Pile and construction method of pile

Abstract

To provide a pile capable of efficiently cutting and removing an obstacle, and to provide a construction method of a pile.SOLUTION: A pile 1 includes: a pile body 10 formed in a cylindrical shape; and a bit part 20 provided at a tip part on one side in the axial direction of the pile body 10. The bit part 20 includes: a bit body 21 formed in a cylindrical shape; and a plurality of protrusions 26 protruding to one side in the axial direction from a tip surface 21d on one side in the axial direction of the bit body 21, and arranged by having an interval in the circumferential direction. The protrusion 26 includes an inclined surface 27 that gradually goes toward the other side in the axial direction as it goes toward the central side in the circumferential direction of each protrusion 26.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a pile and a method for installing the pile. [Background technology]

[0002] Conventionally, ground anchors may be left behind when adjacent buildings are constructed in redevelopment projects and the like. The ground anchors become an obstacle to the support piles to be driven into the newly constructed building. For this reason, the ground anchors must be removed prior to the driving of the support piles. For example, excavation is performed using a caisson foundation method, a backfilling method, an all-casing method, or the like, and the ground anchors are then cut off, after which the ground is backfilled with sand or liquefied treated soil and the piles are driven in. As an example of a pile, a steel pipe pile is known (see Patent Documents 1 and 2). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 4105076 [Patent Document 2] Patent No. 4242251 Summary of the Invention [Problem to be solved by the invention]

[0004] However, the above construction method requires time and effort, and is costly. In addition, when removing the soil and ground anchors using the all-casing method, a hammer grab is used to remove the soil and ground anchors, but this can cause problems such as the hammer grab getting caught on the ground anchor and becoming stuck.

[0005] Therefore, the present invention has been made in consideration of the above circumstances, and provides a pile and a pile installation method that can efficiently cut and remove obstacles. [Means for solving the problem]

[0006] In order to achieve the above object, the present invention employs the following means. The pile of the present invention comprises a cylindrically formed pile body and a bit portion provided at the tip portion on one side in the axial direction of the pile body, and the bit portion has a cylindrically formed bit body and a plurality of protrusions protruding from the tip surface on one side in the axial direction of the bit body to one side in the axial direction and arranged at intervals in the circumferential direction, and the protrusions have an inclined surface that gradually approaches the other side in the axial direction as it approaches the center of each of the protrusions in the circumferential direction.

[0007] In the pile constructed in this way, when the projection on the bit hits an obstacle during rotational driving of the pile, the projection itself and the inclined surface of the projection hit the obstacle, cutting the obstacle. The cut obstacle penetrates into the ground and is removed to the outside or inside of the pile. Thus, the obstacle can be efficiently cut and removed while the pile is being installed.

[0008] In the pile according to the present invention, the projections may be arranged alternately radially inward and outward on the tip face of the bit body.

[0009] In the pile configured in this manner, the projections are alternately arranged radially inward and outward of the tip surface of the bit body, making it possible to cut and remove obstacles on the inside and outside of the tip surface of the bit body.

[0010] In addition, in the pile according to the present invention, the protrusion arranged radially outward of the tip surface of the bit body may protrude radially outward beyond the outer edge of the tip surface.

[0011] In the pile configured in this manner, the projection disposed radially outward of the tip end face of the bit body projects radially outward beyond the outer edge of the tip end face, making it possible to reliably cut and remove obstacles located outside the tip end face of the bit body.

[0012] In addition, the pile of the present invention may include a plurality of nozzles arranged along the inner surface of the bit body through which a fluid flows, and an end portion on one axial side of a first nozzle of the plurality of nozzles is arranged along the axial direction, and an end portion on one axial side of a second nozzle of the plurality of nozzles is gradually inclined radially inward of the bit body as it approaches one axial side.

[0013] In the pile configured in this manner, the fluid is discharged vertically downward from the lower end of the first nozzle, and as the fluid flows downward from the lower end of the second nozzle, it gradually flows radially inward, allowing the fluid to be distributed throughout the portion along the inner circumferential surface of the bit body and the inner portion of the bit body.

[0014] Furthermore, the pile construction method of the present invention is a pile construction method in which the pile described above is used to rotary drive the pile into the ground, and when the protrusion of the bit portion of the rotated pile hits an obstacle when the pile is driven in, the obstacle is cut and the rotary drive of the pile proceeds.

