Rotary buried pile

Abstract

To provide a rotary buried pile allowing enough tip support force to be acquired.SOLUTION: A rotary buried pile 100 comprises: a pile body 10; blades 20, 30 inclining in a rotational direction of the pile body 10 and fixed on a tip of the pile body 10 in an axis direction; and a projected member 40 fixed on the blades 20, 30. The projected member 40 comprises a projected part 42 from surfaces of the blades 20, 30 in the axis direction. The projected part 42 is placed in an area opposite to the tip of the pile body 10.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a rotary buried pile. [Background technology]

[0002] Rotary piles, which are buried in the ground by rotation, generally have blades with a larger diameter than the steel pipe that is the pile body, and a digging blade at the tip of the steel pipe. The digging blade excavates the bottom of the pile hole ahead of the blades. The blades push up the soil excavated by the digging blade, providing bearing capacity after construction. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2001-152446 A Summary of the Invention [Problem to be solved by the invention]

[0004] Rotary buried piles equipped with digging blades dig into the bottom of the pile hole with the digging blade, causing the soil at the bottom of the pile hole to crumble and become soft. This reduces the resistance force on the pile body as the tip of the pile body propels itself through the ground, but because the soil at the bottom of the pile hole becomes soft, it is difficult to obtain sufficient tip bearing strength after construction.

[0005] An object of the present invention is to provide a rotary buried pile capable of obtaining sufficient tip bearing force. [Means for solving the problem]

[0006] A rotary buried pile according to one embodiment includes a pile body, a blade inclined in the rotation direction of the pile body and fixed to the axial tip of the pile body, and a protruding member fixed to the blade. The protruding member has a protruding portion protruding in the axial direction from the surface of the blade. The protruding portion is disposed in a region facing the tip of the pile body.

[0007] With this type of rotary buried pile, the soil at the bottom of the pile hole opposite the tip of the pile body is collapsed by the protruding part of the protruding member, and the collapsed soil can be pushed upward by the blades. Therefore, the soil at the bottom of the pile hole is not collapsed more than necessary, and sufficient tip bearing capacity can be obtained after construction.

[0008] In addition, according to this embodiment of the rotary buried pile, the tip of the protruding part protrudes lower than the tip of the wing or to approximately the same height as the tip of the wing along the axial direction of the pile body. This allows the wing to mainly excavate the pile hole, and the protruding part to function to soften the soil in the center of the bottom of the pile hole, so that the soil at the bottom of the pile hole is not destroyed more than necessary.

[0009] In addition, according to this embodiment of the rotary buried pile, the protruding portion has an inclined surface inclined in the same direction as the surface of the blade, which allows the protruding portion having an inclined surface in the same direction as the surface of the blade to break up the soil in the center of the bottom of the pile hole opposite the tip of the pile body, thereby assisting the excavation by the blade.

[0010] In addition, in this embodiment of the rotary buried pile, the pile body is cylindrical, and the protruding member has a width that allows it to be inserted into the pile body. The protruding member is plate-shaped, and both ends in the width direction are fixed to the inner surface of the pile body. This increases the mechanical strength of the protruding member.

[0011] In addition, according to this embodiment of the rotary buried pile, the vane is fixed to the pile body and the protruding member so as to close the tip of the pile body together with the protruding member, thereby increasing the tip bearing capacity after construction.

[0012] A rotary buried pile according to one embodiment includes a pile body having a tip portion including a first inclined end face inclined with respect to a plane perpendicular to the axial direction and a second inclined end face inclined with respect to the plane perpendicular to the axial direction, a plate-like first blade fixed in contact with the first inclined end face of the tip portion of the pile body, a plate-like second blade fixed in contact with the second inclined end face of the tip portion of the pile body, and a protruding member disposed in a region facing the tip portion of the pile body. The protruding member has a protruding portion protruding from a surface of at least one of the first and second blades.

[0013] With this type of rotary buried pile, the soil in the center of the bottom of the pile hole opposite the tip of the pile body is collapsed by the protruding part of the protruding member, and the collapsed soil can be pushed upward by the first and second blades. Therefore, the soil in the bottom of the pile hole is not collapsed more than necessary, and sufficient tip bearing force can be obtained after construction.

[0014] In addition, in this embodiment of the rotary buried pile, the tip of the protruding part protrudes lower in the axial direction than at least one of the tips of the first and second blades, or protrudes to approximately the same height as at least one of the tips of the first and second blades. This allows the first and second blades to mainly excavate the pile hole, and the protruding part of the protruding member functions to soften the soil in the center of the bottom of the pile hole, preventing the soil at the bottom of the pile hole from collapsing more than necessary.

