Steel pipe removal device

Abstract

To provide a steel pipe pile removal device allowing an existing steel pipe pile laid underground to be easily pulled out.SOLUTION: A steel pipe pile removal device 1, which is attached on a rotary type pile driving machine 2, is to pull out an existing steel pipe pile 3 laid underground. The steel pipe pile removal device 1 is provided with: a connection part 11 connected to the rotary type pile driving machine 2; a suspended wall 13 suspended downward from a lower surface of a based member 12 fixed on the connection part 11 and placed so as to surround over an upper end outer peripheral part of the steel pipe pile 3; a hydraulic cylinder 14 fixed on the suspended wall 13; and a pair of tooth-like projection members 15, on which push pressure of the hydraulic cylinder 14 acts, placed to face each other in a radial direction so as to clamp the outer peripheral surface of the steel pipe pile 3 from an outer side in the radial direction. Action of the push pressure of the hydraulic cylinder 14 clamps the outer peripheral surface of the steel pipe pile 3 with the tooth-like projection members 15 in the radial direction to apply the pull-out force while rotating the steel pipe pile removal device 1 with the rotary type pile driving machine 2, so that the steel pipe pile 3 is pulled out.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a steel pipe pile removal device for extracting existing steel pipe piles buried in the ground. [Background technology]

[0002] Traditionally, work has been carried out to remove foundation piles buried underground after the demolition of existing buildings. Various methods for removing foundation piles have been proposed, including the ring-throwing method, in which a cylindrical casing is rotated and pressed into the existing pile to separate it from the ground, and then a wire is attached to the head of the existing pile and it is pulled out with a crane; and the chucking method, in which a claw attached to the bottom of the casing grips the bottom end of the existing pile and pulls out the casing while it remains inside.

[0003] Furthermore, as a foundation pile, a steel pipe pile has been known in the past that has a spiral drilling blade and a downwardly protruding drilling blade at the bottom end thereof, and is driven into the ground while applying a rotational force and a pressing force. However, such a conventional steel pipe pile has a problem in that the spiral drilling blade is easily deformed during driving.

[0004] In order to solve such problems, the following Patent Documents 1 and 2 disclose a steel pipe pile in which approximately half of the lower cross section of the pile body made of steel pipe is formed at different inclination angles, and the inclination angles are not perpendicular to the axial direction of the pile body but intersect with each other, a plate is welded to approximately the center of the lower cross section of the pile body so as to extend in the same axial direction, to form an axial protruding blade, and approximately half of the lower cross section is welded to the surface of each of two rectangular plates larger than the approximately half of the lower cross section, so that radial protruding blades are formed on both sides of the axial protruding blade. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2001-152446 [Patent Document 2] Japanese Patent Application Laid-Open No. 2005-90128 Summary of the Invention [Problem to be solved by the invention]

[0006] The steel pipe piles described in Patent Documents 1 and 2 are small in diameter, approximately 100 to 400 mm, and when removing such small-diameter steel pipe piles, using the conventional ring tossing method or chucking method described above would result in high costs and a long construction period.

[0007] SUMMARY OF THE INVENTION It is therefore a primary object of the present invention to provide a steel pipe pile removal device that can easily pull out existing steel pipe piles buried in the ground. [Means for solving the problem]

[0008] In order to solve the above problem, the present invention according to claim 1 provides a steel pipe pile removal device that is attached to a rotary pile driver and that pulls out existing steel pipe piles buried in the ground, The steel pipe pile removal device comprises a connecting part connected to the rotary pile driver, a hanging wall hanging downward from the underside of a base member fixed to the connecting part and arranged so as to surround the entire outer periphery of the upper end of the steel pipe pile, a hydraulic cylinder fixed to the hanging wall, and tooth-like protrusion members arranged in pairs facing each other in the diameter direction so as to apply a pressing force from the hydraulic cylinder and to sandwich the outer periphery of the steel pipe pile from the outer side in the diameter direction, the tooth-like projection member is attached to a block-shaped holder, and the holder is surrounded by a guide member that is in sliding contact with the outer peripheral surface of the holder; A steel pipe pile removal device is provided, characterized in that the tooth-like protrusion members clamp the outer surface of the steel pipe pile in the diametrical direction by applying a pressing force from the hydraulic cylinder, and the steel pipe pile is pulled out by applying a pulling force while rotating the steel pipe pile removal device with the rotary pile driver.

