Rotary pile construction jig and rotary pile construction method

Abstract

To provide a rotary pile construction jig and a rotary pile construction method, upon constructing a rotary pile in the ground, which reinforce the driving force of the rotary pile while reducing construction costs.SOLUTION: A rotary pile construction jig is attachable to and detachable from a rotary pile driven into the ground and is rotatably fitted together with the rotary pile. The rotary pile construction jig comprises: rotational force transmission means for transmitting rotational force around an axis of the rotary pile from a construction machine; a body part connected to the rotational force transmission mean; fixing means for fixing the body part to a head part of the rotary pile; a cylindrical casing connected to the body part and disposed at the outside of the rotary pile; and a blade part provided at the outer circumferential face of the casing.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a rotary pile installation jig and a rotary pile installation method. [Background technology]

[0002] Conventionally, a rotary pile is driven into the ground as a foundation for above-ground structures. In the construction of the rotary pile, the rotary pile is rotated above ground and a slat at the tip of the rotary pile is used to dig into the ground.

[0003] However, when the rotary pile has an enlarged portion such as a joint, it may be difficult to penetrate the ground using only the propulsive force of the slats.

[0004] Patent Document 1 describes a configuration in which a wing-shaped member is provided on the outer peripheral surface of the enlarged diameter part of the rotary pile to increase the driving force of the rotary pile. Patent Document 2 describes a configuration in which a spiral blade is provided at the enlarged diameter boundary part to increase the driving force of the rotary pile. Also, as a method for reducing resistance when inserting a rotary pile without changing the structure of the rotary pile, a method of loosening the ground by auger excavation before constructing the rotary pile is known. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2001-123443 A [Patent Document 2] JP 2002-61180 A Summary of the Invention [Problem to be solved by the invention]

[0006] However, the configurations described in Patent Documents 1 and 2 require the manufacture of a rotary pile with a blade in the middle, which increases the manufacturing cost. In addition, the method of auger-drilling the ground before constructing the rotary pile also increases the number of steps, which increases the construction cost.

[0007] Therefore, an object of the present invention is to provide a rotary pile construction jig and a rotary pile construction method that can increase the driving force of a rotary pile while reducing construction costs when constructing a rotary pile into the ground. [Means for solving the problem]

[0008] [1] A rotary pile construction jig that can be attached and detached to a rotary pile to be driven into the ground and that can be rotated integrally with the rotary pile, comprising: a rotational force transmission means for transmitting a rotational force around the axis of the rotary pile from a construction machine; a main body connected to the rotational force transmission means; a fixing means for fixing the main body to the head of the rotary pile; a cylindrical casing connected to the main body and positioned on the outside of the rotary pile; and a blade portion provided on the outer surface of the casing. [2] The blade portion is spiral-shaped, in the construction jig for a rotary pile described in [1]. [3] The fixing means is arranged on at least either the inside or outside of the rotary pile at at least three locations around the circumference of the rotary pile. [4] The main body includes an annular member arranged opposite at least one of the inner or outer circumferential surface of the rotary pile, and the fixing means includes a screw member that screws into a screw hole formed in the annular member and abuts its tip against the inner or outer circumferential surface of the rotary pile. [3] A construction jig for a rotary pile as described in [3]. [5] The construction jig for a rotary pile described in [4] further includes a deformation prevention part that is separate from the main body and is held inside the rotary pile at the head of the rotary pile, the main body part includes an outer annular member arranged opposite the outer peripheral surface of the rotary pile, the deformation prevention part includes an inner annular member arranged opposite the inner peripheral surface of the rotary pile, and the fixing means includes an inner screw member that screws into a screw hole formed in the inner annular member on the inside of the rotary pile and has a tip abutting the inner peripheral surface of the rotary pile, and an outer screw member that screws into a screw hole formed in the outer annular member and has a tip abutting the outer peripheral surface of the rotary pile. [6] The outer screw member includes multiple sets of outer screw members at different axial positions of the rotary pile, and the outer screw member of any set is abutted against the outer peripheral surface of the rotary pile at an axial position corresponding to the inner screw member. [5] A construction jig for a rotary pile as described in [5]. [7] The main body further includes a steel pipe member and a perforated disk-shaped member having the outer annular member joined to one side and the steel pipe member joined to the other side, and the rotational force transmission means includes a protrusion protruding from the outer peripheral surface of the steel pipe member. [5] A construction jig for a rotary pile as described in [8] The main body includes an inner annular member arranged opposite the inner surface of the rotary pile, and an outer annular member arranged opposite the outer surface of the rotary pile, and the fixing means includes an inner screw member that screws into a screw hole formed in the inner annular member and has a tip abutting the inner surface of the rotary pile, and an outer screw member that screws into a screw hole formed in the outer annular member and has a tip abutting the outer surface of the rotary pile. [1] A construction jig for a rotary pile described in [1]. [9] A method for constructing a rotary pile using a construction jig described in any one of [1] to [8], comprising the steps of fixing the construction jig to the head of the rotary pile using the fixing means, transmitting a rotational force from the construction machine to the rotational force transmission means, and penetrating the rotary pile while transmitting the rotational force to the rotary pile via the main body and the fixing means.

