JP6470699B2 - Pile connection structure - Google Patents

Description

  The present invention relates to a pile connection structure.

  Conventionally, as a natural ground reinforcement method for cutting slope reinforcement, retaining wall reinforcement, landslide / slope collapse protection, rock mass reinforcement, etc. There has been a method of injecting a filler and inserting a reinforcing material such as a reinforcing bar (see Patent Document 1).

JP 2000-303480 A

Conventional civil engineering works generally include: (i) drilling holes in the ground with a drill rod of a drilling machine; (ii) extracting the drill rod from the drilling hole and then inserting an injection hose into the drilling hole And (iii) injecting and filling a filling material such as cement milk or mortar into the injection hose, (iv) after pulling out the injection hose, inserting a reinforcing bar or the like into the drilling hole, and (v) Attach the bearing plate and nut to the hole and tighten.
However, there has been a problem that the hole formed by the hole driller collapses. Then, the natural ground reinforcement construction method of patent document 1 is proposed.

Moreover, in order to protect a hole wall, a casing may be used as another construction method. The work process consists of (i) opening a hole, (ii) inserting a casing into the hole, (iii) injecting and filling mortar into the casing, (iv) inserting a reinforcing bar into the casing, (v ) The process of pulling out and collecting the casing with the mortar and the reinforcing bar remaining in the hole is sequentially performed.
However, even if any of the above conventional methods is adopted, the number of steps is increased and the cost is increased. Also, on slopes with poor scaffolding, there was a problem that the use of heavy machinery was restricted and work efficiency was reduced.

  Then, this invention aims at providing the connection structure of the pile which can connect the two piles easily by mechanical structure, and can reduce the man-hour of the work in civil engineering work. In particular, this is an indentation that is indispensable for reducing the number of man-hours and improving efficiency by applying a steel pipe with a dent with high adhesion to the mortar and using the inner diameter of the steel pipe for mortar injection while ensuring a strength higher than the reinforcing bar. It aims at providing the simple mechanical connection structure of a steel pipe.

A pile connection structure according to the present invention is used for civil engineering work involving mortar injection, and is a pile connection structure for connecting pile ends of piles made of steel pipes with a short cylindrical joint, The joint has a through hole perpendicular to the axis, and the joint has a pair of insertion cylinders defined by an inner flange in the middle in the axial direction, and the pile end is the insertion cylinder A through hole and a screw hole are provided on the same axial center as the through hole in the state of being inserted into the insertion part, and are inserted into the insertion cylinder part. When the connection between the joint and the pile is completed, the through hole And a bolt is inserted into the through hole and the screw hole, the male screw portion of the bolt is screwed into the screw hole, and the head of the bolt gives a pressing force to the outer peripheral surface of the pile, and the head is loaded into buried shape to the through hole, by the pressing force from the head of the bolt, on the piles of the insertion tube portion It is unevenly distributed on the screw hole side, a crescent-shaped gap is formed between the outer peripheral surface of the pile and the inner peripheral surface of the insertion tube portion, and the injected mortar is in the state of completion of the civil engineering work, The crescent-shaped gap is filled in the gap .

Moreover, the pile end part of the pile which consists of steel pipes is the connection structure of the pile which connects with a short cylindrical joint, Comprising: The said pile end part has a through-hole of an axial center orthogonal shape, The said joint, It has a pair of insertion cylinders partitioned by an inner flange part in the middle in the axial center direction, and penetrates on the same axial center as the through hole in a state where the pile end part is inserted into the insertion cylinder part A hole and a screw hole are provided in the insertion tube portion, and further, on the outer peripheral surface / inner peripheral surface of the insertion tube portion, a circular planar seating surface centered on the screw hole, When the connection between the joint and the pile is completed, a bolt is inserted into the through hole, the through hole, and the screw hole, and a male thread portion of the bolt is screwed into the screw hole. The head portion applies a pressing force to the outer peripheral surface of the pile, and the head portion is inserted into the through hole in an embedded state.

Moreover, many hollow parts are recessedly provided in the outer peripheral surface of the said pile.
The through hole is a machined hole and is formed slightly larger than the head portion of the bolt, and the diameter of the through hole is set to be 101% to 105% of the diameter of the head portion of the bolt. Ru der those that are.

