JP7285676B2 - Rotating pile and construction method of rotating pile - Google Patents

Description

TECHNICAL FIELD The present invention relates to a rotating pile and a method for constructing a rotating pile.

Conventionally, there is known a technique of embedding a steel pipe pile in the ground by rotationally press-fitting the steel pipe pile into the ground.
For example, Patent Literature 1 discloses a technique related to a rotary pile in which a spiral excavation blade is welded and fixed to the outer peripheral portion of the tip of the steel pipe pile in the excavation direction.
Further, in Patent Document 2, a stirring rod is protruded around a steel pipe pile, and after the steel pipe pile is buried, when pouring a kneaded body such as concrete, the steel pipe pile is rotated and the kneaded body is stirred by the stirring rod. , a technique for improving the bearing strength of a hardened kneaded body is disclosed.

2006-177125 publication 2001-40660 publication

However, in the technique described in Patent Document 1, it is necessary to weld the excavation blade to the steel pipe pile in advance, and there is a problem that it is not possible to cope with the case where the ground strength to be constructed is different.
In addition, since the excavating blades are welded at the factory shipment stage, there is a problem of low transportation efficiency due to taking up space on the platform of the transport vehicle.
Furthermore, in the technique described in Patent Document 2, although the stirring rod can be inserted at the construction site, it can only function as a concrete stirring rod and does not function as a rotary pile excavation blade. There is a problem.

An object of the present invention is to provide a rotating pile and a rotating pile construction method that can change excavation capacity according to the strength of the ground to be constructed and improve transportation efficiency.

The rotary pile of the present invention comprises an excavation blade composed of a twisted flat steel having a twisted portion twisted around a longitudinal axis at least in part, and an insertion hole through which the excavation blade is inserted is formed at the tip in the excavation direction. a formed steel pipe body, wherein the torsion axis of the twisted portion extends in a direction perpendicular to the material axis of the steel pipe body.

According to the present invention, since the rotary pile can be formed simply by inserting the excavation blades into the steel pipe body, if a plurality of types of excavation blades are prepared in advance, the excavation blades can be changed according to the ground strength of the construction site. Rotating piles can be constructed.
In addition, when the rotary pile is transported, the steel pipe body and the excavating blade can be transported separately, so that the transport efficiency is improved without taking up space on the carrier of the transport vehicle.

In the present invention, the insertion holes are formed at positions facing each other centering on the material axis in a cross section perpendicular to the material axis of the steel pipe body, and the excavating blades are arranged point-symmetrically about the material axis. preferably.
According to this invention, the digging blades are arranged point-symmetrically about the material axis of the steel pipe body. Therefore, since the excavation force acting on the excavation blades protruding outward from the steel pipe body acts evenly, the ground can be stably excavated during construction of the rotary pile.

In the present invention, it is preferable that the excavation blade is provided with a retainer pin that penetrates the front and back surfaces of the excavation portion on the outside of the steel pipe body.
According to this invention, since the retaining pin prevents the excavation blade from falling off from the steel pipe body, the rotary pile can be manufactured without welding the excavation blade to the steel pipe body.

A rotating pile construction method of the present invention is a rotating pile construction method for constructing any of the rotating piles described above, comprising a step of inserting the excavation blade into the insertion hole and inserting the excavation blade into the steel pipe A step of fixing to the main body and a step of excavating the ground with the rotating pile to which the excavating blade is fixed are performed.
According to the present invention, the same actions and effects as those described above can be obtained.

In the present invention, a plurality of digging blades having different sizes are prepared, and a step of selecting the digging blade according to the strength of the ground to be excavated is performed before inserting and inserting the digging blades. preferable.
According to the present invention, since the excavating blade can be selected according to the strength of the ground to be excavated, it is possible to perform an appropriate excavation work according to the ground strength of the construction site. Rotating piles can be constructed.

BRIEF DESCRIPTION OF THE DRAWINGS The perspective view of the rotary pile which concerns on the 1st Embodiment of this invention. The plane sectional view of the rotary pile in the said embodiment. The side view of the rotary pile in the said embodiment. The side view of the rotary pile in the said embodiment. The plane sectional view of the rotary pile which concerns on the 2nd Embodiment of this invention. The side view of the rotary pile which concerns on the 3rd Embodiment of this invention. The plane sectional view of the rotary pile which concerns on the 4th Embodiment of this invention.