[10] The rotary pile comprises a pile body, a slat provided at the tip of the pile body, and an expansion section arranged coaxially with the pile body and having an outer diameter larger than the outer diameter of the pile body, and the construction jig is attached to the head of the expansion section, and the rotary pile is driven into ground in which a contaminated aquifer, an impermeable layer, and a supporting layer are layered in that order from the surface side. [9] A construction method for a rotary pile as described in Effect of the Invention

[0009] According to the above configuration, the construction jig provided with the blade portion that enhances the driving force of the rotary pile is detachably attached to the rotary pile, so that the construction jig can be used repeatedly. As a result, when constructing the rotary pile in the ground, the driving force of the rotary pile can be enhanced while reducing construction costs. [Brief description of the drawings]

[0010] [Figure 1] FIG. 1 is a cross-sectional view showing a construction jig for a rotary pile according to a first embodiment of the present invention, showing a state before the jig is attached to the rotary pile. [Diagram 2] FIG. 1 is a diagram showing a construction jig for a rotary pile according to a first embodiment of the present invention, and is a cross-sectional view showing a state in which the jig is attached to the rotary pile. [Diagram 3] FIG. 3 is a diagram showing a construction jig for a rotary pile according to the first embodiment of the present invention, and is a cross-sectional view taken along line III-III in FIG. 2. [Figure 4] FIG. 2 is a diagram illustrating a construction method for a rotary pile according to the first embodiment of the present invention. [Diagram 5] FIG. 11 is a diagram illustrating a construction method for a rotary pile according to Modification 1 of the first embodiment of the present invention. [Figure 6] FIG. 11 is a cross-sectional view showing a construction jig for a rotary pile according to Modification 2 of the first embodiment of the present invention. [Figure 7] FIG. 11 is a perspective view of an embedding jig to which a construction jig for a rotary pile according to Modification 3 of the first embodiment of the present invention is applied. [Figure 8] FIG. 11 is a cross-sectional view showing a construction jig for a rotary pile according to Modification 3 of the first embodiment of the present invention. [Figure 9] FIG. 11 is a cross-sectional view showing a construction jig for a rotary pile according to a second embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In this specification and the drawings, components having substantially the same functional configurations are designated by the same reference numerals, and redundant description will be omitted.

[0012] The rotary pile construction jig of the present invention is a jig that can be attached and detached to a rotary pile to be driven into the ground, and can be attached so as to rotate integrally with the rotary pile, and by being attached, it increases the driving force of the rotary pile.

[0013] [First embodiment] FIG. 1 is a cross-sectional view showing a rotary pile construction jig according to a first embodiment of the present invention. The rotary pile construction jig 10 of this embodiment has a jig body 11 that is placed on the head of the rotary pile 1, and a deformation prevention part 12 that is separate from the jig body 11. For the sake of explanation, FIG. 1 shows a state before the jig 10 is attached to the rotary pile 1. FIG. 2 is a cross-sectional view showing a state in which the jig 10 is attached to the rotary pile 1. FIG. 3 is a cross-sectional view taken along line III-III in FIG. 2. In the following description, unless otherwise specified, "axial direction" means the axial direction of the rotary pile 1.

