dominate simultaneously. There is an advantage in that it is possible to construct a pile economically.

In particular, the steel hollow tube 22 serves as a formwork, it is possible to prevent the external soil to be mixed in the concrete 21 when the concrete 21 is placed, thereby maintaining the quality of the concrete pile 20. In addition, the steel hollow tube 22 forms a composite cross section with the concrete 21 to increase the flexural tensile resistance of the concrete pile 20.

Next, a method for constructing the composite pile 1 according to the present invention will be described. First, the steel hollow tube 22 and the PHC pile 10 are welded and connected at a factory or a site, and then, the steel hollow tube 22 is mounted in a crane or the like, and then the steel hollow tube 22 is driven to form an integral state as shown in FIG. 2 or 3. Penetrate and install underground. In some cases, the head of the PHC pile 10 is driven in advance into the ground by driving the PHC pile 10 so that only the head of the PHC pile 10 remains on the ground, and then the steel plate is joined to the joint steel plate 11 of the exposed PHC pile 10 head. After connecting the hollow tube 22, the head of the steel hollow tube 22 may be driven into the ground as shown in FIG. As described above, after the PHC pile 10 and the steel hollow tube 22 are installed, the reinforcing bars 13 and 23 are installed inside the hollow 12 and the steel hollow tube 22 of the PHC pile 10. After pouring concrete (21). If necessary, as described above, in installing the reinforcing bars 13 and 23, the bottom plate 40 and the coupling plate 50 may be combined. Subsequently, as described above, the lower reinforcing bar 13 and the upper reinforcing bar 23 are inserted and installed, and the concrete 21 is integrated inside the steel hollow pipe 22 and the hollow 12 of the PHC pile 10. By pouring into the composite pile 1 according to the present invention is to be constructed.

On the other hand, in the present invention, the thickness of the steel hollow tube 22 can be made thin, in which case the steel hollow tube 22 may be damaged when the steel hollow tube 22 is penetrated. To this end, the present invention uses a penetration assist pile 70 having a special structure as described later.

6 is a vertical cross-sectional view showing a state in which the penetration of the pile of the synthesized state by using the penetration auxiliary pile 70 in the PHC pile 10 and the concrete pile 20 is synthesized in accordance with the present invention is shown have. In order to prevent the steel hollow tube 22 from being damaged by directly driving the thin steel hollow tube 22, the PHC pile 10 and the concrete pile 20 may be inserted into the ground in a state where the pile is combined. 6, when the penetration auxiliary pile 70 is inserted into the steel hollow tube 22, the pipe auxiliary pressure is applied to the PHC pile 10 by driving the penetration auxiliary pile 70. (10) and the steel hollow pipe 22 is installed in the ground penetration into the pile to the desired depth.

FIG. 7 is a cross-sectional view taken along the line C-C of FIG. 6. Various types of piles may be used as the penetration support pile 70. In the embodiment shown in FIG. 7, the penetration support pile 70 is a member having a cross-section in which two H beams are crosswise coupled to each other. Consists of. The use of the penetration support pile 70 having a cross-sectional shape as shown in the drawing is very advantageous in terms of equal distribution of the driving stress. However, as mentioned above, the penetration auxiliary pile 70 may use various kinds of piles and is not necessarily limited to the embodiment illustrated in the drawings.

On the other hand, the stress is concentrated when driving the penetration auxiliary pile 70 to prevent damage to the end of the penetration auxiliary pile 70 and to ensure that the driving stress is evenly distributed, the penetration auxiliary pile 70 An upper pressure plate 71 and a lower pressure plate 72 are provided as upper and lower portions of the upper and lower pressure plates, respectively. 8 is a cross-sectional view showing a cross-sectional structure of the lower pressure plate 72, the lower end portion of the penetration auxiliary pile 70 is in close contact with the head of the PHC pile 10, the pipe by driving through the penetration auxiliary pile 70 In order to prevent the head of the PHC pile 10 from being broken when an input is transmitted to the PHC pile 10, a cushioning material 73 is provided below the lower pressure plate 72 as shown in FIGS. 7 and 8. It is provided. In the embodiment shown in the figure, the cushion member 73 is integrally coupled with the lower pressure plate 72 by bolts 74. The method of coupling the cushioning material 73 to the lower pressure plate 72 is not limited to bolting, and various methods such as attachment by an adhesive may be used.

When installing the penetration auxiliary pile 70, the inside of the steel hollow tube 22 is sealed by the side of the lower pressure plate 72 and the steel hollow tube 22 close to each other to seal the inside of the steel hollow tube 22 And thus air resistance can occur. In order to prevent the installation of the penetration auxiliary pile 70 due to such air resistance, the lower pressure plate 72 may further include an air vent hole 75 through which air may be discharged. When the cushion member 73 is provided below the lower pressure plate 72, the air vent hole 75 must be formed in the cushion member 73 as well.

