JP2018105086A - Structure of steel pipe pile - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a structure of a steel pipe pile capable of facilitating penetration into the ground with a simple structure while suppressing noise and vibration.SOLUTION: A structure 1 of a steel pipe pile has: a head portion 50 which is structured so as to be separable from a steel pipe 10, has an impactively striking part 53 struck by a striking machine 20 moving into the steel pipe 10, and is propelled by receiving the striking force in the impactively striking part 53; and an elastic member 70 which elastically supports the impactively striking part 53 on the tip side of the steel pipe 10, and is compressed and deformed by receiving the striking force generated when the striking machine 20 strikes the impactively striking part 53, where the head portion 50 is independently propelled with respect to the steel pipe 10 and a spring 70 is compressed and deformed, due to the striking on the impactively striking part 53 by the striking machine 20, and a restoring force of the spring 70 based on the compression and deformation acts on the steel pipe 10 and the steel pipe 10 is energized to a forward direction.SELECTED DRAWING: Figure 1

Description

  The present invention relates to the structure of a steel pipe pile.

  Conventionally, when a foundation of a structure is constructed, a foundation using a steel pipe pile (steel pipe pile) is driven into the ground.

  As a method of placing steel pipes, there is a method of hitting the head of a steel pipe with a hammer or the like, but this method generates a large amount of noise, vibration, etc., so there is a problem as a construction method especially at sites with severe noise regulations. Many. Moreover, when using a pile driving machine, a corresponding work space is required, so it is difficult to cope with construction in a confined area.

  In order to solve such a problem, a pipe driving device (pile driving device) that can suppress generation of noise and vibration with a simple configuration has been proposed (for example, Patent Document 1 below).

  A pipe driving device described in the following Patent Document 1 is housed in a pipe (steel pipe) and has a hammer (blowing machine) having a piston inside, a device housed in a tip portion of the pipe, and a tip portion of the device. And a connected excavation head (head portion). In this pipe driving device, the piston in the hammer is moved up and down by the compressed air supplied from the air compressor so that the piston hits the device, and this hitting force penetrates the excavation head connected below the device into the ground. Let According to the following Patent Document 1, since a hammer that is a source of noise and vibration is driven inside a pipe, the level of noise and vibration is suppressed, and the hammering force is used to make a hole. It is said that pipe press-fitting can be performed simultaneously.

Japanese Patent No. 2636207

  However, in Patent Document 1, since the steel pipe and the excavation head have an integral structure, during the impact by the hammer (in other words, when the excavation head advances in the direction of penetrating the ground), the soil acting on the steel pipe The tightening force becomes the resistance of the penetrating input. That is, in Patent Document 1, although the steel pipe can be embedded in the ground while suppressing the generation level of noise and vibration, the striking force by the hammer does not effectively act on the force in the direction of propelling the excavation head. However, the problem still remained from the viewpoint of smoothly penetrating steel pipe piles into the ground.

  Then, an object of this invention is to provide the structure of the steel pipe pile which can perform the penetration | invasion to a ground easily, suppressing a noise and a vibration with a simple structure.

  The structure of the steel pipe pile according to one aspect of the present invention is a structure of a steel pipe pile embedded in the ground, and is configured to be separable from the steel pipe and is hit by a hitting machine that moves in the steel pipe. A head portion that has a striking portion and is propelled by a striking force received by the striking portion, and elastically supports the striking portion on the tip side of the steel pipe, and when the striking device strikes the striking portion And an elastic member that compresses and deforms in response to a striking force generated on the head, and the head portion is independently driven with respect to the steel pipe by the striking of the striking portion by the hitting machine, and the elastic member is compressively deformed. The restoring force of the elastic member based on the compression deformation acts on the steel pipe so that the steel pipe is urged in the forward direction.

  According to this aspect, the head portion provided on the tip side of the steel pipe is separated from the steel pipe and propelled by hitting with a hitting machine, and this head portion is responsible for penetration into the ground. The tightening force of the working soil does not serve as a resistance to penetration. Thereby, the striking force by the striker is effectively transmitted in the direction of propelling the head part, and the head part can be smoothly propelled in the ground. Also, the head part is configured to be separable from the steel pipe, and the head part is propelled independently from the steel pipe by striking with a hitting machine. Thus, the speed of the head portion when the striking force is applied can be increased. That is, since the collision energy of the head portion can be increased, the penetration input to the ground can be increased as compared with a configuration in which the head portion and the steel pipe are integrated. Moreover, since a head part is hit | damaged from the inside of a steel pipe pile, a noise can be reduced compared with the structure which hits the head of a steel pipe pile, for example. Moreover, since the head part provided in the front end side of the steel pipe in the ground is hit, vibration can also be suppressed. Further, since a pile driving machine is not required, it is not necessary to secure a wide construction space, and it is possible to cope with construction in a confined area.