[0014] The jig body 11 has an outer annular member 13, a first perforated disk-shaped member 14, a steel pipe member 15, and a casing 16. The jig 10 also includes two sets of outer screw members 311A-311H, 312A-312H (sometimes collectively referred to as outer screw members 31) and inner screw members 32A-32H (sometimes collectively referred to as inner screw members 32) as fixing means for fixing the jig 10 to the head of the rotary pile 1.

[0015] The outer annular member 13 is disposed facing the outer peripheral surface of the rotary pile 1 when the jig body 11 is attached to the rotary pile 1, and is fixed to the rotary pile 1 by the outer screw member 31. The outer screw member 31 is screwed into a screw hole formed in the outer annular member 13, and each tip is abutted against the outer peripheral surface of the rotary pile 1. The outer screw member 31 is composed of first outer screw members 311A ​​to 311H (sometimes collectively referred to as the first outer screw member 311) and second outer screw members 312A to 312H (sometimes collectively referred to as the second outer screw member 312), which are disposed in different steps, i.e., at different positions in the axial direction. When the jig 10 is fixed to the rotary pile 1, one of the first outer screw member 311 and the second outer screw member 312 is used. The axial distance L between the first outer screw member 311 and the second outer screw member 312 can be changed as appropriate depending on the configuration of the rotary pile 1 to which the jig 10 is attached, the configuration of the ground, and the like.

[0016] The steel pipe member 15 is a member connected to the outer annular member 13 via the first perforated disk-shaped member 14. The outer peripheral surface of the steel pipe member 15 is provided with a protrusion 17 (rotational force transmission means) that protrudes outward. The protrusion 17 is a rotational force transmission means to which a rotational force around the axis of the rotary pile 1 is transmitted from a construction machine (not shown), and is connected to the main body of the construction jig 10. The main body of this embodiment is the outer annular member 13, the first perforated disk-shaped member 14, and the steel pipe member 15. A reinforcing member 18 that reinforces the steel pipe member 15 is welded to the inside of the steel pipe member 15 at a position corresponding to the protrusion 17 in the axial direction of the steel pipe member 15.

[0017] The first perforated disk-shaped member 14 is a member that connects the steel pipe member 15 and the outer ring-shaped member 13, and the steel pipe member 15 is welded to one surface of the first perforated disk-shaped member 14 (the surface that faces upward when the jig 10 is attached to the rotary pile 1), and the outer ring-shaped member 13 is welded to the other surface.

[0018] The casing 16 has a cylindrical casing body 20 joined to an end of the outer annular member 13 via an annular base 19, and a blade portion 21. The casing body 20 is formed, for example, from a steel pipe. When the jig 10 is attached to the rotary pile 1, the casing 16 covers the outer peripheral surface of the rotary pile 1, following the outer annular member 13. In the illustrated example, the inner diameter of the base 19 is approximately the same as the inner diameter of the outer annular member 13, and the inner diameter of the casing body 20 is slightly larger than the inner diameters of the base 19 and the outer annular member 13.

[0019] The blade portion 21 is provided on the outer peripheral surface of the casing body 20. The blade portion 21 has a continuous spiral shape, and its inner side is welded to the outer peripheral surface of the casing body 20. The range in which the blade portion 21 is provided in the casing 16 can be appropriately set according to the required propulsive force, etc., but it is preferable that the blade portion 21 extends to the lower end of the casing body 20. The shape of the blade portion 21 is not limited to a continuous spiral shape, and it is sufficient that the jig 10 is attached to the rotary pile 1 and rotates around the axis of the rotary pile 1 to provide a propulsive force to the rotary pile 1. In another example, the blade portion 21 may be composed of a plurality of separate wing-shaped members.

[0020] The deformation prevention section 12 has a perforated disk-shaped member 23 and an inner annular member 24 welded to one surface of the perforated disk-shaped member 23. The inner annular member 24 is disposed opposite the inner peripheral surface of the rotary pile 1 and is fixed to the rotary pile 1 by an inner screw member 32. By making the outer diameter of the perforated disk-shaped member 23 substantially the same as the outer diameter of the rotary pile 1, the perforated disk-shaped member 23 can be brought into contact with the end of the rotary pile 1 to easily position the inner annular member 24, and interference with the outer annular member 13 that is placed on the outside of the rotary pile 1 can be avoided.