[0015] Furthermore, in this embodiment of the rotary buried pile, the protruding portion has a first inclined surface inclined in the same direction as the surface of the first blade, and a second inclined surface inclined in the same direction as the surface of the second blade. This allows the protruding portion of the protruding member, which has first and second inclined surfaces inclined in the same direction as the surfaces of the first and second blades, to break up the soil at the bottom of the pile hole, thereby assisting in excavation by the first and second blades.

[0016] In addition, in this embodiment of the rotary buried pile, the pile body is cylindrical, and the protruding member is plate-shaped with a width that allows it to be inserted into the pile body. In addition, both ends of the protruding member in the width direction are fixed to the inner surface of the pile body. This increases the mechanical strength of the protruding member.

[0017] Furthermore, in the rotary buried pile of this embodiment, the first and second wings are fixed to the pile body and the protruding member so as to close the tip of the pile body together with the protruding member, thereby increasing the tip bearing capacity after construction. Effect of the Invention

[0018] According to the present invention, it is possible to provide a rotary buried pile capable of obtaining a sufficient tip bearing force. [Brief description of the drawings]

[0019] [Figure 1] FIG. 1 is a perspective view of a rotary buried pile according to one embodiment, as viewed from the tip side. [Diagram 2] FIG. 2 is a view of the rotary buried pile assembly of FIG. 1 as seen from the direction of arrow F2. [Diagram 3] FIG. 3 is a view of the assembly of FIG. 2 as viewed from the direction of arrow F3 (tip side). [Figure 4] FIG. 4 is a view of the assembly of FIG. 2 as seen from the direction of arrow F4. [Diagram 5] 5(a) is a diagram of the blade support member of the assembly of FIG. 2, FIG. 5(b) is a diagram of the blade support member viewed from the direction of arrow F5b (tip side) of FIG. 5(a), and FIG. 5(c) is a diagram of the blade support member viewed from the direction of arrow F5c of FIG. 5(a). [Figure 6] FIG. 6(a) is a view of one of the blades of the assembly of FIG. 2 as seen from the tip side of the assembly, and FIG. 6(b) is a view of one of the blades as seen from the recess side. [Figure 7] 7(a) is a diagram of the protruding member of the assembly of FIG. 2, FIG. 7(b) is a diagram of the protruding member viewed from the direction of arrow F7b (tip side) of FIG. 7(a), and FIG. 7(c) is a diagram of the protruding member viewed from the direction of arrow F7c of FIG. 7(a). [Figure 8] FIG. 8 is a diagram showing a protruding member according to a first modified example. [Figure 9] FIG. 9 is a diagram showing an assembly of a rotary buried pile according to the second modified example. [Figure 10] FIG. 10 is a view of the assembly of FIG. 9 as seen from the direction of arrow F10. [Figure 11] FIG. 11 is a diagram showing an assembly of a rotary buried pile according to the third modified example. [Figure 12] FIG. 12 is a view of the assembly of FIG. 11 as seen from the direction of arrow F12. [Figure 13] FIG. 13 is a view of the assembly of FIG. 11 as seen from the direction of arrow F13. [Figure 14] FIG. 14 is a view of the rotary buried pile according to the fourth modified example, seen from the tip side. [Figure 15] FIG. 15 is a view of the rotary buried pile according to the fifth modified example, as viewed from the tip side. [Figure 16] FIG. 16 is a view of the rotary buried pile according to the sixth modified example, as viewed from the tip side. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0020] Hereinafter, an embodiment will be described with reference to the drawings. FIG. 1 is a perspective view of a rotary buried pile 100 according to one embodiment, as viewed from the tip side.

[0021] The rotary buried pile 100 has a substantially cylindrical pile body 10, two substantially semicircular blades 20, 30, and a substantially rectangular plate-like protruding member 40. The two blades 20, 30 are fixed to the pile body 10 so as to block the tip side of the pile body 10, in a direction intersecting an imaginary center line passing through the center of the pile body 10. The protruding member 40 is arranged between the two blades 20, 30 along the center line of the pile body 10 by inserting a part of its rear end into the pile body 10, and both ends in the width direction are fixed to the inner surface of the pile body 10.