[0009] The invention described in claim 1 above is provided with tooth-like protrusion members arranged in pairs facing each other in the diameter direction so as to clamp the outer peripheral surface of the steel pipe pile from the outer diametrical side, and a hydraulic cylinder that presses the tooth-like protrusion members, and by applying the pressing force of the hydraulic cylinder, the tooth-like protrusion members clamp the outer peripheral surface of the steel pipe pile in the diameter direction, and the steel pipe pile is pulled out by applying a pulling force while rotating the steel pipe pile removal device with the rotary pile driver. The tooth-like protrusion member is attached to a block-shaped holder, and the holder is surrounded by a guide member that slides against the outer surface of the holder.When the holder is pressed and moved with a hydraulic cylinder, the holder is guided by the surrounding guide member, and the tooth-like protrusion member comes into contact with the steel pipe pile.

[0010] In this way, the upper end of the steel pipe pile is directly clamped with the tooth-like protrusion member and pulled out while rotating it with a rotary pile driver, so there is no need to penetrate the casing as in conventional construction methods, and the pile can be easily pulled out.

[0011] As the present invention according to claim 2, there is provided a steel pipe pile removal device as described in claim 1, which is provided with a pressure support member that is inserted into the interior from the upper end opening of the steel pipe pile and is positioned at the clamping position of the tooth-like protrusion member.

[0012] If the interior of a steel pipe pile is filled with a filler such as mortar, the steel pipe pile will not be crushed even if it is directly clamped with the tooth-like projection members, but if the interior of the steel pipe pile is hollow, the steel pipe pile may be crushed by the high pressing force when clamped with the tooth-like projection members. Therefore, in the invention described in claim 2 above, a pressure support member is placed inside the hollow interior at the clamping position of the tooth-like projection members, preventing the steel pipe pile from being crushed when clamped with the tooth-like projection members. [Effects of the Invention]

[0013] As explained above in detail, according to the present invention, it becomes possible to easily pull out existing steel pipe piles buried in the ground. [Brief explanation of the drawings]

[0014] [Figure 1] 1 is an overall view showing a steel pipe pile removal work using a steel pipe pile removal device 1 according to the present invention. [Figure 2]FIG. 2 is a longitudinal cross-sectional view showing the steel pipe pile removal device 1. [Figure 3] FIG. 2 is a side view showing the steel pipe pile removal device 1. [Figure 4] FIG. 2 is a bottom view showing the steel pipe pile removal device 1. [Figure 5] 1A and 1B show a connecting portion 11, in which (A) is a plan view and (B) is a view taken along the line BB in (A). [Figure 6] 1A shows a base member 12 and a hanging wall 13, where (A) is a bottom view, (B) is a view taken along line BB in (A), and (C) is a view taken along line CC in (A). [Figure 7] 2A shows the attached state of the holder 18, (A) is a cross-sectional view (view taken along line VIIA-VIIA in FIG. 2), (B) is a view taken along line BB in (A), and (C) is a view taken from the C direction in (B). [Figure 8] 10(A) and 10(B) are longitudinal cross-sectional views showing the process of removing the steel pipe pile 3. DETAILED DESCRIPTION OF THE INVENTION

[0015] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

[0016] As shown in FIG. 1, a steel pipe pile removal device 1 according to the present invention is attached to a rotary pile driver 2 and is used to pull out and remove existing steel pipe piles 3 buried in the ground.

