JP2015055077A - Foundation pile structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a foundation pile structure of using a precast pile of integrally manufacturing a pile upper part of requiring load resistant performance and an inexpensive pile lower part.SOLUTION: The foundation pile structure is constituted by burying a concrete precast pile 15 in a pile hole 11 having a foot protection part 13 of injecting cement milk 14 into a tip part. A part positioned on the upper side more than at least the foot protection part 13 of the precast pile 15, is integrally manufactured from the pile upper part 15a of an SC pile structure of integrating a cylindrical steel plate 21 and the pile lower part 15b of a PC structure or being still the PC structure, with a pile of the PC structure or the RC structure as a core material.

Description

  The present invention relates to a foundation pile structure in which a ready-made pile is embedded.

  Mainly in the high bearing capacity pile method, in order to obtain a high bearing capacity, a ready-made pile made of concrete is buried in a pile hole having a root consolidation portion in which a root consolidation liquid is injected into the tip (for example, see Patent Document 1). ), A specially shaped pile with irregularities and nodes on the peripheral surface is used for the purpose of strengthening the bond between the root-solidified portion and the pile (see, for example, Patent Document 2-4).

  Because the cross-sectional force acting on the lower part of the pile fixed in these root consolidation parts is mainly axial force, low-cost deformed PHC piles (pretension type centrifugal force high strength prestressed concrete piles) are used as lower piles It is done.

  On the other hand, since the cross-sectional force per pile is relatively large for the upper part of the pile, the PRC pile (PC steel wire and deformed bar steel is used as the axial rebar and the spiral rebar has higher load-bearing performance than the PHC pile that has been widely used in the past. High-strength prestressed concrete piles with a horizontal restraint bar) and SC piles (centrifugal concrete piles with shell steel pipes) are suitable as upper piles.

  However, in the case of PRC piles, since the number of pile head reinforcing bars that can transmit the cross-sectional force transmitted from the superstructure to the pile head is limited, it is difficult to adopt the PRC pile when the cross-sectional force is large. SC pile is often selected as the upper pile.

  In addition, since the ready-made piles are transported from the factory to the construction site using a general road, the production length in the factory is generally limited to 15 m or less. And according to the depth of the support layer of a construction point, several ready-made piles are added and a required pile foundation is constructed.

  In this case, in order to suppress the cost of the expensive outer shell steel pipe, generally, the pile length of the SC pile as the upper pile is about 5 to 10 m, and the SC is added to the normal PHC pile as the lower pile or the above-described deformed PHC pile. The piles are joined using welding or mechanical fittings.

  That is, as shown in FIG. 11, the lower end end plate 2 of the upper pile (SC pile) 1 and the upper end end plate 4 of the lower pile (deformed PHC pile) 3 are connected by a joint portion 5 such as welding or a joint fitting. ing.

  In addition, since the conventional cylindrical steel plate of SC pile is a shape which cannot be normally accommodated in the formwork of PHC pile, SC pile and PHC pile cannot be manufactured integrally, and conventional cylinder The peripheral frictional force of the steel plate is the same as that of a straight PHC pile, and does not expect much peripheral frictional force.

JP 2006-348564 A JP 2006-125089 A JP 2003-129471 A Japanese Patent No. 4724879

  When trying to secure the structural strength of the upper part of the pile with the SC pile, it is necessary to weld the joint as shown in Fig. 11 or to connect the joint with the SC pile and the PHC pile, increasing the joint fitting cost and construction. There has been a problem of increasing the cost of joining piles on site and increasing costs.

  The present invention has been made in view of such points, and has structural strength and economy by using a prefabricated pile in which a pile upper portion and a cheap pile lower portion, which are required to have load bearing performance, are used. The purpose is to provide a foundation pile structure.

  The present invention is a foundation pile structure formed by embedding a concrete ready-made pile in a pile hole having a root-solidified portion into which a root-setting liquid is injected at the tip, and at least above the root-solidified portion of the ready-made pile The located part is a foundation pile with a PC structure or RC structure pile as the core, and a pile upper part integrated with a steel plate made of steel and a pile lower part with the PC structure or RC structure as a single piece. It is a structure.

  According to the present invention, at least a portion of the ready-made pile embedded in the pile hole having the root-solidified portion into which the root-solidifying liquid has been injected is positioned above the root-solidified portion, the pile of the PC structure or the RC structure is used as a core material, Since the pile top with integrated steel plate and the pile bottom with the PC structure or RC structure are manufactured as one body, the pile top of the SC pile structure that requires load bearing performance and the inexpensive pile bottom are integrated. It can be molded, and a cost reduction effect can be expected by eliminating or reducing welding and joint fitting costs, reducing joint work, and improving workability, and can provide a foundation pile structure that combines structural strength and economy.