[0021] The inner screw member 32 is screwed into a screw hole formed in the inner annular member 24 of the deformation prevention part 12, and each tip is abutted against the inner circumferential surface of the rotary pile 1. With the inner annular member 24 inserted into the rotary pile 1, the deformation prevention part 12 is held on the rotary pile 1 by abutting the tip of the inner screw member 32 against the inner circumferential surface of the rotary pile 1, thereby causing the inner screw member 32 to be inserted into the rotary pile 1. The head of the rotary pile 1 is clamped between the inner screw member 32 and either the first outer screw member 311 or the second outer screw member 312.

[0022] By holding the deformation prevention section 12 inside the rotary pile 1 at the head of the rotary pile 1 and clamping the head of the rotary pile 1 between either the first outer screw member 311 or the second outer screw member 312 and the inner screw member 32, deformation of the rotary pile 1 due to tightening of the outer screw members 311, 312 can be prevented.

[0023] The number and arrangement of the outer screw members 31 and the inner screw members 32 are not particularly limited, but it is desirable to arrange them in at least three locations around the circumference of the rotary pile 1 in order to disperse the positions at which the rotational force is transmitted, and it is also desirable to arrange them at equal intervals around the circumference of the rotary pile 1.

[0024] 2, the jig body 11 is positioned so that the position of the first outer screw member 311 corresponds to the position of the inner screw member 32. In other words, the jig body 11 is disposed so that the axial position of the first outer screw member 311 and the axial position of the inner screw member 32 are the same.

[0025] 2, the user can select a position in the axial direction of the jig body 11 relative to the rotary pile 1, where the inner screw member 32 corresponds to the first outer screw member 311, or a position in which the inner screw member 32 corresponds to the second outer screw member 312. By this selection, the axial position of the jig body 11 relative to the rotary pile 1 can be changed.

[0026] By the above-mentioned fixing means, the jig 10 is attached to the rotary pile 1 so as to be detachable from the rotary pile 1 and to be rotatable integrally with the rotary pile 1. Since the jig 10 and the rotary pile 1 are mechanically connected by the fixing means, no welding work is required to attach the jig 10 to the rotary pile 1.

[0027] In the jig 10, the rotational force transmitted to the protrusion 17, which is a rotational force transmission means, is transmitted to the outer screw member 31, which is a fixing means, via a main body including the steel pipe member 15, the first perforated disk-shaped member 14, and the outer annular member 13, thereby making it possible to transmit the rotational force to the head of the rotary pile 1. The inner screw member 32 applies a radially outward force to the inner circumferential surface of the rotary pile 1 at a position corresponding to the outer screw member 31 to clamp the rotary pile 1, thereby preventing deformation of the rotary pile 1 and allowing the rotational force to be stably transmitted from the outer screw member 31 to the rotary pile 1.

[0028] Next, a construction method for constructing the rotary pile 1 using the jig 10 will be described. FIG. 4 is a diagram for explaining a method of constructing a rotary pile using a jig 10. Here, the rotary pile 1 is driven into a ground in which a contaminated aquifer G1, an impermeable layer G2, a non-contaminated aquifer G3, and a supporting layer G4 are layered in this order from the ground surface side. The rotary pile 1 includes a cylindrical pile body 2 having a spiral blade 4 at its tip, and an expanded diameter portion 3 that is arranged coaxially with the pile body 2 and can be joined to the pile body 2. The expanded diameter portion 3 has an outer diameter larger than that of the pile body 2. The construction method of the rotary pile is a construction method using a so-called joint pile in which the rotary pile 1 is divided into a plurality of pieces and the piles are joined by welding or the like, and the rotary pile 1 of this embodiment is divided into the pile body 2 and the expanded diameter portion 3.

[0029] In the construction of the rotary pile 1 provided with the slats 4, a water path may be formed in the impermeable layer G2 when the slats 4 pass through, and this water path may become a water path through which contaminants contained in the contaminated aquifer G1 flow. With this rotary pile 1, the impermeable layer G2 near the outer periphery of the pile body 2 is consolidated from above with the enlarged diameter portion 3, thereby blocking the water path. This makes it possible to prevent contaminants contained in the soil of the contaminated aquifer G1 from mixing with the uncontaminated aquifer G3.