  In the above aspect, the steel pipe and the hitting machine are urged toward opposite sides in the axial direction by the restoring force of the elastic member based on the compression deformation, and the head portion is propelled by the hitting of the hitting machine and the elastic member is restored. It is also preferable that the steel pipe pile is penetrated into the ground by repeating the propulsion of the steel pipe by force.

  In the above aspect, further comprising an engagement portion provided on the tip side in the steel pipe, and abutting against the striking portion when the striking portion moves to the front side in the axial direction upon receiving a strike of the striking machine, The striking force by the striking device received by the striking portion may be transmitted to the distal end side of the head portion and to the steel pipe via the engaging portion.

  The said aspect WHEREIN: The striking force by the said striker received in the said hit | damage part may be comprised so that it may act on the said head part relatively large among the said steel pipe and the said head part.

  The said aspect WHEREIN: The said head part may comprise the taper shape which diameter-reduces toward the front end side, and the maximum diameter part may be below the outer diameter of the said steel pipe.

  The said aspect WHEREIN: The said head part may comprise the taper shape which diameter-reduces toward the front end side, and the maximum diameter part may be more than the outer diameter of the said steel pipe.

  In the above aspect, the hammer may be a hammer having an outer diameter slightly thinner than the inner diameter of the steel pipe.

  In the above aspect, the hitting machine is a hitting type propulsion machine having a piston that moves up and down in the steel pipe by compressed air supplied from the outside, and hitting the piston against the head portion to give hitting force. May be.

  ADVANTAGE OF THE INVENTION According to this invention, the structure of the steel pipe pile which can perform penetration to a ground easily can be provided, suppressing a noise and a vibration with a simple structure.

It is a schematic sectional drawing for demonstrating the structure of the steel pipe pile which concerns on 1st Embodiment. It is a schematic sectional drawing for demonstrating the structure of the steel pipe pile which concerns on 2nd Embodiment. It is a figure for comparing and explaining the structure in this embodiment, and the conventional structure. It is a schematic sectional drawing which shows the modification of a structure around a head part.

  Embodiments of the present invention will be described below with reference to the accompanying drawings. It should be noted that the following description of the preferred embodiment is merely an example, and is not intended to limit the present invention, its application, or its use.

  First, the structure of the steel pipe pile which concerns on 1st Embodiment is demonstrated. Drawing 1 is an outline sectional view for explaining the structure of the steel pipe pile in a 1st embodiment. As shown in FIG. 1, the structure 1 of a steel pipe pile is applied to a pile (steel pipe pile) used as a foundation of a structure, and includes a steel pipe 10, a hitting machine 20, an engaging portion 60, and a head. The part 50 and the spring 70 are provided at least. In addition, it is suitable for the structure of the steel pipe pile in this embodiment to be used when driving the steel pipe pile in the vertical direction.

  The hitting machine 20 is a device that is housed in the steel pipe 10 and hits the hitting portion 53 from the inside of the steel pipe 10. The hitting machine 20 has an outer dimension slightly smaller than the inner dimension of the steel pipe 10, is suspended by a wire (not shown), etc., is dropped in the vertical direction by its own weight, and hits the hitting part 53 of the head part 50. . Although this embodiment demonstrates the example using the hammer which has an outer diameter a little thinner than the internal diameter of the steel pipe 10 as a hitting machine 20, and falls by self-weight, and gives a striking force, it is not limited to this. Absent. For example, the hitting machine 20 has a built-in piston inside the cylinder, and may be configured to hit the hitting portion 53 by moving the piston up and down by compressed air or hydraulic pressure supplied from an air compressor provided outside. It is possible to select other striking devices as appropriate.

  A substantially cylindrical engaging portion 60 is attached to the tip of the steel pipe 10 by screw fitting or welding. Specifically, the engaging portion 60 has a small-diameter portion 61, a medium-diameter portion 62, and a large-diameter portion 63 that are sequentially enlarged in diameter from the front end side to the rear end side (upward in FIG. 1) of the steel pipe 10. A cylindrical shape with a step is formed. A gap that allows the striking portion 53 to move up and down is provided inside the large diameter portion 63, and the inner diameter of the medium diameter portion 62 is set smaller than the outer diameter of the striking portion 53. Thereby, when the hitting unit 20 hits the hitting part 53 and the hitting part 53 moves downward, the hitting part 53 comes into contact with the upper end (step part 62a) of the medium diameter part 62, and hits. The striking force received by the portion 53 can be transmitted to the steel pipe 10 via the stepped portion 62a.

