Steel pipe pile
The steel pipe pile design addresses the issue of wing portion damage by using overlapping plate-like parts to enhance thickness at the connection area, thereby improving structural integrity and reducing manufacturing costs.
Patent Information
- Application Number
- JP2023194753
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- Filing Date
- 2023-11-15
- Publication Date
- 2025-05-27
AI Technical Summary
Conventional steel pipe piles face issues with damage or bending of the wing portion near the connecting portion with the steel pipe when a load is applied, leading to potential structural failures.
The steel pipe pile design incorporates an excavation part with overlapping first and second plate-like parts, where the first plate-like part is connected to the steel pipe edge, and the second plate-like part is connected to the first plate-like part, enhancing the thickness and reducing the likelihood of damage.
This design effectively secures the thickness of the wing portion at the connection area, reducing the risk of damage or bending under load, while also minimizing manufacturing costs and allowing for easier production of various wing portion shapes.
Smart Images
Figure 2025081166000001_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to steel pipe piles.
Background Art
[0002] Various techniques have been proposed for applying a rotational force to a steel pipe pile having a wing portion at the tip thereof and penetrating it into the ground (for example, Patent Document 1). The configuration of the wing portion includes, for example, a spiral shape and a flat plate shape. In either shape, the thickness of the wing portion is usually constant. By making the wing portion spiral, it becomes easy to ensure a stable propulsive force of the wing portion, and by making the wing portion flat plate-shaped, it becomes easy to suppress the processing cost of the wing portion.
[0003] When the shape of the wing portion is spiral or flat plate-shaped, a moment is generated in the wing portion like a cantilever beam when a load acts on the steel pipe pile. Here, usually, the stress generated is relatively large in the vicinity of the connecting portion between the wing portion and the steel pipe, while the stress generated is relatively small in a portion such as the outer edge side of the wing portion.
Prior Art Documents
Patent Documents
[0004]
Patent Document 1
Summary of the Invention
Problems to be Solved by the Invention
[0005] In conventional steel pipe piles, when a load acts on the steel pipe pile, there is a concern that the wing portion may be damaged or bent in the vicinity of the connecting portion with the steel pipe.
[0006] The present invention has been made in view of such circumstances, and an object thereof is to provide a steel pipe pile capable of suppressing damage to the wing portion.
Means for Solving the Problems
[0007] [1] According to the present invention, there is provided a steel pipe pile having an excavation part at the tip of the steel pipe, wherein the excavation part has wing parts, the wing parts have overlapping first and second plate-like parts, and the first plate-like part is connected to the steel pipe edge part of the tip surface of the steel pipe in a region overlapping the second plate-like part, and the second plate-like part is connected to the first plate-like part.
[0008] In the present invention, in the region where the wing part and the steel pipe edge part are connected, since the first plate-like part and the second plate-like part overlap, a configuration is formed in which it is easy to secure thickness accordingly, and damage to the wing part is suppressed.
[0009] Hereinafter, various embodiments of the present invention will be exemplified. The embodiments shown below can be combined with each other.
[0010] [2] Preferably, there is provided a steel pipe pile which is the steel pipe pile according to [1], wherein the thickness of the second plate-like part is larger than the thickness of the first plate-like part. [3] Preferably, there is provided a steel pipe pile which is the steel pipe pile according to [1] or [2], wherein when the wing part is viewed in plan, the first plate-like part is disposed inside the edge of the second plate-like part. [4] Preferably, there is provided a steel pipe pile which is the steel pipe pile according to [3], wherein the first plate-like part has an outer edge part and an inner edge part, the outer edge part is disposed outside the connection part between the first plate-like part and the steel pipe edge part in the radial direction of the steel pipe, the inner edge part is disposed inside the connection part in the radial direction, and the second plate-like part is connected to both the outer edge part of the first plate-like part and the inner edge part of the first plate-like part. [5] Preferably, there is provided a steel pipe pile which is the steel pipe pile according to any one of [1] to [4], wherein a first outer protrusion width is 30% or more and 70% or less of a second outer protrusion width, the first outer protrusion width is the width by which the first plate-like part protrudes from the outer surface of the steel pipe in the radial direction of the wing part, and the second outer protrusion width is the width by which the second plate-like part protrudes from the outer surface of the steel pipe in the radial direction of the wing part. [6] Preferably, it is the steel pipe pile according to any one of [1] to [5], wherein the first inner protruding width is 30% or more and 70% or less of the second inner protruding width, and the first inner protruding width is the width at which the first plate-like portion protrudes from the inner surface of the steel pipe in the radial direction of the wing portion, and the second inner protruding width is the width at which the second plate-like portion protrudes from the inner surface of the steel pipe in the radial direction of the wing portion. A steel pipe pile is provided. [7] Preferably, it is the steel pipe pile according to any one of [1] to [6], wherein the first and second plate-like portions are flat plates. A steel pipe pile is provided.
