JP2020193534A - Removal method of steel pipe pile - Google Patents

Abstract

To provide a removal method of a steel pipe pile capable of easily removing a small diameter steel pipe pile buried in a ground without causing decrease in ground strength due to generation of a gap and collapse of a porous wall.SOLUTION: A removal method of a steel pipe pile comprises: a water supply step of inserting a liquid supply pipe from a head portion of the steel pipe pile into a pipe, and making the liquid supply pipe reach a tip of the steel pipe pile while injecting water from the liquid supply pipe and removing sediment in the pipe; a filling step of using a filler to fill the inside of the pipe of the steel pipe pile from the liquid supply pipe disposed at the tip of the steel pipe pile; and a pulling-out step of holding the head portion of the steel pipe pile using a holding device connected to a pulling-out machine, and pulling out the steel pipe pile while adding rotation around an axis to the steel pipe pile using the pulling-out machine.SELECTED DRAWING: Figure 1

Description

The present invention relates to a method for removing a steel pipe pile, and the steel pipe pile can be easily removed without causing a decrease in ground strength due to the generation of voids or the collapse of a hole wall, particularly when pulling out a small diameter steel pipe pile buried in the ground. Regarding the removal method of.

As a method of reinforcing the residential ground, a method of placing steel pipe piles in the foundation ground and a method of mixing and stirring a cement-based solidifying material with the ground to construct a columnar body are adopted.
A method called the RES-P method (registered trademark) is known in which a small-diameter steel pipe (single pipe) having a diameter of 48.6 mm is penetrated into the foundation ground to reinforce it. This is a construction method that prevents the ground from subsidence by the combined action of the peripheral friction force of the small diameter steel pipe, the tip bearing capacity, and the bearing capacity of the ground by densely driving the small diameter steel pipe into the ground (patented). Documents 1 and 2).
By the way, when buying and selling land with ground reinforcement in this way, the land owner, who is the seller, is obliged to remove underground obstacles such as small-diameter steel pipes and columns placed in the ground. There are many. These underground obstacles need to be removed without fail to prevent future problems.

The following methods can be considered as a method for removing the small-diameter steel pipe placed in the ground.
[1] Covering and digging the sheath pipe A sheath pipe having an inner diameter larger than the outer diameter of the small-diameter steel pipe is put on the head of the small-diameter steel pipe, and while water or air is sent from the sheath pipe, it is rotationally press-fitted to the outside of the small-diameter steel pipe. The sheath pipe is press-fitted to about 10 to 20 cm below the tip of the small-diameter steel pipe. This is to prevent the small-diameter steel pipe from falling from the sheath pipe when it is pulled up by covering the tip of the sheath pipe with earth and sand by covering it with a sheath pipe below the tip of the small-diameter steel pipe. Pull out the sheath pipe with the small diameter steel pipe taken inside. Sand or the like is thrown from the ground into the trace hole after pulling out.
[2] Pulling out by rotary press-fitting device The head of the small-diameter steel pipe exposed from the ground is grasped by the gripping device, and the small-diameter steel pipe is pulled out while giving rotation around the axis by the rotary press-fitting device. Sand or the like is thrown from the ground into the trace hole after pulling out.
[3] Pulling out with a crane A fixing bracket is attached to the head of a small-diameter steel pipe exposed from the ground, and the fixing bracket is slung on a wire and lifted by a lifting machine such as a crane to pull it out. Sand or the like is thrown from the ground into the trace hole after pulling out.

