JP2010260156A - Method and device for cutting steel pipe buried underground - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method and a device for cutting a steel pipe and the like by which when cutting the steel pipe and the like buried underground, traffic disturbance can be minimized and cutting work can be performed efficiently. <P>SOLUTION: A cutter 1 provided with a plurality of rotary blades 3 is inserted into a lining steel pipe 23. Cutting work for cutting a whole circumference of a peripheral wall of a steel pipe 24 from an inside of the pipe with the rotary blades 3 is sequentially performed at positions at predetermined intervals in a longitudinal direction of the pipe. When performing the cutting work, the rotary blade 3 to be used is switched by a rotary blade switching mechanism 4 provided to the cutter 1. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a method and apparatus for cutting underground steel pipes, and more particularly, when cutting steel pipes buried in the ground, minimizing traffic obstacles and efficiently performing work. The present invention relates to a method and apparatus for cutting steel pipes that can be performed.

  Under the land, a transport pipe (pipeline) for transporting crude oil and a transport pipe for transporting various fluids such as water are buried. These transport pipes use steel pipes such as steel pipes and concrete-lined steel pipes in which concrete is lined on the outer peripheral surface of the steel pipe. In addition, steel pipe piles in which steel pipes are driven into the ground are used for civil engineering work.

  Conventionally, in order to remove a steel pipe buried in the ground, after removing the earth and sand covering the steel pipe, a cutting operation for cutting the exposed steel pipe to a predetermined length from the outside of the pipe has been performed. Subsequently, the steel pipe cut into a predetermined length was lifted and removed using a crane or the like. In this removal method, it is necessary to excavate the upper ground for cutting the steel pipe, so if there is a traffic network such as a road above the steel pipe, there will be obstacles such as blocking or regulating traffic for a long time. .

  When removing steel pipe piles that have been driven into the ground as other steel pipes, insert a cutting device into the pipe and use the cutting blade of the cutting device from the inside of the pipe to cross the circumferential wall of the steel pipe over the entire circumference. A method of lifting a portion of a steel pipe that has been cut and cut to a predetermined length using a crane is known (see Patent Document 1). In this method, since there is only one cutting blade attached to the cutting device, the cutting device is taken out of the steel pipe and damaged or worn when the cutting blade is damaged or when cutting at multiple locations. It is necessary to replace the cutting blade with a new one. Therefore, it was disadvantageous for improving work efficiency.

JP 2000-328570 A

  An object of the present invention is to provide a cutting method and a cutting device for steel pipes that can minimize the traffic obstacles and efficiently perform the work when cutting the steel pipes buried in the ground. There is.

  In order to achieve the above object, the underground steel pipe cutting method according to the present invention includes a steel pipe embedded in or buried in the ground or a protective material-coated steel pipe whose outer peripheral surface is coated with a protective material. A cutting device including a rotary blade and a rotary blade switching mechanism is inserted, and the cutting device inserted into the steel pipe performs a cutting operation for cutting the peripheral wall of the steel pipe from the inside of the pipe over the entire circumference, and the rotary blade switching mechanism. According to the above, the rotary blade used is switched.

  In the present invention, during the cutting operation, the hydraulic pressure of the cylinder or the stroke amount of the cylinder rod that presses the rotating blade being used against the peripheral wall from the inside of the pipe of the steel pipe is detected, and the cutting status of the steel pipe is determined based on this detection data. It can also be grasped. Alternatively, at the time of the cutting operation, the current value of the drive motor of the drive shaft that rotates the rotary blade being used can be detected, and the cutting status of the steel pipe can be grasped based on this detection data. In the present invention, for example, the plurality of rotary blades are sequentially switched one by one for each preset usage time.

  The cutting apparatus for underground steel pipes according to the present invention cuts the steel pipe or the steel pipe embedded in or placed in the ground or the protective material-coated steel pipe whose outer peripheral surface is covered with a protective material. A cutting device inserted into the protective material-coated steel pipe, the cutting means for cutting the steel pipe or the peripheral wall of the steel pipe of the protective material-coated steel pipe, the moving means for moving the cutting means in the longitudinal direction of the pipe, and from the inside of the pipe A drive unit that drives the cutting means so as to cut the peripheral wall of the steel pipe over the entire circumference, and the cutting means is provided with a plurality of rotary blades, and the plurality of rotary blades are arranged at use positions. A rotary blade switching mechanism is provided.

