Cutting device and steel pipe cutting method

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]

[0001] The present invention relates to a cutting device and a steel pipe cutting method for cutting existing steel pipe piles or steel pipe sheet piles. [Background technology]

[0002] Methods for removing existing piles, steel sheet piles, etc. include pulling them out as they are, and cutting the piles, steel sheet piles, etc. on-site and removing the cut pieces in multiple steps. For example, Patent Document 1 discloses a pile extraction method in which a casing with an inner diameter larger than the outer diameter of the pile is set to surround the outer surface of the pile, and high-pressure water is sprayed from nozzles attached to the casing while the casing is pressed into the pile along its axial direction, thereby severing the connection between the pile and the ground, and then the pile is extracted. However, if the pile or other structure is deformed due to soil pressure, water pressure, etc., the casing may come into contact with the pile, making it impossible to press the casing into the pile (i.e., making it impossible to separate the pile from the ground). Furthermore, when removing a long pile with a large diameter, a large-scale device suited to the shape of the pile is required. Patent document 2 also discloses a cutting method in which a nozzle that rotates horizontally is attached to a frame inserted into the main pipe of a steel pipe sheet pile, and high-pressure water is sprayed from the nozzle to cut the joint pipe of the steel pipe sheet pile horizontally. To remove pieces cut horizontally underground or underwater, it is necessary to attach wires to the pieces underground or underwater to pull them up, which is a time-consuming process.In addition, since horizontally cut pieces are subject to earth and water pressure from all sides, a large pulling force is required. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 09-268555 [Patent Document 2] Japanese Patent Publication No. 112819 / 1983 Summary of the Invention [Problem to be solved by the invention]

[0004] From this perspective, the present invention aims to propose a cutting device and a steel pipe cutting method for cutting steel pipe piles or steel pipe sheet piles into small pieces and removing them. [Means for solving the problem]

[0005] The cutting device of the present invention, which solves the above-mentioned problems, is a cutting device for cutting a steel pipe installed underground or underwater along its axial direction, and includes a cutting machine body equipped with a nozzle capable of spraying high-pressure water for cutting the steel pipe, and a frame installed inside the steel pipe. The frame has a pair of rails installed along the axial direction of the steel pipe, and the cutting machine body can move up and down along the rails. It is desirable that the nozzle be capable of spraying high-pressure water between the rails. In addition, a steel pipe cutting method for cutting a steel pipe in the axial direction using the cutting device includes an apparatus installation process for installing the frame inside the steel pipe while suspending the frame inside the steel pipe, and a cutting process for cutting the steel pipe by spraying high-pressure water from the nozzle while moving the cutting machine body along the rails of the frame. With this cutting device and steel pipe cutting method, the steel pipe can be cut along its axial direction. When the steel pipe is cut longitudinally, earth pressure or water pressure acts on the cut pieces from one direction, making them easier to remove. Furthermore, when the steel pipe is cut longitudinally, the axial continuity of the cut pieces is maintained, making them easier to pull out.

[0006] In the device installation step, it is desirable to place a locking member on the upper end of the steel pipe and support the frame with this locking member, which allows the frame to be easily attached to the steel pipe without requiring large-scale equipment or processing of the steel pipe. If the frame is formed by connecting a plurality of separate frame members vertically, the labor required for transporting the frame and assembling it on site can be reduced, which is efficient. In this case, in the equipment installation step, the frame can be formed by fixing another separate frame member to the upper end of the separate frame member inserted into the steel pipe. [Effects of the Invention]

[0007] According to the cutting device and steel pipe cutting method of the present invention, existing steel pipe piles and steel pipe sheet piles can be easily removed by dividing them into smaller pieces in the axial direction. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 2 is a cross-sectional view showing a cutting state of the steel pipe sheet pile according to the embodiment of the present invention. [Figure 2] 1 is a perspective view showing a steel pipe and a cutting device according to an embodiment of the present invention. [Figure 3] FIG. 2(a) is a perspective view showing a frame, and FIG. 2(b) is a perspective view showing a divided frame member. [Figure 4] FIG. 2 is a plan view showing the relationship between the frame and the steel pipe. [Figure 5] FIG. 3 is a cross-sectional plan view showing a state in which a steel pipe is cut by the cutting device. [Figure 6] FIG. 1 is a cross-sectional view showing the excavation status inside a steel pipe. [Figure 7] FIG. 4 is a cross-sectional view showing the assembled state of the frame. DETAILED DESCRIPTION OF THE INVENTION

