JP6284255B1 - Pile cap and pile drawing method - Google Patents

Abstract

[PROBLEMS] To safely extract a heavy existing pile. A pile cap for grasping and pulling off the head of an existing pile, and having a cylindrical cap body provided with an outer cylindrical portion concentrically and a lower end portion of an outer peripheral wall of the outer cylindrical portion. An upper nail whose end is pivotally supported by an upper nail fixing shaft, a lower nail whose one end is pivotally supported by a lower nail fixing shaft on the outer peripheral wall portion of the cap body below the outer cylindrical portion, A movable shaft that pivotally supports the other end portion of the upper claw and the other end portion of the lower claw, and the outer cylindrical portion moves toward the tip of the cap body so that the upper claw and the lower claw are The cap body rises on the center side of the cross section of the cap body, the outer cylindrical portion moves in the direction opposite to the tip direction of the cap body, and the upper and lower claws fall on the inner peripheral wall side of the cap body. I decided to use a pile cap. [Selection] Figure 9

Description

The present invention relates to a method for pulling out an existing pile buried in the ground when rebuilding a building structure or the like.

  Building structures such as buildings and condominiums have piles embedded in the ground to support the load. When rebuilding these building structures, it is necessary to remove the embedded existing piles. Conventionally, in order to remove an existing pile, the existing pile is crushed and taken out, or the existing pile is pulled out with a wire and removed.

  In Patent Literature 1, when a long existing pile is pulled out, a cylindrical casing is embedded around the existing pile, and then the casing is pulled out once and a wire ring is hung on the tip of the casing. Then, the casing is returned to the ground, and a wire ring is hung on the upper part of the existing pile to pull out only the casing. Then, after pulling up the wire hung on the existing pile to the middle, cutting and removing the existing pile that came out on the ground, the method of pulling the casing again by hanging the wire ring on the existing pile is described. .

Patent Document 1: Japanese Patent Application Laid-Open No. 2012-112149

However, in the construction method described in Patent Document 1, it is difficult to confirm whether or not a wire ring is hung on the top of an existing pile in the ground, and when hanging a wire on a heavy existing pile that has been pulled up halfway, There was a problem that an accident could occur in which an existing pile accidentally dropped into the ground and workers were pulled into the ground. In particular, long and thick existing piles called cast-in-place piles (foundation piles) are heavy, so there is a high risk of accidents due to wire-hanging work.

This invention solves the said problem and makes it a subject to extract a heavy existing pile safely.

In order to solve the above problem, the present invention is a pile cap for grasping and pulling off the head of an existing pile,
A cylindrical cap body provided with an outer cylindrical portion concentrically;
An upper nail whose one end is pivotally supported by an upper nail fixing shaft at the lower end of the outer peripheral wall of the outer cylindrical portion;
A lower nail whose one end is pivotally supported by a lower nail fixing shaft on the outer peripheral wall portion of the cap body below the outer cylindrical portion;
A movable shaft that pivotally supports the other end of the upper nail and the other end of the lower nail,
The tip of the upper nail or the lower nail on the movable shaft side is formed at an acute angle,
The outer cylindrical portion moves in the cap body distal direction, the upper claws and the lower claws stand up toward the center of the cross section of the cap body, and the outer cylindrical portion moves in a direction opposite to the cap body distal direction. The pile cap is characterized in that the upper nail and the lower nail fall on the inner peripheral wall side of the cap body.

  By using the pile cap with this configuration, many workers do not work around the existing piles, danger can be prevented, and heavy existing piles can be pulled out safely.

  It is good also as a structure provided with two or more said upper claws and said lower claws.

  With this configuration, the existing pile can be appropriately held according to the weight of the existing pile.

  A hydraulic cylinder may be provided, and the outer cylindrical portion may move in the cap body tip direction or in the direction opposite to the cap body tip direction by extending or compressing the rod tip of the hydraulic cylinder.

  With this configuration, the existing pile can be easily gripped by hydraulic pressure.

