Existing pile removal system and method

Abstract

To provide an existing pile removal system and a method capable of efficiently removing an existing concrete pile embedded in the foundation.SOLUTION: After a casing 1 is extrapolated at the upper end of an existing pile P in the foundation, the casing 1 and a hole boring unit (hammer 3, hammer rod 5, or the like) are integrated to be rotary-driven. The hammer 3 is vertically hit by air supplied through a hose 10. A columnar hole Ph is formed at the upper end of the existing pile P. A cutting unit 16 is installed in the casing 1 in place of the hole boring unit. An expansion-contraction bit 17 is inserted into the columnar hole Ph. The casing 1 and the cutting unit 16 are integrated to be rotary-driven. The expansion-contraction bit 17 is expanded to cut the peripheral wall of the columna hole Ph, thereby forming a cylindrical body P1. The cylindrical body P1 is placed on the expanded expansion-contraction bit 17, and the cutting unit 16 is vertically moved to take out the cylindrical body P1 from the casing 1.SELECTED DRAWING: Figure 21

Description

[Technical field]

[0001] The present invention relates to a system and method for removing existing piles, and more particularly to a system and method for more efficiently removing existing concrete piles buried in the ground. [Background technology]

[0002] Concrete piles are buried in the ground to support structures such as buildings. When demolishing a structure, it is necessary to remove these existing piles that support the structure. Various methods for removing existing piles buried in the ground have been proposed (for example, see Patent Documents 1 to 4).

[0003] Patent Documents 1 and 2 propose a method of crushing existing piles one by one from the top using an auger. However, it takes a long time to crush the existing piles using only the rotational driving force of the auger. In addition, the rotation axis of the auger is prone to vibration relative to the existing piles, which is disadvantageous for stable operation.

[0004] In the methods proposed in Patent Documents 3 and 4, the removal work of the existing pile is performed using a cutting blade (cutting bit) inside a cylindrical casing, so that the work can be carried out stably. However, in the methods proposed in these documents, when the existing pile is cut at a position halfway in the longitudinal direction, the cutting work is performed while changing the cutting edge of the cutting blade (cutting bit) from the outer periphery of the existing pile toward the inner periphery. When the cutting work is performed while changing the direction of the cutting edge of the cutting blade (cutting bit) in this way, an excessive load acts on the cutting device and the cutting blade (cutting bit), so cutting becomes difficult when the outer diameter of the existing pile becomes large. In addition, if the speed at which the cutting edge of the cutting blade (cutting bit) is changed in direction is slowed down to avoid excessive load, the time required for the cutting work will be longer. Therefore, there is room for improvement in order to more efficiently remove the existing concrete pile buried in the ground. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 9-203040 [Patent Document 2] JP 2019-123993 A [Patent Document 3] JP 2005-314871 A [Patent Document 4] JP 2008-303642 A Summary of the Invention [Problem to be solved by the invention]

[0006] An object of the present invention is to provide a system and method for removing existing concrete piles that are buried in the ground and can be removed more efficiently. [Means for solving the problem]

[0007] In order to achieve the above object, the present invention provides a system for removing existing piles, which comprises a casing having a casing bit at its lower end, a rotary drive device for holding the outer peripheral surface of the casing and rotating the casing, a drilling unit having a hammer rod with a hammer with a hammer bit attached to its lower end, and a cutting unit having an expandable bit that moves in an expandable / contractable manner, and the drilling unit and the cutting unit are selectively installed inside the casing. In a drilling mode in which the casing is rotated and driven by the rotary drive device and moved downward to a state where it is extrapolated to the upper end of an existing pile buried in the ground, and then the drilling unit is installed inside the casing, the casing and the drilling unit are integrated and rotated by the rotary drive device, and a hose connected to the hammer rod is connected to the drilling unit. In a cutting mode in which the cutting unit is installed inside the casing, the expandable bit in a reduced diameter state is inserted into the cylindrical hole, the casing and the cutting unit are integrated and rotated by the rotary drive device, and the expandable bit is expanded in diameter to cut the peripheral wall of the cylindrical hole to form a cylindrical body, the casing and the cutting unit that were integrated together are separated, the cylindrical body is placed on the expandable bit in an expanded diameter state, and the cutting unit is moved upward to remove it from inside the casing together with the cylindrical body, and the process of forming the cylindrical hole in the hole-drilling mode and the process of forming the cylindrical body and removing it from inside the casing in the cutting mode are performed a required number of times.

[0008] The method for removing an existing pile of the present invention selectively installs a drilling unit having a hammer rod with a hammer attached to the lower end thereof and a cutting unit having an expansion / contraction bit that moves in an expansion / contract manner inside a casing having a casing bit at the lower end thereof, and a rotary drive device holds the outer peripheral surface of the casing and rotates and moves it downwardly to place the casing in a state in which it is inserted onto the upper end of the existing pile buried in the ground. In a drilling mode in which the drilling unit is installed inside the casing, the casing and the drilling unit are The casing and the cutting unit are integrated and rotated by the rotary drive device, and an upper and lower striking force is applied to the hammer by air supplied through a hose connected to the hammer rod, while the hammer bit forms a cylindrical hole of a predetermined depth at the upper end of the existing pile. In a cutting mode in which the cutting unit is installed inside the casing, the expandable bit in a reduced diameter state is inserted into the cylindrical hole, the casing and the cutting unit are integrated and rotated by the rotary drive device, and the expandable bit is expanded in diameter to cut the peripheral wall of the cylindrical hole to form a cylindrical body. The method is characterized in that the casing and the cutting unit, which were integrated together, are separated, the cylindrical body is placed on the expansion / contraction bit in an expanded diameter state, the cutting unit is moved upward, and the cylindrical body is removed from inside the casing, and the process of forming the cylindrical hole in the hole-making mode and forming the cylindrical body in the cutting mode and removing it from inside the casing is performed the required number of times. Effect of the Invention

