JP7153338B2 - Pile extraction device and extraction method - Google Patents

Description

TECHNICAL FIELD The present disclosure relates to a pile extraction device and a pulling method.

Various techniques related to a pile extraction device and a extraction method for extracting an existing pile are known (see Patent Literatures 1 and 2, for example).

JP-A-2002-256557 JP 2019-015023 A

However, with the conventional technology as described above, it is difficult to pull out the existing pile while rotating it.

Therefore, in one aspect, an object of the present invention is to make it possible to pull out an existing pile while rotating it.

One aspect provides the following solutions.

(1) The pile extraction device of the present invention includes a first member having a tubular shape having an inner diameter corresponding to the outer diameter of the existing pile, and a first member that can be inserted into the outer peripheral side of the first member and radially outward. a second member having a projecting portion; and a chain or string-like third member having one end coupled to the outer periphery of the first member and the other end coupled to the second member, wherein the protrusion is , projecting in a manner inclined with respect to the radial direction of the second member when viewed in the axial direction of the second member.

(2) In the configuration of (1) above, when the second member is rotated about its axis, the protrusion has a higher rotational resistance during clockwise rotation than during counterclockwise rotation. is formed so as to reduce the

(3) In the configuration of (1) or (2) above, the protrusion has an inclination angle with respect to the tangential direction at the root position that is larger than 90 degrees on the clockwise front side.

(4) In any one of the above (1) to (3), a plurality of protrusions are provided.

(5) In any one of the configurations (1) to (4) above, the first member is characterized in that the tip portion in the axial direction is formed in a tooth shape.

(6) The pulling method of the present invention is a pulling method using the pile pulling device according to any one of (1) to (5), and the outer peripheral side of the existing pile whose lower end is buried in the ground and the second member is passed through the outer peripheral side of the first member, the first member is advanced into the ground while rotating the first member clockwise, and the first member is advanced into the ground It is characterized by including returning the advanced first member from the ground while rotating it counterclockwise.

(7) In the construction method of (6) above, the existing pile has a fin at its tip.

In one aspect, according to the present invention, it is possible to pull out an existing pile while rotating it.

1 is a perspective view of a pile extracting device according to an embodiment of the present invention; FIG. It is a top view of a 2nd member. It is explanatory drawing which shows the process (1st process) which inserts a pile extraction apparatus in an existing pile. It is explanatory drawing which shows the process (2nd process) which is made to advance underground, rotating a pile extraction apparatus clockwise. It is explanatory drawing which shows the state (2nd process completion|finish state) which the pile extraction apparatus advanced to the predetermined position in the underground. It is explanatory drawing which shows the time of the start of the process (3rd process) which returns from the underground, rotating a pile extracting apparatus counterclockwise. It is explanatory drawing which shows the state which an existing pile is pulled out by the process (3rd process) returning from the underground, rotating a pile extraction apparatus counterclockwise. FIG. 11 is an explanatory view showing action of the second member during clockwise rotation; It is an explanatory view showing the action of the second member during counterclockwise rotation. It is explanatory drawing which shows the effect|action of the pile extraction apparatus at the time of clockwise rotation. It is explanatory drawing which shows the effect|action of a pile extraction apparatus at the time of counterclockwise rotation.

An embodiment of the present invention will be described in detail below with reference to the accompanying drawings.

[Existing pile]
As shown in FIGS. 3A to 3E, the extraction device 1 according to one embodiment of the present invention shown in FIG. allow it to be removed.

The existing pile 100 exemplified in this embodiment includes a steel pipe pile 110 and a fin 120 provided at the lower end of the steel pipe pile 110 . The fin 120 has a substantially square central portion 121 , four wing-like portions 122 extending outward from four sides of the central portion 121 , and projecting upward from the upper surface of the central portion 121 and connected to the lower ends of the steel pipe piles 110 . and a cylindrical downward protrusion 124 that protrudes downward from the lower surface of the central portion 121 and serves as the center of rotation of the fin 120 when the fin 120 is rotationally press-fitted into the ground.

The four wings 122 are alternately bent upward and downward circumferentially with respect to the central portion 121 and travel downward through the ground due to contact with the soil in response to the clockwise R1 rotation of the fins 120. While generating a propulsive force in the direction (implantation direction), the contact with the soil according to the rotation of the fin 120 in the counterclockwise direction R2 generates a propulsive force in the upward direction (extraction direction) in the ground.

When pulling out such an existing pile 100 from the ground, it is conceivable to connect the upper end of the existing pile 100 (steel pipe pile 110) to a rotary press-in device B and rotate it counterclockwise. , the steel pipe pile 110 may be deteriorated or corroded and the strength may be reduced. Therefore, if the steel pipe pile 110 is rotated by the rotary press-fitting device B, the steel pipe pile 110 may break and be difficult to pull out. In particular, when the steel pipe pile 110 has a small diameter, there is a possibility that the steel pipe pile 110 is twisted by the rotational force of the rotary press-fitting device B.