  According to the pile connection structure of the present invention, in civil engineering work, mortar can be injected and filled into the drilling hole using the internal cavity of the pile, and an injection hose, casing, etc. are no longer necessary. Costs can be reduced by reducing the number of man-hours for construction. Pile connection work can be simplified and work time can be shortened. Since connection work can be performed manually, work efficiency can be improved. The pile ends can be connected by a mechanical structure with joints and bolts, and the connection strength can be made stable and of high quality. The outer peripheral surface of the pile can be pressed and tightened against the inner peripheral surface of the plug-in cylinder portion, so that rattling in the connected state can be prevented and bending strength can be ensured. It has a compressive strength and tensile strength comparable to those of conventional rebars, and can secure a connection strength having a bending strength against bending. Moreover, there is no need to weld the pile end, no fire for welding is brought into the field, there is no fear of fire, and connection work in rainy weather is also possible.

It is an expanded sectional view which shows a connection completion state, (a) is an expanded sectional front view, (b) is an expanded sectional side view. It is an expanded sectional view which shows a connection completion state, (a) is an expanded sectional plan view, (b) is a sectional plan view which expanded the principal part further. It is an expanded sectional view which shows a pile edge part, (a) is an expanded sectional front view, (b) is an expanded sectional side view. It is an expanded sectional view which shows a coupling, (a) is an expanded sectional front view, (b) is an expanded sectional side view. It is a front view which shows a pile. It is AA sectional drawing of FIG. It is a principal part expanded side view. It is a perspective view which shows a coupling. It is simple sectional drawing which shows the use condition of the connection structure of the pile which concerns on this invention, (a) is sectional drawing which shows the process of opening a drilling hole, (b) is sectional drawing which shows the process of inserting a pile. (C) is a cross-sectional view showing the step of injecting mortar, and (d) is a cross-sectional view showing the step of completing filling of the mortar into the hole. It is a principal part expanded sectional view of the state which filled mortar, (a) is an expanded sectional front view, (b) is an expanded sectional top view.

Hereinafter, the present invention will be described in detail with reference to the drawings illustrating embodiments.
As shown in FIG. 1, the connection structure of the pile of this invention is a connection structure at the time of mutually connecting the pile edge parts 2 and 2 of the piles 1 and 1 which consist of steel pipes by the short cylindrical joint 3. As shown in FIG. .
Generally, there is a threaded joint as a method for mechanically connecting the pile ends of the steel pipe. As shown in FIGS. 3, 5 and 6, the pile 1 is a fixed steel pipe (dimple steel pipe). Since a large number of hollow portions 9 are provided in the outer peripheral surface 1A, the cross-sectional shape does not become a perfect circle, so screwing is difficult, and connecting the pile end portions 2 and 2 using a screw joint is It is very difficult. The hollow portions 9 are formed at a predetermined pitch along the axial direction to form a plurality of rows of dimple groups 13. A plurality of oval low protruding portions 12 are formed on the inner peripheral surface 1B of the pile 1 corresponding to the recessed portions 9 of the outer peripheral surface 1A.
As shown in FIG. 3, the pile end portion 2 is formed with (a pair of) through-holes 4 and 4 in a uniaxial direction perpendicular to the pile axis C ₁ . Through-hole 4, distribution from the outermost edge portion 20 of the Kuitan portion 2 in the longitudinal direction a position of a predetermined length L _1, and the 180 ° rotational symmetry positions around the Kuijikukokoro C ₁ It is installed.

The joint 3 is made of, for example, ductile cast iron or mariable cast iron.
As shown in FIG. 4, the joint 3 includes an inner flange portion 10 at an intermediate portion in the axial center direction, and a pair of insertion cylinder portions 6 and 6 into which the pile end portion 2 is inserted by the inner flange portion 10 are partitioned. ing. A through-hole 5 and a screw hole 7 in a uniaxial direction orthogonal to the joint axis C ₃ are provided in each of the insertion tube portions 6 at 180 ° rotationally symmetric positions around the joint axis C ₃ . .
As shown in FIG. 1, the pile end portion 2 is inserted into the insertion tube portion 6, and the through hole 5 and the screw are in a state in which the outermost edge portion 20 of the pile end portion 2 is in contact with the inner flange portion 10. The hole 7 is disposed so as to correspond to the same axial center as the through holes 4 and 4. That is, the length dimension L ₀ from the upper and lower end surfaces 10A, 10B of the inner flange portion 10 to the through hole 5 and the screw hole 7 is the length dimension from the outermost edge 20 of the pile end portion 2 to the through holes 4, 4. and L _1, are set to substantially the same. In addition, as shown to Fig.4 (a), in a pair of insertion cylinder parts 6 and 6, the through-holes 5 and 5 are formed as an opening shape in the same direction, The screw hole is on the opposite side 180 degrees. 7 and 7 are formed in an opening shape in the same direction.