  The shape of the engaging portion 60 is not limited to the illustrated example, and the head portion 50 can move up and down, and the striking force is transmitted to the steel pipe 10 via the engaging portion 60. If it is, the shape and size are not particularly limited. In the above description, an example in which the engaging portion 60 is cylindrical has been described. However, a rectangular tube shape may be used, and the shape and size of the engaging portion 60 can be appropriately changed according to the shape of the head portion 50. .

  The head unit 50 is provided at the tip of the steel pipe 10 and is configured to be movable up and down by striking the striking machine 20. In this embodiment, the head part 50 is comprised as a member separate from the steel pipe 10, and when the impact | damage of the impact machine 20 is received, only the head part 50 is comprised independently. As shown in FIG. 1, the head portion 50 connects the excavation head 51 having an inverted conical shape, the hitting portion 53 that receives the hitting force of the hitting machine 20, and the excavation head 51 and the hitting portion 53. And a connecting portion 52.

  The hitting portion 53 is a portion of the head portion 50 where the hitting machine 20 is hit. The striking force received from the striking machine 20 is configured to be transmitted to the excavation head 51 via the connecting portion 52. In the present embodiment, a spring 70 (elastic member) extending in the axial direction from the large diameter portion 63 to the striking portion 53 is provided so as to cover the periphery of the connecting portion 52. The spring 70 elastically supports the striking portion 53 in a stationary state (a state before receiving a hit), but can be compressed and deformed when the hitting portion 53 is hit and the hitting portion 53 moves downward. It is configured. The restoring force of the spring 70 based on this compressive deformation is configured to act on the steel pipe 10 to bias the steel pipe 10 in the forward direction. Further, in this embodiment, when the hitting portion 53 is hit by the hitting machine 20 and moves downward, the hitting portion 53 becomes the stepped portion 62a (the stepped portion between the large diameter portion 63 and the medium diameter portion 62). Thus, the striking force received by the striking portion 53 is transmitted to the steel pipe 10 via the engaging portion 60. Thus, the striking force by the striking unit 20 received by the striking portion 53 acts in the direction in which the excavation head 51 and the steel pipe 10 are moved forward (downward in FIG. 1), and the striking portion 53 moves. Accordingly, the restoring force of the spring 70 subjected to the compression change acts in a direction in which the steel pipe 10 is propelled (downward in FIG. 1) and acts in a direction to push back the impacting machine 20 (upward in FIG. 1).

  The excavation head 51 is provided at the distal end of the head portion 50 and has a tapered shape with a reduced diameter on the distal end side, for example, an inverted conical shape, and the maximum diameter is formed to correspond to the outer diameter of the steel pipe 10. Has been.

  Next, a process of driving the steel pipe pile into the ground using the steel pipe pile structure 1 having the above-described configuration will be described with reference to FIGS.

  As shown in FIG. 1 (A), an impacting machine 20 accommodated in a steel pipe 10 and capable of moving up and down in the steel pipe 10 is dropped by its own weight.

  Next, as shown in FIG. 1B, the hitting machine 20 is hit by the hitting portion 53, and the hitting force received by the hitting portion 53 is transmitted to the excavation head 51. Since the head portion 50 including the excavation head 51 is configured as a member separate from the steel pipe 10, the striking force received by the hitting portion 53 is directly transmitted to the excavation head 51, and the excavation head 51 is connected to the steel pipe 10. Are divided and penetrated into the ground.

  Next, as shown in FIG. 1 (C), when the striking portion 53 is pushed down further than the state shown in FIG. 1 (B) by the striking from the striking machine 20, the striking portion 53 is engaged. It collides with the stepped part 62a in the part 60. Thereby, the striking force applied to the striking portion 53 from the striking machine 20 is transmitted to the steel pipe 10 via the engaging portion 60, and the spring 70 is moved along with the downward displacement of the striking portion 53. Compressive deformation.

  Next, as shown in FIG. 1D, the restoring force of the compressed spring 70 acts on the steel pipe 10, and the steel pipe 10 is urged in the forward direction (downward in FIG. 1) and the restoring force strikes. Acting on the machine 20, the batting machine 20 is pushed back in the backward direction (upward in FIG. 1). In other words, forces opposite to each other in the axial direction act on the steel pipe 10 and the hitting machine 20 due to the restoring force of the spring 70.

  As described above, as shown in the process described with reference to FIGS. 1A to 1D, the propulsion of the head unit 50 by the strike of the striker 20 and the propulsion of the steel pipe 10 by the restoring force of the spring 70 are repeated. , Piles penetrate into the ground.