[0015] In the pile construction method configured as above, when the projection on the bit hits an obstacle during rotational driving of the pile, the projection itself and the inclined surface of the projection hit the obstacle, cutting the obstacle. The cut obstacle penetrates into the ground and is removed to the outside or inside of the pile. Thus, the obstacle can be efficiently cut and removed while the pile is being installed.

[0016] In addition, in the pile installation method according to the present invention, the pile may be rotatable on both sides in the circumferential direction.

[0017] In the pile installation method configured in this manner, the rotation direction of the pile can be changed according to the situation when the protrusion is worn or damaged, making it possible to flexibly respond to such a situation. Effect of the Invention

[0018] According to the pile and pile installation method of the present invention, obstacles can be efficiently cut and removed. [Brief description of the drawings]

[0019] [Figure 1] FIG. 2 is a diagram showing a pile according to one embodiment of the present invention. [Diagram 2] FIG. 2 is a vertical cross-sectional view of a pile according to one embodiment of the present invention. [Diagram 3] FIG. 2 is a bottom view of the pile according to one embodiment of the present invention. [Figure 4] FIG. 11 is a vertical cross-sectional view of a pile according to a modified example of an embodiment of the present invention. [Diagram 5] FIG. 11 is a bottom view of a pile according to a modified example of an embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0020] A pile and a pile installation method according to a first embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a diagram showing a pile according to one embodiment of the present invention. As shown in Fig. 1, a pile 1 according to this embodiment is a pile that is rotary-driven into ground G using a steel pipe driving machine (not shown) or the like. The pile 1 includes a pile body 10 and a bit portion 20. The pile 1 is a pile formed of, for example, a steel pipe.

[0021] The pile body 10 is formed in a tubular shape. The pile body 10 has, for example, a cylindrical shape. The pile body 10 may have a rectangular or polygonal cross section as long as it is formed in a tubular shape. When pressed into the ground G, the pile body 10 is arranged so that its axis direction is aligned in the vertical direction.

[0022] The bit portion 20 is provided at a lower end portion (a tip portion on one side in the axial direction) 10d of the pile main body 10. The bit portion 20 has a bit body 21 and a plurality of protrusions .

[0023] FIG. 2 is a vertical cross-sectional view of the pile 1. 2, an upper end 21u of the bit body 21 is joined to a lower end 10d of the pile body 10 by, for example, welding. The cross-sectional shape of the bit body 21 is substantially the same as the cross-sectional shape of the pile body 10.

[0024] The projections 26 project downward (to one side in the axial direction) from a lower end surface (tip surface on one side in the axial direction) 21d of the bit body 21. Each projection 26 has an inclined surface 27 that gradually faces upward (to the other side in the axial direction) toward the center in the circumferential direction. The inclined surfaces 27 are disposed on both sides of each projection 26 in the circumferential direction.

[0025] FIG. 3 is a view of the pile 1 as seen from below. As shown in Fig. 3, a plurality of protrusions 26 are arranged at intervals in the circumferential direction on the lower end surface 21d of the bit body 21. In the example shown in Fig. 3, 16 protrusions 26 are provided, but the number of protrusions can be set appropriately.

[0026] The protrusion 26 has a first protrusion 26A and a second protrusion 26B. The first protrusion 26A is disposed toward the outer side of the lower end surface 21d of the bit body 21. The second protrusion 26B is disposed toward the inner side of the lower end surface 21d of the bit body 21. The first protrusions 26A and the second protrusions 26B are disposed alternately on the lower end surface 21d of the bit body 21.

[0027] A radially outer end 26a of the first projection 26A protrudes radially outward beyond an outer edge 21a of a lower end surface 21d of the bit body 21.

[0028] Next, a method of construction of the pile 1 described above in which the pile is rotary driven into the ground G will be described. Using a steel pipe press-in machine or the like, the pile 1 is pressed into the ground G while rotating in the circumferential direction. At this time, if the protrusion 26 of the bit portion 20 of the pile 1 hits an obstacle such as a ground anchor, the protrusion 26 itself and the inclined surface 27 of the protrusion 26 hit the obstacle and cut it off. If one protrusion 26 hits the obstacle and is damaged, the other protrusion 26 can cut the obstacle because the pile 1 is rotating. Since the obstacle is cut off, the rotational pressing-in of the pile 1 progresses. The pile 1 can rotate on both sides in the circumferential direction. When the pile 1 is pressed into a predetermined position, the rotational pressing-in is completed.