[Pile extraction device]
The pile pull-out device 1 of the present invention makes it possible to reliably pull out even the existing pile 100 as described above while rotating it. A first member 2 having a cylindrical shape having an inner diameter according to the second member 3 that can be inserted on the outer peripheral side of the first member 2, and a chain or A string-like third member 4 is provided.

(First member)
As shown in FIG. 1 , the first member 2 of the present embodiment is a metal pipe that can be inserted through the outer peripheral side of the steel pipe pile 110 of the existing pile 100 from above and has a length substantially equal to that of the steel pipe pile 110. Configured. As shown in FIG. 3B , the upper end of the first member 2 can be connected to the rotary press-fitting device B, and the rotational force transmitted from the rotary press-fitting device B and the downward pressing force are applied to the outer circumference of the steel pipe pile 110. You can go underground along the In addition, the first member 2 has a toothed portion 21 formed in a tooth shape on the peripheral edge portion of the axial tip portion, that is, the lower end portion. Accordingly, the first member 2 can smoothly enter the ground by scraping away the soil around the steel pipe pile 110 .

(Second member)
As shown in FIGS. 1 and 2, the second member 3 includes a cylindrical portion 31 that can be inserted into the outer circumference of the first member 2, and a plurality of projecting portions projecting radially outward from the outer circumference of the cylindrical portion 31. 32. The protruding portions 32 of this embodiment are formed by cutting and raising a part of the cylindrical portion 31 made of metal radially outward, thereby forming three protruding portions 32 at regular intervals in the circumferential direction.

The protruding portion 32 protrudes in a manner inclined with respect to the radial direction of the second member 3 when viewed in the axial direction of the second member 3 . When the second member 3 is rotated about its axis, the inclined direction of the projecting portion 32 has less resistance in the rotation direction in the ground when it rotates clockwise R1 than when it rotates counterclockwise R2. is set as Specifically, the protrusion 32 has an inclination angle θ with respect to the tangential direction at the root position that is larger than 90 degrees on the front side of the clockwise rotation R1. The actions of the second member 3 and the projecting portion 32 will be described later.

(Third member)
As shown in FIG. 1, the third member 4 of this embodiment is a metal chain, one end of which is coupled to the outer periphery of the first member 2 and the other end of which is coupled to the outer periphery of the second member 3. . The connecting portion 22 of the third member 4 on the outer periphery of the first member 2 is provided at a position separated upward from the lower end of the first member 2 by at least the height of the second member 3 . As a result, the pile extracting device 1 can enter the ground while the second member 3 is inserted through the outer periphery of the first member 2 . Moreover, it is preferable that the length of the third member 4 is such that it can be wound around the outer circumference of the steel pipe pile 110 of the existing pile 100 two or more times. Specifically, the third member 4 is constructed using a chain having a length about three times as long as the outer circumference of the first member 2 . The action of the third member 4 will be described later.

[Extraction method]
Next, the drawing method of the present invention will be described with reference to FIGS.

The extraction method of the present invention is a method of extracting the existing pile 100 using the above-described pile extraction device 1, and includes a first step, a second step and a third step.

(First step)
As shown in FIG. 3A, in the first step, the first member 2 is passed from above through the outer peripheral side of the steel pipe pile 110 of the existing pile 100 whose lower end is buried in the ground, and the lower end of the outer peripheral side of the first member 2 Pass the second member 3 through. Specifically, the first member 2 is inserted through the outer peripheral side of the steel pipe pile 110 of the existing pile 100 from above while the second member 3 is inserted through the lower end portion of the outer peripheral side of the first member 2 .

(Second step)
As shown in FIG. 3B, in the second step, the upper end portion of the first member 2 inserted into the outer peripheral side of the steel pipe pile 110 of the existing pile 100 is connected to the rotary press-fitting device B of the heavy equipment A, and the first member 2 is connected to the clock The first member 2 is advanced into the ground while being rotated around R1. At this time, the toothed portion 21 formed at the lower end portion of the first member 2 scrapes the soil around the steel pipe pile 110 according to the rotation of the first member 2, so that the first member 2 is buried in the ground. Entry is smooth.

In addition, the second member 3 coupled to the first member 2 via the third member 4 also rotates clockwise R1, and along with this rotation, the protrusion 32 in contact with the soil exerts a resistance R10 against the rotation. 4A and 4B), as described above, the resistance R10 during clockwise rotation R1 is smaller than the resistance R20 during counterclockwise rotation R2. Does not block entry into the ground.

Further, as shown in FIG. 5 , the third member 4 is in a tensioned state due to the resistance R10 generated by the second member 3 and maintains the posture of winding around the outer periphery of the first member 2 . The second step is continued until the lower end of the first member 2 reaches a predetermined depth, more specifically, reaches a position near the fin 120 of the existing pile 100, as shown in FIG. 3C. be done.

(Third step)
As shown in FIG. 3D, in the third step, the first member 2 that has entered the ground is returned from the ground to the ground while being rotated counterclockwise R2. At this time, the second member 3 coupled to the first member 2 via the third member 4 also rotates counterclockwise R2, and along with this rotation, the protrusion 32 in contact with the soil resists the rotation. R20 is generated (see FIGS. 4A and 4B), but as described above, the resistance R20 during counterclockwise rotation R2 is greater than the resistance R10 during clockwise rotation R1. 3 tries to stay in the ground, and the second member 3 comes off the outer circumference of the first member 2.