[0009] According to the present invention, in the drilling mode using the drilling unit, the cylindrical hole can be quickly formed in the upper end of the existing pile by the rotating hammer bit and the up and down striking force of the hammer. In the cutting mode using the cutting unit, the peripheral wall of the cylindrical hole can be cut to form the cylindrical body without excessive load being applied to the cutting unit. The drilling unit and the cutting unit are integrated with the casing, so that axial vibration is suppressed and the drilling unit is stably rotated. Therefore, by combining the drilling mode and the cutting mode, it is possible to efficiently remove even a large-diameter existing pile from the ground. [Brief description of the drawings]

[0010] [Figure 1] 1 is an explanatory diagram illustrating the overall configuration of an embodiment of an existing pile removal system from a front view with the inside of a casing visible. FIG. [Diagram 2] FIG. 1 is an explanatory diagram illustrating the state in which a casing is extrapolated onto the upper end of an existing pile buried in the ground, as viewed from the front with a view into the inside of the casing. [Diagram 3] 2 is an explanatory diagram illustrating a front view of a hole-drilling unit installed inside the casing of FIG. 1. [Figure 4] 4A and 4B are explanatory views illustrating the hammer and hammer rod of FIG. 3, in which FIG. 4A is a top view and FIG. 4B is a front view. [Diagram 5] 4 is an explanatory diagram illustrating an assembled state of the weight and the sleeve body in FIG. 3 as viewed from the front. FIG. [Figure 6] 6A and 6B are explanatory views illustrating the weight of FIG. 5, where FIG. 6A is a front view and FIG. 6B is a bottom view. [Figure 7] 7A and 7B are explanatory views illustrating the periphery of the sleeve body in FIG. 5, in which FIG. 7A is a top view and FIG. 7B is a front view. [Figure 8] 2 is an explanatory diagram illustrating an internal structure of the cutting unit of FIG. 1 as seen from the front; [Figure 9] FIG. 9 is a top view of the cutting unit of FIG. 8. [Figure 10] 9 is a cross-sectional view taken along line AA in FIG. 8. [Figure 11] 9 is an explanatory diagram illustrating a state in which the expansion / contraction bit in FIG. 8 is moved to a diameter expansion position. [Figure 12] 12 is a cross-sectional view of FIG. 11 taken along line B-B. [Figure 13] FIG. 2 is an enlarged view of the inside of the casing of FIG. [Figure 14] 14 is an explanatory diagram illustrating a state in which the weight in FIG. 13 has been moved further downward, as viewed from the front; FIG. [Figure 15] FIG. 15 is an explanatory diagram illustrating a state in which the casing in FIG. 14 is rotated and the hammer rod is moved downward to start drilling a hole in the upper end of the existing pile. [Figure 16] 16 is an explanatory diagram illustrating a state in which the hole drilling step in FIG. 15 has progressed to a predetermined depth. FIG. [Figure 17] This is an explanatory diagram illustrating the state in which the hole-drilling unit is moved upward and removed from inside the casing after the hole-drilling process is completed. [Figure 18] 18 is an explanatory diagram illustrating the state in which the cutting unit is inserted into the casing of FIG. 17 from which the hole-drilling unit has been removed. [Figure 19] 19 is an explanatory diagram illustrating a state in which the cutting unit in FIG. 18 is integrated with a casing. FIG. [Figure 20] 20A is an explanatory diagram showing a schematic top view of the process of integrating the cutting unit and the casing, in which FIG. 20(A) shows the vicinity of the engagement groove of the casing and the connecting portion of the cutting unit separately, FIG. 20(B) shows the state in which each connecting portion is placed on the engagement protrusion and the casing is rotated, and FIG. 20(C) shows the state in which each connecting portion is fitted into the corresponding engagement groove and connected to each other. [Figure 21] 20 is an explanatory diagram illustrating the state in which the casing in FIG. 19 is rotated while the expansion / contraction bit inserted into a drilled hole formed at the upper end of the existing pile is expanded and moved to cut off the upper end of the existing pile. [Figure 22] 22 is an explanatory view illustrating a state in which a casing and a cutting unit are moved upward after the upper end portion of the existing pile in FIG. 21 has been cut off. FIG. [Diagram 23]23 is an explanatory view illustrating a state in which the cutting unit and the casing in FIG. 22 are separated from each other by rotating the casing in the opposite direction. FIG. [Figure 24] 24 is an explanatory diagram illustrating a state in which the upper end portion (cylindrical body) of the existing pile cut together with the cutting unit in FIG. 23 is taken out from inside the casing. FIG. [Diagram 25] 25 is an explanatory diagram illustrating a state in which the casing in FIG. 24 is rotationally driven and moved downward. FIG. [Figure 26] This is an explanatory diagram showing a front view with a see-through view of the inside of the casing, illustrating the state in which the casing and drilling unit are rotated to excavate the ground. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Hereinafter, a system and method for removing an existing pile according to the present invention will be described based on an embodiment shown in the drawings.

[0012] The embodiment of the existing pile removal system illustrated in FIG. 1 is used to remove an existing concrete pile P buried in the ground. The existing pile P is generally made of reinforced concrete. This removal system includes a cylindrical casing 1, a rotary drive device 20 that holds the outer circumferential surface of the casing 1 and rotates the casing 1, a drilling unit including a hammer 3 and a hammer rod 5, and a cutting unit 16. The drilling unit and the cutting unit 16 are configured to be selectively installed inside the casing 1. As illustrated in FIG. 1, when the drilling unit including the hammer 3 and the hammer rod 5 is installed inside the casing 1, the drilling mode is set, and as illustrated in FIG. 18, when the cutting unit 16 is installed inside the casing 1, the cutting mode is set.

