JP5199166B2 - Foundation pile structure by site construction and construction method of foundation pile - Google Patents

Description

  The present invention relates to a so-called in-situ constructed pile, a foundation pile structure by in-situ construction with a strengthened root solidified portion, and a construction method of the foundation pile structure.

  In so-called field-built piles, a pile hole having a root-solidified portion is excavated and filled with concrete, and a structure such as a rebar cage is buried to constitute a foundation pile structure. In this foundation pile structure, the load of the ground structure was mainly transmitted to the solidified part via a structural material such as a rebar cage in the concrete column and supported by the supporting ground.

  In such a foundation pile structure, it was necessary to consider short-term loads caused by earthquakes as well as long-term loads.

  On the other hand, steel pipe piles generally have toughness and high shear strength, but are thin and weak in buckling, and have a relatively small outer diameter to ensure bearing capacity mainly by friction between the ground and the outer surface. It was used as a so-called friction pile. Moreover, it was not used very much as a tip support pile whose bearing capacity is determined by the lower end area of the ready-made pile. When used as a tip support pile, there has also been a proposal for securing tip support force by projecting a blade on the outer peripheral surface of the tip (Patent Document 1).

Moreover, when applying a steel pipe pile to a tip support pile, a tip cylindrical pipe part is provided, the tip cylindrical pipe part is positioned at the root-solidifying part, and the tip cylindrical pipe part is embedded in a state where the root-solidifying material is filled. An invention has also been proposed (Patent Document 2).
Moreover, when burying ready-made piles (mainly concrete system), the proposal which utilizes a steel pipe as a casing is also made | formed (patent documents 3-5). In this case, when excavating the pile hole, the casing was buried and used to prevent the collapse of the pile hole wall before the ready-made pile was installed. Therefore, after installing the ready-made pile, the casing (steel pipe) was pulled up to the ground.

  Also, when digging a vertical hole, in order to prevent the collapse of the vertical hole, the inside of a casing made of a steel pipe was excavated and installed on the ground. In this case, the casing was buried while being connected vertically (Patent Document 6).

JP 2004-270440 A JP 2001-59219 A JP 2005-282149 A JP 2002-371553 A JP 2008-75266 A Japanese Patent Laid-Open No. 11-131961

  In the conventional technology, the strength (rigidity) of the steel pipe is used to protect the pile hole during the drilling (Patent Documents 3 to 6), or the steel pipe is used to increase the strength (rigidity) of the ready-made pile itself. There is no invention that can be used for strengthening the pile hole root consolidation part itself in cooperation with the concrete column. In particular, effective reinforcement could not be achieved for the solidified portion expected to receive an extreme load.

  However, the present invention is a foundation pile structure in which a concrete column is formed in a pile hole having a root consolidation portion, a constraining cylinder (mainly a steel pipe) is disposed on the periphery of the root consolidation portion, and the shaft portion of the pile hole is Since the outer surface of the concrete column and the ground (soil) are in direct contact with each other, the above-mentioned problems can be solved and an effective reinforcement of the rooting portion can be configured.

That is, this invention is the foundation pile structure by the field construction characterized by filling concrete into the pile hole which has a solidified part in a front-end | tip part, and having satisfy | filled all the following requirements.
(1) The tip side of the shaft portion of the pile hole was used as the root hardening portion.
(2) A concrete cylinder was constructed by burying a constraining cylinder along the outer periphery of the side wall of the root portion of the pile hole and filling the pile hole with concrete.
(3) At the shaft portion of the pile hole, the concrete column and the ground are brought into direct contact.

In the above, it is the foundation pile structure by site construction characterized by having all the following requirements.
(1) The diameter of the pile hole was deepened compared to the shaft.
(2) A constraining cylinder was embedded over substantially the entire length of the root-sealed portion.

Moreover, in the above, it is the foundation pile structure by the field construction characterized by having comprised all the following requirements.
(1) The diameter of the pile hole was deepened compared to the shaft.
(2) A spiral protrusion was formed on the outer periphery of the constraining cylinder.