Moreover, in order to solve the above-mentioned problem, the present invention is a pile drawing method for drawing an existing pile,
A cylindrical cap body having an outer cylindrical portion concentrically disposed thereon, an upper nail whose one end is pivotally supported by an upper nail fixing shaft at the lower end of the outer peripheral wall of the outer cylindrical portion, and a lower portion than the outer cylindrical portion A movable shaft that pivotally supports a lower claw whose one end is pivotally supported by a lower claw fixing shaft on the outer peripheral wall of the cap body, and the other end of the upper claw and the other end of the lower claw The tip of the upper nail or the lower nail on the movable shaft side is formed at an acute angle, the outer cylindrical portion moves in the direction of the tip of the cap body, and the upper nail and the lower nail are the cap body Pile cap preparation for preparing a pile cap that rises on the center side of the cross section and that the outer cylindrical portion moves in the direction opposite to the tip direction of the cap body and the upper and lower claws fall on the inner peripheral wall side of the cap body Process,
A casing preparation step of preparing a cylindrical casing having a drilling blade at the lowest end;
A casing embedding step of embedding the casing in the ground so as to be located around an existing pile;
A casing extracting step of extracting all the casings from the ground ;
A pile pulling process is provided, wherein a pile pulling step of holding and pulling the head of an existing pile with the pile cap is performed.

  With this configuration, many workers do not work around the existing piles and can prevent danger, and the heavy existing piles can be safely pulled out.

The pile drawing process
Pile pulling first step of grasping the head of an existing pile with the pile cap and pulling it out halfway;
A pile fall prevention process for holding an existing pile with a pile catcher supported by a plate or the like built on the ground to prevent the fall,
A pile cutting step of cutting the existing pile above the portion holding the existing pile in the pile dropping prevention step;
It is good also as a structure which removes the said pile catcher and performs the pile extraction 2nd process which extracts the remaining existing pile.

  With this configuration, it is possible to safely pull out a heavy existing pile by preventing the existing pile from falling.

The casing is obtained by joining a plurality of divided casings,
The casing drawing step includes
A casing extraction first step of extracting the casing partway;
A casing fall prevention step for preventing the fall by attaching a casing fall prevention jig to the casing;
A ground exposed split casing removing step of removing the split casing exposed to the ground;
It is good also as a structure which consists of a casing extraction 2nd process which extracts the remaining casing.

  With this configuration, the casing fall prevention jig prevents the casing from falling, whereby a long casing can be safely pulled out.

  A heavy existing pile can be safely pulled out by the pile cap and the pile pulling method according to the present invention.

It is a figure explaining the mechanism of the pile catcher in Example 1 of the present invention. It is a figure explaining operation | movement of the pile catcher in Example 1 of this invention. It is a figure explaining the casing preparation process in Example 1 of this invention. It is a figure explaining the casing embedding process in Example 1 of this invention. It is a figure explaining the casing embedding process and casing extraction process in Example 1 of this invention. It is a figure explaining the pile extraction 1st process and pile fall prevention process in Example 1 of this invention. It is a figure explaining the pile cutting process in Example 1 of this invention. It is a figure explaining the pile extraction 2nd process in Example 1 of this invention. It is sectional drawing explaining the principal part of the pile cap in Example 1 of this invention. It is a figure explaining the casing fall prevention process, ground exposure division | segmentation casing removal process, and casing extraction 2nd process in Example 2 of this invention.

  A first embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a diagram for explaining a mechanism of a pile catcher in Embodiment 1 of the present invention. FIG. 2 is a diagram illustrating the operation of the pile catcher according to the first embodiment of the present invention. FIG. 3 is a diagram illustrating a casing preparation process in the first embodiment of the present invention. FIG. 4 is a diagram for explaining a casing embedding process in the first embodiment of the present invention. FIG. 5 is a diagram illustrating a casing embedding process and a casing drawing process in Embodiment 1 of the present invention. Drawing 6 is a figure explaining the pile extraction 1st process and pile fall prevention process in Example 1 of the present invention. FIG. 7 is a diagram illustrating a pile cutting process in Embodiment 1 of the present invention. FIG. 8 is a diagram for explaining the second step of pulling out piles according to the first embodiment of the present invention. FIG. 9 is a cross-sectional view illustrating the main part of the pile cap according to the first embodiment of the present invention.