[0013] Casing bits 2a are provided at intervals in the circumferential direction at the lower end of the casing 1. In addition, mounting portions 2c that protrude inward of the casing 1 are provided at intervals in the circumferential direction at the lower end of the casing 1, and inside cutters 2b are provided on the lower end surfaces of the mounting portions 2c so as to protrude downward.

[0014] As shown in FIG. 2, a plurality of other mounting portions 2c are provided at a midway position in the longitudinal direction of the casing 1. These mounting portions 2c protrude onto the inner peripheral surface of the casing 1 and are arranged spaced apart in the circumferential direction. At a midway position in the longitudinal direction of the casing 1, there are further provided engagement protrusions 2d that protrude onto the inner peripheral surface of the casing 1 at positions spaced below each of the mounting portions 2c. The engagement protrusions 2d are formed in a circular ring shape that is continuous in the circumferential direction. Each mounting portion 2c extends obliquely toward the engagement protrusion 2d located below and is joined to the engagement protrusion 2d. In other words, the upper surfaces of each mounting portion 2c and the engagement protrusion 2d are continuous with each other via an inclined surface.

[0015] The upper and lower gaps between the respective mounting portions 2c and the engaging protrusions 2d form the engaging grooves 2e. Thus, a plurality of engaging grooves 2e extending in the circumferential direction are formed in the middle of the longitudinal direction of the casing 1, and one end of each engaging groove 2a is open and the other end is closed. As illustrated in Fig. 20(A), in this embodiment, four mounting portions 2c and four engaging grooves 2e are provided at intervals in the circumferential direction, but it is sufficient if a plurality of mounting portions 2c and a plurality of engaging grooves 2e are provided.

[0016] The casing 1 is composed of multiple casing sections 1a, 1b, 1c that are connected vertically by fastening means such as bolts, and the casing bit 2a is provided at the lower end of the lowest casing section 1a. The casing sections 1b, which are located at a position midway along the longitudinal direction of the casing 1, are each formed with a mounting section 2c, an engaging protrusion 2d, and an engaging groove 2e. The number of casing sections 1a, 1b, 1c that make up the casing 1 is not limited to three, and can be any number depending on the length of the existing pile P, etc.

[0017] The rotary drive device 20 has a drive motor 20a, a rotary gear 20b that is driven to rotate by the drive motor 20a, a plurality of chuck pieces 22 that rotate together with the rotary gear 20b, and four support legs 21 made of hydraulic cylinders. The plurality of chuck pieces 22 are arranged in an annular shape so as to surround the outer periphery of the casing 1 that passes vertically through the rotary drive device 20. Each of the chuck pieces 22 is configured to be able to move forward and backward in the radial direction of the annular shape in which it is arranged, thereby expanding and contracting the annular shape.

[0018] Each chuck piece 22 is moved toward the outer circumferential surface of the casing 1 to hold the outer circumferential surface of the casing 1. Furthermore, each chuck piece 22 moves up and down as the cylinders of the support legs 21 move back and forth. When the rotation drive device 20 is operated with the outer circumferential surface of the casing 1 held by each chuck piece 22, the casing 1 is driven to rotate about its cylindrical axis. This rotation drive device 20 can drive the casing 1 to rotate in one direction (clockwise) and in the other direction (counterclockwise).

[0019] As illustrated in Fig. 3, in this embodiment, the removal system further includes a weight 8 and a sleeve body 12 that are inserted around the hammer rod 5 inside the casing 1, and a liner 14 that is installed on either the weight 8 or the sleeve body 12. Therefore, in this embodiment, the drilling unit is composed of the hammer 3, the hammer rod 5, the weight 8, the sleeve body 12, and the liner 14. The liner 14 is installed on the sleeve body 12, but the liner 14 can also be installed on the weight 8.

[0020] Next, the hammer 3, hammer rod 5, weight 8, sleeve body 12 and liner 14 that constitute the drilling unit will be described in detail.

[0021] The cylindrical hammer 3 has a hammer bit 4 at its lower end. The hammer 3 is attached to the lower end of a cylindrical hammer rod 5. The hammer rod 5 can also be configured by connecting a plurality of rods.

[0022] An injection passage 3a is provided in the hammer 3, and an injection passage 7a is provided in the hammer rod 5. The injection passages 3a and 7a form an injection passage that communicates from the lower end of the hammer 3 to the upper end of the hammer rod 5. A discharge groove 3b is formed on the side surface of the hammer 3, extending vertically.

[0023] A swivel joint 9 is connected to the upper end of the hammer rod 5, and a hose 10 is connected to the swivel joint 9 via a hose connection part 11. An engagement hole 9a is provided at the upper end of the swivel joint 9. A hoisting wire 23 of a crane or the like is engaged in the engagement hole 9a. Therefore, by controlling the hoisting wire 23 with a crane or the like, the vertical position of the hammer 3 can be controlled.

[0024] Air is supplied from a hose 10 connected to an air supply source on the ground through the injection passages 7a and 3a, and the pressure of the supplied air applies vertical striking forces to the hammer 3. In addition, the excavated material is moved upward through the discharge groove 3b by the pressure of the supplied air and is accumulated inside the casing 1.

[0025] As shown in FIG. 4, a discharge groove 3b extending from the lower end to the upper end is formed on the side surface of the hammer 3. It is preferable that a plurality of discharge grooves 3b are arranged at intervals in the circumferential direction of the hammer 3, and in this embodiment, four discharge grooves 3b are arranged at equal intervals in the circumferential direction. The hammer rod 5 is provided with a fitting key 6a extending in the axial direction. The fitting keys 6a protrude outward from the outer circumferential surface of the hammer rod 5, and a plurality of fitting keys 6a are arranged at intervals in the circumferential direction of the rod. In this embodiment, two fitting keys 6a are arranged at equal intervals in the circumferential direction of the hammer rod 5, but the number of fitting keys 6a may be, for example, two to six.

