JP2023055251A - Cutting device and steel pipe cutting method - Google Patents

Abstract

To provide a cutting device and a steel pipe cutting method for removing a steel pipe pile and a steel pipe sheet pile by fragmenting them.SOLUTION: A cutting device 2 is to cut a steel pipe 11 placed in the underground or the underwater along an axial direction of the steel pipe 11. The cutting device 2 is provided with a cutting machine body 4 provided with a nozzle 41 allowing high-pressured water to be injected for cutting the steel pipe 11 and a frame 3 placed inside of the steel pipe 11. The frame 3 comprises a pair of rails 32, 32 arranged along the axial direction of the steel pipe 11, and the cutting machine body 4 is able to vertically move along the rails 32.SELECTED DRAWING: Figure 2

Description

TECHNICAL FIELD The present invention relates to a cutting device and a steel pipe cutting method for cutting existing steel pipe piles and steel pipe sheet piles.

Methods for removing existing piles, steel sheet piles, etc. include a method of pulling them out as they are, and a method of cutting the piles, steel sheet piles, etc. on site and removing the cut pieces in multiple steps.
For example, in Patent Document 1, a casing having an inner diameter larger than the outer diameter of the pile is set so as to surround the outer peripheral surface of the pile, and high-pressure water is jetted from a nozzle provided in the casing in the axial direction of the pile. A pile pull-out method is disclosed in which the pile is pulled out after cutting the edge between the pile and the natural ground by press-fitting the casing along.
However, if the piles, etc. are deformed due to earth pressure, water pressure, etc., the casing and the piles will come into contact with each other, making it impossible to press-fit the casing along the piles (i.e., the edge between the pile and the natural ground will not be cut). may not be possible). Moreover, when removing a large-diameter long pile, a large-scale device corresponding to the shape of the pile is required.
Further, Patent Document 2 discloses a cutting method in which a nozzle that rotates in a horizontal direction is provided in a frame inserted into a main pipe of a steel pipe sheet pile, and a joint pipe of the steel pipe sheet pile is horizontally cut by high-pressure water jetted from the nozzle. is disclosed.
In order to remove a cut piece horizontally cut in the ground or in water, it is necessary to attach a wire or the like for pulling up the cut piece in the ground or in water to the cut piece, which is a laborious task. In addition, since earth pressure and water pressure act on the cut pieces cut in the horizontal direction from all around, a large pulling force is required.

JP-A-09-268555 JP-A-62-112819

From this point of view, an object of the present invention is to propose a cutting device and a steel pipe cutting method for segmenting and removing steel pipe piles and steel pipe sheet piles.

A cutting device according to the present invention for solving the above-mentioned problems is a cutting device for axially cutting a steel pipe provided in the ground or in water, the cutting device being capable of injecting high-pressure water for cutting the steel pipe. It has a cutting machine body with a nozzle and a frame installed in the steel pipe. The frame has a pair of rails provided along the axial direction of the steel pipe, and the cutting machine body can move up and down along the rails. Preferably, the nozzle is capable of injecting high-pressure water between the rails.
Further, a steel pipe cutting method for cutting a steel pipe in the axial direction using the cutting device includes a device installation step of installing the frame in the steel pipe in a state in which the frame is suspended in the steel pipe; and a cutting step of cutting the steel pipe by jetting high-pressure water from the nozzle while moving the cutting machine main body along the rail.
According to such a cutting apparatus and steel pipe cutting method, the steel pipe can be cut along the axial direction. When the steel pipe is cut longitudinally, earth pressure and water pressure act on the cut piece from one direction, making it easier to remove the cut piece. Further, if the steel pipe is cut in the longitudinal direction, the axial continuity of the cut piece is maintained, so that the cut piece can be easily pulled out.

In the device installation step, it is preferable that a locking member is arranged at the upper end of the steel pipe and the frame is supported by the locking member. By doing so, the frame can be easily attached to the steel pipe without requiring a large-scale device or processing the steel pipe.
If the frame is formed by vertically connecting a plurality of divided frame members, it is possible to reduce the time and effort required for carrying in the frame and assembling it on site, which is efficient. In this case, in the device installation step, the frame may be formed by fixing another split frame member to the upper end of the split frame member inserted into the steel pipe.

According to the cutting device and the steel pipe cutting method of the present invention, the existing steel pipe piles and steel pipe sheet piles can be easily removed by subdividing them in the axial direction.