Brief Description of the Drawings
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MODE FOR CARRYING OUT THE INVENTION
[0012] Hereinafter, embodiments of the present invention will be described with reference to the drawings. Various characteristic matters shown in the following embodiments can be combined with each other. Further, an invention can be established independently for each characteristic matter.
[0013] 1. First Embodiment 1-1. Explanation of the Configuration of the First Embodiment The steel pipe pile 100 shown in FIGS. 1A to 3B is a pile used in a rotary construction method of screwing into the ground in construction work. The steel pipe pile 100 is given a rotational force by a construction machine (not shown) deployed on the ground and is penetrated into the ground. A drilling part 30, which has a shape suitable for drilling and will be described later, is provided at the tip part 1a of the steel pipe pile 100, making it easier to screw the steel pipe pile 100 into the ground.
[0014] As shown in FIGS. 1A to 3B, the steel pipe pile 100 includes a steel pipe 10, an opening part 20, and a drilling part 30.
[0015] 1-1-1. Steel pipe 10 As shown in FIG. 4A, the steel pipe 10 is a hollow steel pipe body with both ends open, and the cross section perpendicular to the central axis C of the steel pipe 10 is circular. As shown in FIGS. 1A to 3B, the steel pipe 10 has a tip part 1a that is screwed into the ground, and the opening part 20 and the drilling part 30 are provided at this tip part 1a.
[0016] As shown in FIG. 4A, the tip part 1a has a tip surface 1b, an inner surface 1c, and an outer surface 1d. As shown in FIG. 4C, on the tip surface 1b, a steel pipe edge part 1e, which is a part connected to the drilling part 30, and a longitudinal edge part 1f extending in the direction of the central axis C of the steel pipe 10 are formed.
[0017] As shown in FIGS. 4A to 4C, the steel pipe edge part 1e has a first steel pipe edge part 1e1 and a second steel pipe edge part 1e2. The steel pipe edge part 1e extends in a spiral or substantially spiral shape in the circumferential direction of the steel pipe 10. In other words, the first steel pipe edge part 1e1 extends so as to form a part of the spiral, and similarly, the second steel pipe edge part 1e2 extends so as to form a part of the spiral. In the first embodiment, the first steel pipe edge part 1e1 and the second steel pipe edge part 1e2 are independent (separated), but they may be connected. Here, the configuration of the steel pipe edge part 1e will be specifically described.
[0018] As shown in FIG. 4C, the first steel pipe edge portion 1e1 has a first tip 1e11 and a first terminal 1e12. The first steel pipe edge portion 1e1 extends away from the tip tp of the steel pipe 10 as it goes from the first tip 1e11 to the first terminal 1e12 in the direction of the central axis C of the steel pipe 10. In the embodiment, the tip tp of the steel pipe 10 and the first tip 1e11 of the first steel pipe edge portion 1e1 coincide, but they do not have to coincide. Also, as shown in FIG. 4C, the second steel pipe edge portion 1e2 has a second tip 1e21 and a second terminal 1e22. The second steel pipe edge portion 1e2 extends away from the tip tp of the steel pipe 10 as it goes from the second tip 1e21 to the second terminal 1e22 in the direction of the central axis C of the steel pipe 10. Also, as shown in FIG. 4B, in the direction of the central axis C of the steel pipe 10, the distance d2 between the second tip 1e21 and the tip tp of the steel pipe 10 is larger than the distance d1 between the first tip 1e11 and the tip tp of the steel pipe 10. In the first embodiment, since the position of the first tip 1e11 of the steel pipe 10 coincides with the position of the tip tp of the steel pipe 10, the distance d1 is 0.
[0019] As shown in FIG. 4C, in the first embodiment, the vertical edge portion 1f extends parallel to the central axis C direction. Note that the vertical edge portion 1f is not limited to extending parallel to the central axis C direction. For example, depending on the shape of the steel pipe edge portion 1e, the extending direction may be deviated from the central axis C direction.