The invention of the first method is a constraining cylinder having a diameter along the outer periphery of the root consolidation part of the pile hole to be constructed and having a length corresponding to the length of the root consolidation part as follows. Is a construction method of a foundation pile by on-site construction, characterized in that a foundation pile is configured by filling the pile hole with concrete.
(1) Excavate a pile hole by a normal method, and fill the pile hole with concrete to construct a concrete column.
(2) Before or after (1), the restraint cylinder is connected to the tip of the burying casing.
(3) In (1) and (2), after excavating the pile hole, before or after filling with concrete, or simultaneously with filling, press the above-mentioned burying casing from the ground at the planned root formation position. The constraining cylinder is pushed into the ground together with the burying casing.
(3) When the constraining cylinder has reached the rooting portion, release the pressing of the embedding casing, release the connection between the embedding casing and the restraining cylinder, and remove only the embedding casing. Pull it up to the ground.

Moreover, the invention of the second method is as follows. The constraining cylinder has a diameter along the outer periphery of the root consolidation part of the pile hole to be constructed and has a length corresponding to the length of the root consolidation part. Is a construction method of a foundation pile by on-site construction, characterized in that a foundation pile is configured by filling the pile hole with concrete.
(1) The restraint cylinder is connected to the tip of the burying casing, and the excavation rod is inserted into the burying casing.
(2) The pile hole is excavated in the restraint cylinder while pressing the burying casing from the ground at the planned root formation position and pushing the restraint cylinder together with the burying casing into the ground.
(3) When the constraining cylinder has reached the root formation portion planned position and the excavation of the root consolidation portion of the pile hole is completed, the pressing of the buried casing is released, and the buried casing and The connection of the restraint cylinder is released, and the burying casing and the excavation rod are pulled up to the ground.
(4) Subsequently, concrete is filled into the pile holes by a normal method to construct a concrete column.

The invention of the third method is as follows. The constraining cylinder has a diameter along the outer periphery of the root consolidation part of the pile hole to be constructed and has a length corresponding to the length of the root consolidation part. Is a construction method of a foundation pile by on-site construction, characterized in that a foundation pile is configured by filling the pile hole with concrete.
(1) The restraint cylinder is connected to the tip of the burying casing, and the excavation rod is inserted into the burying casing.
(2) The pile hole is excavated in the restraint cylinder while pressing the burying casing from the ground at the planned root formation position and pushing the restraint cylinder together with the burying casing into the ground.
(3) When the constraining cylinder has reached the planned root formation position and the excavation of the root consolidation part of the pile hole is completed, the excavation rod is pulled up to the ground.
(4) Subsequently, concrete is filled into the pile holes by a normal method to construct a concrete column.
(5) The connection between the burying casing and the restraining cylinder is released, and the burying casing is lifted to the ground.

The invention of the fourth method is as follows. The constraining cylinder has a diameter along the outer periphery of the root consolidation portion of the pile hole to be constructed and has a length corresponding to the length of the root consolidation portion. Is a construction method of a foundation pile by on-site construction, characterized in that the pile is filled with concrete to form a foundation pile.
(1) The restraint cylinder is connected to the tip of the buried casing.
(2) At the planned root formation position, the burying casing is pressed from the ground, and the restraining cylinder is pushed into the ground together with the burying casing.
(3) When the constraining cylinder has reached the planned root formation position, the pressing of the embedding casing is released, the connection between the embedding casing and the restraining cylinder is released, and the embedding Raise only the casing to the ground.
(4) Subsequently, a pile hole having a solidified portion is excavated by a normal method, and concrete is filled into the pile hole to construct a concrete column.

In the above, the restraint cylinder of “the length corresponding to the length of the root-solidified portion”
・ When the restraint cylinder covers almost the entire length of the rooting part and the length of the restraint cylinder is almost the same as the length of the rooting part ・ The restraint cylinder covers almost the entire length of the rooting part, , When projecting slightly upward from the root-clamping part-This includes any case where the restraint cylinder is located at the root-clamping part and the length of the restraint cylinder is smaller than the length of the root-clamping part.