[0030] The lengths of the pile body 2 and the enlarged diameter portion 3 are set according to the depth of the bearing layer G4 and the impermeable layer G2 in the ground on which the rotary pile 1 is constructed. Specifically, they are set so that the enlarged diameter portion 3 reaches the impermeable layer G2 when the tip of the rotary pile 1 reaches the bearing layer G4. 4, the impermeable layer G2 is shallow (e.g., 6 m) and the required length of the enlarged diameter portion 3 is short, so a jig 10 that corresponds to this is used. Specifically, a jig 10 is used that, when the jig 10 is attached to the enlarged diameter portion 3, can select a position where the bottom end of the casing 16 protrudes downward below the bottom end of the enlarged diameter portion 3, and a position where the casing 16 covers the enlarged diameter portion 3 but does not protrude below the bottom end of the enlarged diameter portion 3.

[0031] The specific construction procedure for the rotary pile is explained below. First, as shown in Fig. 4(a), the pile body 2 is driven into the ground by rotary pressing using a construction machine (not shown). The pile body 2 is driven to a predetermined depth where the slats 4 penetrate the impermeable layer G2. Next, as shown in Fig. 4(b), the enlarged diameter section 3 incorporating the deformation prevention section 12 at its end is joined to the pile body 2.

[0032] 4(c), the jig body 11 is lifted using a lifting device such as a crane, and then the jig body 11 is fixed to the enlarged diameter portion 3. At this time, the jig body 11 is fixed to the enlarged diameter portion 3 in a state where the first outer screw member 311 of the jig body 11 and the inner screw member 32 are aligned to correspond to each other (see FIG. 2). By attaching the jig body 11 in this manner, the lower end of the casing 16 protrudes downward beyond the lower end of the enlarged diameter portion 3.

[0033] Next, as shown in FIG. 4(d), the jig 10 is rotated using a construction machine, and the rotary pile 1 is driven into the ground until the lower end of the casing 16 of the jig 10 reaches the impermeable layer G2. 4(e), after the first outer screw member 311 is loosened, the jig 10 is rotated in the reverse direction and pulled upward, and the jig body 11 is again fixed to the enlarged diameter portion 3 in a state where the second outer screw member 312 of the jig body 11 and the inner screw member 32 are aligned to correspond to each other. As a result, the lower end of the enlarged diameter portion 3 protrudes downward relative to the lower end of the casing 16.

[0034] Next, as shown in FIG. 4(f), the jig 10 is rotated using a construction machine, and the rotary pile 1 is driven in until the lower end of the enlarged diameter portion 3 reaches the impermeable layer G2. 4(g), after the second outer screw member 312 is loosened, the jig 10 is rotated in the reverse direction and removed by being pulled out from the ground, and further, the deformation prevention part 12 is removed from the enlarged diameter part 3. The removed jig 10 can be reused the next time a rotary pile is constructed.

[0035] According to the above-described jig 10, the jig 10 provided with the blade portion 21 that enhances the driving force of the rotary pile 1 is detachably attached to the rotary pile 1, so that the jig 10 can be used repeatedly. As a result, when constructing the rotary pile 1 in the ground, the driving force of the rotary pile 1 can be enhanced while reducing construction costs.

[0036] Furthermore, according to the above-mentioned method, as shown in Figures 4(c) and 4(d), the casing 16 protrudes downward from the enlarged diameter portion 3, so that the blade portions 21 penetrate into the ground before the enlarged diameter portion 3 penetrates into the ground, thereby reducing the resistance of the enlarged diameter portion 3 when the rotary pile 1 penetrates into the ground. Also, by moving the position of the casing 16 upward before the enlarged diameter portion 3 reaches the impermeable layer G2, it is possible to prevent the impermeable layer G2 from being damaged by the blade portions 21.