[0022] The pile main body 10 has a substantially cylindrical blade receiving member 12 and at least one substantially cylindrical connecting member 11. The blade receiving member 12 is a member for attaching the blades 20, 30 and the protruding member 40. The connecting member 11 is a member that adjusts the pile main body 10 to a desired length by connecting one or more connecting members to the rear end of the blade receiving member 12. The blade receiving member 12 and the connecting member 11 may be an integrated member. The connecting member 11 may also be a steel pipe pile, a concrete pile, or an SC pile.

[0023] The blade receiving member 12 and the connecting member 11 are fixed by welding, bolts, or a mechanical method. The blade receiving member 12, the blades 20, 30, and the protruding member 40 are fixed by welding or fitting. The structure in which the blades 20, 30, and the protruding member 40 are fixed to the blade receiving member 12 is the assembly 1.

[0024] Fig. 2 is a view of the assembly 1 as viewed from the direction of arrow F2 in Fig. 1, and is shown upside down compared to Fig. 1. Fig. 3 is a view of the assembly 1 as viewed from the direction of arrow F3 (tip side) in Fig. 2. Fig. 4 is a view of the assembly 1 as viewed from the direction of arrow F4 in Fig. 2. In Figs. 1 to 4, the direction parallel to an imaginary center line passing through the center of the pile main body 10 is indicated by the Z axis, the direction perpendicular to the Z axis and parallel to the protruding member 40 is indicated by the X axis, and the direction perpendicular to the X axis and Z axis is indicated by the Y axis.

[0025] Fig. 5(a) is a view of the blade receiving member 12 seen from the same direction as Fig. 2, Fig. 5(b) is a view of the blade receiving member 12 seen from the direction of arrow F5b (tip side) in Fig. 5(a), and Fig. 5(c) is a view of the blade receiving member 12 seen from the direction of arrow F5c in Fig. 5(a). As shown in Figs. 2 to 5, the tip of the blade receiving member 12 does not have a single annular surface obtained by cutting the blade receiving member 12 in an XY plane perpendicular to its center line, but has two inclined end faces 14 and 16 that are inclined in different directions at the same angle in the X-axis direction.

[0026] The two inclined end faces 14, 16 have axial steps 15 at both circumferential ends. One inclined end face 14 is a surface obtained by dividing the tip face of the blade receiving member 12 in the Y-axis direction into two semicircular annular faces, which is inclined at a predetermined angle in the X-axis direction with respect to the XY plane. The other inclined end face 16 is a surface obtained by dividing the tip face of the blade receiving member 12 in the Y-axis direction into two semicircular annular faces, which is inclined at the same angle in the opposite direction to the X-axis direction with respect to the XY plane. The inclination angle of the inclined end faces 14, 16 in the X-axis direction with respect to the XY plane is, for example, 5 to 15 degrees, and preferably 10 degrees.

[0027] In this embodiment, a case where two inclined end faces 14, 16 are provided at the tip of the blade receiving member 12 will be described, but for example, three or more inclined end faces may be provided at the tip of the blade receiving member 12. When three or more inclined end faces are provided at the tip of the blade receiving member 12, the number of blades may be increased according to the number of inclined end faces and the shape of the protruding member may be changed.

[0028] Fig. 6(a) is a view of one of the blades 20 as seen from the tip side of the assembly 1, which is the surface of the blade 20, and Fig. 6(b) is a view of the blade 20 as seen from the recess 22 side (the direction of the arrow F6b in Fig. 6a). The blades 20 and 30 are formed of flat steel plates having a substantially semicircular shape and have point-symmetric shapes. Therefore, here, the structure of one of the blades 20 will be described, and a detailed description of the other blade 30 will be omitted.

[0029] The blade 20 has a rectangular recess 22 of a size and shape that can receive half the thickness of the protruding member 40 along a diameter that passes through the center of the approximate semicircle. The longitudinal center of the recess 22 is at the center of the approximate semicircle. The blade 20 has a cutout portion 24 that is a shape in which a part of the blade 20 is cut out straight from one end 22a on the lower end side in the inclination direction of the recess 22 toward the arc. The corner where the cutout portion 24 intersects with the arc is the tip 20a of the blade 20. The blade 20 may also have a cutout portion on the upper end side in the inclination direction. The other blade 30 has a recess 32, a cutout portion 34, and a tip 30a of the same shape. Both ends of the recess 22 in the inclination direction are flat surfaces that are parallel to the thickness direction of the blade 20 and perpendicular to the diameter of the blade 20. Since the protruding member 40 is received in an inclined state in the recess 22, there is a play between the recess 22 and the protruding member 40. This play is filled when the protruding member 40 is fixed to the recess 22 by welding. Note that both ends of the recess 22 may have surfaces that are inclined to match the inclination of the blades 20.