  In this invention, a concrete column is formed in the pile hole, a constraining cylinder is disposed in the pile hole rooting portion, and a constraining cylinder is not disposed in the pile hole shaft portion. The body can be constrained as a unit to strengthen the roots. Furthermore, the foundation pile structure with appropriate strength can be realized without excessive reinforcement at the shaft portion.

(A)-(f) represents the embedding method of Example 1 of this invention. (A)-(e) represents the embedding method of Example 2 of this invention. (A)-(e) is Example 3 of this invention, and represents the process until it embeds a restraint cylinder in the ground. (A)-(e) is Example 3 of this invention, and represents the process until it forms a concrete pillar after embedding a restraint cylinder in the ground. In the embodiment in which the constraining cylinder and the casing of the present invention are engaged and disengaged with screws, (a) shows a locked state and (b) shows a separated state. It is a figure showing the other engagement / disengagement of the restraint cylinder of this invention, and a casing, (a) is a longitudinal cross-sectional view of a latching state, (b) is a front view of a latching state, (c) is the front of a separation state Represents the figure. It is a figure showing other engagement / disengagement of the restraint cylinder of this invention, and a casing, (a) is a longitudinal cross-sectional view of a separation locking state, (b) represents the longitudinal cross-sectional view of a locking state. It is a figure showing other engagement / disengagement of the restraint cylinder of this invention, and a casing, (a) is a front view of a separation locking state, (b) represents the front view of a locking state.

1. Foundation pile structure 30

The present invention is a foundation pile structure 30 in which concrete is filled in a pile hole 11 forming a root consolidation portion 13 at a tip portion and a concrete column 21 is embedded, and the restraint cylinder 5 is disposed only at the root consolidation portion 13. (FIG. 1 (f), FIG. 2 (e), FIG. 4 (e)).
(1) The pile hole 11 forms the root consolidation part 13 in the front-end | tip part of the axial part 12, and arrange | positions the root consolidation part 13 in a support ground.
(2) The concrete column 21 is embedded with a structure such as a rebar cage, an H-shaped steel, a steel pipe, etc., in which structural rebars are usually assembled.
(3) In the root hardening part 13 of the pile hole 11, the restraint cylinder 5 is embedded.
It is desirable that the constraining cylinder 5 is arranged over the entire length (total depth) of the root hardening portion 13. Depending on the required performance, it may be a structure arranged in a part of the root consolidation portion 13 in the depth direction, such as being formed to a depth corresponding to the supporting ground. In addition, the upper end 7 of the restraint cylinder 5 can be slightly protruded above the root fixing portion 13, but even in this case, the restraint cylinder 5 is formed on the majority of the shaft portion 12 of the pile hole 11. There will be no state.
(4) In the axial part 12 of the pile hole 11, the pile hole side wall which is a surface of the soil and the outer surface of the concrete column 21 are made to contact directly. In this case, the direct contact means that a structure such as a steel pipe is not interposed, and includes a case where contact is made through a soil cement layer, and a case where soil is improved around the soil.

2. Construction method of foundation pile structure 30 (construction method)

(1) When the restraint cylinder 5 is installed at a predetermined depth, the upper end 5 of the restraint cylinder 5 is detachably attached to the lower end 3 of the burying casing 1 having the same diameter as the restraint cylinder 5. Then, the restraining cylinder 5 is arranged at a predetermined depth while being pressed by the embedding casing 1, and only the embedding casing 1 is pulled up to the ground 18 and the restraining cylinder 5 is left in the ground as it is. In the case of this construction method, the following different procedures can be considered.
(a) After excavating the pile hole 11 to form the concrete column 21, the constraining cylinder 5 is pushed in (FIG. 1, Example 1).
(b) The constraining cylinder 5 is pushed in while excavating the pile hole 11, and then a concrete column is formed (FIG. 2. Example 2).
(c) The constraining cylinder 5 is buried before excavating the pile hole 11 (FIGS. 3 and 4).