[0026] In addition to the fitting keys 6a, a weight retaining key 6b extending in the axial direction is provided at the lower end of the hammer rod 5. The weight retaining keys 6b protrude outward from the outer circumferential surface of the hammer rod 5, and a plurality of weight retaining keys 6b are arranged at intervals in the circumferential direction of the rod. The weight retaining keys 6b are arranged between the fitting keys 6a adjacent to each other in the circumferential direction of the hammer rod 5a. In this embodiment, two weight retaining keys 6b are arranged at equal intervals in the circumferential direction of the hammer rod 5, but the number of weight retaining keys 6a to be arranged may be, for example, two to six.

[0027] The fitting key 6a extends over the entire length of the hammer rod 5 in the axial direction from the lower end to the upper end, while the weight retaining key 6b extends from the lower end of the hammer rod 5 to a position halfway in the axial direction.

[0028] As shown in FIG. 5, inside the casing 1, the sleeve body 12 is installed in a state of being suspended downward from the weight 8. The cylindrical portion 12a constituting the sleeve body 12 is inserted into the weight 8. In this embodiment, the weight 8 and the sleeve body 12 are connected vertically by a spring 15a. A plurality of springs 15a (four springs) are arranged at intervals in the circumferential direction. The spring 15a applies a biasing force that moves the weight 8 downward relative to the sleeve body 12, but the spring 15a may be provided as needed.

[0029] Additionally, an upper wedge piece 13a connected by a horizontally extending connecting pin 15b is suspended from the underside of the weight 8. A plurality of (four) upper wedge pieces 13a are arranged at intervals in the circumferential direction.

[0030] As shown in Fig. 6, the weight 8 is cylindrical. An engagement portion 8b is provided at the upper end of the weight 8, protruding radially inward from its inner circumferential surface. A key groove 8a is provided extending from the lower end to the upper end of the engagement portion 8b. The key grooves 8a correspond to the mating keys 6a, so that a plurality of key grooves 8a, the same number as the mating keys 6a, are arranged at intervals in the circumferential direction.

[0031] The weight 8 further has on its inner peripheral surface a stopper groove 8c extending from the lower end of the weight 8 to the locking portion 8b. That is, the upper end of the stopper groove 8c is closed by the locking portion 8b. A stopper 12e (described later) provided on the sleeve body 12 is fitted into the stopper groove 8c. After the stopper 12e is fitted into the stopper groove 8c, a fastener is attached to the lower end of the stopper groove 8c. The weight 8 has on its lower surface mounting portions spaced apart in the circumferential direction for mounting a spring 15a and an upper wedge piece 13.

[0032] 7, the sleeve body 12 has a cylindrical portion 12a and a flange portion 12b connected to the lower end of the cylindrical portion 12a. The flange portion 12b is formed in an annular shape protruding from the outer circumferential side of the cylindrical portion 12a.

[0033] The inner peripheral surface of the cylindrical portion 12a is provided with a key groove 12d extending from the lower end to the upper end. A plurality of key grooves 12d are arranged at intervals in the circumferential direction. In this embodiment, four key grooves 12d are arranged at equal intervals in the circumferential direction of the cylindrical portion 12a. Since the fitting keys 6a and the weight retaining keys 6b are fitted into the key grooves 12d, the same number of key grooves 12d as the total number of the fitting keys 6a and the weight retaining keys 6b are provided.

[0034] At the upper end of the cylindrical portion 12a, stoppers 12e protruding radially outward are arranged at intervals in the circumferential direction. The stoppers 12e are fitted into the stopper grooves 8c provided in the weight 8, and the cylindrical portion 12a is inserted into the weight 8, and the circumferential positions of the key grooves 8a and 12d are also aligned. By fitting the stoppers 12e into the stopper grooves 8c, the sleeve body 12 can move only in the axial direction (up and down) relative to the weight 8, and circumferential movement is restricted. A fastener is attached to the lower end of the stopper grooves 8c on the weight 8, so that even if the sleeve body 12 moves downward relative to the weight 8, the stoppers 12e are prevented from moving downward by the fastener. Therefore, the sleeve body 12 will not separate from the weight 8 even without the spring 15a.

[0035] Wedge holding portions 12c are arranged at intervals in the circumferential direction on the upper surface of the flange portion 12b. In this embodiment, four wedge holding portions 12c are arranged at equal intervals in the circumferential direction, but the number of wedge holding portions 12c may be, for example, two to six.

[0036] The wedge holding portion 12c holds a lower wedge piece 13b. The lower wedge piece 13b is a member that forms a pair with the upper wedge piece 13a, and the lower wedge piece 13b and the upper wedge piece 13a are provided so that the upper wedge piece 13a can move downward with their opposing inclined surfaces in contact with each other.

[0037] An arc-shaped liner 14 is attached to the outer circumferential surface of the lower wedge piece 13b in a plan view. The liner 14 is guided by the wedge holding portion 12c and moves in the radial direction of the hammer rod 5 together with the lower wedge piece 13b which moves in the radial direction of the hammer rod 5. Mounting portions for fixing springs 15a are further arranged at intervals in the circumferential direction on the upper surface of the flange portion 12b.

[0038] As shown in Fig. 5, the cylindrical portion 12a of the sleeve body 12 is inserted into the weight 8. In this state, the weight 8 and the sleeve body 12 are inserted onto the hammer rod 5 inside the casing 1, as shown in Fig. 3. In this state, the fitting key 6a fits into the key groove 8a and the key groove 12d, and the weight retaining key 6b fits only into the key groove 12d.

[0039] In this way, the weight 8 and sleeve body 12 fitted onto the hammer rod 5 inside the casing 1 are allowed to move up and down while being restricted from rotating in the circumferential direction of the rod. Also, the liner 14 is allowed to move in the radial direction of the rod between the outer circumferential surface of the hammer rod 5 and the inner circumferential surface of the casing 1.