[0030] 7(a) is a view of the protruding member 40 from the same direction as FIG. 2, FIG. 7(b) is a view of the protruding member 40 from the direction of the arrow F7b (tip side) in FIG. 7(a), and FIG. 7(c) is a view of the protruding member 40 from the direction of the arrow F7c in FIG. 7(a). As shown in FIG. 2 and FIG. 3, the protruding member 40 has a width in the X-axis direction slightly shorter than the inner diameter of the blade receiving member 12, and is formed of a substantially rectangular flat steel plate with one end (protruding portion 42) in the Z-axis direction recessed in a V-shape toward the other end. The concave V-shaped protruding portion 42 of the protruding member 40 has an inclined surface 44 parallel to the inclined end surface 14 of the blade receiving member 12 and an inclined surface 46 parallel to the inclined end surface 16 of the blade receiving member 12. The length of the protruding member 40 in the Z-axis direction may be shorter than the length of the blade receiving member 12 in the Z-axis direction, and may be any length that can obtain sufficient fixing strength between the protruding member 40 and the blade receiving member 12.

[0031] The procedure for assembling the assembly 1 of the rotary buried pile 100 by fixing the blade receiving member 12 having the above structure, the two blades 20, 30, and the protruding member 40 can be, for example, the following two procedures. That is, a first procedure is to fix the protruding member 40 to the blade receiving member 12, and then fix the two blades 20, 30 to the blade receiving member 12 and the protruding member 40, and a second procedure is to fix the two blades 20, 30 to the protruding member 40 to form a structure, and then fix this structure to the blade receiving member 12. Such an assembly procedure may be appropriately selected depending on the size of the rotary buried pile 100 and the length of the blade receiving member 12 of the pile main body 10 in the Z-axis direction.

[0032] When assembling the assembly 1 in the first step, first, the other end of the protruding member 40 opposite to the V-shaped protruding portion 42 is inserted into the blade receiving member 12 from the tip side of the blade receiving member 12. At this time, a part of the other end side of the protruding member 40 is inserted from the tip side of the blade receiving member 12 so that an imaginary center plane passing through the center of the thickness direction of the protruding member 40 and perpendicular to the thickness direction overlaps with an imaginary center line passing through the center of the blade receiving member 12 and overlaps with two steps 15 between the two inclined end faces 14, 16 of the blade receiving member 12. The length of insertion of the protruding member 40 into the blade receiving member 12 may be freely determined as long as the protruding portion 42 of the protruding member 40 does not protrude beyond the tips of the blades 20, 30. In this state, both ends of the protruding member 40 in the width direction are fixed to the inner surface of the blade receiving member 12 by welding. At this time, the welding work can be performed by accessing from the leading end side of the blade receiving member 12, and can also be performed by accessing from the rear end side of the blade receiving member 12.

[0033] After the protruding member 40 is fixed to the blade receiving member 12, one of the blades 20 is fixed to the blade receiving member 12 and the protruding member 40. At this time, the back surface of the blade 20 is abutted against the inclined end surface 14 of the blade receiving member 12 so that the half of the protruding member 40 fixed to the blade receiving member 12 on the inclined end surface 14 side in the thickness direction with the center plane as the boundary fits into the recess 22 of the blade 20. In this state, the diameter of the blade 20 overlaps with the imaginary center plane of the protruding member 40, and the blade 20 is inclined in the same direction as the inclined end surface 14. Then, while the blade 20 is kept in this state, the edge of the recess 22 on the front side of the blade 20 and the surface of the protruding member 40 are fixed by welding, and the edge of the inclined end surface 14 on the outer surface side of the blade receiving member 12 and the back surface of the blade 20 are fixed by welding. In addition, the inside of the blade receiving member 12 is accessed from the rear end side of the blade receiving member 12, and the edge of the recess 22 on the back side of the blade 20 is welded to the face of the protruding member 40, and the edge of the inclined end face 14 on the inner side of the blade receiving member 12 is welded to the back side of the blade 20.

[0034] Thereafter, in the same manner, the back surface of the other blade 30 is brought into contact with the inclined end surface 16 of the blade receiving member 12, the other half of the protruding member 40 in the thickness direction is fitted into the recess 32, and the blade receiving member 12, the protruding member 40, and the blade 30 are fixed by welding. When the protruding member 40 and the blades 20, 30 are fixed to the blade receiving member 12 in this manner, the tip of the blade receiving member 12 is completely sealed. However, the tip of the blade receiving member 12 does not have to be completely sealed, and the blade receiving member 12 may have a structure that guides the excavated soil into the inside of the blade receiving member 12.