As shown in FIG. 1, with the pile end 2 inserted into the insertion tube 6, the through hole 5, the through holes 4, 4 and the screw hole 7 are disposed on the same axis, A bolt 8 is inserted into the through hole 5, the through holes 4, 4, and the screw hole 7 in a skewered manner, and the male screw portion 8 </ b> A of the bolt 8 is screwed into the screw hole 7. 1 is connected.
The pile 1 has a plurality of low protrusions 12 on the inner peripheral surface 1B, and the inner diameter dimension is not stable. Therefore, for connection to the joint 3, an outer peripheral surface 1A of the pile 1 is used to connect the pile end 2 Is inserted into the insertion tube portion 6.

With the screwing of the bolt 8, the head 8B of the bolt 8 is applying a pressing force P ₀ on the outer peripheral surface 1A of the pile 1, and the head 8B is loaded into buried form the through hole 5.
The through hole 5 is a machined hole formed by a mechanical drilling means such as a drill, and is formed slightly larger than the head 8B of the bolt 8, and the diameter D ₀ of the through hole 5 is shown in FIG. but what is set to 101% to 105% of the diameter _{D 1} of the head portion 8B of the bolt 8 is desirable.
By burying the head 8 </ b> B of the bolt 8 in the through-hole 5, when tensile force or bending force is applied, bending deformation of the bolt 8 and bending deformation of the pile can be suppressed, and damage to the bolt 8 can be prevented. Moreover, the head 8B of the bolt 8 is embedded in the through-hole 5, and the male threaded portion 8A of the bolt 8 is screwed into the screw hole 7 without using a nut. Does not protrude from the outer peripheral surface 6A of the plug-in cylinder portion 6, and there is an advantage that it is possible to prevent a catch at the time of insertion. The head 8B of the bolt 8 has a hexagonal hole 16 formed in the center. Incidentally, the head 8B of the bolt 8, but the outer peripheral surface may be uneven corrugated or knurled, as smooth planar outer peripheral surface at the machining, the diameter D ₀ of the through hole 5 and the head 8B of when the bending force and tensile force to set small dimensional difference between the diameter D ₁ is applied, Gatatsukazu, strength preferably improved.

As shown in FIG. 1 (a) and FIG. 2 (a), the pile 1, by the pressing force P ₀ from the head 8B of the bolt 8, it is unevenly distributed in the screw hole 7 side of the insertion tube portion 6. By screwing the bolt 8 into the screw hole 7, the outer peripheral surface 1 </ b> A of the pile 1 is pressed against the press contact portions 17, 17 near the screw hole 7 of the inner peripheral surface 6 </ b> B of the plug-in cylinder portion 6 to tighten the pile 1. ing. In the illustrated example, the outer peripheral surface 1 </ b> A of the pile 1 is pressed against the inner peripheral surface 6 </ b> B of the plug-in cylinder portion 6 at the two press contact portions 17, 17, and the two press contact portions 17, 17 The outer peripheral surface 1 </ b> A and the inner peripheral surface 6 </ b> B of the plug-in cylinder portion 6 are in contact (pressure contact) in the linear region or the band-shaped surface region along the axial direction.
By causing the pile 1 to be unevenly distributed on the screw hole 7 side of the insertion tube portion 6, a crescent-shaped gap 11 is formed between the outer peripheral surface 1 </ b> A of the pile 1 and the inner periphery surface 6 </ b> B of the insertion tube portion 6. Has been.