(2) The means for engaging / disengaging the restraining cylinder 5 and the burying casing 1 is configured as follows, for example.
In the first means, a thread is formed on the inner surface of the burying casing 1, and a thread that engages with the outer surface 6 of the constraining cylinder 5 is formed (FIG. 5).
In the second means, the locking projections 32 are formed along the circumference on the outer surface 6 of the upper end portion 7 of the restraint cylinder 5. Further, the connecting cylinder part 33 is fitted on the outer periphery of the lower end part 3 of the burying casing 1 (the outer diameter of the burying casing 1 and the inner diameter of the connecting cylinder part 33 coincide), and the lower end part of the connecting cylinder part 33 is connected to the lower end part. Corresponding to the stop protrusions 32, 32, an entrance 34 into which the stop protrusion 32 is inserted and an accommodating portion 35 that can lock the rotated stop protrusion 32 are formed (FIG. 6).
In the third means, an annular rib 36 protruding from the outer surface 6 and the inner surface 6 a is formed on the upper end 7 a of the constraining cylinder 5. Moreover, the holding tools 37 and 37 which can be opened and closed and can pinch | interpose the annular rib 36 are attached to the lower end part 3 of the burying casing 1 in the radial direction of the burying casing 1 (FIG. 7). The holding tool 37 is opened and closed by raising or lowering the rod from the ground by hydraulic or pneumatic pressure or mechanical operation.
Further, the fourth means forms locking projections 32, 32 along the circumference on the outer surface 6 of the upper end 7 of the constraining cylinder 5. Further, a holding tool 38 that can be opened and closed and can hold the locking projection 32 is provided on the outer periphery of the lower end portion 3 of the burying casing 1 (FIG. 7). The holding tool 38 is disposed so as to protrude downward from the lower edge 3 a along the outer periphery of the burying casing 1.

(3) The excavation rod 41 is optional as long as it can excavate the ground efficiently. For example, the excavation rod 41 has an excavation head 42 at the lower end, and the excavation head 42 is configured by attaching excavation arms 43 and 43 having an excavation blade at the lower end and swinging to a head body connected to the excavation rod. Is desirable (FIG. 2A), and in this case, a drilling blade can also be formed downward at the lower end of the head body (not shown).

  An embodiment of the present invention will be described with reference to FIG. In this embodiment, after the concrete column 21 is constructed, the constraining cylinder 5 is embedded using the burying casing 1.

1. Buried casing 1 and restraint cylinder 5

An upper end portion 7 of a restraining cylinder 5 (length L ₁ , outer diameter D ₁ ) made of a steel pipe is connected to the lower end portion 3 of the burying casing 1 made of a steel pipe. The upper end 7 of the restraint cylinder 5 is threaded, and the lower end 3 of the burying casing 1 is threaded. A vertical pipe is disposed in the burying casing 1, and the discharge port at the lower end of the pipe is positioned at the lower end portion 3 with the discharge port facing downward (not shown). The upper end of the vertical pipe is located on the ground so that soil cement can be supplied from the ground into the vertical pipe.

2. Construction method of foundation pile structure 30 (construction method)

(1) While inserting the reinforcing bar cage into the pile hole 11 in which the root portion 13 (length L ₀ , diameter D ₀ ) is formed at the lower end portion of the shaft portion 12 (diameter D ₀₀ ) by an arbitrary method. After filling concrete and solidifying the concrete, a concrete column 21 is constructed in the pile hole 11 (FIG. 1A).

(2) At the foundation pile construction planned position, the burying casing 1 is attached to the auger and is lowered from above the root consolidation part 13 (FIG. 1A).

