JP3306726B2 - Embedding method of thin steel pipe pile and thin steel pipe pile used for it - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of burying a thin steel pipe pile with wings, which is constructed on soft ground, and a thin steel pipe pile with wings used for the method.

[0002]

2. Description of the Related Art In a city developed in an alluvial plain, a support layer is deep, and construction on a narrow site is required. When constructing a middle-rise building in such a place, the foundation pile used for this requires a longer support pile that reaches a reliable support layer than the friction pile supported by the upper layer,
It is necessary that the construction be performed on a large scale without any earth removal, no vibration and no noise.

[0003] As a basic work in such a case, conventionally,
For example, as described in Japanese Patent Publication No. 2-62848, a steel pipe pile provided with spiral blades is buried. This steel pipe pile is buried with no excavated soil using the rotation propulsion action of the spiral wing, pressing and rotating the steel pipe pile with the drilling blade and spiral wing at the bottom to screw directly into the ground. It is a feature that usually, a hook piece is projected from the head end of the steel pipe pile, a rotating cap attached to the rotating power mechanism is engaged with the hook piece, and the steel pipe pile is rotated. I have.

[0004]

Generally, the tip supporting force of the supporting pile is set to a value which is smaller of the ground strength and the minimum sectional area strength of the pile relative to the projected area of the tip of the pile. The thickness is selected so that the pile strength is slightly higher than the pile tip ground strength. However, in this type of non-discharged steel pipe pile, at the above thickness, the pile head where the torsion force is concentrated deforms and breaks down, so
This required more than 1.5 times the wall thickness, and the cost and construction costs of steel pipe piles were wastefully increased.

[0005] In view of the above, the present invention adds a reinforcing means capable of preventing deformation and destruction to the pile head, so that an economically thin winged steel pipe pile required as a pile supporting force is screwed by rotation. It seeks to provide new construction methods and steel pipe piles that can be reached.

[0006]

The construction of the present invention for achieving the above object will be described with reference to the drawings corresponding to the embodiments. A bottom plate 2 and excavating blades 3 and 3 are provided at the lower end of the pile body 1, and a spiral wing 4 having an outer diameter of about twice the outer diameter of the pile body 1 is provided on the outer periphery of the lower part so as to protrude over substantially one turn. A top plate 10 having substantially the same diameter as the outer diameter of the pile body 1 is provided in the head end of a steel pipe pile A having a plurality of hook pieces 5, 5 protruding from the outer periphery of the head.
A reinforcing body C formed by hanging a thick-walled pipe 11 inserted into the head of the pile body 1 is inserted into the lower surface of the pile body 1, and the above-mentioned hook piece 5 is inserted into a cylindrical portion 6 that can be fitted outside the pile body 1. , 5 is fitted with a rotating cap B provided with locking grooves 9, 9 which are detachably engaged with each other, and the steel pipe pile A is pressed by the rotating cap B so as to be screwed into the ground.
It is characterized by being embedded by the rotational propulsion of the spiral blade 4.

Further, the thin steel pipe pile according to the second aspect of the present invention is a
The bottom plate 2 and the excavating blades 3 and 3 are provided at the lower end of the
A spiral wing 4 having an outer diameter of about twice the outer diameter of the pile main body 1 is protruded over substantially one turn, and a plurality of locking pieces 5, 5 are protruded on the outer periphery of the head of the pile main body 1, and A circular or annular reinforcing plate 12 is fixed to the inside of the position where the hook pieces 5, 5 of the head of the pile main body protrude.

[0008]

The present invention is constructed as described above. As shown in FIG. 6, a reinforcing body B is inserted into the head of a steel pipe pile A, a rotary cap C is put on the steel pipe pile A, and If the locking grooves 9 are engaged and pressed while rotating the rotating cap C, the steel pipe pile A excavates and softens the ground at the tip of the pile by the excavating blades 3 and 3 and bites the spiral blade 4 into the ground. The excavated softened soil is extruded to the side of the pile by the propulsive force of the rotation, and the soil is settled while compacting the ground and buried.

As the burial depth of the steel pipe pile A increases, the resistance increases, and accordingly, the head of the steel pipe pile A receives a large torsional moment, and tends to flatten due to the concentrated load acting on the hooks 3. However, the deformation is prevented by the presence of the reinforcing member C or the thick reinforcing plate.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. 1 and 2 show a steel pipe pile A used in the present invention. A pile body 1 formed of a thin steel pipe is provided with a bottom plate 2 and excavating blades 3 at the tip thereof. On the outer periphery of the lower part of the pile main body 1, a wide spiral wing 4 having an outer diameter of about twice the outer diameter of the pile main body 1 is provided so as to extend over substantially one turn. On the outer peripheral surface of the head of the pile main body 1, a plurality of hook pieces 5, 5 for rotating the steel pipe pile A are provided at positions facing each other.

A rotating cap B is fitted on the head of the steel pipe pile A. As shown in FIGS. 3 and 4, a cylindrical cap with a top plate 7 having an inner diameter slightly larger than the outer diameter of the pile main body 1 is shown. An auger joint 8 connected to the body 6 with a pile rotating power device (not shown)
The tubular body 6 is provided with inverted L-shaped locking grooves 9, 9 which are detachable from the hook pieces 5, 5 of the steel pipe pile A. C is a reinforcing member inserted into the head of the steel pipe pile A. As shown in FIGS. 3 and 4, the lower surface of the disk 10 having substantially the same diameter as the outer diameter of the pile main body 1 is mounted on the lower surface of the pile main body 1. It is formed by suspending a thick-walled tube 11 inserted into the head.