As shown in FIGS. 2B and 8, the joint 3 has circular planar seating surfaces 14, 14 centered on the screw hole 7 on the outer peripheral surface 6 </ b> A and the inner peripheral surface 6 </ b> B of the plug-in cylinder portion 6. have.
The circular planar seat surfaces 14, 14 are provided on the outer surface of the round seat portion 18 projecting from the outer peripheral surface 6 A of the insertion tube portion 6 and the bottom surface of the counterbore portion 19 of the inner peripheral surface 6 B of the insertion tube portion 6. Are formed in parallel planes with each other. In order to maintain the perpendicularity between the screw hole 7 of the insertion tube portion 6 and the axial center of the through-hole 5, a circular seat portion 18 is provided on the outer peripheral surface 6 </ b> A of the insertion tube portion 6 so as to facilitate position indexing. ing. In addition, in order to make it easy to find the position of the screw hole 7 when the bolt 8 is mounted and to make initial biting easier, a guide portion without a male screw is provided at the tip of the bolt 8. Alternatively, it is also preferable that the tip of the bolt 8 be tapered in a conical shape.

The usage method (action) of the above-described pile connection structure of the present invention will be described.
As shown in FIG. 9 (a), the natural ground Z to be reinforced is excavated to open the hole 40, and then the piles 1 and 1 are sequentially connected by the joint 3 and inserted into the hole 40. At this time, since the connected piles 1 and 1 are inserted after the hole 40 is dug, the rotational force (torque) is less likely to act on the piles 1 and 1 and the joint 3, but to facilitate the work. The joint 3 may be prevented from being caught by being rotated in the middle of insertion or in the middle of insertion, and sufficient rotation resistance is provided. That is, the connection part (joint 3 and bolt 8) of the piles 1 and 1 is resistant to compressive load that can withstand the compressive force in the axial direction for supporting structures and the like, and its own weight (maximum The tensile load strength of about 100 kg is required, and further, it has a rotational strength capable of withstanding rotational torque. In addition, in the case of an application where rotation is applied, the diameter of the bolt 8 is increased as necessary.

  The procedure for connecting the pile 1 to the joint 3 will be described. As shown in FIG. 1, the pile end 2 of the pile 1 is inserted into the insertion tube portion 6 of the joint 3 (in the inner fitting shape), and the insertion tube portion is inserted. 6 is aligned so that the through holes 5 and screw holes 7 and the through holes 4 and 4 of the pile end 2 are arranged on the same axis, and then a bolt 8 is inserted from the through hole 5 Then, the bolt 8 is inserted into the through hole 5, the through holes 4, 4 and the screw hole 7 (as a skewered shape), and the bolt 8 is rotated using a hexagon wrench so that the male thread portion 8A of the bolt 8 is The connection between the joint 3 and the pile 1 is completed by screwing into the screw hole 7. The pile end portion 2 is also connected to the other insertion tube portion 6 of the joint 3. In this way, the two piles 1 and 1 can be connected with a uniform connection strength by the mechanical structure of the joint 3 and the bolt 8, and welding is unnecessary.

Next, as shown in FIGS. 9 (c) to 9 (d), liquid mortar M is injected into the internal cavity of the pile 1, and the mortar M is filled and solidified in the hole 40. The filled mortar M penetrates and solidifies the hole wall of the drilling hole 40 by the injection pressure, and reliably reinforces the natural mountain Z. Thus, by injecting the mortar M using the internal cavity of the pile 1, an injection hose, a casing, and the like become unnecessary, and the number of steps can be reduced compared with the conventional method, and the cost can be reduced.
The pile 1 has a large number of depressions 9 on the outer peripheral surface 1A, and the peripheral frictional force is increased, so that the adhesion force between the outer peripheral surface 1A of the pile 1 and the mortar M can be ensured.
As shown in FIG. 10, the injected mortar M enters and fills and solidifies into a crescent-shaped gap 11 between the outer peripheral surface 1 </ b> A of the pile 1 and the inner peripheral surface 6 </ b> B of the plug-in cylinder portion 6. . By filling the crescent-shaped gap 11 with the mortar M, there is an advantage that the strength (bending strength) of the piles 1, 1 and the joint 3 withstanding the bending force is improved.

As shown in FIG. 3, the bending strength is secured by pressing the outer peripheral surface 1 </ b> A of the pile 1 against the inner peripheral surface 6 </ b> B of the plug-in cylinder portion 6 by the pressing force P ₀ from the bolt 8. .
Further, the through-hole 5 formed by machining restricts the movement of the head 8B of the bolt 8 in the hole and prevents the bolt 8 from bending.
When the bolt 8 is inserted from the through hole 5 of the insertion tube portion 6 and the male screw portion 8A is screwed into the screw hole 7, the through holes 5, 5 provided in the pair of insertion tube portions 6, 6 are The bolt 8 can be inserted from the same direction, and work can be performed efficiently.