  Here, a sensor for detecting the hydraulic pressure of the cylinder or the stroke amount of the cylinder rod that presses the rotary blade arranged at the use position from the inside of the pipe of the steel pipe to the peripheral wall, and a control device to which detection data of the sensor is input, It is also possible to provide a monitor for displaying the cutting status of the steel pipe calculated based on the input detection data. Alternatively, a sensor that detects the current value of the drive motor of the drive shaft that rotates the rotary blade disposed at the use position is provided, and the control device to which the detection data of this sensor is input and the calculation based on the input detection data It is also possible to provide a monitor for displaying the cutting status of the steel pipe. In the present invention, for example, the plurality of rotary blades are sequentially switched one by one and arranged at the use position for each preset use time.

  According to the present invention, when the cutting device provided with a plurality of rotary blades inserted into the steel pipes is used to perform a cutting operation for cutting the peripheral wall of the steel pipe from the inside of the pipe over the entire circumference, the rotation installed in the cutting device. Because the blade switching mechanism can be used to switch the rotary blade to be used, even if the rotary blade is damaged or when cutting multiple locations, the cutting device can be damaged without taking it out of the steel pipe. The worn rotary blade can be replaced with a new rotary blade. Therefore, it is advantageous for improving the working efficiency.

  Since this cutting operation is performed in a state where the cutting device is inserted into the steel pipes, it is not necessary to cut the upper ground of the steel pipes. Therefore, even if a traffic network such as a road exists above the steel pipes, it is possible to avoid the occurrence of trouble such as traffic being blocked or restricted. In addition, this cutting work can be performed without being affected by the environmental conditions (rain, wind, etc.) in the area where the steel pipes are buried, so that the work is not subject to time restrictions and must be performed efficiently. Can do.

BRIEF DESCRIPTION OF THE DRAWINGS It is a whole schematic diagram which illustrates the cutting device of the steel pipes of this invention. It is AA sectional drawing of FIG. It is BB sectional drawing of FIG. It is CC sectional drawing of FIG. It is CC sectional equivalent drawing of FIG. 1 which illustrates the state which crimps | bonds the crimping | fixing fixing roller to the surrounding wall inner surface of a steel pipe. It is an AA cross-section equivalent view of Drawing 1 which illustrates the state where the peripheral wall of a steel pipe is cut with a rotary blade. It is explanatory drawing which illustrates the state which lifts up the part of the concrete lining steel pipe corresponded to the part of the steel pipe divided | segmented by predetermined length from underground. It is explanatory drawing which illustrates the state which destroys concrete lining and suspends the concrete lining steel pipe of predetermined length. It is explanatory drawing which illustrates the state which lifts up the part of the steel pipe divided | segmented into the predetermined length of the steel pipe pile driven into the ground. It is explanatory drawing which illustrates the state which lifts the part of the steel pipe parted by the predetermined length of the concrete lining steel pipe from the water bottom.

  A method and apparatus for cutting underground steel pipes according to the present invention will be described based on the embodiments shown in the drawings.

  As illustrated in FIG. 1, the underground steel pipe cutting device 1 (hereinafter referred to as a cutting device 1) of the present invention includes a cutting module 2 serving as a cutting unit and a moving module 11 serving as a moving unit. The cutting module 2 and the moving module 11 are detachably connected by a rotation drive shaft 5 with a universal joint interposed therebetween.

  The cutting module 2 has a base 10 to which a moving roller 6 is attached. A plurality of rotary blades 3 are detachably provided, and a fixing mechanism 7 is disposed in front and rear. The entire cutting module 2 is structured to rotate around a rotational drive shaft 5 that is rotationally driven by a drive motor 5a. The drive motor 5a and the rotary drive shaft 5 serve as a drive unit that drives the cutting module 2 so as to cut the peripheral wall of the steel pipe 24 from the inside of the pipe over the entire circumference.

  Furthermore, in this embodiment, sensors 20a, 20b, and 20c, which will be described later, a control device 18, and a monitor 19 are provided.

  As illustrated in FIGS. 2 and 3, the rotary blade switching mechanism 4 provided on the base 10 includes a switching rotary plate 4a and a rotary plate driving unit 4c that are fixed to the central shaft 4b and rotate around the central shaft 4b. have. The plurality of rotary blades 3 are pivotally supported on a support shaft 3a so as to be freely rotatable, and are attached to a switching rotary plate 4a.