(Pile catcher)
First, the pile catcher 10 is demonstrated with reference to FIG. 1, FIG. The pile catcher 10 prevents the existing pile P pulled up halfway from falling into the ground. As shown in FIG. 1, the mechanism is such that the first arm 1 having a substantially arc shape and the second arm 2 having a substantially arc shape are opposed to each other with the sides facing the centers of the respective arcs, and the movable shafts 5 respectively. One end portions 1a and 2a are pivotally supported, and a plurality of grip portions 4 are provided on the sides of the first arm 1 and the second arm facing the center of the substantially arc. Both the first arm 1 and the second arm 2 are made of iron, and the plurality of grip portions 4 are also made of iron and are welded to the first arm 1 and the second arm 2.

  In the first embodiment, the plurality of gripping portions 4 are made of iron. However, the present invention is not necessarily limited to this and can be appropriately changed. For example, it may be made of rubber or synthetic resin.

  A hydraulic cylinder receiving portion 8 is provided at an intermediate portion of the first arm 1 opposite to the side facing the center of the substantially arc, and the rod end of the hydraulic cylinder 3 is pivotally supported by the fixed shaft 6 on the hydraulic cylinder receiving portion 8. Has been. Further, the other end of the hydraulic cylinder 3 is pivotally supported by a fixed shaft 7 at a tip portion of the second arm 2 where the movable shaft 5 is pivotally supported. The hydraulic cylinder 3 can be driven by hydraulic pressure to extend or compress the rod. By extending the rod, the gripping state for gripping the existing pile P by the first arm 1 and the second arm 2 is selected and compressed. A non-gripping state in which the existing pile P is not gripped can be selected.

  FIG. 2A shows a state where the hydraulic cylinder 3 is compressed, and FIG. 2B shows a state where the hydraulic cylinder 3 is extended. When the hydraulic cylinder 3 is compressed, the first arm 1 moves and the other end 1b of the first arm 1 is separated from the other end 2b of the second arm 2, and the first arm 1 and the second arm The area on the side facing the center of the substantially circular arc widens, and a non-gripping state in which the existing pile P is not gripped can be selected. As will be described later, in the pile fall prevention process, the piles are arranged so as to sandwich the existing piles in this open state. Therefore, the distance between the other end 1b of the first arm 1 and the other end 2b of the second arm 2 in the open state is configured to be larger than the diameter of the existing pile P to be pulled out.

  When the hydraulic cylinder 3 is extended, the first arm 1 is moved and the other end 1b of the first arm 1 is brought into a closed state in which the other end 2b of the second arm 2 approaches, so that the first arm 1 and the second arm The area on the side facing the center of the arc is reduced. And the holding state which can hold the existing pile P with the some holding part 4 provided in the side which faces the center of a substantially circular arc can be selected. At this time, by setting the diameter of the circle connecting the tips of the plurality of gripping portions 4 to be slightly smaller than the diameter of the existing pile P, the pile catcher 10 can firmly hold the existing pile P.

  And the pile catcher 10 substantially prescribed | regulated with the magnitude | size of the 1st arm 1 and the 2nd arm 2 is supported by the structure etc. on the ground, and it can prevent that the existing pile P grasped falls in the ground. . Here, the pile catcher 10 is supported by a structure or the like on the ground so that the pile catcher 10 that holds the existing pile P can withstand the weight of the existing pile P and is not dragged into the ground. That's fine. In the first embodiment, the first arm 1 and the second arm 2 are in contact with a plate material or the like constructed on the ground so as to be held on the ground.

  Although the magnitude | size of the pile catcher 10 can be arbitrarily set with the diameter of a pile, it is desirable to have a certain size so that it may be supported by the structure etc. on the ground. For example, it can be set to approximately 1 mφ to 3 mφ, and the distance between the other end 1 b of the first arm 1 and the other end 2 b of the second arm 2 is larger than the diameter of the existing pile P in the open state described above. Is wide, for example, 160 mm to 510 mm.

  In the first embodiment, the first arm 1 and the second arm 2 are held on the ground by contacting the plate material or the like constructed on the ground. However, the present invention is not necessarily limited to this and can be changed as appropriate. is there. For example, the pile catcher 10 is constructed on the ground by fixing either the first arm 1 and the second arm 2 or the first arm 1 and the second arm 2 with a structure on the ground and a bolt or the like. It may be configured to be supported by.