An embodiment of the present invention will be described below with reference to the drawings.
[1] First Embodiment FIGS. 1 to 4 show a rotating pile 1 according to a first embodiment of the present invention. 1 is a perspective view of the rotating pile 1, FIG. 2 is a plan sectional view of the rotating pile 1, and FIGS. 3 and 4 are side views of the rotating pile 1. FIG.
The rotary pile 1 is a pile that excavates the ground by rotary press-fitting, and is used as a foundation pile of a building structure or a ground reinforcing material that reinforces soft ground. A rotary pile 1 includes a steel pipe body 2 , a tip cap 3 and an excavation blade 4 .

The steel pipe main body 2 is composed of a square steel pipe having a rectangular cross section with a width of 50 mm to 150 mm and a thickness of 2.3 mm to 6 mm.
As shown in FIGS. 2 and 3, at the tip of the steel pipe body 2 in the drilling direction, insertion holes 21 are formed through the inside and outside of the steel pipe body 2 on the opposing surfaces of the square steel pipe. The insertion hole 21 is a slit-shaped rectangular hole that is inclined with respect to the material axis AV of the steel pipe body 2 . Each through-hole 21 is formed in opposite directions about the material axis AV, and two through-holes 21 are provided with excavating blades 4 penetrating through the steel pipe body 2 .
Moreover, the inclination direction of the insertion hole 21 becomes a direction which moves away from the material axis AV in the rotation direction as it goes to the tip of the rotary pile 1 in the excavation direction.

The tip cover 3 is a member that closes the opening at the tip of the steel pipe body 2 in the excavation direction, and includes a cover portion 31 and a bit 32 . The lid portion 31 is made of a rectangular steel plate that is larger than the end face of the steel pipe body 2, and is made of a general structural rolled steel plate such as SM490A or SS400 with a thickness of 4.5 mm to 12 mm. are joined by welding or the like.
The bit 32 is provided to guide the excavation direction of the rotary pile 1 to facilitate rotary press-fitting. The bit 32 is configured by combining triangular steel plates in a cross shape at the apexes of the triangle, and the base of the triangle is welded and joined to the lower surface of the lid portion 31 . The vertices of the cross-shaped triangles are located on the material axis AV of the steel pipe body 2 .

The excavating blade 4 constitutes a main body for excavating the ground by rotational press-fitting of the rotary pile 1 . The excavating blade 4 has a twisted portion 41 as shown in FIG.
The twisted portion 41 is formed by twisting a flat steel around a longitudinal axis, and can be formed by processing a flat steel with a thickness of 6 mm, for example. The twisted portion 41 is housed inside the steel pipe body 2 at its central portion.

In the twisted portion 41, the torsion axis AH extends in a direction orthogonal to the material axis AV of the steel pipe body 2, and the surface of the twisted portion 41 extending in the direction of the material axis AV coincides with the material axis AV in plan view. Therefore, the twisted portions 41 are arranged point-symmetrically about the material axis AV of the steel pipe body 2 . Since the twisted portions 41 of the excavating blade 4 protrude outward from the steel pipe body 2 have twisting directions opposite to each other, the inclination directions of the insertion holes 21 formed in the steel pipe body 2 are also opposite accordingly. becomes.

The end of the twisted portion 41 is positioned at an angle with respect to the material axis AV.
The size of the digging blade 4 can be arbitrarily set by adjusting the length of the end portion of the twisted portion 41 for the projection dimension L of the digging blade 4 protruding from the steel pipe body 2 . As a result, the portion of the excavation blade 4 that contributes to excavation can be arbitrarily set. In addition, by being embedded in the ground, it is possible to adjust the pull-out strength with respect to the ground.

As shown in FIG. 4, retaining pins 43 are provided on both sides of the protruding portion of the excavating blade 4 from the steel pipe body 2 . The retaining pin 43 is composed of a bolt and a nut. Although not shown, the bolt is inserted through a hole penetrating the front and rear surfaces of the excavating blade 4, and the nut is screwed onto the screw shaft that penetrates. The head diameter dimension of the bolt and nut is larger than the width dimension of the slit-like insertion hole 21 formed in the steel pipe body 2 .
As a result, the excavation blade 4 is restricted from moving in the torsion axis AH direction with respect to the steel pipe body 2 , and the excavation blade 4 does not come off the steel pipe body 2 while the rotary pile 1 is being rotationally press-fitted.