[0037] [Modification 1 of the first embodiment] As described above, in the jig 10, the axial distance L between the first outer screw member 311 and the second outer screw member 312 (the axial length of the outer annular member 13) can be changed. In addition, the length of the casing 16 and the inner diameter of the casing 16 can be changed. For example, when driving the rotary pile 1 into ground having an impermeable layer G2 of different depths, the jig 10 having the interval L or the casing 16 of different lengths can be used.

[0038] Below, we will explain the construction method of the rotary pile when the configuration of the ground is different and the configuration of the rotary pile 1 is different accordingly. In the above example, the impermeable layer G2 is shallow, but in the construction method of the rotary pile described below, the impermeable layer G2 is deep (e.g., 10 m) and the required enlarged portion is long. When the required enlarged portion is long, the second enlarged portion is joined to the first enlarged portion during construction.

[0039] The specific construction procedure for the rotary pile is explained below. First, as shown in Fig. 5(a), the pile body 2 is driven into the ground by rotary pressing using a construction machine. Because the impermeable layer G2 is deep, the tip of the pile body 2 does not reach the impermeable layer G2. Next, as shown in Fig. 5(b), the first enlarged diameter portion 3A incorporating the deformation prevention portion 12 is joined to the pile body 2.

[0040] Next, as shown in FIG. 5(c), the jig body 11 is lifted up using a lifting device, and then the jig body 11 is fixed to the first enlarged diameter portion 3A. Next, as shown in Figure 5 (d), the jig 10 is rotated using a construction machine, and the rotary pile 1 is inserted until the entire blade portion 21 of the jig 10 is driven into the ground and the first outer screw member 311 is exposed above the ground. Next, as shown in FIG. 5(e), the jig 10 is rotated in the reverse direction and pulled out from the ground for removal, and further the deformation prevention portion 12 is removed from the enlarged diameter portion 3.

[0041] Next, as shown in Fig. 5(f), the second enlarged diameter portion 3B to which the deformation prevention portion 12 is attached is welded to the first enlarged diameter portion 3A, and then the jig body 11 is attached to the second enlarged diameter portion 3B as shown in Fig. 5(g). At this time, the jig body 11 used has an outer annular member 13 with a long axial length (a long interval L between the first outer screw member 311 and the second outer screw member 312). Specifically, the jig body 11 used corresponds to the length of the enlarged diameter portion of this modification, and has a length such that a part of the blade portion 21 penetrates into the ground when the jig body 11 is attached to the rotary pile 1 in the state shown in Fig. 5(f). In the example shown in Figure 5 (g), the length of the jig body 11 is increased by increasing the axial length of the outer annular member 13, but the length of the jig body 11 may also be increased by increasing the length of the casing 16.

[0042] Next, as shown in Figure 5 (h), the jig 10 is rotated using a construction machine, and the rotary pile 1 is driven into the ground until the lower end of the expansion portion 3 reaches the impermeable layer G2 and the tip of the rotary pile 1 reaches the supporting layer G4. Next, as shown in FIG. 5(i), the jig 10 is removed.

[0043] According to the above-mentioned method, by using the jig 10 having a longer outer annular member 13, it is possible to penetrate a part of the blade portion 21 into the ground in advance even when the enlarged diameter portion 3 is long. As a result, after the jig 10 is attached to the rotary pile 1, when the rotary pile 1 is penetrated into the ground, it is possible to increase the driving force from the beginning of the rotary pressing.

[0044] [Modification 2 of the first embodiment] In a construction method using joint piles, a flange protruding outward is provided at the end of the pile, and a joint-type joint is sometimes used to connect the flanges. The construction jig of the present invention can also be attached to a joint-type joint. When fixing the jig 10 to such a joint, as shown in Fig. 6, the inner diameter of the casing 16 is made larger than the outer diameter of the flange 5. Also, the length of the casing 16 can be set to a length that covers the lower flange 5.

[0045] When fixing the jig 10 to a joint-type coupling, the flange 5 has sufficient strength and there is no need to consider deformation of the rotary pile 1 when fixing the jig 10, so the tip of the outer screw member 31 can be brought into contact with the outer periphery of the flange 5. This makes it possible to omit the deformation prevention part 12 (see FIG. 1).