The design of the present invention can be changed. For example, the through holes 4 and 4 of the pile end 2 may be long holes. By providing a margin in the longitudinal direction with the through-hole 4 as a long hole, processing can be facilitated and cost can be reduced. Moreover, if the longitudinal direction position of the through-holes 4 and 4 of the pile end part 2 and the longitudinal direction position of the through-hole 5 and the screw hole 7 of the plug-in cylinder part 6 are maintained, it will change. The length L ₁ (see FIG. 1) from the outermost edge 20 of the pile end 2 to the through-holes 4 and 4 and the upper and lower end surfaces 10A and 10B of the inner flange 10 through the through-hole 5 and screw It is possible to improve the bending strength of the piles 1 and 1 by extending the length dimension L ₀ (see FIG. 2) up to the hole 7 by an arbitrary length.

As mentioned above, the connection structure of the pile which concerns on this invention is the connection structure of the pile which connects the pile edge parts 2 and 2 of the piles 1 and 1 which consist of steel pipes by the short cylindrical joint 3, The pile end 2 has through-holes 4, 4 orthogonal to the axial center, and the joint 3 has a pair of plug-in cylinders 6, 6 that are partitioned by an inner flange 10 at the axial center. In the state where the pile end portion 2 is inserted into the insertion tube portion 6, the through hole 5 and the screw hole 7 penetrate the insertion tube portion 6 on the same axis as the through holes 4 and 4. When the connection between the joint 3 and the pile 1 is completed, a bolt 8 is inserted into the through-hole 5, the through-holes 4, 4, and the screw hole 7, and a male screw portion 8 </ b> A of the bolt 8 is inserted. Is screwed into the screw hole 7, and the head 8 </ b> B of the bolt 8 applies a pressing force P ₀ to the outer peripheral surface 1 </ b> A of the pile 1, and the head 8 </ b> B is buried in the through hole 5. Charged Therefore, in civil engineering work, the mortar M can be injected into the drilling hole 40 using the internal cavity of the pile 1 and filled and solidified, so that no injection hose or casing is required. Man-hours can be reduced and costs can be reduced. The connection work of the piles 1 and 1 can be simplified, and the work time can be shortened. Since connection work can be performed manually, work efficiency can be improved. The pile end portions 2 and 2 can be connected by a mechanical structure with the joint 3 and the bolt 8, and the connection strength can be stably improved to high quality. The outer peripheral surface 1 </ b> A of the pile 1 can be pressed against the inner peripheral surface 6 </ b> B of the plug-in cylinder portion 6 and tightened, and the bending strength can be ensured. It is possible to prevent rattling when the connection is completed. It has a compressive strength and tensile strength comparable to those of conventional rebars, and can secure a connection strength having a bending strength against bending. Further, it is not necessary to weld the pile end portions 2 and 2, no fire for welding is brought into the site, there is no fear of fire, and connection work can be performed even in rainy weather.

  In addition, since the outer peripheral surface 1A of the pile 1 is provided with a large number of depressions 9, the peripheral frictional force of the pile 1 can be increased, and civil engineering work in which mortar M is injected and solidified is completed. In this state, the adhesive force between the pile 1 and the mortar M can be reliably ensured, and a strong reinforcing material in which the pile 1 and the mortar M are integrated can be formed.

Further, by the pressing force P ₀ from the head 8B of the bolt 8, the pile 1 is localized in the screw hole 7 side of the insertion tube part 6, the outer peripheral surface 1A and the difference of the pile 1 Since the crescent-shaped gap 11 is formed between the inner peripheral surface 6B of the insertion tube portion 6, the outer peripheral surface 1A of the pile 1 can be pressed against the inner periphery surface 6B of the insertion tube portion 6 and tightened. , Can prevent rattling in the connected state.

  Moreover, since it is the connection structure of the pile used for the civil engineering work with mortar injection | pouring, and the injected mortar M is filled in the said crescent-shaped said gap | interval 11 in the said civil engineering completion state, The connection strength of 1 and the joint 3 (particularly the strength against bending) can be improved.