[0035] As described above, when assembly 1 is assembled by the first procedure, one inclined surface 44 of protruding portion 42 of protruding member 40 becomes parallel to the surface of one blade 20, and the other inclined surface 46 of protruding portion 42 of protruding member 40 becomes parallel to the surface of the other blade 30. In other words, inclined surface 44 of protruding member 40 becomes the tip surface of a protrusion that protrudes from the surface of blade 20 at a predetermined height, and inclined surface 46 of protruding member 40 becomes the tip surface of a protrusion that protrudes from the surface of blade 30 at a predetermined height.

[0036] When assembling the assembly 1 in the second procedure, first, a structure is formed in which one blade 20 is fixed to one surface of the protruding member 40 and the other blade 30 is fixed to the other surface of the protruding member 40. The positioning of the blades 20, 30 to the protruding member 40 and the fixing points by welding are the same as those described in the first procedure above. Then, after this, the structure in which the two blades 20, 30 are fixed to the protruding member 40 is attached to the tip of the blade receiving member 12 and fixed at predetermined points by welding. The attachment state of the structure to the blade receiving member 12 and the fixing points by welding are the same as those described in the first procedure above.

[0037] In cases where the size of the rotary buried pile 100 is relatively large and the structure in which the two blades 20, 30 are fixed to the protruding member 40 is difficult to handle, it is desirable to assemble the assembly 1 in the first procedure. Conversely, in cases where the size of the rotary buried pile 100 is relatively small and the structure in which the two blades 20, 30 are fixed to the protruding member 40 is easy to handle, the rotary buried pile 100 may be assembled in the second procedure.

[0038] As described above, the rotary buried pile 100 of this embodiment can be assembled simply by fixing the protruding member 40 and the two blades 20, 30 to the blade receiving member 12 of the pile body 10, and the number of parts is small, the number of work steps is small, the positioning of the parts is easy, and it can be easily assembled in a short time. The protruding member 40 and the blades 20, 30 can be formed by simply processing a flat steel plate, and bending of the steel plate is not required, and the mechanical strength can be easily increased by adjusting the thickness. In addition, according to the first procedure, the alignment of the two blades 20, 30 is easy, and a jig for aligning the blades 20, 30 is not required, and assembly is easy.

[0039] A method for constructing the rotary buried pile 100 having the above-mentioned structure in the ground will be described below. When constructing the rotary buried pile 100 in the ground, first, the rotary buried pile 100 is attached to a pile driver or the like, and the rotary buried pile 100 is placed perpendicular to the ground surface of the ground with the tip of the rotary buried pile 100 facing the ground surface. In this state, the rotary buried pile 100 is rotated clockwise toward the ground and brought into contact with the ground.

[0040] When the rotary buried pile 100 is brought into contact with the ground while being rotated, the tips 20a, 30a of the two blades 20, 30 excavate the ground, and the excavated soil moves from the front surface of the blades 20, 30 through the cutouts 24 to the rear surface of the blades 20, 30, and the excavated soil is pushed upward by the inclination of the blades 20, 30. This provides the driving force for the rotary buried pile 100 to dig into the ground.

[0041] At this time, the protruding member 40 functions to break down and soften the ground within the circular area at the bottom of the pile hole facing the tip of the wing receiving member 12 (the lower end of the pile main body 10) with its protruding portion 42. If the protruding member 40 is not provided, in the case of a type of pile in which the tip of the pile main body 10 is blocked by the wings 20, 30 like the rotary buried pile 100 of this embodiment, it is assumed that the ground in the circular area at the bottom of the pile hole facing the tip of the pile main body 10 would remain hard, and the excavation resistance would be greater than that of the ground radially outside the outer circumferential surface of the pile main body 10, making excavation of the ground difficult. For this reason, in this embodiment, the protruding portion 42 of the protruding member 40, which has concave V-shaped inclined surfaces 44, 46 arranged parallel to the surfaces of the blades 20, 30, breaks down and softens the ground in the circular area at the bottom of the pile hole opposite the tip of the blade receiving member 12, making it easier for the broken down soil from the circular area to flow along the surfaces of the blades 20, 30 toward the outer periphery of the blades 20, 30.