  As illustrated in FIG. 3, the rotary plate drive unit 4 c is a ratchet mechanism, and includes an operating cylinder 4 d and a rotary drive claw 4 e that are connected via a link member 4 h. The rotation driving claw 4e rotates the gear 4f fixed to the central shaft 4b. The gear 4f is provided with a stopper 4g for preventing reverse rotation, and the switching rotary plate 4a is structured to be fixed at a predetermined rotational position.

  By extending and moving the rod of the working cylinder 4d, the rotation driving claw 4e rotates the gear 4f by one tooth, and the central shaft 4b and the switching rotating plate 4a rotate accordingly. By such an operation of the rotary plate driving unit 4c, the rotary blades 3 attached to the switching rotary plate 4a can be sequentially moved to the use position one by one.

  As illustrated in FIG. 4, the fixing mechanism 7 includes a hydraulic cylinder 9 a attached to the base 10 and a pair of arms 8. The pair of arms 8 has a pressure-fixing roller 9c at the tip, and is connected to the base 10 and the cylinder rod 9b via a link member. The number of the pair of arms 8 is not particularly limited as long as the cutting module 2 can be rotated and moved in the pipe circumferential direction while fixing the cutting module 2 in the pipe longitudinal direction of the steel pipe 24.

  As illustrated in FIG. 4, when the cylinder rod 9 b of the hydraulic cylinder 9 a is retracted, each arm 8 is in a state of being retracted with respect to the base 10. As illustrated in FIG. 5, when the cylinder rod 9 b of the hydraulic cylinder 9 a moves forward, each arm 8 moves toward the radially outer side of the base 10. Thus, the fixing mechanism 7 has a structure in which each arm 8 is contracted and expanded in the radial direction of the steel pipe 24 by the operation of the hydraulic cylinder 9a.

  The hydraulic cylinder 9 a functions to press the single rotary blade 3 arranged at the use position against the peripheral wall of the steel pipe 24. A sensor 20a for detecting the hydraulic pressure of the hydraulic cylinder 9a or a sensor 20b for detecting the stroke amount of the cylinder rod 9b is provided.

  The moving module 11 includes a casing 17 having a watertight structure, and a sensor 20 c that detects a current value of the driving motor 5 a and the driving motor 5 a is installed in the casing 17. Any one of the three types of sensors 20a, 20b, and 20c may be provided.

  On the outer surface of the casing 17, there is provided a driving traveling belt 12 that is looped between the driving roller 13 a and the driven roller 13 b. On the outer surface of the casing 17, there are further provided a pressure moving roller 14 and an outrigger 15 that project and move outward in the radial direction of the casing 17. By driving the driving belt 12, the cutting module 2 connected to the moving module 11 can move forward and backward in the longitudinal direction of the pipe.

  The casing 17 is connected with a power cable 16a and a connection wire 16b extending from the outside of the concrete lining steel pipe 23 (hereinafter referred to as the lining steel pipe 23). The necessary power is supplied to the cutting device 1 through the power cable 16a.

  Detection data of any of the installed sensors 20a, 20b, and 20c is input to the control device 18. Based on the input detection data, the cutting state of the steel pipe 24 is calculated by the control device 18. The calculated cutting status of the steel pipe 24 is configured to be displayed on the monitor 19.

  Next, a procedure for removing the lining steel pipe 23 embedded in the ground by applying the present invention will be described.

  As illustrated in FIG. 7, a lining steel pipe 23 is embedded in land and sand G. The inner diameter of the lining steel pipe 23 is, for example, about 1 m to 2 m.

  First, as illustrated in FIG. 1, the cutting device 1 inserted into the lining steel pipe 23 is moved by the moving module 11 to a predetermined position set in the pipe longitudinal direction of the lining steel pipe 23. When the cutting device 1 is moved, the drive travel belt 12 is driven while the crimping moving roller 14 of the moving module 11 is brought into contact with the inner surface of the peripheral wall of the steel pipe 24. In the cutting module 2, the arms 8 of the fixing mechanism 7 are retracted, so that the pressure fixing roller 9 c is not in contact with the inner surface of the peripheral wall of the steel tube 24, and only the moving roller 6 is applied to the inner surface of the peripheral wall of the steel tube 24. Keep in contact.