[0017] The rotary pile driver 2 is a heavy machine equipped with a leader 5 held by a base machine 4 and extending vertically in a straight line, and an auger 6 that is movable vertically along the leader 5 and has an output shaft of a hydraulic motor that serves as a rotary drive source. The rotary pile driver 2 also includes a power transmission 7 that is movable vertically along the leader 5 in response to the vertical movement of the auger 6 and transmits power from the output shaft of the auger 6 to the connecting shaft of the steel pipe pile removal device 1, as needed. The power transmission 7 is positioned such that the axis of the rotating shaft to which the steel pipe pile removal device 1 is connected is farther from the leader 5 than the axis of the output shaft of the auger 6. The power transmission 7 is provided as needed when the steel pipe pile removal device 1 comes into contact with the leader 5 when attached. The power transmission 7 may also function as a reducer.

[0018] The steel pipe pile 3 is a tubular steel pile buried in the ground, and may be buried with the inside of the pipe filled with a filler material such as mortar, or may be buried hollow without being filled with a filler material.

[0019] The steel pipe piles 3 targeted by the steel pipe pile removal device 1 of the present invention are mainly small in diameter, approximately 100 to 400 mm, and are provided with a penetration cutting blade at the lower end of the pile that protrudes circumferentially outward from the pile body.

[0020] Furthermore, examples of particularly suitable steel pipe piles 3 include the steel pipe piles disclosed in the above-mentioned Patent Documents 1 and 2. Specifically, as shown in Fig. 1, this steel pipe pile has a pile body 3a made of a steel pipe, with approximately half of the bottom cross section formed at different inclination angles, each at an inclination angle that is not perpendicular to the axial direction of the pile body but intersects with the axial direction of the pile body, a plate is welded to approximately the center of the bottom cross section of the pile body 3a so as to extend in the same axial direction, to form an axial protruding blade 3b, and two rectangular plates larger than the approximately half of the bottom cross section are welded to the surfaces of the approximately half of the bottom cross section, so that radial protruding blades 3c, 3c are formed on both sides of the axial protruding blade 3b.

[0021] To drive the steel pipe piles disclosed in Patent Documents 1 and 2, the pile member is driven into the ground by applying downward pressure while rotating it in only one direction (for example, clockwise). Once the pile member is buried in the ground, a new pile member is welded to the top end of the pile member, and the process of applying downward pressure while rotating it is repeated to complete the construction of the steel pipe pile. During the above-described steel pipe pile driving process, when the pile member is driven into the ground by applying rotational force and pressing force, the radial protruding blades 3c disturb the ground, reducing its strength, and the steel pipe pushes open the disturbed ground.

[0022] As shown in Figures 2 to 4, the steel pipe pile removal device 1 comprises a connecting portion 11 connected to the output shaft of a power transmission device 7 connected to the output shaft of an auger 6 provided on the rotary pile driver 2, a base member 12 fixed to this connecting portion 11, a hanging wall 13 hanging downward from the underside of the base member 12 and arranged to surround the entire outer periphery of the upper end of the steel pipe pile 3, a hydraulic cylinder 14 fixed to the hanging wall 13, and tooth-like protrusion members 15 arranged in pairs facing each other in the diameter direction so that the pressing force of the hydraulic cylinder 14 acts and the outer periphery of the steel pipe pile 3 is sandwiched from the outer side in the diameter direction.

[0023] 5, the connecting portion 11 is composed of a connecting shaft 16 that is connected to the output shaft of the power transmission device 7, and a disk-shaped connecting plate 17 that is welded to the lower end of the connecting shaft 16. The connecting plate 17 has a large number of through holes 17a formed at intervals in the circumferential direction, penetrating the plate in the thickness direction and through which bolts for fixing the plate to the base member 12 are inserted.

[0024] The base member 12 is disposed on the underside of the connecting portion 11, and the hanging wall 13 is fixed to the underside of this base member 12.

[0025] As shown in FIG. 6 , the base member 12 is a disk-shaped member having approximately the same diameter as the connecting plate 17. A number of through-holes 12a are formed at the same positions as the connecting plate 17, circumferentially spaced apart, penetrating the base member 12 in the thickness direction for inserting bolts for fastening the base member 12 to the connecting plate 17. An opening 12b is formed in the center for inserting the lower end of the connecting shaft 16. Furthermore, a fixed seat 12c is fixed to the lower surface of the base member 12 by welding, straddling the opening 12b. This fixed seat 12c supports the upper end of a shaft portion 22a of a pressure support member 22, which will be described in detail later, by a pin connection. An opening 12d is formed in the center of the plane of the fixed seat 12c, through which the upper end of the shaft portion 22a of the pressure support member 22 is inserted. A pin insertion hole 12e is also formed, passing through the opening 12d and penetrating a pair of opposing side surfaces of the fixed seat 12c.