Japanese Unexamined Patent Publication No. 9-13359 Japanese Unexamined Patent Publication No. 10-237854

The prior art has the following problems.
<1> In the method of covering the sheath pipe, the wall thickness of the small diameter steel pipe is as thin as about 2 mm, so that the tip of the sheath pipe comes into contact with the outer circumference of the small diameter steel pipe during press fitting, so that the small diameter steel pipe is cut. There is a risk. When a small-diameter steel pipe is cut and the tip remains in the ground, it is very difficult to dig it up and remove it, which requires a great deal of labor and cost.
<2> In order to prevent contact between the sheath pipe and the small diameter steel pipe, it is necessary to secure a sufficient clearance between the inner surface of the sheath pipe and the outer surface of the small diameter steel pipe. Therefore, considering the bending of the hole at the time of placing the small diameter steel pipe and the deviation of the axial center from the drilling machine, it is necessary to increase the inner diameter of the sheath pipe as the small diameter steel pipe becomes longer. As a result, a large rotary press-fitting device is required, which increases the construction cost. In addition, if the equipment becomes large, it cannot be installed in a narrow residential site.
<3> Since the drawing with a crane is a method of linearly pulling out a small-diameter steel pipe restrained in the ground, a large lifting gravity exceeding the peripheral frictional force of the long small-diameter steel pipe is required. Therefore, sufficient care must be taken when cutting the wire with a kink or the like.
<4> Since the slenderness ratio of the small-diameter steel pipe is large, the trace hole after drawing is narrow and long. When sand or the like is thrown into such a trace hole from the ground, clogging occurs on the way due to friction with the hole wall, or the hole is often blocked due to the collapse of the hole wall, and there is no gap over the entire length of the trace hole. Difficult to fill. Therefore, voids are likely to occur in the ground. In addition, the collapse of the hole wall may cause loosening of the surrounding ground. In this way, the formation or collapse of voids may significantly reduce the ground strength.
<5> Since the inside of the drawn small diameter steel pipe is clogged with earth and sand, it cannot be disposed of as it is, and it takes time and cost to dispose of it.

An object of the present invention is to provide a method for removing a steel pipe pile that can solve the above-mentioned problems of the prior art.

The method for removing a steel pipe pile of the present invention is characterized by including a water supply step, a filling step, and a drawing step.
According to this configuration, the steel pipe pile can be easily removed without causing a decrease in ground strength due to pulling out.

In the method for removing steel pipe piles of the present invention, the filler may be a fluid mixture whose strength can be adjusted by blending, for example, a cement-bentonite-based self-hardening mixture.
According to this configuration, it is possible to fill the trace holes without gaps and prevent the generation of voids and the collapse of the hole wall.

In the method for removing a steel pipe pile of the present invention, the gripping device includes a cone, two wedges, a cap, and an elastic body, the accommodating groove has an inclined surface, and the wedge has an engaging surface and a sliding surface. May have.
According to this configuration, the pulling force can be converted into a force for gripping the steel pipe pile and the steel pipe pile can be gripped autonomously simply by covering the head of the steel pipe pile with the gripping device.

In the method for removing the steel pipe pile of the present invention, both side surfaces of the wedge may be inclined toward the engaging surface, and both side surfaces of the accommodating groove may be inclined toward the insertion hole.
According to this configuration, it is possible to prevent the wedge from falling toward the insertion hole side and falling from the cone.

In the method for removing the steel pipe pile of the present invention, the wedge may have an introduction surface.
According to this configuration, the head of the steel pipe pile can be introduced between the wedges simply by lowering the gripping device, so that the steel pipe pile can be gripped without any manual work.

In the method for removing the steel pipe pile of the present invention, the cone may have a pin groove.
According to this structure, even a steel pipe pile having a pin connected to the head can be gripped by passing the cone together with the pin.

From the above configuration, the method for removing the steel pipe pile of the present invention has at least one of the following effects.
<1> By using the existing steel pipe pile as a casing, filling the pipe with a filler, and then pulling it out, even if it is a trace hole of a small diameter steel pipe with a large slenderness ratio, a gap can be prevented while preventing the hole wall from collapsing. Can be filled without. Therefore, the steel pipe pile can be removed without causing a decrease in ground strength.
<2> By applying a rotational force to the steel pipe pile, cutting the edge of the steel pipe pile from the ground, and then pulling it out, the steel pipe pile can be pulled out with a relatively small force even in a tightly tightened ground. Therefore, since it can be pulled out with a small device, it can be installed even in a narrow residential site.
<3> Since no sheath pipe is used, there is no risk of cutting steel pipe piles.
<4> Since the pipe is pulled out with the earth and sand removed, it is easy to dispose of the steel pipe pile after the pulling out.