  Moreover, in Example 1, the 1st arm 1 moves to the fulcrum by the compression of the hydraulic cylinder 3, and the 1st arm 1 and the 2nd arm 2 will be in a closed state, and will hold | grip the existing pile P The state is selected, and the first arm 1 moves with the movable shaft 7 as a fulcrum by the extension of the hydraulic cylinder 3 so that the first arm 1 and the second arm 2 are in an open state and the existing pile P is not gripped. However, the present invention is not necessarily limited to this, and can be changed as appropriate. For example, without providing a hydraulic cylinder or a movable shaft, the gripping state in which both ends of the first arm and the second arm are fixed with bolts and the existing pile P is gripped is selected, and the existing pile P is removed by removing the bolts and the like. You may comprise so that the non-gripping state which does not hold | grip may be selected.

(Pile pulling method)
First, the pile catcher preparation step is executed to prepare the pile catcher 10 in the open state in which the non-gripping state in which the existing pile P is not gripped is selected. The size of the pile catcher 10 is prepared so that the distance between the other end 1b of the first arm 1 and the other end 2b of the second arm 2 is larger than the diameter of the existing pile P in the above-described open state. To do.

  Next, a casing preparation process is executed to prepare a cylindrical casing 20 that joins a plurality of divided casings and has a drilling blade at the lowermost end. More specifically, as shown in FIG. 3, a telescopic crawler pile cutting machine 100 that can be moved by a caterpillar and is easy to assemble is prepared. The telescroller pile remover 100 suspends a casing 20 in which five divided casings are joined by a crane 40 by a hydraulic reduction gear 30. The hydraulic reduction gear 30 moves along the leader 50, rotates the casing 20, and embeds it in the ground while digging the ground with a digging blade provided at the lowermost end. Moreover, each division | segmentation casing is each joined with the volt | bolt, and it is set as the structure which can be removed and added.

  An existing pile P is buried in the ground. The existing pile P is approximately 150 mmφ to 1200 mmφ in diameter and 6 m to 22 m in length, and the material is cement (PC pile), pine (pine pile), steel pipe (steel pipe pile), and the like. The casing 20 is selected according to the diameter and length of the existing pile. That is, the casing 20 having an inner diameter larger than the diameter of the existing pile P and a length corresponding to the length of the existing pile P is prepared. And the existing pile P excavates soil so that the head may be seen.

  In addition, in Example 1, although the number of the division | segmentation casings in the casing 20 to prepare was set to five, it is not necessarily limited to this, It can change suitably by convenience, such as the length of the existing pile P. For example, it may be 4 or less, or 6 or more. Further, as will be described later, in the casing embedding step, the divided casings can be further added according to the length of the existing pile P.

  Next, a casing embedding step for embedding the casing 20 in the ground so as to be positioned around the existing pile P is executed. As shown in FIG. 4A, the casing 20 is positioned and lowered around the existing pile P, and as shown in FIG. 4B, the casing 20 is embedded in the ground while rotating. Then, as shown in FIG. 4 (c), once the uppermost divided casing of the casing 20 is embedded to near the ground, the embedding is temporarily stopped and the uppermost divided casing is separated from the divided casing immediately below it. Then lift the top split casing.

  Then, as shown in FIG. 5A, a new divided casing 20c is added. That is, the lower ends of the uppermost divided casing and the uppermost end of the casing 20b embedded in the ground are joined together by bolts in the plurality of divided casings 20c. The split casing 20c is added when the long casing 20 cannot be embedded at one time because the length of the existing pile P is long like a cast-in-place pile. That is, when the existing pile P is short, it is not necessary to add the split casing 20c. And as shown in FIG.5 (b), the casing 20 is embedded deeper than the existing pile P. FIG. Thereby, the existing pile P is released from the earth pressure, and the existing pile P can be pulled out.