[0040] Next, the cutting unit 16 will be described in detail.

[0041] 8 to 10, the cutting unit 16 has an expansion / contraction bit 17, an expansion / contraction mechanism 18 that expands and contracts the expansion / contraction bit 17, and a connecting part 19. The connecting part 19 is disposed at the upper end of the cutting unit 16, and the expansion / contraction bit 17 is disposed at the lower end of the cutting unit 16. The expansion / contraction mechanism 18 is disposed between the connecting part 19 and the expansion / contraction bit 17. The cutting unit 16 has a housing that covers almost the entire cutting unit 16, but the housing is omitted in the drawings to make the structure of the cutting unit 16 easier to understand.

[0042] The expansion / contraction mechanism 18 has an actuator 18a such as a hydraulic cylinder, and a link portion 18b connected to the tip of the cylinder rod of the actuator 18a. The link portion 18b may be of any of various known link structures. The expansion / contraction bit 17 is connected to the lower end of the link portion 18b.

[0043] 9, four plate-shaped connecting portions 19 are provided at equal intervals in the circumferential direction around the axis of the cutting unit 16. The number of connecting portions 19 is not limited to four, and it is sufficient that a plurality of connecting portions are provided at intervals in the circumferential direction.

[0044] As shown in FIG. 10, the expansion / reduction bits 17 are arranged in two opposing areas of the cutting unit 16 in a plan view. Three expansion / reduction bits 17 are arranged in a line in the circumferential direction in each area. The expansion / reduction bits 17 arranged in each area move together in the radial direction in a plan view (expand / contract movement). That is, the expansion / reduction bits 17 arranged in each area move toward and away from each other. In FIG. 10, the expansion / reduction bits 17 in each area are located close to each other, and each expansion / reduction bit 17 is in a reduced diameter state.

[0045] The number of regions where the expansion / contraction bits 17 are arranged is not limited to two regions, but may be three or more, and is preferably a plurality of regions arranged at equal intervals in the circumferential direction. The number of reduction bits 17 arranged in each region is not limited to three, but may be one, two, or four or more.

[0046] When the cylinder rod of the actuator 18a advances from the retreated position illustrated in Fig. 8 to the position illustrated in Fig. 11, the action of the link portion 18b causes each of the expansion / contraction bits 17 to move radially outward (to expand in diameter). That is, the expansion / contraction bits 17 arranged in each region move away from each other as illustrated in Fig. 12, and each of the expansion / contraction bits 17 enters an expanded diameter state. Therefore, when the cylinder rod of the actuator 18a is retreated, each of the expansion / contraction bits 17 enters a contracted diameter state as illustrated in Fig. 10.

[0047] A rotatable connector such as a swivel joint is connected to the upper end of the cutting unit 16, similar to the drilling unit, and a hoisting wire 23 of a crane or the like is engaged with this connector. A hose that supplies hydraulic oil to operate the actuator 18a is also connected to this connector. The vertical position of the cutting unit 16 is controlled by controlling the hoisting wire 23 with a crane or the like.

[0048] Below, an example of a procedure for removing an existing pile P buried in the ground using this removal system will be described.

[0049] First, as shown in Fig. 2, the casing 1 is inserted onto the upper end of the existing pile P. The casing 1 is then rotated in one direction by the rotary drive device 20 and moved downward, and the ground on the outer periphery of the existing pile P buried in the ground is drilled by the casing bit 2a and inside cutter 2b, which are also rotated. As a result, the casing 1 is inserted onto the upper end of the existing pile P, and the placement portion 2c, the engagement protrusion 2d, and the engagement groove 2e, which are located midway along the length of the casing 1, are positioned above the upper end surface of the existing pile P.

[0050] Next, a process in a hole-drilling mode in which a hole-drilling unit is installed inside the casing 1 and a process in a cutting mode in which a cutting unit 16 is installed inside the casing 1 are performed in sequence. Then, one set in which the process in the hole-drilling mode and the process in the cutting mode are performed in sequence is performed the required number of sets.

[0051] In the drilling mode, as shown in FIG. 1, the hammer rod 5 is suspended by the suspension wire 23, and the drilling unit is inserted into the casing 1 buried in the ground. The weight 8 and the sleeve body 12 are fitted onto the suspended hammer rod 5, and the weight 8 and the sleeve body 12 are allowed to move vertically while restricting the rotation of the weight 8 and the sleeve body 12 in the circumferential direction of the rod. The weight 8 is suspended from the hammer rod 5 at a midpoint in the vertical direction of the hammer rod 5 by engaging the upper end surface of the weight retaining key 6b with the engaging portion 8b of the weight 8. As a result, the sleeve body 12 is installed in a state of being suspended downward from the weight 8. The sleeve body 12 is suspended at a predetermined position by the spring 15a stretched between the weight 8 and the flange portion 12b.

[0052] The upper wedge piece 13a protruding downward from the weight 8 is embedded in the wedge holding portion 12c and abuts against the lower wedge piece 13b held by the wedge holding portion 12c, but does not move sufficiently downward relative to the lower wedge piece 13b. Therefore, the lower wedge piece 13b hardly moves radially outward of the hammer rod 5. Therefore, the liner 14 is located radially inward from the outer edge of the flange portion 12b. The hammer 3 is located in a position protruding downward from the flange portion 12b.

[0053] 13, the flange portion 12b is placed on the placement portion 2c located at a longitudinal midpoint of the casing 1. The placement portion 2c and the engagement projection 2d are positioned so as not to interfere with the hammer 3 and the hammer rod 5.