The flow chart of the method of removing a steel pipe pile of this invention. Explanatory drawing (1) of the method of removing a steel pipe pile of this invention. Explanatory drawing (2) of the method of removing a steel pipe pile of this invention. The explanatory view of the gripping device which concerns on the method of removing the steel pipe pile of this invention. Explanatory drawing of a cap and a cone. Explanatory drawing of the wedge. Explanatory drawing of the gripping function.

Hereinafter, the method for removing the steel pipe pile of the present invention will be described in detail with reference to the drawings.
In addition, each direction such as "up", "down", "vertical", "horizontal" in this specification means each direction at the time of carrying out of this invention, that is, each direction in FIGS.

[How to remove steel pipe piles]
<1> Overall configuration (Fig. 1).
The method for removing the steel pipe pile of the present invention is a method for pulling out and removing the steel pipe pile that has penetrated into the ground.
The method for removing the steel pipe pile of the present invention is at least a water supply step of removing the earth and sand in the pipe of the steel pipe pile P, a filling step of filling the pipe with the filler S, and a pulling step of pulling out the steel pipe pile P by the gripping device 1. And. In this example, a pile cueing process is further provided before the water supply process, and a replenishment process is provided after the drawing process.

<1.1> Applicable ground.
The ground to which the method for removing steel pipe piles of the present invention is applied will be described.
The ground according to the present invention is mainly the foundation ground of a house, and is the ground on which a steel pipe pile P is placed for the purpose of ground reinforcement at the time of new construction of a house (Fig. 2 [1]). The steel pipe piles P are arranged in a grid pattern from the ground surface to the support layer in the ground.
The steel pipe pile P is a hollow small-diameter steel pipe used as a pile body. In this example, as the steel pipe pile P, a single pipe made of carbon steel for general structure having an outer diameter of φ48.6 mm, a wall thickness of 2.4 mm, and a length of 2 m will be described as an example.
In such a small diameter steel pipe with a small inner diameter, it is structurally difficult to use a special jig that obtains a pulling force by contact with the inner wall of the steel pipe, and damage is likely to occur. A method using a means for gripping from is adopted.
The above configuration is only an example, and for example, ground reinforcement may be used for civil engineering work or other purposes.

<2> Pile cueing process.
The circumference of the steel pipe pile P buried up to the head in the ground is dug down by a heavy machine M such as a backhoe to expose the pile head by about 20 cm from the ground (Fig. 2 [2]).
If the head of the steel pipe pile P is covered with a pile head cap, remove it.

<3> Water supply process.
The inside of the steel pipe pile P is clogged with earth and sand. Therefore, the liquid feeding pipe T is used to remove the earth and sand in the pipe.
The liquid feed pipe T is made of a steel pipe, a vinyl chloride pipe, a polyethylene hose, or the like, and can inject water from the tip by receiving water supply via a water swivel.
The liquid feed pipe T is inserted into the head of the steel pipe pile P, and water is sprayed from the tip of the liquid feed pipe T to wash the earth and sand in the pipe. The washed earth and sand become a slurry and are sequentially removed from the head of the steel pipe pile P to the outside.
The liquid pipe T is inserted while removing the earth and sand (FIG. 2 [3]) to reach the tip of the steel pipe pile P (FIG. 2 [4]).