FIG. 3 is a cross-sectional view showing how the steel pipe sheet pile according to the embodiment of the present invention is cut. 1 is a perspective view showing a steel pipe and a cutting device according to an embodiment of the present invention; FIG. (a) is a perspective view showing a frame, and (b) is a perspective view showing a divided frame member. FIG. 4 is a plan view showing the relationship between a frame and steel pipes; FIG. 4 is a cross-sectional plan view showing how a steel pipe is cut by a cutting device; FIG. 4 is a cross-sectional view showing the state of excavation in the steel pipe; FIG. 4 is a cross-sectional view showing how the frame is assembled;

In the embodiment of the present invention, when removing an underground wall remaining at a position where a new structure is to be installed, the steel pipe sheet pile 1 constituting the underground wall is cut into pieces in the ground, and then cut into pieces. A case of extracting from the ground will be described. FIG. 1 is a cross-sectional view showing how a steel pipe sheet pile 1 is cut. As shown in FIG. 1, a steel pipe sheet pile 1 is cut axially (vertically) from the inside of a steel pipe 11 using a cutting device 2 . The steel pipe sheet pile 1 and the cutting device 2 are shown in FIG.
The steel pipe sheet pile 1 consists of a steel pipe 11 and a joint 12 fixed to the side surface of the steel pipe 11, and is installed in the ground in a state where the joint 12 is engaged with the joint 12 of another adjacent steel pipe sheet pile 1. , forming a continuous underground wall.
Earth pressure and groundwater pressure are acting on the steel pipe sheet pile 1 (steel pipe 11) from the surroundings (all directions). By cutting the steel pipe 11 in the vertical direction, earth pressure or water pressure acts on the cut piece from one direction, making it easier to remove (pull out) the cut piece.

The cutting device 2 includes a frame 3 and a cutting machine main body 4, as shown in FIG.
The frame 3 is installed inside the steel pipe 11 to guide the movement of the cutting machine body 4 . Frame 3 is shown in FIG.
The frame 3 is formed by vertically connecting a plurality of divided frame members 31, 31, . . . as shown in FIG. 3(a).
As shown in FIG. 3B, the divided frame member 31 is composed of rails 32, joint plates 33, horizontal members 34, and diagonal members 35. As shown in FIG.
The joint plates 33 are provided at the upper and lower ends of the split frame member 31, respectively. The joint plate 33 is an annular member having an outer diameter smaller than the inner diameter of the steel pipe 11 (see FIG. 4). A plurality of through holes (not shown) are formed in the joint plate 33 so that it can be joined to the joint plate 33 of another adjacent split frame member 31 via bolts.
The rail 32 is arranged between upper and lower joint plates 33 . The rail 32 is provided perpendicular to the joint plate 33 so as to extend along the axial direction of the steel pipe 11 when the frame 3 is arranged inside the steel pipe 11 . FIG. 4 shows a plan view of the frame 3. As shown in FIG. As shown in FIG. 4 , the rails 32 are arranged in pairs, and in this embodiment, four pairs of rails 32 are arranged at equal intervals in the circumferential direction of the joint plate 33 . That is, the pair of rails 32, 32 are arranged at the corners of a regular polygon (square in this embodiment) in plan view.
As shown in FIG. 3(b), one rail 32 of the set of rails 32, 32 is connected to the other set of rails 32, which is adjacent to the other rail 32 on the opposite side, and horizontal members 34 and diagonal members. 35.

As shown in FIGS. 3A and 3B, a plurality of horizontal members 34 (in this embodiment, four for each divided frame member 31) are arranged vertically at equal intervals. That is, as shown in FIG. 4, the horizontal member 34 is arranged at a position corresponding to one side of a square in plan view, and one of the pair of rails 32, 32 arranged at one corner and adjacent to the corner. and one of a pair of rails 32, 32 arranged at the other corner. The horizontal member 34 is made of a steel material such as an angle member, and has its tip portion welded to the rail 32 .
The diagonal members 35 are arranged at the upper ends of one of the pair of rails 32, 32 arranged at the corners of a square in a plan view, and the pair of rails arranged at the other corners adjacent to the corners. It is obliquely provided so as to connect the lower ends of the rails 32 , 32 . In this embodiment, two diagonal members 35, 35 are provided in an X shape. The diagonal member 35 is made of steel such as an angle member, and has its tip portion welded to the rail 32 .
Also, the pair of rails 32 , 32 arranged at the corners of the square in plan view are connected by a connecting material 36 . The joint material 36 is made of steel and is perpendicular to the rail 32 . A plurality of connecting members 36 are vertically arranged side by side at predetermined intervals. The connecting material 36 is provided with a sensor (hydraulic type, electric type, etc.) 37 for detecting cutting failure and cutting position (see FIG. 5). 5 shows the positional relationship between the rail 32 and the cutting machine main body 4. As shown in FIG.