[0054] Next, when the hammer rod 5 is moved further downward as shown in FIG. 14, the weight 8 and the biasing force of the spring 15a move the weight 8 downward. Since the flange portion 12b is placed on the placement portion 2c, the sleeve body 12 does not move up and down. Therefore, the inclined surface of the upper wedge piece 13a, which moves downward, presses the inclined surface of the lower wedge piece 13b, and the liner 14 moves radially outward in the rod. As a result, the liner 14 presses the inner peripheral surface of the casing 1, and the casing 1 and the hammer 3 are integrated through the liner 14. In other words, the casing 1 and the drilling unit are integrated.

[0055] Next, the hammer rod 5 is moved downward as appropriate to set the hammer 3 at a predetermined depth. The outer peripheral surface of the casing 1 is held by the chuck piece 22 of the rotary drive device 20. In this state, the rotary drive device 20 is operated as shown in FIG. 15 to rotate the casing 1 integrated with the drilling unit in one direction, and air is supplied from the hose 10 through the injection path 7a, and the pressure of the supplied air applies vertical striking forces to the hammer 3. As a result, the hammer bit 4 starts to form a cylindrical hole Ph at the upper end of the existing pile P.

[0056] Next, as shown in Fig. 16, the casing 1 integrated with the drilling unit is rotated in one direction while the hammer rod 5 is moved further downward, so that the hammer bit 4 forms a cylindrical hole Ph of a predetermined depth at the upper end of the existing pile P. The predetermined depth and outer diameter of the cylindrical hole Ph are set to any desired value. A peripheral wall is formed around the cylindrical hole Ph with a thickness of half the value obtained by subtracting the inner diameter of the cylindrical hole Ph from the outer diameter of the existing pile P.

[0057] In this drilling mode, a cylindrical hole Ph of a predetermined depth is formed in a shorter time by the cutting force of the rotating hammer bit 4 and the up and down striking force of the hammer 3. Also, by using a configuration in which the spring 15a applies a biasing force that moves the weight 8 downward relative to the sleeve body 12 as in this embodiment, the liner 14 can be pressed more strongly against the inner circumferential surface of the casing 1. Accordingly, the casing 1 and the drilling unit can be more firmly integrated, and the cylindrical hole Ph can be formed more stably.

[0058] After forming a cylindrical hole Ph of a predetermined depth, the rotational drive of the casing 1 integrated with the drilling unit is stopped. Then, as illustrated in FIG. 17, the drilling unit is lifted by the hanging wire 23 and removed from the inside of the casing 1. In order to move the liner 14 pressing against the inner peripheral surface of the casing 1 inward in the radial direction of the rod and release the integration of the casing 1 and the drilling unit, it is only necessary to move the hammer rod 5 upward. In detail, the hammer rod 5 is moved upward to engage the upper end surface of the weight retaining key 6b with the engaging portion 8b of the weight 8, and the weight 8 is moved upward relative to the sleeve body 12. As a result, the upper wedge piece 13a moves upward relative to the lower wedge piece 13b, so that the pressing force pressing the liner 14 outward in the radial direction of the rod is eliminated, and the integrated casing 1 and the drilling unit can be separated. That is, in this embodiment, the casing 1 and the drilling unit can be integrated or released through the liner 14 simply by moving the hammer rod 5 up and down, which is advantageous for improving work efficiency.

[0059] Next, as shown in FIG. 18, the cutting unit 16 is installed inside the casing 1 and a process in the cutting mode is performed. In the cutting mode, the cutting unit 16 is suspended by the hoisting wire 23 and inserted into the casing 1. At this time, the expansion / contraction bit 17 is inserted into the cylindrical hole Ph while being in a reduced diameter state. The expansion / contraction bit 17 is inserted as deep as possible into the cylindrical hole Ph. In addition, while the cutting unit 16 is suspended by the hoisting wire 23, each connecting portion 19 is placed on the engaging protrusion 2d located midway in the longitudinal direction of the casing 1.

[0060] In this state, the cutting unit 16 and the casing 1 are integrated by rotating the casing 1 in one direction as illustrated in FIG. 19. The process of integrating the cutting unit 16 and the casing 1 will be described in detail as follows: First, the cutting unit 16 illustrated in FIG. 20(A) is inserted into the casing 1. The engagement grooves 2e are present below the respective mounting portions 2c of the casing 1. Then, as illustrated in FIG. 20(B), the respective connecting portions 19 are placed on the engaging protrusions 2d. Then, when the casing 1 is rotated in one direction, the circumferential positions of the respective connecting portions 19 do not change substantially, but the respective engaging grooves 2e move in the circumferential direction to change their circumferential positions. As a result, as illustrated in FIG. 20(C), the respective connecting portions 19 enter the engaging grooves 2e at the corresponding positions, and the connecting portions 19 and the engaging grooves 2e are fitted and connected. This integrates the casing 1 and the cutting unit 16.

[0061] Next, as shown in FIG. 21, the casing 1 integrated with the cutting unit 16 is rotated in one direction while the expansion / contraction bit 17 is expanded in diameter. That is, the actuator 18a is operated to advance its cylinder rod to expand the diameter of the expansion / contraction bit 17 while rotating the expansion / contraction bit 17. As a result, the peripheral wall of the cylindrical hole Ph is cut by the expansion / contraction bit 17. When the peripheral wall of the cylindrical hole Ph is cut up to the outer circumferential surface of the existing pile P, the peripheral wall of the cylindrical hole Ph is separated from the existing pile P to form a cylindrical body P1. When the cylindrical body P1 is formed, the rotation of the casing 1 integrated with the cutting unit 16 is stopped.

[0062] Each of the expansion / reduction bits 17 moves to expand while being driven to rotate, but this expansion movement is simply a linear movement and does not change the direction of the cutting edge of the expansion / reduction bit 17. Therefore, it is advantageous to avoid excessive load acting on each of the expansion / reduction bits 17 and the cutting unit 16. Therefore, it is advantageous to shorten the cutting work because there is no need to extremely slow down the expansion speed of each of the expansion / reduction bits 17. Also, by simply increasing the amount of expansion movement of each of the expansion / reduction bits 17, it is possible to cut up to the outer periphery of the existing pile P with a large diameter.