  Next, a casing extraction process is performed, the casing 20 is extracted from the ground (see FIG. 5C), and the casing 20 is removed (see FIG. 6A). And a pile extraction 1st process is performed. That is, the uppermost end portion of the existing pile P is gripped by the pile cap 60, and the existing pile P is slightly pulled out (see FIG. 6B). As will be described later, the pile cap 60 has a configuration in which it is covered with the head of the existing pile P and easily gripped by hydraulic pressure. It is possible to prevent danger without working around P.

  Here, when the existing pile P is pulled up, there is a space in the ground, and the existing pile P may fall, in which case there is a risk that an operator will be drawn. In order to prevent the danger of this worker being drawn in, as shown in FIG. 6 (c), a pile catcher in which the pile fall prevention process is executed and the grip state of the existing pile P exposed on the ground is selected. The pile catcher 10 is supported by a ground structure or the like. More specifically, after the pile catcher 10 in the open state in which the non-gripping state with respect to the existing pile P is selected is arranged so that the existing pile P is sandwiched between the first arm 1 and the second arm 2, the first arm is driven by the hydraulic cylinder 3. 1 is moved and the other end portions 1b and 2b of the first arm 1 and the second arm 2 are in a closed state in which the other ends 1b and 2b approach each other, and a gripping state for gripping the existing pile P is selected. In addition to gripping the existing pile P exposed to the ground, the first arm 1 and the second arm 2 support the pile catcher 10 on the ground to prevent the existing pile P from falling. That is, the pile catcher 10 is supported by a plate material or the like built on the ground, and accordingly, the existing pile P is supported on the ground and can be prevented from falling, thereby preventing an accident of the worker in the subsequent work. it can.

  Next, a pile cutting process is performed. That is, in the state where the existing pile P is supported on the ground by the pile catcher 10 and prevented from falling, as shown in FIG. 7A, the pile cap 60 is removed and the existing pile is inserted with the wire 70 while injecting cement milk. Pull up the top of P. At this time, another wire is hung on a little upper part of the portion gripped by the pile catcher 10 of the existing pile P. And the existing pile P is cut | disconnected by a large-scale machine etc. slightly above the part which hung another above-mentioned wire (refer FIG.7 (b)). The cut existing pile Pa is lowered to the ground with the wire 70 (see FIG. 7C). And the pile cap 60 is made to hold | grip to the uppermost end part of the existing pile P, the pile catcher 10 is removed, a pile extraction 2nd process is performed, and the remaining existing pile P is extracted.

  In the case of a longer existing pile P, the first pile extraction process, the pile drop prevention process, the pile cutting process, and the second pile extraction process are repeated any number of times according to the length of the existing pile P, and all the existing piles P are extracted. (See FIG. 8 (a)). Finally, in the underground space after being pulled out, as shown in FIGS. 8B and 8C, cement milk and sand are poured into the ground to backfill the underground space, Complete the withdrawal of P.

(Pile cap)
Here, the pile cap 60 used in the first step of pile extraction will be described with reference to FIG. FIG. 9 is a cross-sectional view illustrating the main part of the pile cap 60. The pile cap 60 has a structure that can be suspended from above by a wire or the like by a mechanism (not shown). Moreover, the cap main body 63 is substantially cylindrical so that the lower end part of the pile cap 60 can be put on the head of the existing pile P.

  An outer cylindrical portion 64 is provided concentrically on the outer periphery near the tip of the cap body 63. On the outer peripheral wall of the outer cylindrical portion 64, an upper claw fixing shaft mounting portion 72 (72a, 72b) is provided every 180 °, and one end of the upper claw 61 (61a, 61b) is connected to the upper claw fixing shaft 65 (65a). 65b) is pivotally supported in a direction orthogonal to the tip direction D of the cap body 63. Further, the outer peripheral wall portion of the cap body 63 below the outer cylindrical portion 64 is provided with a lower claw fixing shaft attaching portion 73 (73a, 73b) at a position on the substantially same circumference as the upper claw 61 (61a, 61b). One end of the lower claw 62 (62a, 62b) is pivotally supported by the lower claw fixing shaft 66 (66a, 66b) in a direction orthogonal to the tip direction D of the cap body 63. Further, the other end of the upper claw 61 (61a, 61b) and the other end of the lower claw 62 (62a, 62b) are perpendicular to the tip direction D of the cap body 63 by the movable shaft 67 (67a, 67b). Is pivotally supported.