[0046] [Modification 3 of the first embodiment] When the head of the rotary pile 1 is buried without being exposed above the ground after construction, an burying jig 50 as shown in Fig. 7 is used. After driving the rotary pile 1 using the burying jig 50, the head of the rotary pile 1 can be buried to a depth of, for example, 2 m by pulling out the burying jig 50. The construction jig of the present invention can also be attached to such an burying jig.

[0047] 7, the embedding jig 50, like the jig body 11 shown in FIG. 1 etc., has a steel pipe member 55 and a protrusion 57 protruding outward from the steel pipe member 55. An engaging portion 60 is provided below the steel pipe member 55. The engaging portion 60 is provided with a recess 61 that engages with an engaging protrusion 62 described below.

[0048] An engaging protrusion 62 that engages with the engaging portion 60 of the burying jig 50 is provided on the inner peripheral surface of the pile that is to be connected to the burying jig 50. A notch 63 that allows the engaging protrusion 62 to be inserted from below is formed in the recess 61. The burying jig 50 and the rotary pile 1 can be connected by inserting the burying jig 50 into the rotary pile 1 while inserting the engaging protrusion 62 through the notch 63, and then rotating the entire burying jig 50 to engage the engaging portion 60 with the engaging protrusion 62.

[0049] Fig. 8 is a cross-sectional view showing a construction jig for a rotary pile according to this modified example, and shows a state in which the jig 10 is attached to the embedding jig 50 connected to the rotary pile 1. The rotary pile 1 is buried below the ground level GL, and the rotary pile 1 is embedded by removing the jig 10 from the state shown in Fig. 8 and then pulling out the embedding jig 50. The deformation prevention part 12 is attached to the upper end of the embedding jig 50.

[0050] In the jig of this modified example, the overall length of the casing 16 is long so as to be attached to the embedding jig 50. Specifically, the casing 16 of this modified example is formed to be long enough to cover the upper part of the rotary pile 1 when the jig 10 is attached to the embedding jig 50 connected to the rotary pile 1. Moreover, in the jig 10 of this modified example, an outer screw member 313 is added corresponding to the embedding jig 50. Specifically, when attaching the jig 10 to the embedding jig 50, the outer screw member 313 can be added so that the outer screw member 313 is located at a position corresponding to the inner screw member 32 in a state in which the base of the casing 16 abuts against the upper end of the projection 57 of the embedding jig 50.

[0051] Second Embodiment FIG. 9 is a cross-sectional view showing a construction jig for a rotary pile according to the second embodiment of the present invention. In the first embodiment, the jig 10 was separated into the jig body 11 and the deformation prevention portion 12, but as shown in Figure 9, in the jig 10A of this embodiment, the inner annular member 24A is welded to the other surface of the first perforated disk-shaped member 14, similar to the outer annular member 13. The outer screw member 31 has a single-stage configuration, and the outer screw member 31 and the inner screw member 32 are disposed at the same position in the axial direction.

[0052] In the jig 10A of this embodiment, the rotational force transmitted to the protrusion 17 can be transmitted to the head of the rotary pile 1 by transmitting it to the fixing means, that is, the inner screw member 32 and the outer screw member 31, via the main body including the steel pipe member 15, the first perforated disk-shaped member 14, the inner annular member 24A and the outer annular member 13.

[0053] In the jig of this embodiment, the rotational force is also transmitted to the inner annular member 24A, so that the rotational force can be transmitted more efficiently than in the first embodiment. Also, since the inner annular member 24A is integrated with the outer annular member 13 and the like via the first perforated disk-shaped member 14, there is no need to attach the deformation prevention part 12 (see FIG. 1) to the rotary pile 1, and the construction procedure can be simplified.

[0054] Although the preferred embodiment of the present invention has been described in detail above with reference to the accompanying drawings, the present invention is not limited to such an example. It is clear that a person having ordinary knowledge in the technical field to which the present invention pertains can conceive of various modified or amended examples within the scope of the technical ideas described in the claims, and it is understood that these also naturally belong to the technical scope of the present invention. [Explanation of symbols]

[0055] Reference Signs List 1...rotary pile, 2...pile body, 3...expansion portion, 5...flange, 10, 10A...construction jig, 11...jig body, 12...deformation prevention portion, 13...outer ring-shaped member (body portion), 14...first perforated disc-shaped member (body portion), 15...steel pipe member (body portion), 16...casing, 17...projection (rotational force transmission means), 18...reinforcing member, 19...base, 20...casing body, 21 ...blade portion, 23...second perforated disc-shaped member, 24, 24A...inner annular member, 31, 311, 311A~H, 312, 313A~H...outer screw member (fixing means), 32, 32A~H...inner screw member (fixing means), 50...embedding jig, 60...engaging portion, 62...engaging protrusion, G1...contaminated aquifer, G2...impermeable layer, G3...non-contaminated aquifer, G4...supporting layer.