(3) The axis of the pile hole shaft 12 and the concrete column 21 and the axis of the constraining cylinder 5 are aligned with each other, and the constraining cylinder 5 is pushed into the ground 18 (FIG. 1B), and the constraining cylinder 5 is rooted. The descent of the burying casing 1 is stopped in a state where it is positioned at the hardened portion 13 (FIG. 1 (c)). At this time, if necessary, the buried casing 1 can be pushed in while being rotated.

(4) Subsequently, the burying casing 1 is reversely rotated, the screwing of the burying casing 1 and the restraining cylinder 5 is released and separated (FIG. 2 (d)), and only the burying casing 1 is placed on the ground. Pull up (FIG. 1 (e)). At this time, in order to repair the ground (consolidate the loose ground), the soil cement can be protruded from the discharge port of the lower end portion 3 of the burying casing 1 to the ground.

(5) The foundation pile structure 30 is comprised by the above (FIG.1 (f)). In this state, the constraining cylinder 5 (length L ₁ = L ₀ , diameter) over the entire length of the root consolidation portion 13 (length L ₀ , diameter D ₀ ) of the pile hole, that is, the root consolidation portion of the concrete column 21. D ₁ = D ₀ ) is arranged. Moreover, in the axial part 12 of the pile hole 11, the soil (or soil which the soil cement penetrate | infiltrated) is located in the outer surface of the concrete pillar 21 (FIG.1 (f)).

(6) In this embodiment, for example,
・ Shaft hole 11 shaft diameter D ₀₀ = 1200 mm
・ Dense root diameter D ₀ = 1600-2600 mm (= diameter D ₁ of restraint cylinder 5)
In this case, the thickness of the constraining cylinder 5 is assumed to be about 20 to 40 mm.

3. Other examples

(1) In the said Example, although the concrete was filled in the pile hole 11, and the constraining cylinder 5 was embed | buried after concrete solidified, the constraining cylinder 5 can also be embed | buried before solidifying.

(2) Moreover, in the said Example, the restraint cylinder 5 can also be set as the structure which formed the spiral blade | wing on the outer surface (not shown).

(3) Moreover, in the said Example, it can also embed, forming a saw blade and other unevenness | corrugations in the lower end part 8 of the restraint cylinder 5, and cutting the ground in the lower edge of the restraint cylinder 5, If it uses together with the said drilling liquid, even if it is a comparatively hard ground, the restraint cylinder 5 can be installed easily.

(4) Further, in the above embodiment, the length L ₁ of the restraint cylindrical body 5 and the length L ₀ of the root hardened portion 13 has substantially the same, at least, at the root hardened portion 13, the bottom of the ready-made pile 21 It is desirable that the constraining cylinder 5 is located below the height including the height of the protrusion 23.

An embodiment of the present invention will be described with reference to FIG. In this embodiment, the pile hole 11 is excavated with the diameter D ₀₀ of the shaft portion 12 and the diameter D ₀ (D ₀ > D ₀₀ ) of the root hardening portion 13.

1. Buried casing 1 and restraint cylinder 5

An upper end portion 7 of a restraining cylinder 5 (length L ₁ , outer diameter D ₁ ) made of a steel pipe is connected to the lower end portion 3 of the burying casing 1 made of a steel pipe. The upper end 7 of the restraint cylinder 5 is threaded, and the lower end 3 of the burying casing 1 is threaded. A vertical pipe is disposed in the burying casing 1, and the discharge port at the lower end of the pipe is positioned at the lower end portion 3 with the discharge port facing downward (not shown). The upper end of the vertical pipe is located on the ground so that soil cement can be supplied from the ground into the vertical pipe.

2. Construction method of foundation pile structure 30 (construction method)

(1) At the planned foundation pile construction position, the burying casing 1 is attached to the excavator, and the digging rod 41 in which the digging head 42 having the digging blade is disposed is inserted into the burying casing 1. Connect the upper end to the excavator. The axis of the excavation rod 41 and the axes of the burying casing 1 and the constraining cylinder 5 are made to coincide. The excavation head 42 is constituted by excavating arms 43 and 43 having excavation blades at their tips so as to be swingable (FIG. 2A).