As shown in FIG. 5, the cutting machine body 4 includes a nozzle 41 capable of injecting high-pressure water W for cutting the steel pipe 11, wheels 42 running on the rails 32, and a support member 43 supporting the nozzle 41. I have.
The cutting machine main body 4 moves up and down along the rails 32 as the wheels 42 run on the rails 32 . Wheels 42 are rotatably supported by support members 43 . As shown in FIG. 2 , in this embodiment, wheels 42 are provided in four directions corresponding to the positions of the rails 32 of the frame 3 . That is, the support member 43 is provided with four sets of wheels 42 , 42 in two stages, corresponding to the four sets of rails 32 , 32 provided on the frame 3 .

As shown in FIG. 5, the nozzle 41 is supported by a support member 43 and can jet high-pressure water between the pair of rails 32,32. The steel pipe 11 is cut by high pressure water jetted from the nozzle 41 . The nozzle 41 is arranged so as to jet the high-pressure water W toward between the left and right wheels 42, 42 running on the pair of rails 32, 32. As shown in FIG. Four nozzles 41 are arranged on the support member 43 at regular intervals in the circumferential direction, and jet high-pressure water W between the pair of rails 32 , 32 provided on the frame 3 . That is, the cutter main body 4 can jet the high-pressure water W in all directions.
As shown in FIG. 2, the support member 43 of this embodiment consists of a columnar member. The cutting machine main body 4 of this embodiment has four support members 43, 43, . That is, the cutting machine main body 4 is provided with wheels 42 corresponding to the rails 32 , and the wheels 42 are in contact with the rails 32 . Supported. That is, the cutting machine main body 4 secures the reaction force when the high-pressure water W is jetted from the nozzle 41 from the frame 3 via the wheels 42, thereby preventing the jetting direction of the high-pressure water W from fluctuating.

A steel pipe cutting method using the cutting device 2 of the present embodiment will be described below.
The steel pipe cutting method includes an excavation step, a device installation step, and a cutting step.
In the middle moat process, as shown in FIG. 6, the inside of the steel pipe 11 is excavated using an excavator M such as a hammer grab.
The apparatus installation step is a step of installing the frame 3 inside the steel pipe 11 from which the earth and sand have been removed. FIG. 7 shows how the frame 3 is assembled. The frame 3 is installed inside the steel pipe 11 by connecting another split frame member 31 to the upper surface of the split frame member 31 inserted inside the steel pipe 11 . The divided frame members 31 are inserted into the steel pipes 11 in a state of being suspended by a lifting machine C such as a crane. The split frame member 31 is supported by the locking member 5 arranged at the upper end of the steel pipe 11 with its upper end protruding above the upper end of the steel pipe 11 . In this embodiment, a steel material is used as the locking member 5 . The split frame member 31 is locked to the upper end of the steel pipe 11 by placing the horizontal member 34 on the locking member 5 .

Next, another split frame member 31 suspended by the lifting machine C is placed on the upper end of the split frame member 31 locked to the upper end of the steel pipe 11, and the joint plates of both split frame members 31, 31 are placed. 33 are bolted together. When the joining of the split frame members 31 is completed, the locking member 5 is removed and the frame 3 is lowered.
After the frame 3 having a predetermined length is formed by connecting the plurality of divided frame members 31 , the frame 3 is supported by the locking member 5 arranged at the upper end of the steel pipe 11 . A positioning member 38 is fixed to the frame 3 as shown in FIG. By bringing the positioning member 38 into contact with the locking member 5 , positioning within the steel pipe 11 is performed so that the rail 32 is arranged at a predetermined position.

In the cutting step, the steel pipe 11 is cut (divided into four) along the axial direction. The steel pipe is cut by jetting high-pressure water W from nozzles 41 while moving the cutting machine body 4 along the rails 32 of the frame 3 (see FIG. 5). At this time, the joint material 36 connecting the rails 32 is also cut. In this embodiment, the steel pipe 11 is cut from the lower end side of the steel pipe 11 .
As shown in FIG. 1, the cutting machine main body 4 suspended by the lifting machine C is inserted into the steel pipe 11 to a predetermined depth. At this time, the wheels 42 of the cutting machine main body 4 are lowered along with the rails 32 . Next, as shown in FIG. 5, high-pressure water is jetted from the nozzle 41 to start longitudinal cutting of the steel pipe sheet pile 1 (steel pipe 11). The cutting machine main body 4 is raised along the rails 32 at a predetermined speed while jetting high-pressure water from the nozzles 41 . The moving speed of the cutting machine body 4 is determined by the cutting capacity and the thickness of the steel pipe 11 . A sensor 37 for detecting a cutting position is attached to a connecting material 36 that connects the rails 32 to each other.