[0009] In an embodiment of the present invention, a case will be described in which a diaphragm wall remaining at a location where a new structure will be constructed is removed, and steel pipe sheet piles 1 constituting the diaphragm wall are cut underground into small pieces, and the cut pieces are then extracted from the ground. Fig. 1 is a cross-sectional view showing the cutting of the steel pipe sheet pile 1. As shown in Fig. 1, the steel pipe sheet pile 1 is cut in the axial direction (vertical direction) from the inside of the steel pipes 11 using a cutting device 2. Fig. 2 shows the steel pipe sheet pile 1 and the cutting device 2. The steel pipe sheet pile 1 consists of a steel pipe 11 and a joint 12 fixed to the side of the steel pipe 11, and is installed underground with the joint 12 engaged with the joint 12 of another adjacent steel pipe sheet pile 1 to form a continuous underground wall. Earth pressure and groundwater pressure act on the steel pipe sheet pile 1 (steel pipe 11) from all directions. By cutting the steel pipe 11 vertically, earth pressure and water pressure act on the cut pieces from one direction, making the cut pieces easier to remove (pull out).

[0010] As shown in FIG. 2, the cutting device 2 includes a frame 3 and a cutting machine main body 4. The frame 3 is installed inside the steel pipe 11 and guides the movement of the cutting machine body 4. The frame 3 is shown in FIG. As shown in FIG. 3(a), the frame 3 is formed by vertically connecting a plurality of divided frame members 31, 31, . . . As shown in FIG. 3(b), the divided frame member 31 is made up of a rail 32, a joint plate 33, a horizontal member 34, and a diagonal member 35. Joint plates 33 are provided at the upper and lower ends of the split frame member 31. The joint plates 33 are annular members with an outer diameter smaller than the inner diameter of the steel pipes 11 (see FIG. 4). The joint plates 33 have a plurality of through holes (not shown) formed therein, allowing them to be joined to the joint plates 33 of adjacent split frame members 31 via bolts. The rails 32 are disposed between the upper and lower joint plates 33. The rails 32 are disposed perpendicular to the joint plates 33 so as to follow the axial direction of the steel pipe 11 when the frame 3 is disposed inside the steel pipe 11. Fig. 4 shows a plan view of the frame 3. As shown in Fig. 4, the rails 32 are disposed in pairs, and in this embodiment, four pairs of rails 32 are disposed at equal intervals around the circumferential direction of the joint plate 33. In other words, a pair of rails 32, 32 is disposed at each of the corners of a regular polygon (a square in this embodiment) in plan view. As shown in FIG. 3( b ), one rail 32 of a set of rails 32 , 32 is connected to the other adjacent rail 32 of another set on the opposite side of the other rail 32 by a horizontal member 34 and a diagonal member 35 .

[0011] As shown in Figures 3(a) and (b), a plurality of horizontal members 34 (four for each divided frame member 31 in this embodiment) are arranged vertically at equal intervals. That is, as shown in Figure 4, the horizontal member 34 is arranged at a position that forms one side of a square in a plan view, and is laid across between one of a pair of rails 32, 32 arranged at one corner and one of a pair of rails 32, 32 arranged at another corner adjacent to that corner. The horizontal member 34 is made of steel such as an angle bar, and its tip is welded to the rail 32. The diagonal member 35 is disposed obliquely so as to connect the upper end of one of the pair of rails 32, 32 disposed at a position that forms a square corner in plan view to the lower end of the other pair of rails 32, 32 disposed at the adjacent corner. In this embodiment, the two diagonal members 35, 35 are disposed in an X-shape. The diagonal member 35 is made of steel such as an angle bar, and its tip is welded to the rail 32. Furthermore, a pair of rails 32, 32, which are arranged at the corners of a square in plan view, are connected by a connecting member 36. The connecting member 36 is made of steel and is perpendicular to the rails 32. A plurality of connecting members 36 are arranged vertically at predetermined intervals. The connecting members 36 are provided with sensors (hydraulic, electric, etc.) 37 for detecting cutting defects and cutting positions (see FIG. 5). Note that FIG. 5 shows the positional relationship between the rails 32 and the cutting machine main body 4.

[0012] As shown in Figure 5, the cutting machine body 4 includes a nozzle 41 capable of spraying high-pressure water W for cutting the steel pipe 11, wheels 42 that run on the rails 32, and a support member 43 that supports the nozzle 41. The cutting machine body 4 moves up and down along the rails 32 as the wheels 42 travel on the rails 32. The wheels 42 are rotatably supported by a support member 43. As shown in FIG. 2 , in this embodiment, the wheels 42 are provided facing in all directions in correspondence with the positions of the rails 32 on the frame 3. That is, four sets of wheels 42, 42 are provided on the support member 43 in two rows, one above the other, corresponding to the four sets of rails 32, 32 provided on the frame 3.