(2) The excavation head 42 of the excavation rod 41 and the lower end 8a of the restraint cylinder 5 are brought close to the ground 18 and the ground 18 is excavated by the excavation head 42 while pushing the lower end 8 of the restraint cylinder 5 into the ground 18 (FIG. 2). (A)). At this time, the embedded casing 1 is pushed in while rotating in the direction in which the screw is tightened. In the middle, if necessary, the burying casing 1 is joined by connecting the top and bottom by welding.
At this time, the excavation head 42 excavates with the diameter D ₀₀ of the shaft portion 12 of the pile hole 11, and is pushed in while rotating at the diameter D ₁ (= D ₀ ) of the constraining cylindrical body 5 coaxially. Therefore, in this state, the ground remains in a cylindrical shape at the inner diameter D ₀₀ and the outer diameter D ₀ . At this time, excavation and push-in are advanced with the lower end position of the excavation head excavation and the lower end position of the constraining cylinder 5 being substantially the same (FIG. 2A).
If the diameter D ₀₀ of the shaft portion 12 of the pile hole 11 is the same as the diameter D ₀ of the root hardening portion 13 (D ₀₀ = D ₀ ), that is, the diameter D ₀₀ of the shaft portion 12 = restraint cylinder 5 the diameter _{D 1.} In this case, the ground does not remain cylindrical.

(3) Following the drilling Kuiana 11 shaft section 12 of the drill rod 41 is reversely rotated, enlarged drilling diameter, drilling arm 43, drilling root hardened portion 13 in diameter D ₀ (FIG. 2 (b) Therefore, the excavation head 43 advances excavation along the inner surface of the constraining cylinder 5 when excavating the root hardening portion 13.

(4) If the root consolidation part 13 of the predetermined pile hole 11 in the excavation rod 41 is excavated, the restraint cylinder 5 is brought to a predetermined depth (depth position of the root consolidation part of the foundation pile to be constructed). Install.

(5) Subsequently, the burying casing 1 is rotated in the reverse direction to release the screwing between the burying casing 1 and the constraining cylinder 5 (FIG. 2D). Subsequently, only the burying casing 1 is lifted to the ground. Therefore, only the constraining cylinder 5 is left in the root hardening portion 13 (FIG. 1 (d)).
At this time, in order to repair the ground (consolidate the loose ground), soil cement is projected from the discharge port of the lower end 3 of the burying casing 1 to the ground.

(6) Also, the excavation rod 43 is pulled up to the ground before or after (5).

(7) Subsequently, by a conventional method, the pile hole 11 is filled with a reinforcing steel cage (not shown) and concrete, and after solidification, the concrete column 21 is constructed in the pile hole 11 to obtain a foundation pile structure. 30 is configured (FIG. 2E). In this state, the constraining cylinder 5 (length L ₁ = L ₀ , diameter D ₁ = D ₀ ) is disposed over the entire inner surface of the root consolidation portion 13 (length L ₀ , diameter D ₀ ). Is done. Moreover, in the axial part 12 of the pile hole 11, soil (or soil which soil cement penetrate | infiltrated) is located in the outer surface of the concrete pillar 21 (FIG.2 (e)).

3. Other examples

  In the said Example, after raising the casing 1 for embedding to the ground, the pile hole 11 was filled with concrete, However, the excavation rod 41 is pulled up to the ground 18, the concrete is filled in the pile hole 11, and it is used for embedding after that. The casing 1 can also be pulled up to the ground 18 (not shown).

  An embodiment of the present invention will be described with reference to FIGS. This embodiment is an embodiment in which the pile hole 11 is excavated after the restraining cylinder 5 is buried using the burying casing 1.