It is sectional drawing which shows 1st Embodiment of the foundation pile structure which concerns on this invention. It is a pile sectional view of a pile structure same as the above. It is explanatory drawing which shows the example of a modified process of the cylindrical steel plate in a pile structure same as the above. It is explanatory drawing which shows the other modified example of a cylindrical steel plate in a pile structure same as the above. It is sectional drawing which shows 2nd Embodiment of the foundation pile structure which concerns on this invention. It is a pile sectional view of a pile structure same as the above. It is sectional drawing which shows 3rd Embodiment of the foundation pile structure which concerns on this invention. It is a pile sectional view of a pile structure same as the above. It is sectional drawing which shows 4th Embodiment of the foundation pile structure which concerns on this invention. It is a pile sectional view of a pile structure same as the above. It is sectional drawing which shows the conventional foundation pile structure.

  Hereinafter, the present invention will be described with reference to the first embodiment shown in FIGS. 1 to 4, the second embodiment shown in FIGS. 5 and 6, and the third embodiment shown in FIGS. A detailed description will be given based on the fourth embodiment shown in FIGS.

  First, the first embodiment shown in FIGS. 1 to 4 will be described.

  As shown in FIG. 1, the excavated pile hole 11 has a shaft portion 12 and a root solidifying portion 13 at the tip portion of the shaft portion 12. Cement milk 14 as a root-setting liquid is injected into the root consolidation portion 13 of the pile hole 11, and a concrete ready-made pile 15 is buried in the pile hole 11, and the shaft portion 12 and the ready-made pile 15 of the pile hole 11 are embedded. Cement milk 14 filled as a pile circumference fixing liquid is consolidated in the gap between the two.

  In this way, the concrete-made pile 15 is buried in the pile hole 11 having the root consolidation portion 13 in which the cement milk 14 is injected into the tip portion, and the following foundation pile structure is configured.

(1) As shown in FIG. 2, the ready-made pile 15 is an RC having a PC structure in which a PC steel wire 19 is tensioned between an end plate 17 at the upper end of the pile and an end plate 18 at the lower end of the pile, or a reinforcing bar. A pile upper portion 15a configured as an SC pile structure and a pile lower portion 15b using a PC structure or RC structure pile as they are are integrally formed using the structure pile as a core material.

(2) The ready-made pile 15 is formed by integrating a cylindrical steel plate 21 on the outer peripheral surface portion of the core material of the pile upper portion 15a as shown in FIG. 1 and FIG. The cylindrical steel plate 21 is generally a spiral steel pipe formed into a cylindrical shape by winding and welding a strip-shaped steel plate in a spiral shape. The cylindrical steel plate 21 is obtained by cutting the weld bead protrusion generated in the above. Alternatively, the tubular steel plate 21 may be an ERW steel pipe in which a seam is electrically resistance welded while the steel plate is formed into a cylindrical shape, and the projections of the weld beads generated during the welding are removed. .

(3) The tubular steel plate 21 may be a normal steel plate having a non-processed surface, but may be a steel plate having a deformed surface. For example, it is preferable to perform the uneven processing of the striped pattern 22 shown in FIG. 3, the uneven processing of the check pattern 23 shown in FIG. 4, or the uneven processing of the embossed pattern (not shown).

(4) The pile lower portion 15b of the ready-made pile 15 may be formed in a straight pile structure without irregularities or nodes on its peripheral surface, or a modified PHC pile or irregular RC pile structure with irregularities or nodes. You may form in. As shown in FIGS. 1 and 2, the portion of the ready-made pile 15 located in the root consolidation portion 13 is different from the straight pile structure in the entire circumference of the axial position corresponding to the root consolidation portion 13 of the pile hole 11. It is a grooved pile provided with one or more grooves 24 on its surface. That is, the portion of the ready-made pile 15 located in the root consolidation portion 13 is formed in a modified PHC pile or a modified RC pile structure different from the straight pile structure. Can be strengthened.

(5) At least the groove 24 of the deformed PHC pile or the deformed RC pile structure is positioned in the root consolidation portion 13 as shown in FIG. In the example shown in the figure, the root hardening portion 13 has a bottomed shape in which the shaft portion 12 of the pile hole 11 is expanded, but may be applied when the bottom is not expanded.

(6) The pile upper portion 15a and the pile lower portion 15b are integrally manufactured by a centrifugal molding machine. At that time, as shown in FIG. 2, the surface of the cylindrical steel plate 21 of the pile upper portion 15a from which the weld bead has been removed and the concrete molding surface of the pile lower portion 15b are integrated with each other in the same rotary mold. Molded.

  That is, this cylinder so that the tubular steel plate 21 with the weld bead removed is integrated with a necessary portion located above the deformed PHC pile as the PC structure pile or the deformed RC pile as the RC structure pile. The SC pile and the deformed PHC pile or the deformed RC pile are integrally manufactured by arranging the steel plate 21 in a part of the rotary mold of the centrifugal molding machine. Thereby, welding between two types of piles or a joint metal fitting can be abolished.