Further, the through hole 5 is a machining hole is slightly larger than the head 8B of the bolt 8, the diameter D ₀ of the through hole 5, the diameter of the head 8B of the bolt 8 because it is set to 101% to 105% of D _1, and restrict the head 8B of the bolt 8 is moved in the through hole 5 can be prevented bending deformation of the bolts 8. Both ends of the bolt 8 are supported by the through-hole 5 and the screw hole 7 of the plug-in cylinder portion 6 to ensure connection strength (tensile load strength).

  Further, since the outer peripheral surface 6A and the inner peripheral surface 6B of the plug-in cylinder part 6 have circular flat seat surfaces 14 and 14 centering on the screw hole 7, the plug-in cylinder part 6 The right angle with the axial center of the screw hole 7 and the through hole 5 can be maintained, and the position can be easily indexed.

DESCRIPTION OF SYMBOLS 1 Pile 1A Outer peripheral surface 2 Pile end part 3 Joint 4 Through-hole 5 Through-hole 6 Insertion cylinder part 6A Outer peripheral surface 6B Inner peripheral surface 7 Screw hole 8 Bolt 8A Male thread part 8B Head 9 Recessed part 10 Inner collar part 11 Gap 13 Lined dimple group 14 Circular planar seating surface P ₀ pressing force M mortar D ₀ diameter of through hole D ₁ head diameter of bolt

Claims (4)

It is used for civil engineering work with mortar injection, and the pile end (2) (2) of the pile (1) (1) made of steel pipe is connected to the pile with a short tubular joint (3). There,
The pile end (2) has through-holes (4) and (4) orthogonal to the axis,
The joint (3) has a pair of plug cylinders (6) (6) partitioned by an inner flange part (10) at an axial center intermediate part, and the pile end part (2) is the plug. A through hole (5) and a screw hole (7) are inserted into the insertion tube portion (6) on the same axis as the through holes (4) and (4) while being inserted into the tube portion (6). Established,
In the connection completion state of the joint (3) and the pile (1), a bolt (8) is inserted into the through hole (5), the through hole (4), (4) and the screw hole (7). Then, the male screw portion (8A) of the bolt (8) is screwed into the screw hole (7), and the head (8B) of the bolt (8) is connected to the outer peripheral surface (1A) of the pile (1). ) Is applied with a pressing force (P ₀ ), and the head (8B) is inserted into the through hole (5) in an embedded manner, and the bolt (8) from the head (8B) is Due to the pressing force (P ₀ ), the pile (1) is unevenly distributed on the screw hole (7) side of the insertion tube portion (6), and the outer peripheral surface (1A) of the pile (1) and the insertion A crescent-shaped gap (11) in cross section is formed between the inner peripheral surface (6B) of the cylindrical portion (6),
A pile connection structure , wherein the injected mortar (M) is filled in the crescent-shaped gap (11) in a state where the civil engineering work is completed . A pile connection structure for connecting pile ends (2) and (2) of piles (1) and (1) made of steel pipes with a short tubular joint (3),
The pile end (2) has through-holes (4) and (4) orthogonal to the axis,
The joint (3) has a pair of plug cylinders (6) (6) partitioned by an inner flange part (10) at an axial center intermediate part, and the pile end part (2) is the plug. A through hole (5) and a screw hole (7) are inserted into the insertion tube portion (6) on the same axis as the through holes (4) and (4) while being inserted into the tube portion (6). Further, on the outer peripheral surface (6A) and inner peripheral surface (6B) of the plug-in cylinder portion (6), a circular planar seat surface (14) (14) centered on the screw hole (7). )
In the connection completion state of the joint (3) and the pile (1), a bolt (8) is inserted into the through hole (5), the through hole (4), (4) and the screw hole (7). Then, the male screw portion (8A) of the bolt (8) is screwed into the screw hole (7), and the head (8B) of the bolt (8) is connected to the outer peripheral surface (1A) of the pile (1). ) to impart a pressing force (P _0), and the connection structure of the pile, characterized in that the head (8B) is charged to buried shape to the through hole (5). The connection structure of the pile of Claim 1 or 2 with which many hollow parts (9) are recessedly provided in the outer peripheral surface (1A) of the said pile (1) . The through hole (5) is a machined hole and is formed slightly larger than the head (8B) of the bolt (8),
The through diameter of the hole (5) _{(D 0)} is the bolt (8) the head (8B) of the diameter _{(D 1)} of 101% to 105% claim 1, is set to 3 Connection structure of the described pile.

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