<4> Filling process.
After removing the earth and sand in the pipe to the tip of the steel pipe pile P, the filler S is pumped from the tip of the steel pipe pile P by the liquid feed pipe T to fill the pipe.
In this example, a cement-bentonite-based self-hardening mixed material is used as the filler S. The cement-bentonite-based self-hardening mixed material is a mixed material obtained by blending water, cement, and bentonite, has extremely high fluidity, and has excellent filling property and water stopping property in the ground. Further, the strength after solidification can be easily changed in a wide range by adjusting the composition.
However, the filler S is not limited to this, and for example, fluidized soil, cement paste whose strength has been appropriately adjusted, a slurry whose flow has been adjusted by adding a thickener to sand, or the like may be adopted.
If the strength of the filler S is made extremely larger than the ground strength, it may become an underground obstacle in the future, so the strength is set to be slightly higher than the ground strength.
The filler S is discharged from the tip of the steel pipe pile P so that the material is not separated by groundwater or the like existing in the pipe, and fills the inside of the pipe upward (FIG. 2 [5]). As a result, the muddy water accumulated in the pipe by the water feeding process is replaced with the filler S.
After filling the filler S up to the head of the steel pipe pile P, the liquid feed pipe T is pulled out (FIG. 3 [6]).
The filling step and the drawing step described later may be performed at the same time. That is, the filler S may be filled in the mine while pulling out the steel pipe pile P.

<5> Pulling process.
As the drawing machine of the steel pipe pile P, a rotary press-fitting device used for driving the steel pipe pile P can be used. The gripping device 1 is fixed to the tip of the rod R of the drawing machine in advance via means such as welding.
The pulling out of the steel pipe pile P is performed by the procedure of chucking the steel pipe pile P, cutting the edge with the ground, and pulling out the steel pipe pile P.

<5.1> Chucking of steel pipe piles.
The leader of the drawing machine is aligned to the side of the steel pipe pile P, the rod R is lowered to the upper part of the steel pipe pile P along the leader, and the head of the steel pipe pile P is accommodated in the insertion hole 22 of the gripping device 1. (Fig. 3 [7]).
The rod R is slightly pulled up to chuck (grip) the head of the steel pipe pile P into the gripping device 1 (FIG. 7 [2]). The specific function of the gripping device 1 will be described later.

<5.2> Cutting the edge with the ground.
It is possible to pull out the steel pipe pile P upward as it is, but since the steel pipe pile P is firmly restrained in the ground after the service period of the house, a large pulling force is required for pulling out.
Therefore, in the method for removing the steel pipe pile of the present invention, after gripping the steel pipe pile P, the steel pipe pile P is first rotated about an axis by the rod R of the drawing machine to form an edge between the ground and the peripheral surface of the steel pipe pile P. Cut. As a result, the restraint by the ground is released, and the steel pipe pile P can be pulled out with a small force.

<5.3> Pulling out steel pipe piles.
The steel pipe pile P is pulled upward along the leader while being rotated about the axis by the drawing machine (FIG. 3 [8]).
When the rod R reaches the top of the leader, the above-ground portion of the steel pipe pile P is cut leaving a head of about 20 cm.
The gripping device 1 and the rod R are lowered to the lower end of the reader, and the gripping device 1 grips the head of the steel pipe pile P after cutting.
Pull the steel pipe pile P upward along the leader again.
By repeating the above, the steel pipe pile P is completely pulled out from the ground.
When the steel pipe pile P is pulled out, the filler S filled in the steel pipe pile P fills the trace hole, fills the fine voids in the surrounding soil, stabilizes the hole wall, and prevents collapse.

<6> Replenishment process.
In the filler S in the trace hole, the volume integral liquid level of the steel pipe pile P is lowered by pulling out the steel pipe pile P, and an unfilled space is created between the ground surface and the liquid level of the filler S.
Therefore, the filler S is replenished in this unfilled space with the liquid feeding pipe T (FIG. 3 [9]).
By hardening the filler S, the trace holes are completely closed and the ground is restored to its original state (FIG. 3 [10]).

[Gripping device]
<1> Overall configuration (Fig. 4).
Subsequently, the gripping device 1 used in the method for removing the steel pipe pile of the present invention will be described.
The gripping device 1 includes a cone 20, a cap 10 connected to the head of the cone 20, two wedges 30 arranged facing each other in the cone 20, and an elastic body 40 inserted between the cap 10 and the wedge 30. And at least.
In this example, the cap 10 is screwed into the head of the cone 20 to be connected, and the locking bolt 50 is communicated and fixed to both screw portions.
The gripping device 1 is used by attaching the cap 10 to the tip of the rod R of the drawing machine by welding or screwing.