Claims

1. A construction jig for a rotary pile that can be attached and detached to a rotary pile to be driven into the ground and can be rotatably attached integrally with the rotary pile, A rotational force transmission means for transmitting a rotational force around the axis of the rotary pile from the construction machine; A main body portion connected to the rotational force transmission means; A fixing means for fixing the main body to the head of the rotary pile; A cylindrical casing connected to the main body and disposed outside the rotary pile; a blade portion provided on an outer peripheral surface of the casing; A rotary pile construction jig comprising:

2. The rotary pile construction jig according to claim 1 , wherein the blade portion is spirally shaped.

3. The rotary pile construction jig according to claim 1 , wherein the fixing means is arranged on at least either the inside or the outside of the rotary pile at at least three positions in a circumferential direction of the rotary pile.

4. The main body includes an annular member arranged to face at least one of an inner circumferential surface or an outer circumferential surface of the rotary pile, 4. The rotary pile construction jig according to claim 3, wherein the fixing means includes a screw member that is screwed into a screw hole formed in the annular member and has a tip that is abutted against the inner or outer circumferential surface of the rotary pile.

5. The construction jig further includes a deformation prevention part that is separated from the main body part and is held inside the rotary pile by the head part of the rotary pile, The main body includes an outer annular member arranged opposite to an outer circumferential surface of the rotary pile, The deformation prevention portion includes an inner annular member arranged opposite to an inner circumferential surface of the rotary pile, 5. The rotary pile construction jig of claim 4, wherein the fixing means includes an inner screw member that screws into a screw hole formed in the inner annular member on the inside of the rotary pile and abuts the inner peripheral surface of the rotary pile, and an outer screw member that screws into a screw hole formed in the outer annular member and abuts the outer peripheral surface of the rotary pile.

6. The rotary pile construction jig of claim 5, wherein the outer screw member includes a plurality of sets of outer screw members at different axial positions of the rotary pile, and the outer screw member of any one of the sets is abutted against the outer peripheral surface of the rotary pile at the axial position corresponding to the inner screw member.

7. The main body further includes a steel pipe member and a perforated disk-shaped member having one surface to which the outer annular member is joined and the steel pipe member is joined to the other surface, The rotary pile construction jig according to claim 5 , wherein the rotational force transmission means includes a protrusion protruding from an outer circumferential surface of the steel pipe member.

8. The main body includes an inner annular member arranged opposite to an inner circumferential surface of the rotary pile, and an outer annular member arranged opposite to an outer circumferential surface of the rotary pile, 2. The rotary pile construction jig of claim 1, wherein the fixing means includes an inner screw member that screws into a screw hole formed in the inner annular member and abuts the inner peripheral surface of the rotary pile, and an outer screw member that screws into a screw hole formed in the outer annular member and abuts the outer peripheral surface of the rotary pile.

9. A method for constructing a rotary pile using the construction jig according to any one of claims 1 to 8, A step of fixing the construction jig to the head of the rotary pile using the fixing means; transmitting a rotational force from the construction machine to the rotational force transmission means, and penetrating the rotary pile while transmitting the rotational force to the rotary pile via the main body and the fixing means; A method for installing a rotary pile, including:

10. The rotary pile includes a pile body, a blade plate provided at the tip of the pile body, and an expanded diameter portion arranged coaxially with the pile body and having an outer diameter larger than the outer diameter of the pile body; The construction jig is attached to the head of the enlarged diameter portion, 10. The method for constructing a rotary pile according to claim 9, further comprising driving the rotary pile into a ground having a contaminated aquifer, an impermeable layer, and a bearing layer layered in that order from the ground surface side.

Images