[0026] The hanging wall 13 is formed by connecting a plurality of wall members together to form a generally polygonal shape that closes in plan view so as to surround the entire outer periphery of the upper end of the steel pipe pile 3. The upper edges of these wall members are fixed by welding to the underside of the base member 12. This forms a space that is open downward and whose periphery is surrounded by the hanging wall 13 and whose upper surface is covered by the base member 12.

[0027] In the illustrated example, a pair of tooth-like projection members 15 are arranged opposite each other in the diameter direction of the steel pipe pile 3, and therefore the planar shape of the space surrounded by the hanging wall 13 is formed as a rectangle that is long in the direction in which these tooth-like projection members 15, 15 are arranged. However, if, in addition, a pair of tooth-like projection members 15, 15 are arranged opposite each other in a direction perpendicular to this, thereby providing a total of two pairs of tooth-like projection members 15 (if the tooth-like projection members 15 are arranged at 90° intervals in a plan view of the steel pipe pile 3), the planar shape of the space can be made approximately square, and if the tooth-like projection members 15 are arranged at 60° intervals in a plan view of the steel pipe pile 3, thereby providing a total of three pairs of tooth-like projection members 15, the planar shape of the space can be made approximately hexagonal.

[0028] The hydraulic cylinder 14 is a device that hydraulically moves a piston inside the cylinder to move an output shaft fixed to the piston in the axial direction, and a wide variety of commercially available devices can be used. The hydraulic cylinder 14 is fixed to each of the opposing hanging walls 13, 13 on which the tooth-like protrusion members 15 are provided. The hydraulic cylinder 14 is fixed to the hanging wall 13 by fixing the main body of the hydraulic cylinder 14 to the outer surface of the hanging wall 13 with bolts or the like, while the tip of the output shaft faces the interior of the space surrounded by the hanging wall 13 through a through hole formed in the hanging wall 13.

[0029] A toothed member 15 is attached to the tip of the output shaft of the hydraulic cylinder 14 via a block-shaped holder 18. That is, the toothed member 15 is attached to the block-shaped holder 18, and this holder 18 is attached to the tip of the output shaft of the hydraulic cylinder 14.

[0030] As shown in FIG. 7(A), the tooth-like projection member 15 is a member having a tooth-like projection surface on its contact surface with the outer circumferential surface of the steel pipe pile 3, in which multiple vertically extending recessed grooves and protrusions are alternately arranged. The tooth-like projection member 15 is inserted into a recess formed in the front end surface of a retainer 18 (the surface facing the steel pipe pile 3) with the tooth-like projection surface facing outward, and the retainer 18 and tooth-like projection member 15 are pin-connected by a pin member 19 that passes integrally through the retainer 18 and tooth-like projection member 15. The tooth-like projection members 15, 15 are arranged in pairs facing each other in the diametrical direction, with two tooth-like projection members 15 spaced apart on the left and right sides around the output shaft of the hydraulic cylinder 14. The tooth-like projection surfaces of the tooth-like projection members 15 spaced apart on the left and right sides are arranged obliquely, inclined to opposite sides in accordance with the curvature of the steel pipe pile 3, so that they face each other as vertically as possible when they abut against the outer circumferential surface of the steel pipe pile 3.

[0031] A recess is formed in the center of the rear end face of the holder 18, into which the tip of the output shaft of the hydraulic cylinder 14 is inserted, and with the output shaft of the hydraulic cylinder 14 inserted into this recess, the holder 18 and the output shaft are connected by a pin member 20 that passes through the holder 18 and the output shaft together.