<2> Cap (Fig. 5).
The cap 10 is a component that connects the cone 20 to the rod R of the drawing machine.
The cap 10 has a cap main body 11 and a communication hole 12 provided in the cap main body 11.
The communication hole 12 is a hole through which the steel pipe pile P is inserted, and is configured to be at least larger than the outer diameter of the steel pipe pile P.
In this example, as the cap 10, a cylindrical lid-shaped steel member in which a screw groove for wearing a cone 20 screw is engraved on the inner circumference is adopted.
In this example, a bolt hole for communicating the lock bolt 50 is drilled on the side surface.
The cap 10 and the cone 20 may have an integral structure instead of a separate member.

<3> Cone (Fig. 5).
The cone 20 is a component that houses the wedge 30.
The cone 20 has a cone body 21, an insertion hole 22 that connects the cone body 21 up and down, and two accommodating grooves 23 formed on both sides of the insertion hole 22.
The insertion hole 22 is a hole through which the steel pipe pile P is inserted, and is configured to be at least larger than the outer diameter of the steel pipe pile P.
In this example, as the cone 20, a columnar steel member having a screw groove for wearing a cap 10 screw is adopted on the outer periphery.
In this example, a bolt hole for communicating the lock bolt 50 is drilled on the side surface.

<3.1> Storage groove.
The accommodating groove 23 is a groove that slidably holds the wedge 30 inside.
The accommodating groove 23 has a shape generally corresponding to the wedge 30, and a part of the accommodating groove 23 communicates with the insertion hole 22.
The accommodating groove 23 has a smooth inclined surface 23a facing the insertion hole 22 and two side surfaces connecting the inclined surface 23a and the insertion hole 22.
The inclined surface 23a inclines inward of the insertion hole 22 from the upper side to the lower side of the cone body 21.
The two sides of the accommodation groove 23 are inclined toward the insertion hole 22 so as to be close to each other.

<3.2> Pin groove.
In this example, a pair of pin grooves 24 are provided on the inner surface of the insertion hole 22.
In the ground reinforcement by the small diameter steel pipe, the steel pipe pile P may be connected and connected, and the connecting pin may be communicated with the head of the steel pipe pile P in the orthogonal direction.
If the pin protrudes outward from the insertion hole 22, the head of the steel pipe pile P cannot pass through the insertion hole 22, and the steel pipe pile P cannot be inserted inside the cone 20.
In such a case, by providing the pin groove 24 in the insertion hole 22, the pin of the steel pipe pile P can be passed through the pin groove 24 and inserted into the cone 20.

<4> Wedge (Fig. 6).
The wedge 30 is a component that converts the pulling force of the cone 20 into the gripping force of the steel pipe pile P.
The wedge 30 has a thin plate-shaped wedge main body 31, an engaging surface 32 on the front surface of the wedge main body 31, and a sliding surface 33 on the back surface of the wedge main body 31.
Both side surfaces of the wedge body 31 are inclined so as to approach each other from the sliding surface 33 toward the engaging surface 32.

<4.1> The state of wedges in the containment ditch.
The wedges 30 are arranged facing each other in the two accommodating grooves 23.
The head of the wedge 30 projects above the accommodating groove 23.
The wedge 30 can slide in the accommodating groove 23 in the vertical direction along the inclined surface 23a.
When the wedge 30 is lowered to the lowermost portion in the accommodating groove 23, the engaging surface 32 partially extends into the insertion hole 22. That is, the distance between the engaging surfaces 32 is smaller than the inner diameter of the insertion hole 22.
As the wedge 30 moves upward in the accommodating groove 23, the distance between the engaging surfaces 32 increases and becomes larger than the inner diameter of the insertion hole 22.