Next, the construction method of the rotating pile 1 mentioned above is demonstrated.
First, a plurality of types of excavating blades 4 having different projecting lengths L from the steel pipe body 2 are prepared in advance. The projection dimension L can be easily changed by adjusting the dimension of the twisted portion 41 .
The ground strength at the construction site of the rotary pile 1 is measured, and the design pull-out strength and excavation capacity required for the excavation blade 4 are calculated.

An appropriate digging blade 4 is selected from a plurality of types of digging blades 4 based on the calculated pulling strength and digging ability. The excavation blade 4 is inserted through the insertion hole 21 while rotating the selected excavation blade 4 around the torsion axis AH in accordance with the twist of the twisted portion 41 .
After the excavation blade 4 is inserted through the steel pipe body 2, the retaining pin 43 is attached to the excavation blade 4 to fix the excavation blade 4.例文帳に追加
After the rotating pile 1 is attached to the auger motor of the pile driving machine and the rotating pile 1 is set at the pile driving position, the ground is excavated by rotating and press-fitting the rotating pile 1 using a press-fitting machine.
When the rotary pile 1 is buried to the desired ground, the auger motor of the pile driver is removed to complete the construction.

According to this embodiment, the following effects are obtained.
Since the rotary pile 1 can be formed simply by inserting the excavation blade 4 into the steel pipe body 2, if a plurality of types of excavation blades 4 are prepared in advance, the excavation blade 4 can be changed according to the ground strength of the construction site and rotated. Construction of the pile 1 can be performed.
In addition, since the steel pipe body 2 and the excavating blade 4 can be separately conveyed when the rotary pile 1 is conveyed, the transportation efficiency is improved without taking up space on the carrier of the carrier.

The excavating blades 4 are arranged point-symmetrically about the material axis AV of the steel pipe body 2 . Therefore, since the excavation force acting on the excavation blades 4 protruding outward from the steel pipe body 2 acts evenly, the ground can be stably excavated when the rotary pile 1 is constructed.
By providing the retaining pin 43 , it is possible to prevent the excavating blade 4 from falling off from the steel pipe body 2 . Therefore, since the rotary pile 1 can be manufactured without welding the excavation blade 4 to the steel pipe main body 2, the rotary pile 1 can be manufactured at the construction site.

[2] Second Embodiment Next, a second embodiment of the present invention will be described. In the following description, the same reference numerals are given to the same parts as those already described, and the description thereof will be omitted.
In the above-described first embodiment, the excavating blade 4 is composed of one piece of twisted flat steel penetrating through the steel pipe body 2 .
On the other hand, in the rotating pile 5 according to the present embodiment, as shown in FIG. The difference is that the original digging blade 5A is used.

The rotary pile 5 includes a steel pipe body 2 and an excavating blade 5A, and an insertion hole 21A of the steel pipe body 2 is a vertical slit hole along the material axis AV of the steel pipe body 2. The excavation blade 5</b>A includes a twisted portion 51 formed in a portion projecting from the steel pipe body 2 and a flat steel portion 52 inserted inside the steel pipe body 2 .
A second retaining pin 53 is provided on the flat steel portion 52, and together with the retaining pin 43 provided on the twisted portion 51, prevents the excavating blade 5A from falling out of the insertion hole 21A of the steel pipe body 2. ing.
This embodiment can also enjoy the same functions and effects as those of the first embodiment.

[3] Third Embodiment Next, a third embodiment of the present invention will be described.
In the first embodiment described above, the steel pipe body 2 of the rotary pile 1 is provided with only one excavating blade 4 .
On the other hand, in the present embodiment, as shown in FIG. 6, the steel pipe body 2 of the rotary pile 6 is provided with two stages of excavation blades 4 in the material axis AV direction.

The dimension of the excavation blade 4 protruding outside the steel pipe body 2 may be the same for the upper and lower stages, or may be different. For example, the projecting dimension on the lower stage side may be set small and the projecting dimension on the upper stage side may be increased so that the excavating force of the excavating blade 4 gradually increases when the rotary pile 6 is rotationally press-fitted.