Also, as shown in FIG. 6, the third member 4 is in tension due to the large resistance R20 generated by the second member 3. The third member 4 winds around the outer circumference of the steel pipe pile 110 between the first member 2 and the second member 3 with a strong tightening force. As a result, the rotational force of the counterclockwise rotation R2 of the first member 2 is transmitted to the steel pipe pile 110 via the third member 4, so that the existing pile 100 rotates together with the first member 2 as shown in FIG. 3E. It is lifted upward while rotating clockwise R2 (installation depth changes from H1 to H2).

In addition, the existing pile 100 of this embodiment has a fin 120 at its lower end, and generates a propulsive force to move itself in the pull-out direction by rotating counterclockwise R2, so that the pile can be pulled out smoothly from the ground. can be done.

Although each embodiment has been described in detail above, it is not limited to a specific embodiment, and various modifications and changes are possible within the scope described in the claims. It is also possible to combine all or more of the constituent elements of the above-described embodiments.
For example, in the above-described embodiment, a steel pipe pile was exemplified as an existing pile to be pulled out, but the pile extraction device and the extraction method of the present invention can be used with a cement pile formed by solidifying cement or the like, or with other materials. It can also be applied to the drawing of formed piles.

In addition, the following additional remarks will be disclosed with respect to the above examples.

(Appendix 1)
a first member having a cylindrical shape having an inner diameter corresponding to the outer diameter of the existing pile;
a second member that can be inserted through the outer peripheral side of the first member and has a protruding portion that protrudes radially outward;
a chain or string-like third member having one end coupled to the outer periphery of the first member and the other end coupled to the second member;
The pile extracting device, wherein the protruding portion protrudes so as to be inclined with respect to the radial direction of the second member when viewed in the axial direction of the second member.

(Appendix 2)
Supplementary Note 1, wherein the protruding portion is formed so that when the second member is rotated about its axis, resistance in the clockwise direction is smaller than that in the counterclockwise direction. The pile extracting device according to .

(Appendix 3)
3. The pile extracting device according to appendix 1 or 2, wherein the protruding portion has an inclination angle with respect to the tangential direction at the base position that is greater than 90 degrees on the clockwise front side.

(Appendix 4)
The pile extracting device according to any one of Appendices 1 to 3, wherein a plurality of the protrusions are provided.

(Appendix 5)
5. The pile extracting device according to any one of Appendices 1 to 4, wherein the first member has a toothed tip in the axial direction.

(Appendix 6)
A pulling method using the pile pulling device according to any one of Appendices 1 to 5,
Passing the first member through the outer peripheral side of the existing pile whose lower end is buried in the ground, and passing the second member through the outer peripheral side of the first member,
advancing the first member into the ground while rotating the first member clockwise;
A pull-out method, including returning the first member, which has been advanced into the ground, from the ground while rotating counterclockwise.

(Appendix 7)
The extraction method according to appendix 6, wherein the existing pile has a fin at its tip.

1 Pile extraction device 2 First member 21 Toothed portion 22 Joint portion 3 Second member 31 Cylindrical portion 32 Protruding portion 4 Third member 100 Existing pile 110 Steel pipe pile 120 Fin 121 Central portion 122 Wing-shaped portion 123 Upper protruding portion 124 Downward Protruding portion A Heavy equipment B Rotational press-fitting device R1 Clockwise rotation R10 Resistance force (clockwise rotation)
R2 counterclockwise R20 resistance (when rotating counterclockwise)

Claims (7)

a first member having a cylindrical shape having an inner diameter corresponding to the outer diameter of the existing pile;
a second member that can be inserted through the outer peripheral side of the first member and has a protruding portion that protrudes radially outward;
a chain or string-like third member having one end coupled to the outer periphery of the first member and the other end coupled to the second member;
The pile extracting device, wherein the protruding portion protrudes so as to be inclined with respect to the radial direction of the second member when viewed in the axial direction of the second member. 3. The protrusion is formed so that when the second member is rotated about its axis, resistance in the clockwise direction is smaller than that in the counterclockwise direction. 2. The pile extraction device according to 1. The pile extracting device according to claim 1 or 2, wherein the protruding portion has an inclination angle with respect to the tangential direction at the root position of greater than 90 degrees on the clockwise front side. The pile extracting device according to any one of claims 1 to 3, wherein a plurality of said protrusions are provided. The pile extracting device according to any one of claims 1 to 4, wherein the first member has a toothed tip in the axial direction. A pulling method using the pile pulling device according to any one of claims 1 to 5,
Passing the first member through the outer peripheral side of the existing pile whose lower end is buried in the ground, and passing the second member through the outer peripheral side of the first member,
advancing the first member into the ground while rotating the first member clockwise;
A pull-out method, including returning the first member, which has been advanced into the ground, from the ground while rotating counterclockwise. The pulling method according to claim 6, wherein the existing pile has a fin at its tip.

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