  Rod tips of two hydraulic cylinders 68 (68a, 68b) are attached to the upper part of the outer cylindrical part 64, and the outer cylindrical part 64 is attached to the cap body by the extension of the hydraulic cylinders 68 (68a, 68b). The cap body 63 can be moved along the outer periphery thereof in the tip direction D of 63. Further, by compressing the hydraulic cylinder 68 (68a, 68b), the outer cylindrical portion 64 can be moved along the outer periphery of the cap body 63 in the direction opposite to the distal end direction D of the cap body 63.

  The structure and movement of the upper claw 61 (61a, 61b) and the lower claw 62 (62a, 62b) will be described in detail. FIG. 9A shows a state in which the hydraulic cylinder 68 is compressed and the upper claws 61 (61a, 61b) and the lower claws 62 (62a, 62b) are lying on the inner peripheral wall 63N side of the cap body 63. . The upper claws 61 (61a, 61b) and the lower claws 62 (62a, 62b) are made of iron as a main material, can withstand the weight of the existing piles P to be pulled out, and have dimensions that come into contact with the existing piles P. In Example 1, the length is 200 to 300 mm, the width is 100 mm, and the thickness is about 50 mm.

  When the hydraulic cylinder 68 (68a, 68b) is compressed, as shown in FIG. 9 (a), the outer cylindrical portion 64 is moved in the direction opposite to the tip direction D of the cap body 63, and the upper claw 61 (61a, 61b) is moved. Falls on the inner peripheral wall 63N side. Then, the upper claws 61 (61a, 61b) lie down on the inner peripheral wall 63N side, so that the other ends of the lower claws 62 (62a, 62b) are pivoted on the other ends of the upper claws 61 (61a, 61b). By being supported, the lower claws 62 (62a, 62b) also fall on the inner peripheral wall 63N side.

  FIG. 9B shows a state in which the hydraulic cylinder 8 is extended and the upper claws 61 (61 a, 61 b) and the lower claws 62 (62 a, 62 b) are standing on the center side of the cross section of the cap body 63. That is, the upper claw 61 (61a, 61b) and the lower claw 62 (62a, 62b) penetrate the cap main body 63 by extending the hydraulic cylinder 8 and moving the outer cylindrical portion 64 in the tip direction D of the cap main body 63. The casing window 63 </ b> W is provided to stand on the inner side of the inner peripheral wall 63 </ b> N of the cap body 63. And the existing pile P can be hold | gripped with the upper nail | claw 61 (61a, 61b) and the lower nail | claw 62 (62a, 62b) which stood up.

  In addition, in Example 1, although the number of the upper nail | claw and the lower nail | claw was two, it is not necessarily limited to this, According to the weight etc. of the existing pile, it can change suitably. For example, the number of upper nails and lower nails may be three or more. In the first embodiment, two hydraulic cylinders are provided. However, the present invention is not necessarily limited to this, and can be appropriately changed depending on the weight of the existing pile. For example, three or more hydraulic cylinders may be used according to the number of upper claws and lower claws.

  Moreover, in Example 1, the edge part of the side supported by the movable shaft 67 (67a, 67b) in the upper nail | claw 61 (61a, 61b) and the lower nail | claw 62 (62a, 62b) is formed roundly. However (see FIG. 9), it is not necessarily limited to this and can be changed as appropriate. For example, the gripping force on the existing pile P may be improved by forming the tip at an acute angle.

  Furthermore, in Example 1, although the pile cap 60 was set as the structure which hold | grips the existing pile P with the upper nail | claw 61 (61a, 61b) and the lower nail | claw 62 (62a, 62b), it is not necessarily limited to this but changes suitably. Is possible. For example, it is good also as a structure gripped by making two arms into a closed state like the above-mentioned pile catcher 10.