According to this embodiment, it is possible to obtain the same functions and effects as those of the first embodiment.
In addition, by reducing the projecting dimension of the excavating blade 4 on the lower side and increasing the projecting dimension on the upper stage, the excavation ability of the excavating blade 4 can be improved in stages, so that the rotation press-fitting process by the rotary pile 6 Efficiency can be improved.

[4] Fourth Embodiment Next, a fourth embodiment of the present invention will be described.
In the first embodiment described above, the surface of the excavating blade 4 of the rotary pile 1 extending along the material axis AV of the twisted portion 41 coincides with the material axis AV of the steel pipe body 2 in plan view (Fig. 2).
On the other hand, in the present embodiment, as shown in FIG. 7, the plane orthogonal to the material axis AV of the twisted portion 41 of the excavation blade 4 of the rotary pile 7 coincides with the material axis AV in plan view. There are differences.

The rotary pile 7 of the present embodiment protrudes from the steel pipe body 2 depending on the position at which the excavating blade 4 is stopped when it is inserted into the insertion hole 21 of the steel pipe body 2 while being rotated around the torsion axis AH. The twisted portion 41 that contributes to excavation can be changed.
Therefore, since the excavation capability of the rotary pile 7 and the ground support strength can be changed only by changing the insertion position of the excavation blade 4, the convenience of handling at the construction site can be achieved.

[5] Modifications of the Embodiments The embodiments of the present invention are not limited to the above-described embodiments, and include the following modifications.
Although a rectangular steel pipe was used as the steel pipe main body 2 in each of the above-described embodiments, the present invention is not limited to this. For example, the present invention may be applied to circular steel pipes and polygonal steel pipes.

In the first embodiment described above, the retaining pin 43 prevents the excavating blade 4 from falling off from the steel pipe body 2, but the present invention is not limited to this. For example, the connecting portion between the steel pipe body 2 and the excavating blade 4 may be retained by spot welding or the like.
In the above-described first embodiment, the bit 32 is provided on the tip end cap 3 of the steel pipe body 2, but the cap portion 31 alone may constitute the tip end cap.
In addition, the specific structure, shape, and the like in carrying out the present invention may be other structures and the like as long as the object of the present invention can be achieved.

DESCRIPTION OF SYMBOLS 1... Rotating pile 2... Steel pipe body 3... Tip lid 4... Excavating blade 5... Rotary pile 5A... Excavating blade 6... Rotary pile 7... Rotary pile 21... Insertion hole 21A... Insertion hole, 31 Lid portion 32 Bit 41 Twisted portion 43 Retaining pin 51 Twisted portion 52 Flat steel portion 53 Stopping pin AH Twisted shaft AV Material shaft L Projection dimension .

Claims (5)

a digging wing composed of a twisted flat steel having at least a portion thereof twisted about a longitudinal axis;
A steel pipe body having an insertion hole through which the excavation blade is inserted is formed at the tip in the excavation direction,
the torsion axis of the torsion portion extends in a direction orthogonal to the material axis of the steel pipe body ,
The excavation blade is a rotary pile composed of one of the twisted flat steels penetrating the steel pipe body . In the rotating pile according to claim 1,
The through holes are formed at positions facing each other centering on the material axis in a cross section perpendicular to the material axis of the steel pipe body,
The excavation blades are rotary piles arranged point-symmetrically about the material axis. In the rotating pile according to claim 1 or claim 2,
The rotating pile, wherein the excavating blade is provided with a retainer pin that penetrates the front and back surfaces of the excavating blade outside the steel pipe body. A rotating pile construction method for constructing the rotating pile according to any one of claims 1 to 3,
a step of inserting and inserting the excavating blade into the insertion hole;
a step of fixing the excavation blade to the steel pipe body;
a step of excavating the ground with a rotary pile to which the excavation blade is fixed;
Construction method of rotating pile to carry out. In the rotary pile construction method according to claim 4,
A plurality of digging blades of different sizes are prepared for the digging blades,
A rotary pile construction method, comprising selecting an excavation blade according to the strength of the ground to be excavated before inserting and inserting the excavation blade.

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