[0013] As shown in Figure 5, the nozzle 41 is supported by a support member 43 and is capable of spraying high-pressure water between the pair of rails 32, 32. The steel pipe 11 is cut by the high-pressure water sprayed from the nozzle 41. The nozzle 41 is arranged so that it can spray high-pressure water W toward the gap between the left and right wheels 42, 42 that travel on the pair of rails 32, 32. Four nozzles 41 are arranged at equal intervals in the circumferential direction on the support member 43, and spray high-pressure water W between the pair of rails 32, 32 provided on the frame 3. In other words, the cutting machine body 4 is capable of spraying high-pressure water W in all four directions. 2, the support member 43 in this embodiment is made of a columnar member. The cutting machine body 4 in this embodiment has four support members 43, 43, ... corresponding to the arrangement of the rails 32. That is, the cutting machine body 4 is provided with wheels 42 corresponding to each rail 32, and the wheels 42 abut against the rails 32, and the reaction force when the high-pressure water W is sprayed is supported by the frame 3. That is, the cutting machine body 4 secures the reaction force when the high-pressure water W is sprayed from the nozzle 41 from the frame 3 via the wheels 42, thereby preventing the spray direction of the high-pressure water W from being deviated.

[0014] A steel pipe cutting method using the cutting device 2 of this embodiment will be described below. The steel pipe cutting method includes a core excavation step, a device installation step, and a cutting step. In the inner excavation step, as shown in FIG. 6, an excavator M such as a hammer grab is used to excavate the inside of the steel pipe 11. The device installation process is a process of installing the frame 3 inside the steel pipe 11 from which soil and sand have been removed. Figure 7 shows the assembly status of the frame 3. The frame 3 is installed inside the steel pipe 11 by connecting another divided frame member 31 to the upper surface of a divided frame member 31 inserted into the steel pipe 11. The divided frame member 31 is inserted into the steel pipe 11 while suspended by a lifting machine C such as a crane. The divided frame member 31 is supported by a 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 divided frame member 31 is locked to the upper end of the steel pipe 11 by placing a horizontal member 34 on the locking member 5.

[0015] Next, another separate frame member 31 suspended by a crane C is placed on the upper end of the separate frame member 31 that has been locked onto the upper end of the steel pipe 11, and the joint plates 33 of both separate frame members 31, 31 are bolted together. Once the joining of the separate frame members 31 has been completed, the locking members 5 are removed and the frame 3 is lowered. Once multiple split frame members 31 are connected to form a frame 3 of a predetermined length, the frame 3 is supported by locking members 5 arranged at the upper ends of the steel pipes 11. Note that, as shown in FIG. 4, positioning members 38 are fixed to the frame 3. By abutting the positioning members 38 against the locking members 5, the rails 32 are positioned within the steel pipes 11 so that they are arranged in predetermined positions.

[0016] In the cutting process, the steel pipe 11 is cut (divided into four) along the axial direction. The steel pipe is cut by spraying high-pressure water W from the nozzle 41 while moving the cutting machine body 4 along the rails 32 of the frame 3 (see FIG. 5). At this time, the connecting members 36 connecting the rails 32 to each other are 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 body 4 suspended by the crane C is inserted to a predetermined depth into the steel pipe 11. At this time, the wheels 42 of the cutting machine body 4 are lowered in line with the rails 32. Next, as shown in FIG. 5, high-pressure water is sprayed from the nozzle 41 to start vertical cutting of the steel pipe sheet pile 1 (steel pipe 11). The cutting machine body 4 is raised along the rails 32 at a predetermined speed while spraying high-pressure water from the nozzle 41. The movement speed of the cutting machine body 4 is determined by the cutting capacity and the wall thickness of the steel pipe 11. A sensor 37 that detects the cutting position is attached to the connecting member 36 that connects the rails 32.

[0017] The steel pipe 11 is cut by replacing the nozzle 41 as needed. The timing for replacing the nozzle 41 is determined based on the cutting length by the nozzle 41, the high-pressure water spray time, or the measurement results of the sensor 37. For example, if the sensor 37 is a hydraulic sensor, the cutting status is confirmed when the hydraulic pipe is cut along with the connecting material 36, causing a drop in hydraulic pressure. Also, if the sensor 37 is an electrical sensor (electrode sensor), the cutting status is confirmed when the connecting material 36 is cut, thereby interrupting the current. When replacing the nozzle 41, cutting is temporarily stopped, the cutting machine body 4 is pulled up, and the replacement work is performed.