  Then, the structure 1 of the steel pipe pile in 2nd Embodiment is demonstrated. FIG. 2 is a schematic cross-sectional view for explaining the structure of the steel pipe pile in the second embodiment. The second embodiment has a configuration in which the hitting portion 53 and the engaging portion 60 do not come into contact with each other even if the hitting portion 53 is displaced by receiving the hitting force (in other words, the structure of the engaging portion 60). Is different from the first embodiment, and other configurations and functions are the same as those of the first embodiment. Therefore, the description of the same parts as those in the first embodiment is omitted.

  As shown in FIG. 2, the engaging portion 60 in the second embodiment has a stepped cylindrical shape having a small diameter portion 61 and a large diameter portion 63 that are reduced in diameter toward the front side in the axial direction. A gap that allows the striking portion 53 to move up and down is provided inside the large diameter portion 63, covers the periphery of the connecting portion 52, and extends in the axial direction from the small diameter portion 61 toward the striking portion 53. The existing spring 70 is disposed. The spring 70 elastically supports the hitting portion 53 in a stationary state (a state before receiving a hit), while the lower end surface of the hitting portion 53 is displaced when the hitting portion 53 receives a hitting force and is displaced downward. And the spring 70 is compressed and deformed. On the other hand, unlike the first embodiment, the hitting portion 53 does not contact the engaging portion 60 (for example, the small diameter portion 61) even if the hitting portion 53 receives the hitting force. Therefore, in the second embodiment, the striking force received by the hitting portion 53 is not transmitted to the steel pipe 10 via the engaging portion 60, and the striking force acts on the excavation head 51. In other words, the striking force received by the striking portion 53 is configured to act on the excavation head 51 relatively more than on the steel pipe 10. In this manner, the striking force acts on the excavation head 51, and the excavation head 51 penetrates into the ground.

  Subsequently, a process of driving the steel pipe pile into the ground when the steel pipe pile structure 1 in the second embodiment is used will be described with reference to FIGS.

  First, as shown in FIG. 2 (A), the hitting machine 20 accommodated in the steel pipe 10 is dropped to the front side in the axial direction of the steel pipe 10 (the tip side of the steel pipe 10) by its own weight.

  Next, as shown in FIG. 2B, the hitting device 20 is hit against the hitting portion 53 to move the hitting portion 53 to the front side in the axial direction (downward in FIG. 2). As a result, the spring 70 is pressed and deformed by compression. Further, in conjunction with the movement of the striking portion 53 on the front side in the axial direction, the excavation head 51 connected to the striking portion 53 via the connecting portion 52 is propelled and penetrates into the ground. In this way, when the hitting portion 53 is hit by the hitting machine 20, the head portion 50 configured to be separable from the steel pipe 10 is propelled independently with respect to the steel pipe 10, and the tip portion of the head portion 50 (excavation) The head 51) penetrates into the ground. That is, the striking force received by the hitting unit 53 by the hitting machine 20 does not act directly on the steel pipe 10 (or only acts indirectly on the steel pipe 10), and the head part 50 of the steel pipe 10 and the head part 50. It is comprised so that it may act largely on.

  Next, as shown in FIG. 2C, the restoring force of the spring 70 compressed and deformed in the state of FIG. 2B acts on the steel pipe 10, whereby the steel pipe 10 moves forward. Further, the restoring force of the spring 70 also acts on the hitting machine 20 and moves in the direction in which the hitting machine 20 is pushed back. As described with reference to FIGS. The excavation head 51 is repeatedly propelled and the steel pipe 10 is advanced by the restoring force of the spring 70.

  The effects of the configurations provided in the first and second embodiments described above will be described with reference to FIG. In addition, in FIG. 3, although the example of 2nd Embodiment is shown as a separation-type small hitting pile, the same effect is show | played also in 1st Embodiment.

In the “integrated batting pile (conventional configuration example)” shown in FIG. 3, the sum of the mass M1 of the batting machine 20, the mass m2 of the steel pipe 10 and the mass m1 of the excavating head 90 is M2 (before hitting). If the speed V of the machine 20 is defined as the speed V1 of the excavation head 51 after hitting (after the hitting machine 20 hits the excavation head 51), the speed v1 can be expressed as follows based on the law of conservation of momentum.
M1 * V = M2 * v1
v1 = (M1 / M2) × V (1)

In the “separated small hitting pile” shown in FIG. 3, the mass M1 of the hitting machine 20, the mass m1 of the excavating head 51, the speed V of the hitting machine 20 (before hitting), and after hitting (the hitting machine 20 is the hitting part Based on the law of conservation of momentum, the speed V2 can be expressed as follows if the speed v2 of the excavation head 51 after hitting 53) is defined.
M1 × V = m1 × v2
v2 = (M1 / m1) × V (2)

Since v2> v1 from Equation (1) and Equation (2), the speed of the head portion 50 at the time of hitting by the hitting machine 20 compared to the conventional configuration (a configuration in which the head portion and the steel pipe are integrated). Can be increased. That is, the collision energy (E = 1/2 mv ² ) is increased, and the penetration input to the ground can be increased as compared with the configuration in which the head portion and the steel pipe are integrated.