[0029] In the pile 1 and pile construction method thus configured, when the projection 26 provided on the bit portion 20 hits an obstacle during rotational driving of the pile 1, the projection 26 itself and the inclined surface 27 of the projection hit the obstacle, cutting the obstacle. The cut obstacle enters the ground G and is removed to the outside or inside of the pile 1. Thus, the obstacle can be efficiently cut and removed while the pile 1 is being installed.

[0030] Moreover, the protrusions 26 are alternately disposed radially inward and outward of the lower end surface 21d of the bit body 21. Therefore, it is possible to cut and remove obstacles on the inside and outside of the lower end surface 21d of the bit body 21.

[0031] In addition, the protrusion 26A disposed radially outward of the lower end surface 21d of the bit body 21 protrudes radially outward beyond the outer edge 21a of the lower end surface 21d. Therefore, it is possible to reliably cut and remove obstacles located outside the lower end surface 21d of the bit body 21.

[0032] In addition, if the projection 26 becomes worn or damaged, the rotation direction of the pile 1 can be changed to flexibly cope with the situation.

[0033] (Modification) Next, the modified examples will be described mainly with reference to Figures 4 and 5. In the following description of the modified examples, the same reference numerals will be used for the same or similar members and parts as those in the above-described embodiment, and the description will be omitted, and only configurations different from the embodiment will be described.

[0034] Fig. 4 is a vertical sectional view of a pile according to a modified example of one embodiment of the present invention, and Fig. 5 is a view of the pile according to a modified example of one embodiment of the present invention seen from below. As shown in FIGS. 4 and 5, a pile 1A according to this modified example includes a pile main body 10, a bit portion 20, a plurality of nozzles 30, and an inner bit 40.

[0035] The multiple nozzles 30 include a first nozzle 31 and a second nozzle 32. The first nozzle 31 and the second nozzle 32 are arranged along the inner circumferential surface of the pile main body 10 and the inner circumferential surface of the bit portion 20, respectively. Inside the first nozzle 31 and the second nozzle 32, a fluid such as water can flow.

[0036] As shown in Fig. 4, the first nozzle 31 extends in the vertical direction. A lower end portion (an end portion on one side in the axial direction) 31d of the first nozzle 31 also extends in the vertical direction. The lower end portion 31d of the first nozzle 31 is located above the lower end surface 21d of the bit body 21. The fluid is discharged vertically downward from the lower end portion 31d of the first nozzle 31.

[0037] The second nozzle 32 extends in the up-down direction except for its lower end 32d (one end in the axial direction). The lower end 32d of the second nozzle 32 is inclined so as to gradually move inward in the radial direction of the bit body 21 as it extends downward. The lower end 32d of the second nozzle 32 is located above the lower end surface 21d of the bit body 21. The fluid is discharged gradually toward the inner radial direction of the bit body 21 as it extends downward from the lower end 32d of the second nozzle 32.

[0038] The first nozzle 31 and the second nozzle 32 are covered in the vertical direction by an angle iron 34. The angle iron 34 is formed to have a horizontal cross section at a substantially right angle. The shape of the angle iron 34 can be set appropriately.

[0039] The inner bit 40 is provided on the inner peripheral surface of the pile body 10 and the inner peripheral surface of the bit body 21. The inner bit 40 is provided over approximately the entire length of the pile body 10 and the bit body 21 in the vertical direction. The inner bit 40 is formed into a substantially rectangular shape in horizontal cross section. The shape of the inner bit 40 can be set as appropriate.

[0040] When the pile 1A is rotated in the circumferential direction and pressed into the ground G using a steel pipe press-in machine or the like, a fluid is passed through the first nozzle 31 and the second nozzle 32. The fluid discharged from the lower end 31d of the first nozzle 31 and the fluid discharged from the lower end 32d of the second nozzle 32 causes the ground G to contain the fluid, facilitating excavation of the ground. The fluid is discharged vertically downward from the lower end 31d of the first nozzle 31, and gradually toward the inside in the radial direction as the fluid moves downward from the lower end of the second nozzle 32. Thus, the fluid can be distributed throughout the portion along the inner circumferential surface of the bit body 21 and the inner portion of the bit body 21.