[0018] When restarting cutting of the steel pipe 11 after replacing the nozzle 41, the cutting machine body 4 is lowered with the wheels 42 aligned with the rails 32, and the cutting work is restarted from the position where cutting was interrupted. When the cutting of the steel pipe 11 reaches the top of the steel pipe 11, the spraying of high-pressure water from the nozzle 41 is stopped and the cutting machine body 4 is pulled up. After the operation of cutting the steel pipe 11 along its axial direction on one set of rails 32, 32 has been completed at the position of four sets of rails 32, 32, the frame 3 is pulled out from the steel pipe 11 while removing the upper split frame member 31. The pulled-out divided frame members 31 have their rails 32 connected to each other with new connecting members 36, and are used again to cut another steel pipe 11.

[0019] As described above, the cutting device 2 of this embodiment can cut the steel pipe 11 along the axial direction. When the steel pipe 11 is cut in the longitudinal direction, earth pressure or water pressure acts on the cut pieces from one direction, making it easier to remove the cut pieces. Furthermore, when the steel pipe 11 is cut in the longitudinal direction, the axial continuity of the cut pieces is maintained, making it easier to pull out the cut pieces. It should be noted that the number of divisions into which the steel pipe 11 is cut is not limited to four. Furthermore, since the frame 3 is supported by a 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. Furthermore, since the frame 3 is made up of a plurality of divided frame members 31, the labor required for transporting the frame 3 and assembling it on site can be reduced, which is efficient. When replacing the nozzle 41, it is performed while the nozzle is raised above ground, so there is no need for workers, divers, etc. to descend into the steel pipe 11, resulting in excellent workability. Furthermore, because the nozzle 41 is moved along the rails 32, when replacing the nozzle 41 and resuming cutting of the steel pipe 11, the nozzle 41 can be guided to the position where the work was interrupted. This ensures the continuity of the cutting line, which in turn makes it possible to smoothly pull out the cut pieces. Furthermore, even when the joints of the steel pipes 11 are adjacent to each other, the cut pieces of the adjacent steel pipes can be carried out together.

[0020] The above describes an embodiment of the present invention, but the present invention is not limited to the above embodiment, and each of the above components can be modified as appropriate within the scope of the invention. In the above embodiment, the case of cutting a steel pipe sheet pile 1 has been described, but the cutting device 2 of the present invention may also be used to cut, for example, a steel pipe pile, and the object to be cut is not limited as long as it is a component having a steel pipe 11. Furthermore, the number and arrangement of the rails 32 provided on the frame 3 are not limited and may be determined appropriately. Similarly, the number and arrangement of the nozzles 41 and wheels 42 provided on the cutting machine body 4 may be determined appropriately. The configuration of the locking member 5 is not limited and may be determined appropriately. The sensor 37 may be provided as needed. [Explanation of symbols]

[0021] 1 Steel pipe sheet pile 11 Steel pipe 12 Joints 2 Cutting device 3 frames 31 Divided frame member 32 Rail 4 Cutting machine body 41 nozzle 42 wheels 43 Support member 5 Locking member

Claims

1. A cutting device that cuts a steel pipe installed underground or underwater along the axial direction of the steel pipe, a cutting machine body provided with a nozzle capable of spraying 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, The cutting machine body is movable up and down along the rail, The cutting device is characterized in that the nozzle is capable of spraying high-pressure water between the rails.

2. A cutting device that cuts a steel pipe installed underground or underwater along the axial direction of the steel pipe, a cutting machine body provided with a nozzle capable of spraying high-pressure water for cutting the steel pipe; a frame installed within the steel pipe; The frame is formed by vertically connecting a plurality of divided frame members, and has a pair of rails provided along the axial direction of the steel pipe, The cutting device is characterized in that the cutting machine body is movable up and down along the rail.

3. 2. The cutting device according to claim 1, wherein the frame is formed by connecting a plurality of divided frame members one above the other.

4. A steel pipe cutting method for cutting a steel pipe in an axial direction using the cutting device according to any one of claims 1 to 3, an apparatus installation step of installing the frame in the steel pipe in a state where the frame is suspended in the steel pipe; a cutting step of moving the cutting machine body along the rails of the frame while spraying high-pressure water from the nozzle to cut the steel pipe.

5. 5. The steel pipe cutting method according to claim 4, wherein in the device installation step, a locking member is disposed on an upper end of the steel pipe, and the frame is supported by the locking member.

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