  Since the casing 17 of the moving module 11 has a watertight structure and is filled with gas, buoyancy is generated when water enters the lining steel pipe 23. This buoyancy makes it difficult to obtain a driving force from the driving traveling belt 12, but the crimping moving roller 14 provided at a position facing the driving traveling belt 12 is pressed against the inner surface of the peripheral wall of the steel pipe 24, thereby Since the inner surface of the peripheral wall of the steel pipe 24 is pressure-bonded, it is possible to reliably obtain the driving force by the driving traveling belt 12.

  The moving means for moving the cutting module 2 in the longitudinal direction of the tube is not limited to the moving module 11 as described above, and other configurations can also be adopted. For example, a string-like body such as a wire is connected to the front and rear ends of the cutting device 1. When the cutting device 1 is inserted into the concrete-lined steel pipe 23, one string-like body is extended to the outside of one end in the longitudinal direction of the concrete-lined steel pipe 23, and the other string-like body is extended to the concrete-lined steel pipe 23. It extends to the outside of the other end portion in the longitudinal direction. And by pulling one of these string-like bodies from the outside of the concrete lining steel pipe 23, the cutting device 1 (cutting module 2) can be moved to an arbitrary position.

  After the cutting device 1 is moved to a predetermined position, the cylinder rod 9b of the hydraulic cylinder 9a is advanced as illustrated in FIG. The pressure-fixing roller 9 is pressure-bonded to the inner surface of the peripheral wall of the steel pipe 24 by moving radially outward. Thereby, the cutting module 2 is fixed in the pipe longitudinal direction at a predetermined position in the pipe longitudinal direction of the lining steel pipe 23. Further, the outrigger 15 of the moving module 11 is protruded and moved outward in the radial direction of the casing 17, and its tip is crimped to the inner surface of the peripheral wall of the steel pipe 24. Accordingly, the moving module 11 is fixed at a predetermined position set in the pipe longitudinal direction of the lining steel pipe 23.

  The base 10 of the moving module 11 moves close to the inner surface of the peripheral wall of the lining steel pipe 23 by the forward movement of the cylinder rod 9b of the hydraulic cylinder 9a that moves the arm 8 in the radially outward direction of the base 10. As the base 10 moves, the entire cutting module 2 also moves close to the inner surface of the peripheral wall of the lining steel pipe 23.

  By moving the entire cutting module 2, as illustrated in FIG. 6, only one rotary blade 3 arranged at the use position among the plurality of rotary blades 3 is brought into a state of being crimped to the inner surface of the peripheral wall of the steel pipe 24. . Then, the entire cutting module 2 is rotated around the rotation drive shaft 5 by driving the drive motor 5a. Thereby, the one rotary blade 3 arrange | positioned in a use position rotates centering on the spindle 3a, pressing the blade edge | tip on the surrounding wall inner surface of the lining steel pipe 23. FIG.

  In this way, the blade edge of the rotary blade 3 is crimped to the peripheral wall of the steel pipe 24, and the rotary blade 3 is moved in the circumferential direction, thereby leaving the concrete lining 25 from the inner side of the pipe of the steel pipe 24 and the peripheral wall of the steel pipe 24. Cut along the entire circumference. The concrete lining 25 may be cut, but at least the peripheral wall of the steel pipe 24 is cut over the entire circumference. Since the cutting module 2 presses the pressure fixing roller 9c on the inner surface of the peripheral wall of the steel pipe 24, the cutting module 2 smoothly rotates and moves in the pipe circumferential direction along the inner surface of the peripheral wall of the steel pipe 24.

  When the cutting operation of the steel pipe 24 is completed at one predetermined position, as illustrated in FIG. 4, each arm 8 is returned to the retracted state, and the outrigger 15 that has been protruded is returned to the original position.

  The cutting state of the steel pipe 24 can be grasped based on detection data of any of the installed sensors 20a, 20b, and 20c. When the sensor 20a is installed, the cutting state can be grasped by the change in the hydraulic pressure of the hydraulic cylinder 9a. When this hydraulic pressure is reduced from the high pressure state during cutting, it can be determined that the cutting edge of the rotary blade 3 being used has penetrated the peripheral wall of the steel pipe 24 and the cutting operation has been completed. Accordingly, the change over time of the hydraulic pressure is displayed on the monitor 19.