[0063] 22, the cylinder of the support leg 21 is moved backward, and the hoisting wire 23 is lifted to move the casing 1 and the cutting unit 16 slightly upward. This moves the cylindrical body P1 upward and reliably separates it from the existing pile P.

[0064] Next, as shown in FIG. 23, the casing 1 is rotated in the other direction (counterclockwise) while the cutting unit 16 is suspended by the suspending wire 23, and the integrated casing 1 and cutting unit 16 are separated. The process of separating the two is described in detail by performing the reverse procedure of the procedure of integrating the casing 1 and cutting unit 16 illustrated in FIG. 20. That is, when the casing 1 is rotated in the other direction in the state illustrated in FIG. 20(C), each of the connecting parts 19 is pulled out from the connecting engagement groove 2e, and the connection between the two is released. As a result, the casing 1 and the cutting unit 16 are separated. In this way, the casing 1 and the cutting unit 16 can be easily separated by simply rotating the casing 1 in the other direction. When releasing the connection between each of the connecting parts 19 and the engagement groove 2e, it is preferable to hang the cutting unit 16 by the suspending wire 23 so that the load of the cutting unit 16 does not act too much on each of the engagement grooves 2e.

[0065] In this embodiment, the upper surface of the engagement projection 2d and the upper surface of each of the mounting portions 2c are continuous with each other through an inclined surface, and each of the engagement grooves 2e protrudes upward with respect to the engagement projection 2d. By rotating the casing 1 in the other direction, each of the connecting portions 19 extracted from the connected engagement grooves 2e moves in the circumferential direction along the upper surface of the engagement projection 2d and abuts against an inclined surface (step) at a position corresponding to the circumferentially adjacent engagement groove 2e. This is advantageous in reliably extracting each of the connecting portions 19 from the connected engagement grooves 2e without excessively rotating the casing 1 in the other direction.

[0066] Next, as illustrated in Fig. 24, by maintaining each of the expansion / contraction bits 17 in an expanded state, the cylindrical body P1 is placed on each of the expansion / contraction bits 17. In this state, the cutting unit 16 is moved upward by the hoisting wire 23 and removed from the inside of the casing 1 together with the cylindrical body P1. After that, each of the expansion / contraction bits 17 is brought into a contracted state, and the cylindrical body P1 is removed from the cutting unit 16. The casing 1, which has been removed from the inside together with the cylindrical body P1, is moved downward by moving the cylinder of the support leg 21 forward, and is pushed into the ground again.

[0067] By carrying out one set of the above-mentioned drilling mode step and cutting mode step in sequence, one tubular body P1 is removed from the existing pile P, so by carrying out this set as necessary, it is possible to remove all of the existing pile P from the ground. If it is acceptable to leave part of the existing pile P in the ground, the number of sets to be carried out can be reduced.

[0068] When the next step in the hole-drilling mode is to be performed, as illustrated in Fig. 25, the casing 1 is rotated in one direction by the rotary drive device 20 and moved downward so that the casing 1 is inserted onto the upper end of the existing pile P. That is, in the same state as illustrated in Fig. 2, the step in the hole-drilling mode and the step in the cutting mode are performed in that order.

[0069] According to this removal system, in the drilling mode by the drilling unit, a cylindrical hole Ph of a predetermined depth can be quickly formed at the upper end of the existing pile P by the hammer bit 4 that is rotated and the hammer 3 that is given an upper and lower impact force. In the cutting mode by the cutting unit 16, the peripheral wall of the cylindrical hole Ph can be cut to form a cylindrical body P1 without causing an excessive load on the cutting unit 16. The drilling unit and the cutting unit 16 are integrated with the casing 1, so that axial vibration is suppressed and the pile is stably rotated. Therefore, by combining the drilling mode and the cutting mode described above, even an existing pile P with a large diameter can be efficiently removed from the ground.

[0070] This removal system can be used as a drilling system for forming a vertical hole in the ground as illustrated in FIG. 26. That is, the casing 1 is constructed excluding the casing part 1b connected to the casing 1 in the longitudinal direction in the previous embodiment. To form a vertical hole in the ground, a drilling unit is installed inside the casing 1, and the flange part 12b is placed on the mounting part 2c at the lower end of the casing 1. Then, the respective liners 14 are pressed against the inner peripheral surface of the casing 1 to integrate the drilling unit and the casing 1. In this state, the casing 1 integrated with the drilling unit is rotated in one direction to start excavating the ground. As the rotary drive device 20 is rotated, the cylinder of the support leg 21 is gradually contracted to move the casing 1 downward.

[0071] Air is supplied from the hose 10 through the injection passage 7a, and the pressure of the supplied air applies vertical striking forces to the hammer 3, while the ground is excavated by the rotating casing bit 2a, inside cutter 2b, and hammer bit 4. The excavated material moves upward through the discharge groove 3b due to the pressure of the air supplied through the injection passages 7a and 3a, and is accumulated inside the casing 1. The excavated material accumulated inside the casing 1 is discharged to the ground by a hammer grab or the like after a vertical hole has been constructed.