[0020] Specifically, for example, the outer diameter (mm) of the steel pipe 10 is 400, 500, 600, 700, 800, 900, 1000, 1100, 1200, 1300, 1400, 1500, 1600, 1700, 1800, 1900, 2000, and it may be within the range between any two of the values exemplified here.
[0021] Specifically, for example, the wall thickness (mm) of the steel pipe 10 is 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 22, 24, 26, 28, 30, and it may be within the range between any two of the values exemplified here.
[0022] The length (m) of the steel pipe 10 in the direction of the central axis C is specifically, for example, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 22, 24, 26, 28, 30, 32, 34, 36, 38, 40, 42, 44, 46, 48, 50, 52, 54, 56, 58, 60, 62, 64, 66, 68, 70, 72, 74, 76, 78, 80, and it may be within the range between any two of the numerical values exemplified here.
[0023] 1-1-2. Open portion 20 The open portion 20 shown in FIGS. 1A to 3B is a configuration for taking in the material to be excavated (for example, earth and sand, etc.) into the steel pipe 10, and the open portion 20 is defined by the steel pipe 10 and the excavation portion 30. Specifically, as shown in FIG. 3A, the open portion 20 has a trapezoidal opening defined by a region surrounded by wings 3 (the first wing 3a and the second wing 3b) described later and a pair of vertical edge portions 1f. As the steel pipe pile 100 rotates, the material to be excavated is taken into the steel pipe 10 through the opening of the open portion 20, and the steel pipe pile 100 penetrates into the ground.
[0024] 1-1-3. Excavation portion 30 As shown in FIGS. 3A and 3B, the excavation portion 30 has wings 3. In the first embodiment, the wings 3 are composed of a plurality (two in the first embodiment) of independent wings (the first wing 3a and the second wing 3b). Note that although the number of wings is described as two, it is not limited thereto, and the steel pipe pile 100 may have a form having three or more independent wings. The plurality of independent wings are flat plate-like members adjacent to each other. Each wing is provided so as to be inclined when the steel pipe pile 100 is viewed from the side.
[0025] 1-1-3-1. First wing 3a As shown in FIGS. 3A and 3B, the first wing 3a has overlapping first plate-like portion 3c1 and second plate-like portion 3c2. In the first embodiment, each wing 3 (the first wing 3a and the second wing 3b) is composed of a two-stage overlapping plate-like portion.
[0026] <First plate-like portion 3c1 of the first wing portion 3a> As shown in FIGS. 5A to 6, the first plate-like portion 3c1 is a flat plate extending in an arc shape, and has a function as a reinforcing plate that suppresses damage to the wing portion 3 due to the moment applied to the wing portion 3 during construction.
[0027] As shown in FIGS. 5B and 6, the first plate-like portion 3c1 has an outer edge portion 3c11 and an inner edge portion 3c12. The outer edge portion 3c11 is disposed outside the connection portion between the first plate-like portion 3c1 and the steel pipe edge portion 1e (first steel pipe edge portion 1e1) in the radial direction of the steel pipe 10 (radial direction of the first wing portion 3a). The inner edge portion 3c12 is disposed inside the connection portion between the first plate-like portion 3c1 and the steel pipe edge portion 1e (first steel pipe edge portion 1e1) in the radial direction of the steel pipe 10 (radial direction of the first wing portion 3a). The outer edge portion 3c11 and the inner edge portion 3c12 extend in an arc shape (circular arc shape in the first embodiment).
[0028] The first plate-like portion 3c1 is disposed inside the second plate-like portion 3c2 when viewed in plan. In other words, the first plate-like portion 3c1 is disposed so as not to protrude outside the edge of the second plate-like portion 3c2. In the first embodiment, the edge of the second plate-like portion 3c2 is composed of a portion extending in an arc shape with a central angle of 180 degrees and a portion extending in a straight line passing through the center. Also, the positions of the peripheral edge of the first plate-like portion 3c1 and the inside of the second plate-like portion 3c2 may coincide.
[0029] The first plate-like portion 3c1 has a central angle (degrees) of 180 degrees in plan view. Note that the central angle is not limited to this, and specifically, for example, it is 90, 100, 110, 120, 130, 140, 150, 160, 170, 180, 190, 200, 210, 220, 230, 240, and may be within the range between any two of the values exemplified here.