<4.2> Engagement surface.
The engaging surface 32 is a surface that comes into contact with the outer circumference of the steel pipe pile P and grips the steel pipe pile P.
The engaging surface 32 has a substantially concave shape corresponding to the outer circumference of the steel pipe pile P.
It is desirable that the engaging surface 32 is processed to prevent the steel pipe pile P from slipping. In this example, a plurality of horizontal grooves are carved over the entire surface of the engaging surface 32.

<4.3> Sliding surface.
The sliding surface 33 is a smooth surface for sliding along the inclined surface 23a of the cone 20.
The sliding surface 33 is the opposite surface of the engaging surface 32, and is inclined toward the engaging surface 32 from the upper edge to the lower edge of the wedge body 31.

<4.4> Introduction surface.
In this example, the introduction surface 34 is provided on the lower edge of the engaging surface 32.
The introduction surface 34 is formed by chamfering between the lower surface of the wedge main body 31 and the engaging surface 32 at an angle.
When the gripping device 1 is lowered above the steel pipe pile P, the outer edge of the head of the steel pipe pile P comes into contact with the introduction surface 34, and the wedge 30 is pushed up diagonally outward. As a result, the distance between the engaging surfaces 32 is widened so that the diameter of the steel pipe pile P is wider than the diameter of the steel pipe pile P, so that the head of the steel pipe pile P is introduced between the engaging surfaces 32 along the introduction surface 34.
As described above, the introduction surface 34 eliminates the need to manually widen the interval between the wedges 30 when inserting the head of the steel pipe pile P into the gripping device 1, so that the head of the steel pipe pile P can be inserted without any manual work. Can be grasped.

<4.5> Wedge fall prevention function.
Both side surfaces of the wedge body 31 are inclined so as to be close to the engaging surface 32 side, and both side surfaces of the accommodating groove 23 are inclined so as to be close to the insertion hole 22 side.
Therefore, when the wedge 30 tries to fall toward the insertion hole 22, the side surface of the wedge body 31 comes into contact with the side surface of the accommodating groove 23, so that the movement of the wedge 30 to the insertion hole 22 side is restricted.
As a result, it is possible to prevent the wedge 30 from falling into the insertion hole 22 and falling when the gripping device 1 is not gripping the steel pipe pile P.

<5> Elastic body.
The elastic body 40 is a component that urges the wedge 30 downward in the cone 20.
In this example, as the elastic body 40, a steel compression coil spring having an inner diameter larger than the outer diameter of the steel pipe pile P is adopted.
By screwing the cap 10 to the head of the cone 20 with the elastic body 40 inserted between the wedge 30 and the cap 10, the lower portion of the elastic body 40 presses the heads of the two wedges 30. It is urged downward in the accommodating groove 23.
However, the configuration of the elastic body 40 is not limited to the above, and for example, small compression coil springs may be individually arranged on the two wedges 30.

<6> Gripping function.
The gripping function of the gripping device 1 (insertion of steel pipe pile, gripping of steel pipe pile, rotary pulling out) will be described.
The gripping device 1 has one feature in that it can autonomously grip the steel pipe pile P by converting the pulling force into a gripping force simply by covering the head of the steel pipe pile P from above and pulling it up.

<6.1> Insertion of steel pipe pile (Fig. 7 [1]).
The gripping device 1 is lowered from above the steel pipe pile P, and the head of the steel pipe pile P is inserted into the insertion hole 22.
Then, when the upper edge of the steel pipe pile P comes into contact with the introduction surface 34 of the wedge 30, the wedge 30 is pushed up diagonally upward along the inclined surface 23a (opening of the wedge), and the distance between the two engaging surfaces 32. Spreads to the outer diameter of the steel pipe pile P and allows the steel pipe pile P to pass through. The elastic body 40 is pressed from below by the wedge 30 and is compressed and deformed.
When the gripping device 1 is continuously lowered, the head of the steel pipe pile P slides between the engaging surfaces 32 of the two wedges 30 and passes through the inside of the elastic body 40 and the communication hole 12 of the cap 10. , Reach the inside of the rod R.