  When inserting the penetration auxiliary pile 70 into the vertically erected pile in a state where the PHC pile 10 and the steel hollow tube 22 are coupled, the insertion is not easy due to shaking, and the steel hollow tube 22 The collision may cause damage to the hollow steel pipe 22 as well as the penetration auxiliary pile 70 itself. In order to prevent this may be installed by further installing a funnel-shaped insertion guide member 80 at the upper inlet of the steel hollow tube (22). 9 is a schematic view showing a shape in which the insertion guide member 80 is installed at the upper inlet of the steel hollow tube 22, and when the funnel-shaped insertion guide member 80 is installed, the auxiliary penetration pile ( 70 can be easily inserted into the steel hollow tube 22 as well as to prevent the collision and the resulting damage between the steel hollow tube 22 and the penetration auxiliary pile 70. In the embodiment shown in the drawings, the insertion guide member 80 is manufactured in a divided state to the left and the right, and has a structure that is assembled through bolting and the like in the field. However, in the present invention, the insertion guide member 80 is not necessarily limited to the assembly structure as described above.

In addition, in the present invention, in order to prevent shaking or eccentricity of the penetration auxiliary pile 70 due to the insertion of the penetration auxiliary pile 70 into the steel hollow tube 22 and the impact at the time of driving, the following spacer ( 76 may be further provided. FIG. 10 is a detailed view of circle D of FIG. 7 for showing the installation structure of the spacer 76 in detail. As shown in the figure, the spacer 76 has a protruding shape so as to maintain a gap between the penetration support pile 70 and the inner wall of the steel hollow pipe 22 and is attached to one side of the penetration support pile 70. The spacer 76 preferably has elasticity, such as a leaf spring. For this purpose, in the embodiment shown in the drawing, only the upper portion of the spacer 76 is fixed to the penetration support pile 70 so that the elasticity like the leaf spring is improved. By having, it is configured to absorb the stress is easily deformed and restored during the shaking or lateral movement due to the driving of the penetration auxiliary pile (70).

After inserting the penetration auxiliary pile 70 into the steel hollow tube 22 and installing the penetration auxiliary pile 70 as described above, the steel hollow tube 22 and the PHC pile 10 are inserted into the ground to the required depth. do. Subsequently, as described above, the lower reinforcing bar 13 and the upper reinforcing bar 23 are inserted and installed, and the concrete 21 is integrated inside the steel hollow pipe 22 and the hollow 12 of the PHC pile 10. By pouring into the composite pile 1 according to the present invention is to be constructed.

As described above, the composite pile 1 according to the present invention has a structure in which the PHC pile 10 and the concrete pile 20 made of the steel hollow pipe 22 and the cast-in-place concrete 21 are integrally synthesized. Have Therefore, in the construction of the pile, the PHC pile 10 having a large compressive strength is positioned in the lower section where the compressive stress dominates, and the concrete pile 20 having a large flexural strength in the upper section where the bending stress and the compressive stress dominates simultaneously. By positioning, it is possible to economically construct piles according to the load conditions of the site.

In particular, in the present invention, it is easy to adjust the thickness of the steel hollow tube 22 or the size or number of reinforcing bars 13 and 23 according to the magnitude of the stress acting on the pile, so that the pile according to the site situation It is possible to construct economically.

In addition, in the construction of the composite pile 1 according to the present invention can be used in the penetration auxiliary pile 70, when using the penetration auxiliary pile 70, on the other hand, to drive the synthetic pile 1 to penetrate When it is possible to prevent the breakage of the steel hollow tube 22 due to the driving, it is possible to thin the thickness of the steel hollow tube 22, there is an advantage that the economical construction is possible.

In the above described the configuration and features of the present invention based on the embodiment according to the present invention, the present invention is not limited to this, it is possible to be freely modified according to the technical idea of the present invention.