[0042] That is, the protruding portion 42 of the protruding member 40 is a protrusion protruding from the surface near the center of rotation of the blades 20, 30 in order to break up the ground in the circular area facing the tip of the pile body 10. Unlike a conventional excavation blade fixed to the tip of the steel pipe of a steel pipe pile for the sole purpose of improving excavation performance, a part of the surface of the blades 20, 30 is protruded at a predetermined protruding height in order to give the surface of the blade the ability to break up the ground. The protruding portion 42 of the protruding member 40 has an inclined surface 44 parallel to the surface of the blade 20 and an inclined surface 46 parallel to the surface of the blade 30. The protruding member 40 uses such a concave V-shaped protruding portion 42 to break up and soften a part of the ground to be excavated by the blades 20, 30 (the part of the ground in the circular area in the center of the bottom of the pile hole that is the most difficult to excavate) in advance, thereby assisting the blades 20, 30 in excavating the ground.

[0043] The protruding portion 42 of the protruding member 40, which is a protrusion protruding from the surface of the blades 20, 30, may have any shape as long as it protrudes from the surface of the blades 20, 30 to a predetermined protruding height. For example, instead of making the protruding portion 42 of the protruding member 40 into a radially continuous blade shape protruding from the surface of the blades 20, 30 as in the above-mentioned embodiment, it may be made into a shape in which multiple sharp protrusions 48 of the same protruding height are arranged in the radial direction as in the first modified example shown in Figure 8. In this case, the tips 48a of the multiple protrusions 48 become the tips of the protruding portion, the imaginary line connecting the multiple tips 48a becomes the inclined surface of the protruding portion, and the tips 48a of the multiple protrusions 48 are arranged on a surface parallel to the surface of the blades 20, 30.

[0044] As described above, in this embodiment, in order to provide a protrusion of a predetermined height from the surface close to the rotation center of the blades 20, 30, the protruding member 40 is provided by shaping the tip of a single steel plate. However, instead of providing the protruding member 40, for example, as in the second modified example shown in Figs. 9 and 10, a plurality of substantially conical protrusions 50 of the same height may be provided protruding from the surface close to the rotation center of the blades 20, 30. In this case, for example, a plurality of protrusions 50 of the same shape may be manufactured and fixed to the surface of the blades 20, 30 by welding. Note that the shape of the protrusions 50 is not limited to a substantially conical shape, and may be a substantially triangular pyramid, a substantially cube, or the like.

[0045] Furthermore, if the focus is solely on the excavation function, then it is sufficient for the protruding member 40 of the rotary buried pile 100 of this embodiment to only have the portion protruding from the surface of the blades 20, 30; however, the rear end portion of the protruding member 40 inserted into the blade receiving member 12 of the pile body 10 contributes to increasing the fixing strength of the protruding member 40, and as a result, the mechanical strength of the protrusions provided on the surfaces of the blades 20, 30 can be increased.

[0046] As described above, according to the above-mentioned embodiment and its modified example, the soil in the circular area at the bottom of the pile hole facing the tip of the pile body 10 of the rotary buried pile 100 can be broken down and softened by the protruding portion 42 of the protruding member 40, and the excavation of the ground by the blades 20, 30 can be effectively assisted. In addition, since the protruding portion 42 of the protruding member 40 is a protrusion that protrudes from the surface of the blades 20, 30 at a predetermined height, a sufficient tip bearing force can be obtained after the rotary buried pile 100 is constructed. In other words, since the protruding portion 42 of the protruding member 40 has a protruding height that does not protrude beyond the tips of the blades 20, 30, the amount of soil that softens the ground in the circular area at the bottom of the pile hole facing the tip of the pile body 10 can be minimized, and the amount of softened soil existing between the surfaces of the blades 20, 30 and the bottom of the pile hole after construction can be reduced as much as possible, and a sufficient tip bearing force can be obtained.

[0047] Furthermore, when the protruding portion of the protruding member is shaped as an array of multiple protrusions 48 as in the first modified example described above, the excavation resistance can be reduced and the stress acting on the protruding member 40 from the ground can be suppressed, compared to when the protruding portion 42 is shaped like a concave V-shape blade as in the embodiment described above. Therefore, according to the first modified example, the thickness of the protruding member 40 can be made thin and the length of the fixed portion relative to the blade receiving member 12 can be shortened.

