JP6853990B1 - Extraction method of existing piles - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for pulling out an existing pile, which prevents a decrease in the strength of the ground around the trace of pulling out an existing pile. SOLUTION: A step of building an outer peripheral casing 13 on the outer peripheral ground of an existing pile 10 and an end portion of a wire rope 16 for drawing are wound around the outer periphery of a tip portion between the outer peripheral casing 13 and the existing pile 10 to form a ring. A step of building the inner peripheral casing 14 in which the portion 16a is formed, a step of winding the ring portion of the wire rope 16 so as to be deposited on the outer periphery of the tip portion of the existing pile 10, and then pulling out the inner peripheral casing 14 and a wire rope. A step of pulling out the existing pile 10 by pulling up 16 and a step of inserting a spiral auger 18 inside the outer peripheral casing 13 and projecting the tip head portion 19 from the tip of the outer casing 13 to expand the stirring blade 20. The spiral auger 18 is rotated, and the spiral auger 18 and the outer peripheral casing 13 are pulled up while pouring out the solidifying material from the tip head portion 19. [Selection diagram] Fig. 1

Description

The present invention relates to an existing pile drawing method.

In recent years, due to urban redevelopment, construction work to remove existing piles buried underground is increasing. There are two methods for removing existing piles: a crushing method for crushing piles and a pulling method for pulling out piles by cutting off the friction between the piles and the ground.

As one of the latter drawing methods, a casing is built around the outer ground of the existing pile so as to surround the pile, the friction between the ground and the pile is cut off, and the ring part of the wire rope wound around the tip of the casing is used as the existing pile. A method of pulling out an existing pile (generally referred to as a "quoits method") by pulling up a wire rope after depositing and pulling up a casing is known (see, for example, Patent Document 1).

However, in the conventional drawing method, although the filler is injected into the pile hole and backfilled after the existing pile is pulled out, the hole around the pile pulling trace collapses, so not only the pile hole of the existing pile but also the ground around the pile hole The strength decreases. In addition, since the strength of the upper and lower parts of the pile hole and the strength of the existing pile hole and the surrounding ground are not constant, there are problems such as the pile core of the new pile being displaced and the strength of the pile not being stable in the subsequent construction of the new pile. is there.

Japanese Unexamined Patent Publication No. 2010-255300

The present invention has been made based on the above technical background, and achieves the following object.
An object of the present invention is to prevent the ground from collapsing around the existing pile removal trace, prevent the strength of the pile hole and the ground around the pile hole from decreasing, maintain a constant strength from the upper part to the lower part of the pile hole, and then maintain a constant strength. The purpose is to provide a pull-out method for existing piles that does not adversely affect the construction of new piles.

The present invention employs the following means in order to achieve the above object.
That is, the present invention is a method for drawing out existing piles buried in the ground.
A process of building an outer casing surrounding the existing pile on the outer ground of the existing pile,
A step of building an inner casing in which an end portion of a wire rope for pulling is wound around the outer periphery of the tip portion and a ring portion is formed on the ground between the outer peripheral casing and the existing pile together with the wire rope. ,
A step of pulling out the inner peripheral casing after winding the wire rope so that the loop portion of the wire rope is deposited on the outer periphery of the tip portion of the existing pile.
The process of pulling out the existing pile by pulling up the wire rope and
A step of inserting a spiral auger having a stirring blade capable of expanding and contracting at the tip head portion inside the outer peripheral casing, and projecting the tip head portion from the tip of the outer peripheral casing to expand the stirring blade.
The existing pile drawing method is characterized in that it includes a step of rotating the spiral auger and simultaneously pulling up the spiral auger and the outer peripheral casing while pouring out a solidifying material from the tip head portion.

According to this invention construction method, it is possible to prevent the ground from collapsing around the existing pile removal trace, prevent the strength of the pile hole and the ground around the pile hole from decreasing, and maintain a constant strength from the upper part to the lower part of the pile hole. It can be maintained and does not adversely affect the subsequent construction of new piles.
Further, according to this invention method, since the ground around the existing pile is protected by the outer casing, the range in which the ground is disturbed by the pulling out of the existing pile can be minimized, and therefore the solidifying material is injected. The range of improvement can also be minimized.

It is a figure which shows the procedure of embodiment of this invention. It is a figure which shows the procedure following FIG. It is a figure which shows the procedure following FIG.

Embodiments of the present invention will be described below with reference to the drawings. 1 to 3 are diagrams showing the procedure of the embodiment of the present invention.

First, as shown in FIG. 1A, the ground around the pile head of the existing pile 10 is excavated to expose the pile head, and the surface casing 12 for preventing collapse is installed on the peripheral wall of the excavation hole 11. Next, as shown in FIG. 3B, the outer peripheral casing 13 surrounding the existing pile 10 is built in the outer peripheral ground of the existing pile 10 while excavating. As shown in FIG. 3C, the outer casing 13 is built until the tip reaches a depth slightly below the tip of the existing pile 10.