Claims (11)

The lower part is composed of a PHC pile 10 having a hollow 12, and the upper part is composed of a cast-in-place concrete pile 20 made of cast-in-place concrete 21 and steel hollow pipes 22; The steel hollow tube 22 is located at the upper portion of the PHC pile (10) is integrally connected to the PHC pile (10); A hollow reinforcing bar (13) having a bottom plate (40) for closing the hollow (12) at a lower end thereof is inserted into the hollow (12) of the PHC pile (10); An upper surface or a lower surface edge of the bottom plate 40 is provided with a contact plate 44 in close contact with the inner surface of the hollow 12 of the PHC pile 10; An upper reinforcing bar (23) is inserted into the steel hollow tube (22) to continuously reinforce with the lower reinforcing bar (13); In the state where the reinforcing bars 13 and 23 are installed, the concrete 12 is continuously poured into the hollow 12 and the steel hollow tube 22 of the PHC pile 10 so that the PHC pile 10 and the Synthetic pile, characterized in that the cast-in-place concrete pile 20 has a structure that is integrally synthesized. The method of claim 1,  It is made of a steel plate formed with a through hole in the center and is provided with a plurality of coupling holes so that the upper end of the lower reinforcing bar 13 and the lower end of the upper reinforcing bar 23 are coupled to the respective coupling holes. , 23) is a composite pile, characterized in that the coupling plate 50 is further provided to be connected integrally up and down integrally. delete delete The lower portion is composed of a PHC pile 10 having a hollow 12, the upper portion is a synthetic pile having a composite structure consisting of the cast-in-place concrete pile 20 consisting of the cast-in-place concrete 21 and the steel hollow pipe 22 ( As a construction method of 1), Placing the steel hollow tube 22 on the PHC pile 10 and then integrally connecting the steel hollow tube 22 with the PHC pile 10; Inserting a penetration auxiliary pile (70) into the steel hollow pipe (22) such that an end of the penetration auxiliary pile (70) contacts the head of the PHC pile (10); In order to facilitate insertion of the penetration auxiliary pile 70 and to prevent damage caused by collision with the steel hollow tube 22, the head of the steel hollow tube 22 has a funnel-shaped insertion guide member 80. Installing); Driving the head of the penetration auxiliary pile 70 to penetrate and install a pile in a state in which the PHC pile 10 and the steel hollow pipe 22 are integrally connected; After removing the penetration auxiliary pile 70, and inserted into the hollow 12 of the PHC pile 10, the lower reinforcing bar 13 having a bottom plate 40 for closing the hollow 12 in the lower end and Inserting the upper reinforcing bar (23) in the interior of the steel hollow tube (22) so that the continuous reinforcement with the lower reinforcing bar (13); And Continuously placing concrete 21 in the hollow 12 and the steel hollow tube 22 of the PHC pile 10 in the state where the reinforcing bars 13 and 23 are inserted. (10) and the construction method of the composite pile, characterized in that the cast-in-place concrete piles 20 to be integrally synthesized. The method of claim 5, On the side of the penetration assisting pile 70, it has a protruding shape and elasticity so as to maintain a gap between the penetration assistance pile 70 and the steel hollow pipe 22 inner wall to the driving of the penetration assistance pile 70 Method of constructing a composite pile, characterized in that for attaching a spacer (76) that is absorbed by the stress is deformed and restored during shaking or lateral movement. The method of claim 6, A lower pressure plate 72 is provided at the lower portion of the penetration assisting pile 70 to prevent stress concentration at the time of driving and to distribute the stress evenly. In the lower pressure plate 72, air to prevent the air resistance due to the sealing inside the steel hollow tube 22 is generated when the penetration auxiliary pile 70 is inserted into the steel hollow tube 22 Construction method of a synthetic pile, characterized in that the air vent hole 75 is formed that can be discharged. The method of claim 7, wherein A lower portion of the lower pressure plate 72 is provided with a cushioning material 73 for preventing the head of the PHC pile 10 from being damaged when the penetration auxiliary pile 70 is driven. The air vent hole (75) is also formed in the cushion member (73). delete As the penetration auxiliary pile 70 is inserted into the interior of the steel hollow tube 22 to penetrate into the ground by the driving force, so that the steel hollow tube 22 also penetrates into the ground together, A lower pressure plate 72 is provided at the lower portion of the penetration assisting pile 70 to prevent stress concentration at the time of driving and to distribute the stress evenly. In the lower pressure plate 72, air to prevent the air resistance due to the sealing inside the steel hollow tube 22 is generated when the penetration auxiliary pile 70 is inserted into the steel hollow tube 22 An air vent hole 75 through which gas can be discharged is formed; On the side of the penetration assisting pile 70, it has a protruding shape and elasticity so as to maintain a gap between the penetration assistance pile 70 and the steel hollow pipe 22 inner wall to the driving of the penetration assistance pile 70 Penetration aid pile that is provided with a spacer (76) that is absorbed by the deformation and restoration when the shake or lateral movement due to. The method of claim 10, A lower portion of the lower pressure plate 72 is provided with a cushioning material 73 for preventing the head of the PHC pile 10 from being damaged when the penetration auxiliary pile 70 is driven. Penetration assistance pile, characterized in that the air vent hole (75) is also formed in the cushion material (73).

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