[0030] The first plate-shaped portion 3c1 is connected to the steel pipe edge portion 1e (the first steel pipe edge portion 1e1) of the tip surface 1b of the steel pipe 10 in the region overlapping with the second plate-shaped portion 3c2. Thereby, the wing portion 3 can gain thickness at the connection portion with the steel pipe 10, and even if a moment generated in the connection portion and its vicinity increases due to a load being applied to the steel pipe pile 100, it is possible to suppress the wing portion 3 from being damaged or bent. Note that the first plate-shaped portion 3c1 and the steel pipe edge portion 1e (the first steel pipe edge portion 1e1) are connected to each other by welding, but alternatively, alternative connecting means such as an adhesive or bolts can be used alone or in combination with welding.
[0031] The thickness (mm) of the first plate-shaped portion 3c1 is, for example, 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, 110, 120, 130, 140, 150, and may be within the range between any two of the values exemplified herein.
[0032] <The second plate-shaped portion 3c2 of the first wing portion 3a> The second plate-shaped portion 3c2 is a flat plate having a fan shape (semicircular shape in the first embodiment) in plan view. The second plate-shaped portion 3c2 has a central angle (degrees) of 180 degrees in plan view. Note that the central angle is not limited to this, and specifically, for example, it is 90, 100, 110, 120, 130, 140, 150, 160, 170, 180, 190, 200, 210, 220, 230, 240, and may be within the range between any two of the values exemplified herein.
[0033] The second plate-shaped portion 3c2 is connected to the first plate-shaped portion 3c1. That is, the second plate-shaped portion 3c2 is not directly connected to the steel pipe 10, but is fixed to the steel pipe 10 via the first plate-shaped portion 3c1. The second plate-shaped portion 3c2 is connected to both the outer edge portion 3c11 and the inner edge portion 3c12 of the first plate-shaped portion 3c1. Note that these connection portions are connected to each other by welding, but alternatively, alternative connecting means such as an adhesive or bolts may be used alone or in combination with welding. Note that although the welded portions described here are omitted in each figure, they are formed, for example, in a tapered shape at the outer edge portion 3c11 and the inner edge portion 3c12.
[0034] The thickness (mm) of the second plate-like portion 3c2 is, for example, 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, 110, 120, 130, 140, 150, and may be within the range between any two of the values exemplified here.
[0035] 1-1-3-2. Second wing portion 3b Since the second wing portion 3b has a symmetrical shape with the first wing portion 3a, the different parts will be described centered, and the description of the same content will be omitted.
[0036] Most of the second wing portion 3b is disposed above the first wing portion 3a. The second wing portion 3b has the first plate-like portion 3c1 and the second plate-like portion 3c2 that are overlapped, similar to the first wing portion 3a. The first plate-like portion 3c1 is connected to the steel pipe edge portion 1e (the second steel pipe edge portion 1e2) of the tip surface 1b of the steel pipe 10 in the region where it overlaps with the second plate-like portion 3c2.
[0037] In the first embodiment, when the steel pipe pile 100 is viewed from the side such that the opening portion 20 comes to the front side, the second wing portion 3b has a portion that intersects (overlaps) with the first wing portion 3a. The intersecting portion is disposed outside the steel pipe 10 when the steel pipe pile 100 is viewed from the side such that the opening portion 20 comes to the front side.
[0038] <Outer protrusion width and inner protrusion width> Referring to FIG. 5B, the first outer protrusion width W1, the second outer protrusion width W2, the first inner protrusion width L1, and the second inner protrusion width L2 are defined. The first outer protrusion width W1 is the width by which the first plate-like portion 3c1 protrudes from the outer surface 1d of the steel pipe 10 in the radial direction of the wing portion 3. Note that in FIG. 5B, the position of the outer surface 1d of the steel pipe 10 corresponds to the position P1d. The second outer protrusion width W2 is the width in the radial direction of the wing portion 3 where the second plate-shaped portion 3c2 protrudes from the outer surface 1d of the steel pipe 10. The first inner protrusion width L1 is the width in the radial direction of the wing portion 3 where the first plate-shaped portion 3c1 protrudes from the inner surface 1c of the steel pipe 10. In addition, in FIG. 5B, the position of the inner surface 1c of the steel pipe 10 corresponds to the position P1c. The second inner protrusion width L2 is the width in the radial direction of the wing portion 3 where the second plate-shaped portion 3c2 protrudes from the inner surface 1c of the steel pipe 10.