  When the sensor 20b is installed, the cutting state can be grasped by changing the stroke amount of the cylinder rod 9b. When the stroke amount suddenly increases from the cutting state (gradual increase state), it can be determined that the cutting edge of the rotary blade 3 being used has penetrated the peripheral wall of the steel pipe 24 and the cutting operation has been completed. Therefore, the change over time of the stroke amount is displayed on the monitor 19.

  When the sensor 20c is installed, the cutting state can be grasped based on the change in the current value of the drive motor 5a. When this current value deviates from a certain range during cutting, it can be determined that the cutting operation has been completed with the cutting edge of the rotary blade 3 being used penetrating the peripheral wall of the steel pipe 24. Accordingly, the monitor 19 displays this change in current value over time.

  After completion of the cutting operation at one predetermined position, the moving module 11 moves the cutting device 1 to a position opened by a predetermined length in the tube longitudinal direction. Even at the newly moved position, the steel pipe 24 is cut as described above. The predetermined length for moving the cutting device 1 is, for example, about 10 m to 30 m.

  In this manner, the steel pipe 24 is cut into a predetermined length by sequentially performing the cutting operation of the steel pipe 24 described above by the cutting device 1 at a position where the predetermined length in the pipe longitudinal direction is opened. For example, the above-described cutting operation of the steel pipe 24 is sequentially performed from one end side to the other end side in the pipe longitudinal direction of the lining steel pipe 23. And the cutting operation | work of the steel pipe 24 in each predetermined position preset in the pipe longitudinal direction is completed. Thereafter, the cutting device 1 is moved toward the other end side of the lining steel pipe 23 by the moving module 11 and is moved out of the lining steel pipe 23.

  Since the rotary blade 3 is consumed by the cutting operation of the steel pipe 24, the rotary rotary plate 4a is rotated by the rotary blade switching mechanism 4, and new rotary blades 3 are sequentially arranged at the use positions. Thus, the cutting operation of the steel pipe 24 is performed by sequentially switching the plurality of rotary blades 3 one by one.

  For example, a preset usage time of one rotary blade 3 is input to the control device 18, and a plurality of rotary blades 3 are sequentially arranged at the usage position one by one for each preset usage time. And switch to use.

  In the present invention, since the plurality of rotary blades 3 are sequentially switched one by one by the rotary blade switching mechanism 4 installed in the cutting device 1, the rotary blade 3 may be damaged or cut at a plurality of locations. However, in order to replace the rotating blade 3, the damaged and worn rotating blade 3 can be replaced with a new rotating blade 3 without moving the cutting device 1 out of the lining steel pipe 23 each time. Further, when the steel pipe 24 is extremely thick (about 40 mm to 60 mm) or is a high-tensile steel pipe, a plurality of rotary blades 3 may be required even when cutting at one place. Even in such a case, the rotary blade 3 can be replaced while the cutting device 1 is inserted in the lining steel pipe 23. Therefore, the present invention is advantageous for improving the working efficiency.

  In addition, when the detection data of the sensors 20a, 20b, and 20c change remarkably on the way, it can be determined that the rotary blade 3 is damaged.

  Next, as illustrated in FIG. 7, the earth and sand G around the position where the steel pipe 24 is cut is removed. When removing the earth and sand G, sheet piles and the like are driven on both sides of the lining steel pipe 23 along the longitudinal direction of the lining steel pipe 23 so that the ground does not collapse by the removal of the earth and sand G. Then, the crane 22 is moved to an area where the lining steel pipe 23 is buried, and the suspension wire 22a is locked to the exposed lining steel pipe 23.

  7 and 8, the position where the steel pipe 24 is cut is indicated by a dotted line. Accordingly, a portion between the adjacent dotted lines is a lining steel pipe portion 23a (hereinafter referred to as a divided equivalent portion 23a) corresponding to the steel pipe portion 24a divided to a predetermined length. The method for locking the suspension wire 22a to the divided equivalent portion 23a is not particularly limited, but in the embodiment, the suspension wire 22a is locked to a member or the like fixed to the outer peripheral surface of the lining steel pipe 23.

  Next, as illustrated in FIG. 8, the part corresponding to parting 23 a is lifted by the crane 22 via the suspension wire 22 a. Since the peripheral wall of the steel pipe 24 has already been cut over the whole circumference in the circumferential direction, the concrete lining 25 around the position where the cutting work of the steel pipe 24 of the divided portion 23a to be lifted is lifted by the hanging wire 22a. Can be destroyed without any special cutting operation.