<6.2> Gripping of steel pipe piles (Fig. 7 [2]).
When the rod R is pulled up, the engaging surface 32 of the wedge 30 is pulled into the peripheral surface of the steel pipe pile P, and the wedge 30 moves downward along the inclined surface 23a.
By lowering the wedge 30, the distance between the engaging surfaces 32 is reduced, and the steel pipe pile P is strongly sandwiched from both sides (fastening of the wedge).
In this way, the gripping device 1 can autonomously grip the steel pipe pile P by converting the pulling force of the pulling machine into a force of sandwiching the steel pipe pile P with the wedge 30.

<6.3> Rotational pull-out (Fig. 7 [3]).
When the rod R is pulled up while rotating while the steel pipe pile P is being gripped, the wedge 30 bites into the steel pipe pile P deeper and grips the steel pipe pile P even more strongly.
The rotational force of the rod R is transmitted to the steel pipe pile P via the contact surface between the side surface of the accommodating groove 23 and the side surface of the wedge 30, and rotates the steel pipe pile P.

1 Gripping device 10 Cap 11 Cap body 12 Communication hole 20 Cone 21 Cone body 22 Insertion hole 23 Storage groove 23a Inclined surface 24 Pin groove 25 Connection hole 30 Wedge 31 Wedge body 32 Engagement surface 33 Sliding surface 34 Introduction surface 40 Elastic body 50 Loosening prevention bolt M Heavy equipment P Steel pipe pile R Rod S Filler T Liquid feed pipe

Claims (6)

It is a method of removing steel pipe piles for removing small diameter steel pipe piles buried in the ground.
A water feeding step in which a liquid feeding pipe is inserted into a pipe from the head of the steel pipe pile, water is injected from the liquid feeding pipe to remove earth and sand in the pipe, and the liquid feeding pipe reaches the tip of the steel pipe pile. When,
A filling step of filling the inside of the pipe of the steel pipe pile from the liquid feed pipe arranged at the tip of the steel pipe pile.
The steel pipe pile is gripped by a gripping device connected to the drawing machine, and the steel pipe pile is pulled out while being rotated around the axis by the drawing machine.
How to remove steel pipe piles. The method for removing steel pipe piles according to claim 1, wherein the filler is a fluid mixture whose strength can be adjusted by blending. The gripping device
A cone having an insertion hole communicating vertically and two accommodating grooves formed on both sides of the insertion hole.
Two wedges placed facing each other in the two storage grooves,
With the cap connected to the top of the cone,
An elastic body inserted between the two wedges and the cap is provided.
The accommodating groove has an inclined surface that inclines toward the insertion hole side from the upper side to the lower side.
The wedge has a substantially concave engaging surface corresponding to the outer circumference of the steel pipe pile, and a sliding surface facing the engaging surface and inclined from above to downward toward the engaging surface. And
By combining the inclined surface of the accommodating groove and the sliding surface of the wedge, the pulling force applied to the cone can be converted into the gripping force of the steel pipe pile by the engaging surface.
The method for removing a steel pipe pile according to claim 1 or 2. Both sides of the wedge are inclined toward the engaging surface so as to be close to each other, and both sides of the accommodating groove are inclined so as to be close to each other toward the insertion hole, so that the inside of the accommodating groove of the wedge is inclined. The method for removing a steel pipe pile according to claim 3, wherein the movement in the insertion hole direction is regulated. The method for removing a steel pipe pile according to claim 3 or 4, wherein the wedge has a chamfered introduction surface between the lower surface of the wedge and the engaging surface. A claim, wherein the cone is a pin groove formed on the inner surface of the insertion hole and has a pin groove that allows the passage of a protrusion of a pin communicating in a direction orthogonal to the head of the steel pipe pile. Item 8. The method for removing a steel pipe pile according to any one of Items 3 to 5.