[0039] Here, the first outer protrusion width W1 is preferably 30% or more and 70% or less of the second outer protrusion width W2, more preferably 35% or more and 65% or less, and even more preferably 40% or more and 60% or less.
[0040] Also, the first inner protrusion width L1 is 30% or more and 70% or less of the second inner protrusion width L2, more preferably 35% or more and 65% or less, and even more preferably 40% or more and 60% or less.
[0041] Due to the relationship between the first outer protrusion width W1 and the second outer protrusion width W2 (hereinafter also referred to as the first relationship) and the relationship between the first inner protrusion width L1 and the second inner protrusion width L2 (hereinafter also referred to as the second relationship) being as described above, it becomes possible to perform reinforcement according to the distribution of the moment applied to the wing portion 3, and it is possible to effectively reinforce the wing portion 3 while suppressing the material of the plate material (the material of the first plate-shaped portion 3c1). It is preferable that both the first and second relationships are as described above, but an effect can be expected even if only one of them is satisfied.
[0042] 1-2. Operational effects of the first embodiment 1-2-1. Regarding the configuration of stacking a plurality of plate-shaped portions As the excavation part provided in the steel pipe, configurations such as arranging plate-shaped parts in a spiral shape like in the first embodiment or a spiral shape have been proposed. The excavation parts of these configurations basically have a constant plate thickness. Here, during construction using steel pipe piles or when a load acts on the steel pipe piles, a moment is generated in the excavation part like a cantilever beam, so a large stress is generated at the part where the excavation part is connected to the steel pipe, while the stress generated in parts such as the outer peripheral side of the excavation part is small. Therefore, ideally, it is considered that the plate thickness of the excavation part may be thick at the part connected to the steel pipe and thin at the outer peripheral side part and the inner peripheral side part. However, such an excavation part has the following problems (1) to (3).
[0043] (1) First, it is not easy to obtain a single plate material (flat steel plate) with a thick plate thickness at the part connected to the steel pipe and a thin plate thickness at the outer peripheral side part or the like. (2) Although there are some narrow-width rolled flat steels with different plate thicknesses at both ends, the size of the plate thickness is limited, and it is not easy to process them into an arc shape. (3) It is possible to process a single plate material by mechanical cutting or the like to change the plate thickness of the plate material according to the part, but the cost increases significantly due to processing labor, yield, etc. Based on these (1) to (3), it is not easy to manufacture the above-mentioned ideal cutting part using a single plate material.
[0044] Also, it is conceivable to use casting in the manufacturing method. However, even in this case, there is a problem as described in the following (4). (4) When performing casting processing, the plate thickness can be changed in the outer peripheral radial direction. However, it is necessary to prepare molds for each pile diameter and wing diameter. When manufacturing many types of products, the number of molds increases, and when manufacturing large products, the molds become large, raising concerns about management problems and increased manufacturing costs. In addition, productivity drops, such as the cooling after casting taking a long time. Thus, although casting can manufacture an excavation part having parts with different thicknesses, there are problems in terms of management, cost, and productivity.
[0045] 1-2-1-1. Suppression of damage, etc. In the first embodiment, in the region where the wing portion 3 and the steel pipe edge portion 1e are connected, since the first plate-shaped portion 3c1 and the second plate-shaped portion 3c2 overlap, it is easy to secure the thickness of the wing portion 3 in that region. Here, although this region is a portion where stress is likely to increase, the thickness is secured, and the wing portion 3 is suppressed from being damaged or bent.
[0046] 1-2-1-2. Regarding manufacturing cost In the first embodiment, it is not necessary to perform processing or the like so that the thickness of a single plate material changes according to the part. Since the first plate-shaped portion 3c1 and the second plate-shaped portion 3c2 are overlapped to increase the thickness, it is possible to expect the effect of suppressing an increase in manufacturing cost when manufacturing an excavation part with different thicknesses according to the part. Also, the first plate-shaped portion 3c1 is a plate-shaped portion for reinforcement at the connection portion with the steel pipe 10 and does not need to have the same size as the second plate-shaped portion 3c2. For this reason, it is not necessary to stack two plates of the same shape as the second plate-shaped portion 3c2, and it is possible to suppress the manufacturing cost by suppressing the weight of the material of the excavation part (cost reduction by reducing steel weight).