[0041] In the pile 1A and pile construction method thus configured, when the projection 26 provided on the bit portion 20 hits an obstacle during rotational driving of the pile 1A, the projection 26 itself and the inclined surface 27 of the projection hit the obstacle, cutting the obstacle. The cut obstacle enters the ground G and is removed to the outside or inside of the pile 1A. Thus, the obstacle can be efficiently cut and removed while the pile 1A is being installed.

[0042] Furthermore, the lower end 31d of the first nozzle 31 extends in the up-down direction. The lower end 32d of the second nozzle 32 is inclined so as to gradually move inward in the radial direction of the bit body 21 as it extends downward. The fluid is discharged vertically downward from the lower end 31d of the first nozzle 31, and is discharged gradually toward the inside in the radial direction as it extends downward from the lower end 32d of the second nozzle 32. This allows the fluid to spread throughout the portion along the inner circumferential surface of the bit body 21 and the inner portion of the bit body 21.

[0043] In addition, since the inner bit 40 is provided, soil pressure acting on the angle iron 34 protecting the first nozzle 31 and the second nozzle 32 can be prevented from causing the angle iron 34 to come off the pile body 10 and the bit body 21.

[0044] In addition, the inner bit 40 can prevent the cut anchor and the excavated soil from blocking the lower end 31d of the first nozzle 31 and the lower end 32d of the second nozzle 32.

[0045] In addition, the inner bit 40 can prevent the cut anchor from entering the pile 1A and blocking the inside of the lower end face 21d of the pile 1A, making it impossible to penetrate the pile 1A.

[0046] In addition, the inner bit 40 can cut the ground G inside the pile 1A to facilitate the penetration of the pile 1A.

[0047] The shapes and combinations of the components shown in the above-described embodiment are merely examples, and various modifications can be made based on design requirements, etc., without departing from the spirit of the present invention.

[0048] For example, in the embodiment described above, the protrusions 26 are alternately disposed radially inward and outward on the lower end surface 21d of the bit body 21, but are not limited to this. The protrusions 26 may be disposed at the same radial position on the lower end surface 21d of the bit body 21.

[0049] In the embodiment described above, the protrusion 26A disposed radially outward of the lower end face 21d of the bit body 21 protrudes radially outward beyond the outer edge 21a of the lower end face 21d, but this is not limited thereto. The protrusion 26A disposed radially outward of the lower end face 21d of the bit body 21 does not have to protrude radially outward beyond the outer edge 21a of the lower end face 21d.

[0050] In the embodiment described above, the pile 1 is rotatable in both directions in the circumferential direction, but this is not limited thereto. The pile 1 may be rotatable only in one direction in the circumferential direction. [Explanation of symbols]

[0051] 1 stake 10 Pile body 20 bit section 21 bit body 21a Outer edge 21d Lower end surface (tip surface) 26 Protrusion 27 Slope G. Ground

Claims

1. A pile body formed in a cylindrical shape; A bit portion provided at a tip portion on one side in the axial direction of the pile main body, The bit section includes: A cylindrical bit body; A plurality of protrusions are provided which protrude from a tip surface on one side of the axial direction of the bit body to one side in the axial direction and are arranged at intervals in the circumferential direction, The protrusion is A pile having an inclined surface that gradually slopes toward the other side in the axial direction as it approaches the center of each of the projections in the circumferential direction.

2. The pile according to claim 1 , wherein the projections are alternately arranged radially inward and outward on the tip surface of the bit body.

3. The pile according to claim 1 or 2, wherein the protrusion arranged radially outwardly of the tip surface of the bit body protrudes radially outward beyond an outer edge of the tip surface.

4. A plurality of nozzles are provided along an inner circumferential surface of the bit body, through which a fluid flows; An end portion of a first nozzle among the plurality of nozzles is disposed on one side in the axial direction along the axial direction, A pile as described in claim 1 or 2, wherein an end portion on one side of the axial direction of a second nozzle among the plurality of nozzles is gradually inclined so as to approach radially inward of the bit body as it approaches one side of the axial direction.

5. A method for constructing a pile by rotary driving into ground using the pile according to claim 1, This is a pile construction method in which, when the protrusion of the bit portion of the rotating pile hits an obstacle while the pile is being driven in, the obstacle is cut and the rotational driving of the pile proceeds.

6. The pile installation method according to claim 5 , wherein the pile is rotatable in both directions in the circumferential direction.

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