The outer peripheral casing 13 is mounted on a leader of a three-point pile driver (not shown) and has an upper end connected to a drive device that moves up and down, and the ground is excavated and built by the drive. If there is groundwater, it is injected into the casing 13 and excavated while maintaining a balance with the groundwater level.

Next, as shown in FIG. 3D, the upper end portion of the inner peripheral casing 14 is connected to a drive device mounted on the leader of the above-mentioned three-point pile driver and moved up and down. The inner peripheral casing 14 has a plurality of blades 15 on the outer periphery of the tip portion. Using these blades 15, one end of a wire rope 16 for pulling out is wound around the outer periphery of the tip of the inner casing 14 to form a ring portion 16a. The other end side of the wire rope 16 is hung on the top sheave of the leader so that it can be extended.

After the inner peripheral casing 14 is set in the drive device, as shown in FIG. 2 (e), the inner peripheral casing 14 is built between the existing pile 10 and the outer peripheral casing 13 by the drive device. At this time, as the inner peripheral casing 14 is inserted into the ground, the wire rope 16 is also pulled into the ground. Then, when the tip of the inner peripheral casing 14 reaches near the tip of the existing pile 10, as shown in FIG. 3F, the ring portion 16a of the wire rope 16 wound around the inner peripheral casing 14 is moved to the tip of the existing pile 10. After winding the rope around the outer circumference of the portion, the inner casing 14 is pulled out.

Next, as shown in FIG. 6 (g), the existing pile 10 is pulled out by connecting the wire rope 16 to the hoisting rope (not shown) of the crane and pulling up the wire rope 16. If the pile head protrudes above the construction base surface during the pulling work of the existing pile 10, a new wire rope 17 is wound around the pile head as shown in FIG. The existing pile 10 is pulled out by 17. Since there is a risk of boiling when the existing pile 10 is pulled out, water is injected into the outer casing 13 to prevent this.

The step of pulling out the existing pile 10, that is, the step itself shown in FIGS. 1 (d) to 2 (h) is a well-known method as a quoits method as described above, and the details thereof are described in, for example, Patent Document 1 (Japanese Patent Laid-Open No. 2010). -255300 (No. -25300).

After the drawing of the existing pile 10 is completed, the spiral auger 18 is inserted into the outer casing 13 as shown in FIG. 3 (i). The upper end of the spiral auger 18 is mounted on the leader of the above-mentioned three-point pile driver and is connected to a drive device that moves up and down. Further, the outer casing 13 is also mounted on the leader of the same three-point pile driver and connected to another drive device that moves up and down.

The tip head 19 of the spiral auger 18 is provided with a stirring blade 20. The stirring blade 20 is projected from the tip of the outer peripheral casing 13 together with the tip head 19, and then expanded as shown by the reverse rotation / normal rotation of the tip head 19.

Then, as shown in FIGS. (J) and (k), the stirring blade 20 is rotated (normally rotated) by the rotation of the spiral auger 18, and the spiral auger is discharged from the tip head 19 while a solidifying material such as cement milk is discharged. Both 18 and the outer casing 13 are pulled up at the same time. As a result, the ground around the excavated trace of the existing pile 10 becomes the improved ground 21 to which the solidifying material is poured out and strengthened.

After pulling out the spiral auger 18 and the outer peripheral casing 13, as shown in FIG. 1 (l), the surface layer casing 12 is pulled out and removed, the excavation hole 11 is backfilled with the backfill material 22, and the improved ground leveling is performed.

According to the above-mentioned construction method, the collapse of the ground around the existing pile removal trace can be prevented, the strength of the pile hole and the ground around the pile hole can be prevented from decreasing, and the pile hole is constant from the upper part to the lower part. The strength can be maintained and it does not adversely affect the subsequent construction of new piles.

Further, according to this invention method, since the ground around the existing pile is protected by the outer casing, the range in which the ground is disturbed by the pulling out of the existing pile can be minimized, and therefore the solidifying material is injected. The range of improvement can also be minimized.

10: Existing pile 13: Outer casing casing 14: Inner circumference casing 16: Wire rope for pulling out 16a: Ring part 18: Spiral auger 19: Tip head 20: Stirring blade 21: Improved ground

Claims (1)

It is a method of pulling out existing piles buried in the ground.
A process of building an outer casing surrounding the existing pile on the outer ground of the existing pile,
A step of building an inner casing in which an end portion of a wire rope for pulling is wound around the outer periphery of the tip portion and a ring portion is formed on the ground between the outer peripheral casing and the existing pile together with the wire rope. ,
A step of pulling out the inner peripheral casing after winding the wire rope so that the loop portion of the wire rope is deposited on the outer periphery of the tip portion of the existing pile.
The process of pulling out the existing pile by pulling up the wire rope and
A step of inserting a spiral auger having a stirring blade capable of expanding and contracting at the tip head portion inside the outer peripheral casing, and projecting the tip head portion from the tip of the outer peripheral casing to expand the stirring blade.
A method for pulling out an existing pile, which comprises a step of rotating the spiral auger and simultaneously pulling up the spiral auger and the outer peripheral casing while pouring out a solidifying material from the tip head portion.

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