[0048] Furthermore, when multiple protrusions 50 are fixed in a dispersed manner on the surfaces of the blades 20, 30 as in the above-mentioned second modified example, the stress acting on the blades 20, 30 can be dispersed more effectively than when blade-shaped protruding members 40 are provided along the diameter of the blades 20, 30. This makes it possible to reduce the stress acting on the tip of the pile main body 10, such as the fixing points of the blades 20, 30 to the blade receiving member 12 and the fixing points of the blades 20, 30 to the protruding members 40.

[0049] The present invention is not limited to the above-described embodiment and its modified examples, and can be modified in various ways in the implementation stage without departing from the gist of the invention. The above-described embodiment and its modified examples include various inventions, and various inventions can be extracted by combinations selected from the multiple components disclosed. For example, if the problem can be solved and an effect can be obtained even if some components are deleted from all the components shown in the present embodiment and its modified examples, the configuration from which the components are deleted can be extracted as an invention.

[0050] For example, in the above-mentioned embodiment and its modifications, the blades 20, 30 are provided with the cutouts 24, 34, but as in the third modification shown in Figures 11 to 13, substantially semicircular blades 120, 130 without cutouts may be used, and the present invention can be applied to such rotary buried piles as well. The third modification has a larger bearing capacity since it does not have cutouts.

[0051] Also, notches may be provided on both circumferential sides of the blades 20, 30, or notches may be provided only on the upper ends of the blades 20, 30 in the inclination direction, not on the lower ends. The shape of the blades 20, 30 is not limited to a flat plate shape, and may be, for example, a bowl shape. The number of blades 20, 30 is not limited to two, and may be three or more.

[0052] Fig. 14 is a view of the rotary buried pile according to the fourth modified example seen from the tip side, Fig. 15 is a view of the rotary buried pile according to the fifth modified example seen from the tip side, and Fig. 16 is a view of the rotary buried pile according to the sixth modified example seen from the tip side. The rotary buried piles according to the fourth to sixth modified examples have substantially the same structure as the above-mentioned embodiment except that the shapes of the blades 20, 30 are different, so a description of the configuration that functions in the same way as the above-mentioned embodiment will be omitted.

[0053] The two blades 141 and 142 of the rotary buried pile according to the fourth modified example have shapes that are point symmetrical with respect to the central axis of the rotary buried pile. Therefore, here, one blade 141 will be described, and the description of the other blade 142 will be omitted. The blade 141 is formed of a flat steel plate having a substantially semicircular shape. The blade 141 has an arc-shaped first surface 141a, a flat second surface 141b, a flat third surface 141c, and a flat fourth surface 141d on its outer periphery. The second surface 141b abuts against an end surface 142d on the outer periphery of the other blade 142 and one surface 401 of the protruding member 40. The third surface 141c abuts against an end surface 402 in the width direction of the protruding member 40. The fourth surface 141d abuts against an end surface 142b on the outer periphery of the blade 142.

[0054] Like the blade 20 of the embodiment described above, the blade 141 is fixed to the blade receiving member 12, the protruding member 40, and the other blade 142 with the surface opposite to the surface 1410 abutting against the inclined end surface 14 of the blade receiving member 12. The other blade 142 is similarly fixed to the blade receiving member 12, the protruding member 40, and the blade 141 with the surface abutting against the inclined end surface 16, thereby blocking the tip side of the blade receiving member 12. The inclination directions of the two blades 141, 142 may be reversed.

[0055] The two blades 151, 152 of the rotary buried pile according to the fifth modified example have shapes that are point symmetrical with respect to the central axis of the rotary buried pile. Therefore, here, one of the blades 151 will be described, and the description of the other blade 152 will be omitted. The blade 151 is formed of a flat steel plate having a substantially semicircular shape. The blade 151 has an arc-shaped first surface 151a and a flat second surface 151b on its outer periphery. The second surface 151b abuts against one surface 401 of the protruding member 40.

[0056] Like the blade 20 of the embodiment described above, the blade 151 is fixed to the blade receiving member 12 and the protruding member 40 with the surface opposite to the surface 1510 abutting against the inclined end surface 14 of the blade receiving member 12. The other blade 152 is similarly fixed to the blade receiving member 12 and the protruding member 40 with the surface abutting against the inclined end surface 16, thereby blocking the tip side of the blade receiving member 12.

[0057] The two blades 161, 162 of the rotary buried pile according to the sixth modified example have different shapes. One blade 161 is formed of a flat steel plate having a substantially semicircular shape. The blade 161 has an arc-shaped first surface 161a and a flat second surface 161b on its outer periphery. The second surface 161b abuts against a second surface 162b and a sixth surface 162f on the outer periphery of the other blade 162, and one surface 401 of the protruding member 40.