Thus, in Example 1 of the present invention, a pile cap for grasping and pulling off the head of an existing pile,
A cylindrical cap body provided with an outer cylindrical portion concentrically;
An upper nail whose one end is pivotally supported by an upper nail fixing shaft at the lower end of the outer peripheral wall of the outer cylindrical portion;
A lower nail whose one end is pivotally supported by a lower nail fixing shaft on the outer peripheral wall portion of the cap body below the outer cylindrical portion;
A movable shaft that pivotally supports the other end of the upper nail and the other end of the lower nail,
The outer cylindrical portion moves in the cap body distal direction, the upper claws and the lower claws stand up toward the center of the cross section of the cap body, and the outer cylindrical portion moves in a direction opposite to the cap body distal direction. A heavy existing pile can be safely pulled out by the pile cap characterized in that the upper and lower claws fall on the inner peripheral wall side of the cap body.

In addition, it is a pile drawing method that pulls an existing pile,
A cylindrical cap body having an outer cylindrical portion concentrically disposed thereon, an upper nail whose one end is pivotally supported by an upper nail fixing shaft at the lower end of the outer peripheral wall of the outer cylindrical portion, and a lower portion than the outer cylindrical portion A movable shaft that pivotally supports a lower claw whose one end is pivotally supported by a lower claw fixing shaft on the outer peripheral wall of the cap body, and the other end of the upper claw and the other end of the lower claw And the outer cylindrical portion moves toward the tip of the cap body so that the upper and lower claws stand up toward the center of the cross section of the cap body, and the outer cylindrical portion is opposite to the tip direction of the cap body. A pile cap preparation step of preparing a pile cap that moves to the inner peripheral wall side of the cap body and the upper claws and the lower claws
A casing preparation step of preparing a cylindrical casing having a drilling blade at the lowest end;
A casing embedding step of embedding the casing in the ground so as to be located around an existing pile;
A casing pulling process for pulling out the casing;
It is possible to safely pull out a heavy existing pile by a pile pulling method that performs a pile pulling process in which the head of the existing pile is gripped and pulled out by the pile cap.

  The second embodiment is different from the first embodiment in that the casing is pulled out while preventing the casing slightly pulled up from the ground using a casing fall prevention jig. A second embodiment of the present invention will be described with reference to FIG. FIG. 10 is a diagram for explaining a casing fall prevention process, a ground exposed divided casing removal process, and a casing extraction second process in Embodiment 2 of the present invention.

  When the casing 20 is long and cannot be pulled out at once, the casing 20 is pulled out several times in the above-described casing drawing process. First, the casing pulling first step is executed to pull the casing 20 halfway. Next, a casing fall prevention process is performed. That is, as shown in FIG. 10 (a), the casing fall prevention jig 80 is inserted into the through hole provided in the casing 20, and both ends are supported by a plate-like structure provided on the ground to prevent the fall. To do.

  Next, the ground exposed divided casing removing step is executed to remove the divided casing 20e exposed to the ground (see FIG. 10B). In order to remove the split casing 20e, the bolts joining the split casings are loosened. And a casing extraction 2nd process is performed. That is, first, the lower end of the uppermost divided casing 20a is joined to the uppermost part of the casing 20f supported by the casing drop prevention jig 80 (see FIG. 10C). Next, after removing the casing drop prevention jig 80, the casing 20 is all pulled out.

  The casing drop prevention jig 80 is formed of a metal such as iron and may have a cylindrical shape or a plate shape. The structure that supports the casing fall prevention jig 80 on the ground can use a block-shaped metal or the like in addition to a plate-shaped member such as iron.

  The casing drawing is completed as described above. However, when the casing is longer, the casing pulling first step, the casing drop prevention step, the ground exposure divided casing removing step, and the casing pulling second step may be executed again.

  In the second embodiment, the casing fall prevention jig 80 having a cylindrical shape or a plate shape is configured to be inserted into the through hole provided in the casing 20, but the present invention is not necessarily limited thereto and can be changed as appropriate. It is. For example, a casing drop prevention jig may be configured as a jig that can grip the casing 20 from the periphery.

  In this way, by pulling out the casing little by little using the casing drop prevention jig, even a long casing can be safely pulled out without being pulled into the ground.

The pile cap and the pile drawing method in the present invention can be widely used in the field of existing pile drawing.