1. Buried casing 1 and restraint cylinder 5

An upper end portion 7 of a restraining cylinder 5 (length L ₁ , outer diameter D ₁ ) made of a steel pipe is connected to the lower end portion 3 of the burying casing 1 made of a steel pipe. The upper end 7 of the restraint cylinder 5 is threaded, and the lower end 3 of the burying casing 1 is threaded. A vertical pipe is disposed in the burying casing 1, and the discharge port at the lower end of the pipe is positioned at the lower end portion 3 with the discharge port facing downward (not shown). The upper end of the vertical pipe is located on the ground so that soil cement can be supplied from the ground into the vertical pipe.

2. Construction method of foundation pile structure (construction method)

(1) At the planned foundation pile construction position, the embedding casing 1 is attached to a pile driving machine for embedding a steel pipe pile and brought close to the ground 18 (FIG. 3 (a)), and the lower end of the restraint cylinder 5 on the ground 18 8 is pushed in (FIG. 3B). At this time, the embedded casing 1 is pushed in while rotating in the direction in which the screw is tightened. In the middle, if necessary, the burying casing 1 is joined by connecting the top and bottom by welding.
When the constraining cylinder 5 reaches a predetermined depth (depth position of the root consolidation portion of the foundation pile to be constructed) (FIG. 3 (c)), the burying casing 1 is reversely rotated to bury the burying casing. 1 and the restraining cylinder 5 are unscrewed and separated (FIG. 3D). Subsequently, only the burying casing 1 is lifted to the ground, and the restraint cylinder 5 is left at the rooting portion installation position (FIGS. 3E and 4A).

(2) Subsequently, the shaft portion 12 of the pile hole 11 is excavated with a drilling rod (not shown) by a normal method (FIG. 4B), and the vicinity of the bottom of the root consolidation portion 13 (restraint cylinder) Excavation is carried out to the vicinity of the lower end of (Fig. 4 (c)). Subsequently, the root consolidation portion is expanded and excavated to expand to the inner surface 6a of the restraint cylinder 5, and the root consolidation portion 13 (length L ₀ , diameter D ₀ ) is excavated to form the pile hole 11 ( FIG. 4 (d)), lifting the excavation rod to the ground.
Subsequently, the pile hole 11 is filled with a rebar cage (not shown) and concrete to form a concrete column 21 to constitute the foundation pile structure 30.
In this state, the constraining cylinder 5 (length L ₁ = L ₀ , diameter D ₁ = D ₀ ) is disposed over the entire inner surface of the root consolidation portion 13 (length L ₀ , diameter D ₀ ). Is done. Moreover, in the axial part 12 of the pile hole 11, soil (or soil which soil cement penetrate | infiltrated) is located in the outer surface of the concrete pillar 21 (FIG.4 (e)).

DESCRIPTION OF SYMBOLS 1 Buried casing 2 Upper end 3 of buried casing 3 Lower end 5 of buried casing 5 Restraint cylinder 6 Outer surface 6a of restraint cylinder 7 Upper surface 7 of restraint cylinder 7a Upper end 7a of restraint cylinder Restraint cylinder Lower end part 8a Lower end 11 of constraining cylinder Pile hole 12 Shaft part 13 of pile hole 13 Solidified part 18 of pile hole Ground 21 Concrete column 30 Foundation pile structure 31 Locking projection 32 of constraining cylinder Connection of buried casing Cylindrical part 33 Entrance 34 of connecting cylindrical part 35 Containing cylindrical part receiving part 35 Annular rib 37 of constraining cylindrical body Embedding casing clamping tool 38 Embedding casing clamping tool 41 Excavation rod 42 Excavation head 43 Excavation head excavation arm

Claims (7)