[0072] That is, this removal system can function as a hole-drilling system simply by designing the casing 1 so that it does not have the mounting portion 2c, the engaging protrusion 2d, and the engaging groove 2e at the midpoint of the longitudinal direction, as shown in Fig. 26. Therefore, the equipment for removing the existing piles and the equipment for excavating the ground can be shared, which contributes to reducing the costs of the equipment. [Explanation of symbols]

[0073] 1 Casing 1a, 1b, 1c Casing part 2a Casing Bit 2b Inside cutter 2c Placement section 2d engaging protrusion 2e Engagement groove 3. Hammer 3a Injection path 3b Discharge groove 4 Hammer Bits 5 Hammer Rod 6a Mating Key 6b Weight retention key 7a Injection path 8 Weight 8a Key groove 8b Locking part 8c Stopper groove 9 Swivel joint 9a Locking hole 10 Hose 11 Hose connection 12 Sleeve body 12a Cylindrical part 12b Flange part 12c Wedge holder 12d keyway 12e Stopper 13a Upper wedge piece 13b Lower wedge piece 14 Raina 15a Spring 15b Connecting pin 16 Cutting unit 17 Scaling Bits 18 Expansion / contraction mechanism 18a Actuator (hydraulic cylinder) 18b Link section 19 Connecting part 20 Rotational drive unit 20a Drive motor 20b Rotating gear 21 Support legs 22 Chuck piece 23 Suspension Wire P Existing pile P1 Cylindrical body Ph cylindrical hole

Claims

1. The drilling machine includes a casing having a casing bit at a lower end, a rotary drive device that holds the outer peripheral surface of the casing and rotates the casing, a drilling unit having a hammer rod with a hammer to which a hammer bit is attached attached at the lower end, and a cutting unit having an expandable bit that expands and contracts, An existing pile removal system in which the drilling unit and the cutting unit are selectively installed inside the casing, The casing is rotated and moved downward by the rotary drive device so as to be inserted onto the upper end of the existing pile buried in the ground, and then In a drilling mode in which the drilling unit is installed inside the casing, the casing and the drilling unit are integrated and rotated by the rotary drive device, and an upper and lower striking force is applied to the hammer by air supplied through a hose connected to the hammer rod, while a cylindrical hole of a predetermined depth is formed in the upper end of the existing pile by the hammer bit. In a cutting mode in which the cutting unit is installed inside the casing, the expandable bit in a reduced diameter state is inserted into the cylindrical hole, and the casing and the cutting unit are integrated and rotated by the rotary drive device, and the expandable bit is expanded in diameter to cut the peripheral wall of the cylindrical hole, thereby forming a cylindrical body. The casing and the cutting unit, which have been integrated together, are separated, the cylindrical body is placed on the expansion / contraction bit in an expanded diameter state, and the cutting unit is moved upward to be removed from the inside of the casing together with the cylindrical body, A system for removing an existing pile, in which the process of forming the cylindrical hole in the drilling mode and the process of forming the cylindrical body in the cutting mode and removing it from inside the casing are performed as many times as necessary.

2. The hammer rod is fitted inside the casing with a weight and a sleeve body that are movable up and down while being restricted from rotating in the circumferential direction of the rod, and a liner is installed on either the weight or the sleeve body and is movable in the radial direction of the rod between the outer circumferential surface of the hammer rod and the inner circumferential surface of the casing, The casing has a plurality of mounting portions at a midpoint in the longitudinal direction, the mounting portions protruding from an inner peripheral surface of the casing and spaced apart in the circumferential direction, An existing pile removal system as described in claim 1, wherein in the hole-drilling mode, the sleeve body is installed in a state where it is suspended downward from the weight, and as the weight moves downward relative to the sleeve body placed on each of the aforementioned mounting sections, the liner moves radially outward in the rod and presses against the inner surface of the casing, thereby integrating the casing and the hole-drilling unit.

3. The cutting unit has a plurality of connecting portions that protrude toward the outer periphery and are arranged at intervals in the circumferential direction, The casing has an engagement protrusion protruding downward from the inner circumferential surface of the casing at a midpoint in the longitudinal direction and spaced apart from each of the mounting portions, and a plurality of engagement grooves are formed by upper and lower gaps between each of the mounting portions and the engagement protrusions, In the cutting mode, the casing is rotated in one direction with each of the connecting portions placed on the engaging projections, whereby each of the connecting portions is engaged with the engaging grooves at the corresponding positions, and the casing and the cutting unit are integrated together. An existing pile removal system as described in claim 2, wherein the casing integrated with the cutting unit is rotated in the other direction, whereby the connection between each of the connecting portions and the engagement grooves at corresponding positions is released, and the integrated casing and the cutting unit are separated.

4. An existing pile removal system as described in claim 3, wherein the casing is formed by connecting a plurality of casing sections, and each of the mounting sections, the engagement protrusions, and each of the engagement grooves are formed in one of the plurality of casing sections.

5. A drilling unit having a hammer rod with a hammer to which a hammer bit is attached attached at its lower end, and a cutting unit having an expandable bit that expands and contracts are selectively installed inside a casing having a casing bit at its lower end, The rotary drive device holds the outer peripheral surface of the casing, drives it to rotate, and moves it downward so that the casing is inserted onto the upper end of the existing pile buried in the ground. In a drilling mode in which the drilling unit is installed inside the casing, the casing and the drilling unit are integrated and rotated by the rotary drive device, and an upper and lower striking force is applied to the hammer by air supplied through a hose connected to the hammer rod, while a cylindrical hole of a predetermined depth is formed in the upper end of the existing pile by the hammer bit, In a cutting mode in which the cutting unit is installed inside the casing, the expandable bit in a reduced diameter state is inserted into the cylindrical hole, and the casing and the cutting unit are integrated and rotated by the rotary drive device, and the expandable bit is expanded in diameter to cut the peripheral wall of the cylindrical hole to form a cylindrical body. The casing and the cutting unit, which have been integrated together, are separated, the cylindrical body is placed on the expansion / contraction bit in the expanded diameter state, and the cutting unit is moved upward to remove the cylindrical body from inside the casing; A method for removing an existing pile, comprising the steps of forming the cylindrical hole in the drilling mode and forming the cylindrical body in the cutting mode and removing it from inside the casing as many times as necessary.

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