[0032] The holder 18 is formed in the shape of a substantially rectangular parallelepiped block, and is surrounded by guide members 21 that make sliding contact with the outer circumferential surface of the holder 18. Specifically, as shown in FIG. 7(C), upper and lower guide members 21a, 21a are disposed above and below the holder 18, respectively, with both end surfaces fixed to the opposing hanging walls 13, 13, and left and right guide members 21b, 21b are disposed on the left and right sides of the holder 18, respectively, with the same height as the holder 18 and one end surface fixed to the adjacent hanging wall 13. When the hydraulic cylinder 14 is operated to move the holder 18, the outer circumferential surface of the holder 18 slides against the opposing surfaces of the surrounding guide members 21, guiding the movement direction of the holder 18. A surface material or surface treatment may be applied to the sliding surfaces of each guide member 21 that come into contact with the holder 18 to reduce friction and facilitate sliding of the holder 18.

[0033] If the steel pipe pile 3 is buried hollow without being filled with filler, the pressing force of the hydraulic cylinder 14 may crush the steel pipe pile 3 at the clamping position of the tooth-like projection members 15, making it impossible for the tooth-like projection members 15 to clamp it. Therefore, if the steel pipe pile 3 is buried hollow, the steel pipe pile removal device 1 is provided with a pressure support member 22, as shown in Figure 2, which is inserted into the steel pipe pile 3 from the upper end opening and is placed at the clamping position of the tooth-like projection members 15. The provision of this pressure support member 22 supports the pressing force of the tooth-like projection members 15, preventing the steel pipe pile 3 from being crushed when the steel pipe pile 3 is clamped diametrically by the tooth-like projection members 15.

[0034] The pressure support member 22 is composed of a shaft portion 22a extending downward from the fixed seat 12c of the base member 12, and a pressure support portion 22b that engages with the shaft portion 22a. As described above, the shaft portion 22a is attached to the fixed seat 12c by inserting the upper end of the shaft portion 22a into the opening 12d provided in the fixed seat 12c of the base member 12, and then inserting a pin member 23 into the pin insertion hole 12e of the fixed seat 12c to integrally pin-couple the upper end of the fixed seat 12c and the shaft portion 22a. A step portion 22c that protrudes outward in the circumferential direction is provided at the middle portion of the shaft portion 22a, and the pressure support portion 22b engages with the step portion 22c, thereby supporting the pressure support portion 22b on the shaft portion 22a.

[0035] The pressure support portion 22b is a cylindrical or columnar member formed with an outer diameter slightly smaller than the inner diameter of the steel pipe pile 3. Although it varies depending on the size of the steel pipe pile 3, the outer diameter of the pressure support portion 22b is formed to be approximately 10 to 30 mm smaller than the inner diameter of the steel pipe pile 3. A plurality of types of the pressure support portion 22b with different outer diameter dimensions are prepared to match the inner diameter of the steel pipe pile 3.

[0036] On the other hand, if the steel pipe pile 3 is buried with a filler material such as mortar filled inside, there is no need to provide the pressure support member 22, and the pressing force of the tooth-like protrusion member 15 is supported by the internal filler material.

[0037] As shown in Figures 2 to 4, a cover 24 is fixed in a hanging state to the outer periphery of the lower surface of the base member 12 so as to surround each component arranged on the lower surface side of the base member 12.

[0038] Next, a procedure for extracting an existing steel pipe pile 3 buried in the ground using the steel pipe pile removal device 1 will be described.

[0039] First, as shown in Figure 1, a heavy excavation machine such as a hydraulic excavator is used to excavate the ground around the steel pipe pile 3, exposing the head of the steel pipe pile 3. Then, a rotary pile driver 2 equipped with a steel pipe pile removal device 1 is placed nearby. If the steel pipe pile 3 is buried hollow without being filled with filler material, as in the illustrated example, a pressure support part 22a that fits the inner diameter of the steel pipe pile 3 is set in advance in the steel pipe pile removal device 1.

[0040] Next, as shown in Figure 8(A), with the center of the pressure support member 22 aligned with the center of the steel pipe pile 3, the auger 6 of the rotary pile driver 2 is lowered to insert the pressure support member 22 into the inside of the steel pipe pile 3.