  In this way, the part corresponding to the division 23a is pulled up to the ground as it is by the suspension wire 22a and removed. This lifting operation is also sequentially performed on the remaining parting equivalent portion 23a, and the target lining steel pipe 23 is removed.

  As described above, according to the present invention, it is not necessary to cut the upper ground of the lining steel pipe 23 when the steel pipe 24 is cut. Therefore, even if a traffic network such as a road exists above the lining steel pipe 23, it is possible to avoid the occurrence of trouble such as traffic being blocked or restricted. Therefore, the traffic obstacle of the upper ground of the lining steel pipe 23 can be suppressed to the minimum.

  Moreover, this cutting operation can be performed without being affected by the environmental conditions (rain, wind, etc.) in the region where the lining steel pipe 23 is embedded. Accordingly, the work is not subjected to large time constraints, and the time freedom of the work is increased, so that the lining steel pipe 23 can be efficiently cut. Further, the cutting operation can be performed regardless of the burying angle of the lining steel pipe 23.

  The lining steel pipe 23 buried in the ground can be removed by the following procedure by applying the present invention.

  First, similarly to the previous embodiment, the cutting device 1 is inserted into the lining steel pipe 23, and the peripheral wall of the steel pipe 24 is left from the inside of the pipe at a predetermined position set in the pipe longitudinal direction of the lining steel pipe 23. Is cut along the entire circumference. Here, before the cutting work of the steel pipe 24 at all predetermined positions in the longitudinal direction of the pipe set in advance is completed, the portion that has already been cut by the suspension wire 22a of the above-described cutting equivalent portion 23a is used. Perform lifting work.

  For example, while cutting the steel pipe 24 sequentially from one end side to the other end side in the pipe longitudinal direction of the lining steel pipe 23, the lining steel pipe 23 has already been divided into a predetermined length in order from the one end side to the other end side. The part corresponding to the parting 23a is lifted and pulled up to the ground and removed. It is preferable that the parting portion 23a to be lifted be two or more parts away from the position where the cutting work is performed so that the cutting work of the steel pipe 24 is not affected.

  According to this procedure, the cutting operation of the steel pipe 24 and the lifting operation of the part corresponding to the division 23a can be performed in parallel, so that the time required for the operation can be shortened compared to the previous embodiment. Become.

  In the above embodiment, the concrete-lined steel pipe 23 is taken as an example of the protective material-coated steel pipe in which the outer peripheral surface of the steel pipe 24 is covered with the protective material. However, the present invention can be applied to other protective material-coated pipes. Examples of the protective material-coated steel pipe include an asphalt-coated steel pipe in which the protective material is asphalt, and a resin-coated steel pipe in which the protective material is a synthetic resin.

  The present invention can also be applied when part of a steel pipe 24 (steel pipe pile) driven into the ground as illustrated in FIG. 9 is removed. In the case of a steel pipe pile, the basic procedure is the same as that of the above-described embodiment. However, in this case, as the moving means (moving module 11) for moving the cutting module 2, a winch, a crane, or the like that hangs the cutting module 2 and moves it in the longitudinal direction of the pipe may be used.

  And the steel pipe 24 is cut | disconnected to predetermined length by performing the cutting | disconnection operation | work of the steel pipe 24 mentioned above with the cutting device 1 in the predetermined position (one place) of a pipe longitudinal direction. Thereafter, the cutting device 1 is moved toward the upper end side of the steel pipe 24 by the moving means and moved out of the steel pipe 24. Next, the steel pipe portion 24a cut to a predetermined length is lifted to the ground as it is by the suspension wire 22a and removed.

  The present invention can be applied not only to the protective material-coated steel pipe but also to a simple steel pipe 24 not covered with the protective material. Even when a simple steel pipe 24 is buried in the ground, the steel pipe 24 can be cut and removed by the same procedure.

  In addition, the present invention can be applied not only to steel pipes embedded in the land of the land (simple steel pipe 24 and lining steel pipe 23) but also to steel pipes embedded in the bottom of the water. The procedure for cutting and removing the steel pipes buried in the bottom of the water is the same as in the above embodiment.

  That is, the cutting operation of cutting the peripheral wall of the steel pipe 24 from the inside of the pipe over the entire circumference in the pipe longitudinal direction by the cutting device 1 in which the steel pipe buried in the water bottom is inserted into the steel pipe. At a position where a predetermined length is opened. Next, as illustrated in FIG. 10, the steel pipe 24 is lifted and removed by sequentially performing a lifting operation for lifting the steel pipe portion 24 a divided by a predetermined length by cutting the steel pipe 24 (or the divided equivalent portion 23 a). To do. For the lifting work, a crane 22 mounted on the work boat 21 is used as illustrated in FIG.