To rotate and bury the steel pipe pile A, a thick pipe 11 of a reinforcing body B is fitted into the head end of the pile body 1 and then a rotating cap C connected to a rotary power unit is mounted on the pile body 1. 4 and 5, the engaging grooves 9, 9 are engaged with the retaining pieces 5, 5, and the steel pipe pile A and the rotating cap B are connected. Then, the rotary power unit is operated to turn the rotary cap B
Is rotated, the steel pipe pile A is rotated via the hook pieces 5,5. At this time, the steel pipe pile A is attached to the rotating cap B
Is pressed simultaneously with the rotation. As a result, as shown in FIG. 6, the ground at the tip of the pile is excavated and softened by the excavating blades 3 and 3, and the spiral wings 4 bite into the excavated soil at the side of the pile, as shown in FIG. Due to the rotational propulsion of the spiral wing 4, the steel pipe pile A sinks. At that time, the earth and sand excavated and softened by the excavation blades 3 and 3 is pushed out to the side of the pile as the pile is settled, and is compacted, so that the ground strength around the pile is increased.

When the steel pipe pile A is buried in rotation, concentrated stress due to torsion deformation is generated at the pile head that applies the rotational force, but the torsion deformation is avoided by the reinforcing member C. In addition, since the steel pipe pile A is generally a fixed length object for transportation and the like, the pile body 1 is appropriately added according to the depth of the burial, but in this case, the pile main body 1 is hooked to the head of the added upper pile. Pieces 5 and 5 are provided.

FIG. 7 shows another embodiment of the steel pipe pile A used in the present invention. Like the steel pipe pile, a bottom plate 2 and excavating blades 3, 3 are provided at the lower end of the pile main body 1. A spiral wing 4 is provided at the lower part of the wing. A circular reinforcing plate 12, such as a circular plate, a perforated circular plate, or an annular plate, is fixed to the inside of the position where the hook pieces 5, 5 of the head of the pile body are protruded by welding. . In the case of this steel pipe pile, as shown in FIG. 8, without using the above-mentioned reinforcing body C, the rotating cap B is directly put on the head of the pile main body 1 and the hook pieces 5, 5 and the locking grooves 9, 9 will be engaged.

[0015]

As described above, according to the method of the present invention, when the steel pipe pile is rotated and buried, the thick pipe of the reinforcing member is fitted into the head of the steel pipe pile which receives concentrated rotational force. For,
Deformation that tends to flatten due to torsion caused by the rotational force is prevented. Therefore, the thickness of the steel pipe pile can be reduced to a thickness corresponding to the pile supporting force, and the cost of the steel pipe pile and the construction cost can be reduced.

Further, since the steel pipe pile of the present invention has a structure in which a reinforcing plate is fixed to the head end thereof, similarly to the above, deformation which tends to be flattened due to twisting due to rotational force is prevented, and the steel pipe pile is prevented. The thickness of the pile can be made thin, and the construction can be performed efficiently without the need for the trouble of attaching and detaching the reinforcing body every time the pile is buried.

The steel pipe pile is settled and buried by merely pushing and rotating the spiral blade into the ground, and the ground at the tip of the pile is excavated and softened. It is extruded to the side of the pile to consolidate the surrounding ground, thereby strengthening the ground. In addition, since the steel pipe pile is provided with a large-diameter spiral blade, a large supporting force according to the projected area can be obtained.

[Brief description of the drawings]

FIG. 1 is a side view showing one embodiment of a steel pipe pile used in the present invention.

FIG. 2 is a plan view of the same.

FIG. 3 is a perspective view showing a steel pipe pile, a rotating cap, and a reinforcing body separately.

FIG. 4 is a partial longitudinal sectional view showing a state at the time of rotary embedding.

FIG. 5 is a perspective view of the same.

FIG. 6 is an overall view of the same.

FIG. 7 is a partially cutaway side view showing another embodiment of the steel pipe pile.

FIG. 8 is a partial longitudinal sectional view showing a state of the steel pipe pile at the time of rotary embedding.

[Explanation of symbols]

 A Steel pipe pile B Rotating cap C Reinforcement body 1 Pile body 2 Bottom plate 3 Drilling blade 4 Spiral wing 5 Hanging piece 6 Cylindrical body 9 Lock groove 10 Top plate 11 Thick pipe 12 Reinforcement plate

Claims (2)

(57) [Claims] A bottom plate and a digging blade are provided at a lower end of a pile main body, and a spiral wing having an outer diameter of about twice the outer diameter of the pile main body is protrudingly provided over substantially one turn on an outer periphery of the lower part thereof. A thickness that is inserted into the head of the pile main body on the lower surface of the top plate, which is approximately the same diameter as the outer diameter of the pile main body, within the head end of a steel pipe pile formed by projecting a plurality of hanging pieces around the outer periphery of the head A reinforcing body formed by vertically extending a meat pipe is fitted and fitted, and a rotating cap provided with a locking groove for removably engaging with the locking piece is fitted to a cylindrical portion which can be fitted to the pile body,
A method of burying a thin-walled steel pipe pile, characterized in that the steel pipe pile is pressed by a rotating cap so as to be screwed into the ground, and is buried by the rotational propulsion of a spiral blade. 2. A bottom plate and a digging blade are provided at a lower end of the pile main body, and a spiral wing having an outer diameter of about twice the outer diameter of the pile main body is provided on the outer periphery of the lower portion so as to protrude over substantially one turn. A plurality of retaining pieces are protruded around the outer periphery of the head, and a circular or annular reinforcing plate is fixed inside the position where the retaining pieces 5, 5 of the pile main body are protruded. A thin steel pipe pile.