[0047] 1-2-1-3. Diversification of shape and rationalization of inventory management In the first embodiment, the wing portion 3 is manufactured by overlapping plate-shaped portions. Here, by preparing plate-shaped portions with several types of plate thicknesses, it is possible to easily increase the types of wing portions 3 that can be manufactured by their combination. If an attempt is made to manufacture a wing portion with only a single plate material, the problems as described in (1) to (3) above will occur. However, in the case of the laminated plate method as in the first embodiment, by procuring plate-shaped portions with different plate thicknesses, wing portions 3 of various shapes can be easily manufactured, and inventory management can also be significantly rationalized.
[0048] 1-2-2. Reduction of penetration resistance In the first embodiment, when the wing portion 3 is viewed in plan view, the first plate-like portion 3c1 is disposed inside the edge of the second plate-like portion 3c2. That is, the first plate-like portion 3c1 is smaller in size than the second plate-like portion 3c2. For this reason, although the thickness of the wing portion 3 is thick at the connecting portion with the steel pipe 10, the thickness of other portions (outer peripheral portions, etc.) is suppressed. As a result, when the steel pipe pile 100 is viewed from the front side (see FIG. 3A), the area of the wing portion 3 is suppressed, and it is easy to bite into the ground. Therefore, the rotational torque when the steel pipe pile 100 is being penetrated, and the force required when the steel pipe pile 100 is being pushed in or pulled out can be suppressed, and it is possible to reduce the penetration resistance of the steel pipe pile 100.
[0049] 1-3. Modification Example of the First Embodiment 1-3-1. Modification Example 1: Making the Thicknesses of a Plurality of Plate-Like Portions Different As shown in FIGS. 7A and 7B, in Modification Example 1, the thickness T2 of the second plate-like portion 3c2 is made larger than the thickness T1 of the first plate-like portion 3c1.
[0050] When manufacturing the wing portion by stacking plate-like portions, usually, the outer peripheral portion of the upper plate-like portion is fixed by fillet welding. When sufficient fixing performance is obtained, the displacement between the first plate-like portion 3c1 (upper plate-like portion) and the second plate-like portion 3c2 (lower plate-like portion) does not occur. Therefore, the two plates as a built-up beam structure exhibit the bending rigidity as a composite cross-section. On the other hand, when a vertical load acts on the two plate-like portions, a force that causes the plate-like portions to shift relative to each other due to bending of the plate-like portions acts. The shear force that causes such displacement changes depending on the bending rigidity of the plate-like portion. For example, even if the total thickness of the first plate-like portion 3c1 and the second plate-like portion 3c2 is the same, when the second plate-like portion 3c2 is thick and the first plate-like portion 3c1 is thin, the shear force generated in the first plate-like portion 3c1 is small. When the thickness relationship is reversed, the shear force generated in the first plate-like portion 3c1 becomes large.
[0051] Therefore, the shear force generated according to the plate thickness of the plate-like part is different. When the plate thickness of the first plate-like part 3c1 is thin, the fillet welding required to prevent displacement can be made small, whereas when the plate thickness of the first plate-like part 3c1 is thick, the welding amount (fillet welding amount) required for the first plate-like part 3c1 becomes large. Therefore, when overlapping the plate-like parts, it is possible to reduce the processing cost by making the thickness of the first plate-like part 3c1 thinner than the thickness of the second plate-like part 3c2 and reducing the welding amount. As shown in FIG. 7B, it can be seen that the welded portion WE between the first plate-like part 3c1 and the second plate-like part 3c2 is suppressed by the amount that the first plate-like part 3c1 is thin.
[0052] 1-3-2. Modification 2: Number of plate-like parts of each wing part In the first embodiment, the case where the number of plate-like parts of the wing part 3 is two has been described as an example, but the present invention is not limited thereto. As shown in FIGS. 8A and 8B, in Modification 2, the wing part 3 further includes a third plate-like part 3c3 in addition to the first plate-like part 3c1 and the second plate-like part 3c2. The third plate-like part 3c3 is welded to the second plate-like part 3c2 and fixed to the second plate-like part 3c2. Note that the number of plate-like parts may be four or more, and can be set according to, for example, the rigidity required for the wing part 3.
[0053] 2. Second Embodiment 2-1. Configuration Explanation of the Second Embodiment In the second embodiment, the same reference numerals are given to the configurations common to the first embodiment, and the different parts will be mainly described, and the description of the same content will be omitted.