1: 1st arm 1a: One end 1b: The other end
2: Second arm 2a: One end 2b: The other end
3: Hydraulic cylinder 4: Gripping part
5: Movable shaft 6: Fixed shaft 7: Fixed shaft 8: Hydraulic cylinder receiving part
10: Pile catcher 20: Cap body 630: Hydraulic reducer 40: Crane
50: Leader 60: Pile cap
61 (61a, 61b): Upper nail 62 (62a, 62b): Lower nail
63: Cap body 63N: Inner wall 63W: Cap body window
64: Outer cylindrical part
65 (65a, 65b): Upper nail fixing shaft 66 (66a, 66b): Lower nail fixing shaft
67 (67a, 67b): movable shaft
68 (68a, 68b): Cap body hydraulic cylinder
72 (72a, 72b): Upper claw fixing shaft mounting portion
73 (73a, 73b): Lower claw fixing shaft mounting portion
70: Wire 80: Casing fall prevention jig
100: Telescopic crawler pile remover
P: Existing pile

Claims (6)

A pile cap for grasping and pulling the head of an existing pile,
A cylindrical cap body provided with an outer cylindrical portion concentrically;
An upper nail whose one end is pivotally supported by an upper nail fixing shaft at the lower end of the outer peripheral wall of the outer cylindrical portion;
A lower nail whose one end is pivotally supported by a lower nail fixing shaft on the outer peripheral wall portion of the cap body below the outer cylindrical portion;
A movable shaft that pivotally supports the other end of the upper nail and the other end of the lower nail,
The tip of the upper nail or the lower nail on the movable shaft side is formed at an acute angle,
The outer cylindrical portion moves in the cap body distal direction, the upper claws and the lower claws stand up toward the center of the cross section of the cap body, and the outer cylindrical portion moves in a direction opposite to the cap body distal direction. The pile cap, wherein the upper nail and the lower nail fall on the inner peripheral wall side of the cap body.   The pile cap according to claim 1, comprising a plurality of the upper claws and the lower claws. It includes a hydraulic cylinder, according to claim 1 or 2 rod end of the hydraulic cylinder and said outer cylindrical portion by extension or compression is moved to the cap body distal direction or the cap body distal direction opposite Pile cap as described in. Pile pulling method to pull existing piles,
A cylindrical cap body having an outer cylindrical portion concentrically disposed thereon, an upper nail whose one end is pivotally supported by an upper nail fixing shaft at the lower end of the outer peripheral wall of the outer cylindrical portion, and a lower portion than the outer cylindrical portion A movable shaft that pivotally supports a lower claw whose one end is pivotally supported by a lower claw fixing shaft on the outer peripheral wall of the cap body, and the other end of the upper claw and the other end of the lower claw The tip of the upper nail or the lower nail on the movable shaft side is formed at an acute angle, the outer cylindrical portion moves in the direction of the tip of the cap body, and the upper nail and the lower nail are the cap body Pile cap preparation for preparing a pile cap that rises on the center side of the cross section and that the outer cylindrical portion moves in the direction opposite to the tip direction of the cap body and the upper and lower claws fall on the inner peripheral wall side of the cap body Process,
A casing preparation step of preparing a cylindrical casing having a drilling blade at the lowest end;
A casing embedding step of embedding the casing in the ground so as to be located around an existing pile;
A casing extracting step of extracting all the casings from the ground ;
A pile pulling process in which a pile pulling step of holding and pulling the head of an existing pile with the pile cap is performed. The pile drawing process
Pile pulling first step of grasping the head of an existing pile with the pile cap and pulling it out halfway;
A pile fall prevention process for holding an existing pile with a pile catcher supported by a plate or the like built on the ground to prevent the fall,
A pile cutting step of cutting the existing pile above the portion holding the existing pile in the pile dropping prevention step;
The pile pulling method according to claim 4, wherein the pile catcher is removed and the second pile pulling step of pulling out the remaining existing piles is executed. The casing is obtained by joining a plurality of divided casings,
The casing drawing step includes
A casing extraction first step of extracting the casing partway;
A casing fall prevention step for preventing the fall by attaching a casing fall prevention jig to the casing;
A ground exposed split casing removing step of removing the split casing exposed to the ground;
The pile drawing method according to claim 4 or 5, characterized by comprising a casing drawing second step of drawing the remaining casing.

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