[0058] Like the blade 20 in the embodiment described above, the blade 161 is fixed to the blade support member 12, the protruding member 40, and the other blade 162 with the surface opposite to its surface 1610 abutting the inclined end surface 14 of the blade support member 12.

[0059] The other blade 162 is formed of a flat steel plate having a substantially semicircular shape. The blade 162 has an arc-shaped first surface 162a, a flat second surface 162b, a flat third surface 162c, a flat fourth surface 162d, a flat fifth surface 162e, and a flat sixth surface 162f on its outer periphery. The second surface 162b abuts against the second surface 161b of the one blade 161. The third surface 162c abuts against the end surface 404 in the width direction of the protruding member 40. The fourth surface 162d abuts against the other surface 403 of the protruding member 40. The fifth surface 162e abuts against the end surface 402 in the width direction of the protruding member 40. The sixth surface 162f abuts against the second surface 161b of the one blade 161.

[0060] Like the blade 30 in the above-described embodiment, the blade 162 is fixed to the blade receiving member 12, the protruding member 40, and one of the blades 161 with the surface opposite to the surface 1620 in contact with the inclined end surface 16 of the blade receiving member 12. By fixing the two blades 161, 162 to the blade receiving member 12 and the protruding member 40, the tip side of the blade receiving member 12 is closed. The inclination directions of the two blades 161, 162 may be reversed. [Explanation of symbols]

[0061] DESCRIPTION OF THE PREFERRED EMBODIMENTS 1...assembly, 10...pile body, 11...connecting member, 12...blade support member, 14, 16...inclined end surface, 15...step, 20, 30...blade, 20a, 30a...tip of blade, 22, 32...recess, 22a...one end of lower end side in the inclined direction of recess, 24, 34...cutout portion, 40...protruding member, 42...protruding portion, 44, 46...inclined surface, 48, 50...protrusion, 40a, 48a...tip of protrusion, 100...rotatable buried pile, 120, 130...blade.

Claims

1. A pile body, A blade inclined in the rotation direction of the pile body and fixed to the axial tip of the pile body; a protruding member fixed to the blade, the protruding member has a protruding portion protruding in the axial direction from a surface of the blade, The protruding portion is disposed in a region facing the tip of the pile body. Rotary buried pile.

2. Along the axial direction of the pile body, the tip of the protruding portion has a lower protruding height than the tip of the wing, or protrudes to approximately the same height as the tip of the wing. The rotary pile according to claim 1 .

3. The protruding portion has an inclined surface inclined in the same direction as the surface of the blade. The rotary pile according to claim 1 .

4. The pile body is cylindrical, The protruding member has a width that allows it to be inserted into the pile body. The rotary pile according to claim 1 .

5. The protruding member is plate-shaped and both ends in the width direction are fixed to the inner surface of the pile main body. The rotary pile according to claim 4.

6. The blade is fixed to the pile body and the protruding member so as to close the tip of the pile body together with the protruding member. The rotary buried pile according to claim 4 or 5.

7. A pile body having a tip portion including a first inclined end surface inclined with respect to a plane perpendicular to the axial direction in a circumferential direction and a second inclined end surface inclined with respect to the plane perpendicular to the axial direction in another part of the circumferential direction; A plate-shaped first blade fixed in contact with the first inclined end surface of the tip portion of the pile main body; A plate-shaped second blade fixed in contact with the second inclined end surface of the tip portion of the pile main body; A protruding member disposed in a region facing the tip portion of the pile main body, The protruding member has a protruding portion protruding from a surface of at least one of the first and second blades. Rotary buried pile.

8. Along the axial direction, a tip of the protruding portion has a protruding height lower than at least one of the tip of the first blade and the tip of the second blade, or protrudes to approximately the same height as at least one of the tip of the first blade and the tip of the second blade. The rotary pile according to claim 7.

9. The protruding portion has a first inclined surface inclined in the same direction as a surface of the first blade, and a second inclined surface inclined in the same direction as a surface of the second blade. The rotary pile according to claim 7.

10. The pile body is cylindrical, The protruding member is a plate having a width that can be inserted into the pile body. The rotary pile according to claim 7.

11. The protruding member has both ends in the width direction fixed to the inner surface of the pile main body. The rotary pile according to claim 10.

12. The first and second blades are fixed to the pile body and the protruding member so as to close the tip of the pile body together with the protruding member. The rotary pile according to claim 10 or 11.

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