[0054] As shown in FIGS. 9A to 11B, the steel pipe pile 100 includes a steel pipe 10, an open part 20, an excavation part 30, and a reinforcing member 40.
[0055] 2-1-1. Steel Pipe 10 In the second embodiment, since the steel pipe 10 is the same as that described in the description of the first embodiment (1-1-1. Steel Pipe 10), the description thereof will be omitted.
[0056] 2-1-2. Open Part 20 In the second embodiment, the opening portion 20 is the same as that described in the description of the first embodiment (1-1-2. Opening portion 20), and thus the description thereof is omitted.
[0057] 2-1-3. Excavation portion 30 As shown in FIGS. 9A to 11B, in the second embodiment, each wing portion of the excavation portion 30 does not have a form in which plate-like portions are stacked. That is, the first wing portion 3a in the second embodiment is the second plate-like portion 3c2 of the first wing portion 3a described in the first embodiment. Similarly, the second wing portion 3b in the second embodiment is the second plate-like portion 3c2 of the second wing portion 3b described in the first embodiment.
[0058] The excavation portion 30 has wing portions 3. In the second embodiment, the wing portions 3 are composed of a plurality (two in the second embodiment) of independent wing portions (the first wing portion 3a and the second wing portion 3b). Note that although the number of wing portions is described as two, the same as in the first embodiment, it is not limited thereto, and the steel pipe pile 100 may have a form having three or more independent wing portions. The plurality of independent wing portions are flat plate-like members adjacent to each other. Each wing portion is provided so as to be inclined when the steel pipe pile 100 is viewed from the side. However, as shown in FIG. 11A, the inclination angles of the two wing portions are different.
[0059] 2-1-3-1. First wing portion 3a The first wing portion 3a is a flat plate having a fan shape (semicircular shape in the second embodiment) in plan view. The first wing portion 3a is connected to the steel pipe edge portion 1e (the first steel pipe edge portion 1e1) of the tip surface 1b of the steel pipe 10.
[0060] The first wing portion 3a has a central angle (degrees) of 180 degrees in plan view. Note that the central angle is not limited thereto, and specifically, for example, it is 90, 100, 110, 120, 130, 140, 150, 160, 170, 180, 190, 200, 210, 220, 230, 240, and may be within the range between any two of the numerical values exemplified herein.
[0061] The thickness (mm) of the first wing portion 3a is, for example, 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, and may be within the range between any two of the values exemplified herein.
[0062] 2-1-3-2. Second wing portion 3b Since the shape of the second wing portion 3b is symmetric with that of the first wing portion 3a and the other aspects are the same, the different parts will be described centeredly, and the description of the same content will be omitted.
[0063] Most of the second wing portion 3b is disposed above the first wing portion 3a. The second wing portion 3b is connected to the steel pipe edge portion 1e (second steel pipe edge portion 1e2) of the front end surface 1b of the steel pipe 10.
[0064] In the second embodiment, when the steel pipe pile 100 is viewed from the side such that the opening portion 20 comes to the front side, the second wing portion 3b has a portion that intersects (overlaps) with the first wing portion 3a. The intersecting portion is disposed outside the steel pipe 10 when the steel pipe pile 100 is viewed from the side such that the opening portion 20 comes to the front side.
[0065] <Inclination angle> As shown in FIG. 11A, the first virtual plane P1 is a plane that is orthogonal to the central axis C of the steel pipe 10 and passes through the central height position between the first terminal 1e12 of the first steel pipe edge portion 1e1 and the second tip 1e21 of the second steel pipe edge portion 1e2. Here, let the angle formed by the first wing portion 3a and the first virtual plane P1 be the first inclination angle θ1, and the angle formed by the second wing portion 3b and the first virtual plane P1 be the second inclination angle θ2. In the second embodiment, as shown in FIG. 11A, the second inclination angle θ2 is larger than the first inclination angle θ1.
[0066] Here, the first inclination angle (degrees) is specifically, for example, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, and may be within the range between any two of the values exemplified herein. For example, the first inclination angle is 2 degrees or more and 20 degrees or less.
[0067] Further, the second inclination angle (degrees) is specifically, for example, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, and may be within the range between any two of the values exemplified herein. For example, the second inclination angle is 3 degrees or more and 30 degrees or less.