  As described above, according to the present invention, when cutting the steel pipe 24, the work boat 21 that becomes an obstacle to water traffic becomes unnecessary. Therefore, the obstacle to the water traffic in this water area can be minimized.

  Moreover, the cutting operation of the steel pipe 24 can be performed without being affected by the environmental conditions (waves, wind, tidal current, etc.) of this water area, and can be performed day and night. As a result, the work is not subject to significant restrictions in time, and the time freedom of the work is increased, so that the steel pipes can be cut efficiently.

1 Cutting device 2 Cutting module (cutting means)
DESCRIPTION OF SYMBOLS 3 Rotating blade 3a Support shaft 4 Rotating blade switching mechanism 4a Switching rotating plate 4b Center shaft 4c Rotating plate driving part 4d Actuating cylinder 4e Rotating driving claw 4f Gear 4g Stopper 4h Link member 5 Rotating driving shaft 5a Driving motor 6 Moving roller 7 Fixing mechanism 8 Arm 9a Hydraulic cylinder 9b Cylinder rod 9c Crimp fixing roller 10 Base 11 Moving module (moving means)
Reference Signs List 12 drive belt 13 drive roller 14 driven roller 15 outrigger 16a power cable 16b connecting wire 17 casing 18 control device 19 monitor 20a, 20b, 20c sensor 21 work ship 22 crane 22a hanging wire 23 lining steel pipe 23a parting equivalent part 24 steel pipe 24a predetermined Steel pipe part 25 divided into lengths Concrete lining

Claims (8)

  Insert a cutting device equipped with multiple rotary blades and rotary blade switching mechanism into a steel pipe buried or placed in the ground or a protective material-coated steel pipe whose outer peripheral surface is covered with a protective material. A method for cutting underground steel pipes in which underground cutting is performed by cutting the peripheral wall of the steel pipe from the inside of the pipe over the entire circumference with the cutting device inserted into the pipe, and the rotary blade used by the rotary blade switching mechanism is switched.   In the cutting operation, the hydraulic pressure of the cylinder or the stroke amount of the cylinder rod that presses the rotary blade being used against the peripheral wall from the inside of the pipe of the steel pipe is detected, and the cutting status of the steel pipe is grasped based on this detection data Item 2. A method for cutting underground steel pipes according to item 1.   The underground embedment according to claim 1, wherein a current value of a drive motor of a drive shaft that rotates a rotary blade being used is detected during the cutting operation, and a cutting state of the steel pipe is grasped based on the detection data. Cutting method of steel pipes.   The method for cutting underground steel pipes according to any one of claims 1 to 3, wherein the plurality of rotary blades are sequentially switched one by one for each preset usage time.   A cutting device that is inserted into the steel pipe or the protective material-coated steel pipe when cutting the steel pipe buried in the ground or the protective material-coated steel pipe whose outer peripheral surface is covered with a protective material. A cutting means for cutting the peripheral wall of the steel pipe or the steel pipe of the protective material-coated steel pipe; a moving means for moving the cutting means in the longitudinal direction of the pipe; and And a drive unit for driving the cutting means, and a plurality of rotary blades are provided on the cutting means, and a rotary blade switching mechanism for arranging the plurality of rotary blades at use positions is provided. Cutting device.   A sensor for detecting the hydraulic pressure of the cylinder or the stroke amount of the cylinder rod that presses the rotary blade arranged at the use position against the peripheral wall from the inside of the steel pipe is provided, and a control device to which detection data of the sensor is input, and The cutting device for underground steel pipes according to claim 5, further comprising a monitor for displaying a cutting state of the steel pipe calculated based on the detection data.   A sensor that detects a current value of a drive motor of a drive shaft that rotates the rotary blade arranged at the use position is provided, and a control device to which detection data of the sensor is input and calculated based on the input detection data 6. The underground steel pipe cutting device according to claim 5, further comprising a monitor that displays a cutting status of the steel pipe.   The cutting device for underground steel pipes according to any one of claims 5 to 7, wherein the plurality of rotary blades are sequentially switched one by one for each preset usage time and arranged at the use position.

Images