Cutting of the steel pipe 11 is performed while exchanging the nozzle 41 as appropriate. The timing of replacement of the nozzle 41 is determined based on the cut length by the nozzle 41 , the high-pressure water injection time, or the measurement result of the sensor 37 . For example, if the sensor 37 is a hydraulic pressure sensor, the state of cutting is confirmed when the hydraulic pipe is cut together with the connecting material 36 and the hydraulic pressure drops. Further, when the sensor 37 is an energization sensor (electrode sensor), the state of cutting is checked by interrupting the energization when the connecting material 36 is cut.
When replacing the nozzle 41, the cutting is temporarily interrupted, the cutting machine main body 4 is pulled up, and the replacement work is performed.

When resuming the cutting of the steel pipe 11 after replacing the nozzle 41, the cutting machine main body 4 is lowered with the wheels 42 aligned with the rails 32, and the cutting work is resumed from the position where the cutting was interrupted.
When the cutting of the steel pipe 11 reaches the top of the steel pipe 11, the injection of high-pressure water from the nozzle 41 is stopped, and the cutting machine main body 4 is pulled up. After the operation of axially cutting the steel pipe 11 along the set of rails 32 , 32 at the positions of the four sets of rails 32 , 32 , the frame 3 is cut into the steel pipes 11 while removing the upper split frame member 31 . pull out from
The pulled-out divided frame member 31 connects the rails 32 with a new connecting material 36 and is used again for cutting another steel pipe 11 .

As described above, according to the cutting device 2 of the present embodiment, the steel pipe 11 can be cut along the axial direction. When the steel pipe 11 is cut in the vertical direction, earth pressure and water pressure act on the cut pieces from one direction, so that the cut pieces can be easily removed. Further, if the steel pipe 11 is cut in the longitudinal direction, the continuity of the cut pieces in the axial direction is maintained, so that the cut pieces can be easily pulled out.
Note that the number of divisions when cutting the steel pipe 11 is not limited to four.
In addition, since the frame 3 is supported by the locking member 5 provided at the upper end of the steel pipe 11, the frame 3 can be easily attached to the steel pipe 11 without requiring a large-scale holding device or processing of the steel pipe 11. can be done.
In addition, since the frame 3 is composed of a plurality of divided frame members 31, it is possible to reduce the time and effort required for carrying in the frame 3 and assembling it on site, which is efficient.
When exchanging the nozzle 41, since it is carried out in a state of being raised above the ground, there is no need for workers, divers, etc. to get down into the steel pipe 11, and workability is excellent. Further, since the nozzle 41 is moved along the rail 32, when the nozzle 41 is replaced and the cutting of the steel pipe 11 is restarted, the nozzle 41 can be guided to the position where the operation was stopped. Therefore, the continuity of the cutting line can be ensured, and the cut pieces can be pulled out smoothly.
Furthermore, even when the joints of the steel pipes 11 are competing with each other, the cut pieces of the adjacent steel pipes can be carried out together.

Although the embodiments according to the present invention have been described above, the present invention is not limited to the above-described embodiments, and each of the above-described constituent elements can be changed as appropriate without departing from the scope of the present invention.
In the above embodiment, the case of cutting the steel pipe sheet pile 1 has been described, but the cutting device 2 of the present invention may be used for cutting steel pipe piles, for example, as long as it is a member having a steel pipe 11, the object to be cut is It is not limited.
Moreover, the number and arrangement of the rails 32 provided in the frame 3 are not limited, and may be determined as appropriate.
Similarly, the number and arrangement of nozzles 41 and wheels 42 provided in the cutting machine body 4 may be determined as appropriate.
The configuration of the locking member 5 is not limited and may be determined as appropriate.
The sensor 37 may be provided as required.

Reference Signs List 1 steel pipe sheet pile 11 steel pipe 12 joint 2 cutting device 3 frame 31 division frame member 32 rail 4 cutting machine body 41 nozzle 42 wheel 43 support member 5 locking member

Claims (5)

A cutting device for cutting a steel pipe provided in the ground or underwater along the axial direction of the steel pipe,
a cutting machine body including a nozzle capable of injecting high-pressure water for cutting the steel pipe;
a frame installed within the steel pipe;
The frame has a pair of rails provided along the axial direction of the steel pipe,
A cutting device, wherein the cutting machine main body is vertically movable along the rail. 2. The cutting device according to claim 1, wherein said nozzle is capable of injecting high-pressure water between said rails. 3. The cutting device according to claim 1, wherein the frame is formed by vertically connecting a plurality of divided frame members. A steel pipe cutting method for cutting a steel pipe in the axial direction using the cutting device according to any one of claims 1 to 3, comprising:
a device installation step of installing the frame in the steel pipe with the frame suspended in the steel pipe;
a cutting step of cutting the steel pipe by jetting high-pressure water from the nozzle while moving the cutting machine body along the rail of the frame. 5. The steel pipe cutting method according to claim 4, wherein, in said device installation step, a locking member is arranged at the upper end of said steel pipe, and said frame is supported by said locking member.

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