A foundation pile structure by site construction characterized by filling concrete in a pile hole having a root-solidified portion at the tip and having all the following requirements.
(1) The tip side of the shaft portion of the pile hole was used as the root hardening portion.
(2) A concrete cylinder was constructed by burying a constraining cylinder along the outer periphery of the side wall of the root portion of the pile hole and filling the pile hole with concrete.
(3) At the shaft portion of the pile hole, the concrete column and the ground are brought into direct contact. The foundation pile structure by site construction according to claim 1, characterized in that all of the following requirements are satisfied.
(1) The diameter of the pile hole was deepened compared to the shaft.
(2) A constraining cylinder was embedded over substantially the entire length of the root-sealed portion. The foundation pile structure by site construction according to claim 1, characterized in that all of the following requirements are satisfied.
(1) The diameter of the pile hole was deepened compared to the shaft.
(2) A spiral protrusion was formed on the outer periphery of the constraining cylinder. As shown below, a constraining cylinder having a diameter along the outer circumference of the root consolidation part of the pile hole to be constructed and corresponding to the length of the root consolidation part is arranged, and the concrete is placed in the pile hole. Construction method of foundation pile by on-site construction characterized by filling and constituting foundation pile.
(1) Excavate a pile hole by a normal method, and fill the pile hole with concrete to construct a concrete column.
(2) Before or after (1), the restraint cylinder is connected to the tip of the burying casing.
(3) In (1) and (2), after excavating the pile hole, before or after filling with concrete, or simultaneously with filling, press the above-mentioned burying casing from the ground at the planned root formation position. The constraining cylinder is pushed into the ground together with the burying casing.
(3) When the constraining cylinder has reached the rooting portion, release the pressing of the embedding casing, release the connection between the embedding casing and the restraining cylinder, and remove only the embedding casing. Pull it up to the ground. As shown below, a constraining cylinder having a diameter along the outer circumference of the root consolidation part of the pile hole to be constructed and corresponding to the length of the root consolidation part is arranged, and the concrete is placed in the pile hole. Construction method of foundation pile by on-site construction characterized by filling and constituting foundation pile.
(1) The restraint cylinder is connected to the tip of the burying casing, and the excavation rod is inserted into the burying casing.
(2) The pile hole is excavated in the restraint cylinder while pressing the burying casing from the ground at the planned root formation position and pushing the restraint cylinder together with the burying casing into the ground.
(3) When the constraining cylinder has reached the root formation portion planned position and the excavation of the root consolidation portion of the pile hole is completed, the pressing of the buried casing is released, and the buried casing and The connection of the restraint cylinder is released, and the burying casing and the excavation rod are pulled up to the ground.
(4) Subsequently, concrete is filled into the pile holes by a normal method to construct a concrete column. As shown below, a constraining cylinder having a diameter along the outer circumference of the root consolidation part of the pile hole to be constructed and corresponding to the length of the root consolidation part is arranged, and the concrete is placed in the pile hole. Construction method of foundation pile by on-site construction characterized by filling and constituting foundation pile.
(1) The restraint cylinder is connected to the tip of the burying casing, and the excavation rod is inserted into the burying casing.
(2) The pile hole is excavated in the restraint cylinder while pressing the burying casing from the ground at the planned root formation position and pushing the restraint cylinder together with the burying casing into the ground.
(3) When the constraining cylinder has reached the planned root formation position and the excavation of the root consolidation part of the pile hole is completed, the excavation rod is pulled up to the ground.
(4) Subsequently, concrete is filled into the pile holes by a normal method to construct a concrete column.
(5) The connection between the burying casing and the restraining cylinder is released, and the burying casing is lifted to the ground. In the following manner, a constraining cylinder having a diameter along the outer periphery of the root consolidation portion of the pile hole to be constructed and corresponding to the length of the root consolidation portion is disposed, and concrete is placed in the pile hole. A method for constructing foundation piles by site construction, characterized in that the foundation pile is constructed by filling
(1) The restraint cylinder is connected to the tip of the buried casing.
(2) At the planned root formation position, the burying casing is pressed from the ground, and the restraining cylinder is pushed into the ground together with the burying casing.
(3) When the constraining cylinder has reached the planned root formation position, the pressing of the embedding casing is released, the connection between the embedding casing and the restraining cylinder is released, and the embedding Raise only the casing to the ground.
(4) Subsequently, a pile hole having a solidified portion is excavated by a normal method, and concrete is filled into the pile hole to construct a concrete column.

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