  In the embodiment described above, the shape of the excavation head 51 is arbitrary as long as it is a tapered shape whose diameter is reduced at the tip side, and may be, for example, an inverted cone type or an inverted pyramid type. The maximum diameter of the excavation head 51 can be arbitrarily set. For example, as shown in FIG. 4A, the maximum diameter D2 of the excavation head 51 may be equal to or less than the outer diameter D1 of the steel pipe 10, or If the purpose is simply to drive in the steel pipe 10, the maximum diameter D2 of the excavation head 51 is set to a steel pipe as shown in FIG. It may be larger than 10 outer diameter D1.

  In the embodiment described above, an example in which one spring 70 is provided has been described. However, the number and arrangement of the springs 70 can be arbitrarily selected. For example, as shown in FIG. 4C, in an example in which the shape of the head portion 50 is changed (an example in which a plurality of connecting portions 52 that connect the excavation head 51 and the striking portion 53 are provided), a plurality of connecting portions. Each of the springs 70 may be arranged at 52, that is, two springs 70 may be arranged in parallel.

  The embodiments of the present invention have been described above with reference to specific examples. However, the present invention is not limited to these specific examples. Each element included in the embodiment and its arrangement, material, condition, shape, size, and the like are not limited to those illustrated, and can be changed as appropriate. In addition, the structures shown in different embodiments can be partially replaced or combined.

DESCRIPTION OF SYMBOLS 10: Steel pipe 20: Blow 50: Head part 51: Excavation head 52: Connection part 53: Impact part 60: Engagement part 61: Small diameter part 62: Medium diameter part 62a: Step part 63: Large diameter part 70: Spring

Claims (8)

A steel pipe pile structure buried in the ground,
A head part configured to be separable from the steel pipe, and having a striking part that is hit by a hitting machine that moves in the steel pipe, and propelled by a striking force received by the striking part;
An elastic member that elastically supports the striking portion on the tip side of the steel pipe, and that compresses and deforms by receiving a striking force generated when the striking device strikes the striking portion,
By hitting the hitting portion by the hitting machine, the head portion is independently propelled with respect to the steel pipe and the elastic member is compressed and deformed, and the restoring force of the elastic member based on the compressive deformation acts on the steel pipe. And the structure of the steel pipe pile comprised so that the said steel pipe may be urged | biased in the advance direction. The steel pipe and the hitting machine are urged to opposite sides in the axial direction by the restoring force of the elastic member based on the compression deformation,
The steel pipe pile is configured to penetrate into the ground by repeating the propulsion of the head portion by the impact of the hammer and the propulsion of the steel pipe by the restoring force of the elastic member. Steel pipe pile structure. Further provided with an engaging portion that is provided on the tip side in the steel pipe, and that comes into contact with the striking portion when the striking portion moves to the front side in the axial direction upon receiving a striking of the striking machine,
The striking force by the striking device received by the striking portion is transmitted to the head portion and is also transmitted to the steel pipe via the engaging portion. Steel pipe pile structure.   3. The steel pipe pile according to claim 1, wherein a striking force by the hitting machine received by the striking part is configured to act relatively greatly on the head part of the steel pipe and the head part. Structure.   5. The steel pipe pile according to claim 1, wherein the head portion has a tapered shape that is reduced in diameter toward a tip end side thereof, and a maximum diameter portion thereof is equal to or less than an outer diameter of the steel pipe. Construction.   The steel pipe pile according to any one of claims 1 to 4, wherein the head portion has a tapered shape that is reduced in diameter toward a tip end side thereof, and a maximum diameter portion thereof is equal to or greater than an outer diameter of the steel pipe. Construction.   The structure of the steel pipe pile according to any one of claims 1 to 6, wherein the hammer is a hammer having an outer diameter slightly thinner than an inner diameter of the steel pipe.   The striking propulsion device has a piston that moves up and down in the steel pipe by compressed air supplied from outside, and strikes the head portion to apply striking force. The structure of the steel pipe pile of any one of 1-7.