  1 and 2 show an example in which the joint by welding or joint fitting is abolished as described above. However, when the support layer is deep and the overall length of the pile exceeds 15 m, the PC structure of the pile lower portion 15b is used. Or you may comprise RC structure by a some pile. That is, at least a portion of the ready-made pile 15 that is positioned above the root-solidified portion 13 is a pile upper portion 15a in which a cylindrical steel plate 21 is integrated with a PC structure or RC structure pile as a core, and a PC structure or RC structure. The lower pile 15b may be manufactured as a single piece, and the lower pile of the PC structure or RC structure embedded in the root consolidation portion 13 may be manufactured separately and welded or joined with fittings. Anyway.

  For example, when the total length of the pile is 30 m, the pile was previously made as a three-piece pile with 6 to 10 m SC pile and 12 to 10 m PHC pile. With a 15 m upper pile consisting of a structured pile lower part 15b and a 15 m PC structure or RC structure lower pile, it can be made into a two-piece pile, and welding or fittings can be moved from two places to one place. Can be reduced.

  In this way, at least a portion of the ready-made pile 15 embedded in the pile hole 11 having the root-solidified portion 13 into which the cement milk 14 has been injected is positioned above the root-solidified portion 13, and a pile having a PC structure or an RC structure is used as a core material. Since the pile upper part 15a in which the cylindrical steel plate 21 with the weld beads removed is integrated and the pile lower part 15b with the PC structure or the RC structure are integrally manufactured, the SC pile structure that requires load-bearing performance The upper pile 15a and the cheap lower pile 15b can be realized as a single pile, and the cost reduction effect can be expected by eliminating or reducing welding and fitting costs, reducing joint work and improving workability. The foundation pile structure which has both strength and economy.

  Furthermore, when the surface of the cylindrical steel plate 21 of the pile upper portion 15a is subjected to a deforming process as shown in FIG. 3 or FIG. 4, the peripheral frictional force of the pile upper portion 15a against the cement milk hardened layer and the ground is improved. And the bearing capacity of the pile can be increased.

  Next, referring to the second to fourth embodiments shown in FIG. 5 to FIG. 10, the pile upper portion 15 a of the SC pile structure and the portion located in the root consolidation portion 13 are formed as a modified PHC pile or a modified RC pile. The foundation pile structure using ready-made piles 15A, 15B, and 15C formed integrally with the pile lower part 15b that is structured will be described. The same parts as those in the first embodiment shown in FIG. 1 and FIG.

  The second embodiment shown in FIG. 5 and FIG. 6 is an example using a pile-type ready-made pile 15A with an expanded groove, and in the solidified portion 13 of the pile hole 11 with respect to the upper half of the pile lower portion 15b. Since the bottom half 25 is formed with a large diameter bottom half and is provided with one or a plurality of grooves 24 on the peripheral surface of the bottom widened portion 25, an increase in support force by the wide bottom 25 is intended. Can do.

  The third embodiment shown in FIG. 7 and FIG. 8 is an example using a pile-type ready-made pile 15B with a head-expanded groove, and a pile-type ready-made pile with a bottom-extended groove shown in FIG. 5 and FIG. The head expansion 26 is added to 15A, and in addition to the increase in the supporting force by the bottom expansion portion 25, the load bearing performance can be increased by the head expansion 26.

  The fourth embodiment shown in FIG. 9 and FIG. 10 is an example using a ready-made pile 15C of a joint pile type, and the entire circumferential surface of the axial position corresponding to the inside of the solidified portion 13 of the pile lower portion 15b is used. Since one or a plurality of nodes 27 are provided, the supporting force by the nodes 27 can be increased.

  The surface of the cylindrical steel plate 21 of the pile upper portion 15a in the second to fourth embodiments may also be subjected to irregular processing such as a striped pattern, a check pattern or an embossed pattern.

  According to the second to fourth embodiments, the SC pile structure can be formed by the pile upper portion 15a in which the tubular steel plate 21 is integrated with the PC structure or the RC structure pile as a core material. Since the structure and the PC structure or RC structure pile are manufactured integrally, the pile upper portion 15a of the SC pile structure and the inexpensive pile lower portion 15b, which require load-bearing performance, can be realized by an integrated pile. Cost reduction effects can be expected by eliminating or reducing joint fitting costs, reducing joint work, and improving workability.

  INDUSTRIAL APPLICABILITY The present invention has industrial applicability for businesses that construct foundation pile structures.

11 Pile hole
13 Rooting part
14 Cement milk as root hardening liquid
15 Ready-made piles
15a Pile top
15b Pile bottom
21 Tubular steel plate

Claims (3)

It is a foundation pile structure formed by embedding a ready-made pile made of concrete in a pile hole having a root-solidified portion injected with a root-solidifying liquid at the tip,
The portion located above at least the root-solidified portion of the ready-made pile,
PC structure or RC structure pile as the core material,
A foundation pile structure characterized in that a pile upper part integrated with a cylindrical steel plate and a pile lower part with a PC structure or an RC structure are integrally manufactured. 2. The foundation pile structure according to claim 1, wherein a portion of the ready-made pile located in the root-solidified portion is formed in a modified PHC pile as a PC structure pile or a modified RC pile structure as an RC structure pile. . The base pile structure according to claim 1 or 2, wherein the tubular steel plate is a steel plate whose surface is deformed.

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