[0041] As shown in Figure 8(B), once the steel pipe pile 3 has been lowered until its upper edge abuts against the underside of the fixed pedestal 12c of the base member 12, the pair of hydraulic cylinders 14 are operated evenly to press the tooth-like projection members 15 against the outer circumferential surface of the steel pipe pile 3. At this time, as shown in Figure 8(B), the portion of the steel pipe pile 3 pressed by the tooth-like projection members 15 may be deformed inward, and a pressing force may be applied until the steel pipe pile 3 is sandwiched between the internal pressure support member 22 and the tooth-like projection members 15, or if the steel pipe pile 3 is thick, it may be clamped in a state where it is sandwiched between the tooth-like projection members 15, 15 that face each other in the diametric direction of the steel pipe pile 3 without being deformed that much.

[0042] Once the steel pipe pile 3 has been clamped by the tooth-like projection member 15, the auger 6 is driven to rotate the steel pipe pile removal device 1, and the steel pipe pile 3 is pulled out.

[0043] When extracting the steel pipe pile 3, the auger 6 first performs a swinging rotation, repeatedly rotating left and right at a predetermined rotation angle, to loosen the restraint of the steel pipe pile 3 due to ground pressure. The swinging rotation angle is initially small and gradually increased. When the left and right rotations can be performed by approximately 180° each, the steel pipe pile 3 is rotated in the opposite direction to the direction of rotation used when penetrating (e.g., left), and a pulling force is applied to extract the steel pipe pile 3. When the auger 6 reaches the top of the leader 5, the bottom end of the steel pipe pile 3 exposed above ground is cut off by a cutting means such as gas fusing. The pressing force of the hydraulic cylinder 14 is released, and the top part of the cut steel pipe pile 3 is removed from the steel pipe pile removal device 1. The top end of the buried steel pipe pile 3 is then clamped again by the tooth-like projection member 15, and the process of pulling it out upward while rotating is repeated until all of the steel pipe piles 3 have been removed.

[0044] In the process of removing the steel pipe pile 3 as described above, when the steel pipe pile 3 is being pulled out by applying a rotational force and a pulling force to it, the axial protruding blades 3b and radial protruding blades 3c, 3c provided at the lower end of the steel pipe pile 3 disturb the surrounding ground, reducing the ground strength, and this disturbed surrounding ground collapses into the area where the steel pipe pile 3 was buried, causing the opening to close naturally and eliminating the need for backfilling. [Explanation of symbols]

[0045] 1...steel pipe pile removal device, 2...rotary pile driver, 3...steel pipe pile, 4...base machine, 5...leader, 6...auger, 7...power transmission machine, 11...connecting part, 12...base member, 13...hanging wall, 14...hydraulic cylinder, 15...tooth-shaped projection member, 16...connecting shaft, 17...connecting plate, 18...holding device, 19...pin member, 20...pin member, 21...guide member, 22...pressure support member, 23...pin member, 24...cover

Claims

1. A steel pipe pile removal device attached to a rotary pile driver for extracting existing steel pipe piles buried in the ground, The steel pipe pile removal device comprises a connecting part connected to the rotary pile driver, a hanging wall hanging downward from the underside of a base member fixed to the connecting part and arranged so as to surround the entire outer periphery of the upper end of the steel pipe pile, a hydraulic cylinder fixed to the hanging wall, and tooth-like protrusion members arranged in pairs facing each other in the diameter direction so as to apply a pressing force from the hydraulic cylinder and to sandwich the outer periphery of the steel pipe pile from the outer side in the diameter direction, the tooth-like projection member is attached to a block-shaped holder, and the holder is surrounded by a guide member that is in sliding contact with the outer peripheral surface of the holder; A steel pipe pile removal device characterized by applying a pressing force from the hydraulic cylinder to the tooth-like protrusion members to clamp the outer surface of the steel pipe pile in the diametrical direction, and then applying a pulling force while rotating the steel pipe pile removal device with the rotary pile driver, thereby pulling out the steel pipe pile.

2. 2. The steel pipe pile removal device according to claim 1, further comprising a pressure support member that is inserted into the steel pipe pile from an upper end opening and is positioned at a clamping position of the tooth-like projection members.

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