[0068] <Opening area> As shown in FIG. 11A, the opening area of the opening 20 between the first wing portion 3a and the first virtual plane P1 is defined as the first opening area Ar1, and the opening area of the opening 20 between the second wing portion 3b and the first virtual plane P1 is defined as the second opening area Ar2. In the second embodiment, the second opening area Ar2 is larger than the first opening area Ar1. More specifically, as shown in FIG. 11A, the first opening area Ar1 is the area of a trapezoidal region surrounded by the upper surface of the first wing portion 3a, the longitudinal edge portions 1f on both sides, and the first virtual plane P1 when the steel pipe pile 100 is viewed from the side (front side) on the opening 20 side. Also, as shown in FIG. 11A, the second opening area Ar2 is the area of a trapezoidal region surrounded by the lower surface of the second wing portion 3b, the longitudinal edge portions 1f on both sides, and the first virtual plane P1 when the steel pipe pile 100 is viewed from the side (front side) on the opening 20 side.
[0069] <Support area> As shown in FIG. 14, when the excavation portion 30 is viewed from the direction of the central axis C of the steel pipe 10, a circular region Rg is defined with the position of the central axis C as the center O and the distance between the center O and the farthest position p as the radius. The farthest position p is the position of the portion of the excavation portion 30 that is farthest from the central axis C of the steel pipe 10. When the excavation portion 30 is viewed from the direction of the central axis C of the steel pipe 10, the range where the excavation portion 30 is provided is preferably 70% or more of the total area of the circular region Rg. Note that this value is not limited to 70%. Specifically, for example, it may be 70, 75, 80, 85, 90, 95, 100%, or may be within the range between any two of the values exemplified herein. By setting the value in this way, it is possible to secure a wider area for the lower surface of the excavation part 30, making it easier to secure the supporting force of the steel pipe pile 100.
[0070] <Distribution of the wing part 3> As shown in FIG. 14, when the space is divided into a first divided space Sp1 and a second divided space Sp2 by a second virtual plane P2 passing through the central axis C of the steel pipe 10, the first wing part 3a is arranged in the first divided space Sp1, and at least a part of the second wing part 3b is arranged in the second divided space Sp2. Note that the second virtual plane P2 bisects the space into the first divided space Sp1 and the second divided space Sp2. In the second embodiment, the entire first wing part 3a is arranged in the first divided space Sp1, and the entire second wing part 3b is arranged in the second divided space Sp2. Thus, in the second embodiment, the arrangement of the wing part 3 is not unevenly distributed in one divided space, but is distributed in both spaces (the first divided space Sp1 and the second divided space Sp2). In particular, in the second embodiment, the wing part 3 is arranged so as to be evenly distributed in the first divided space Sp1 and the second divided space Sp2. For example, the entire first wing part 3a may be arranged in the first divided space Sp1, and the second wing part 3b may be arranged across the first divided space Sp1 and the second divided space Sp2. Also, the first wing part 3a may be arranged across the first divided space Sp1 and the second divided space Sp2, and the entire second wing part 3b may be arranged in the second divided space Sp2. Note that the distribution of the wing part 3 described here is the same in the first embodiment as well.
[0071] 2-1-4. Reinforcing member 40 As shown in FIGS. 13A and 13B, the reinforcing member 40 is provided in the opening part 20 (the tip part 1a of the steel pipe 10) along the inner surface 1c of the steel pipe 10. The part of the steel pipe 10 where the opening part 20 is formed is a part that collides with the object to be excavated, and strength is required. For this reason, the steel pipe 10 is internally equipped with the reinforcing member 40.
[0072] As shown in FIG. 11A, the reinforcing member 40 is attached to the longer vertical edge portion 1f of the pair of vertical edge portions 1f. Specifically, the reinforcing member 40 is provided along the inner surface 1c of the steel pipe 10 at a position corresponding to the vertical edge portion 1f. When the height width of the reinforcing member 40 is w1 and the height width of this vertical edge portion 1f is w2, the value of w1 / w2 is specifically, for example, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, 1.1, 1.2, and it may be within the range between any two of the numerical values exemplified here.
[0073] The reinforcing member 40 is formed to taper in a cross section parallel to the first virtual plane P1. In other words, the reinforcing member 40 has a wedge shape in a cross section parallel to the first virtual plane P1. The tapered tip portion of the reinforcing member 40 is provided so as to face the opening of the opening portion 20. Note that the tapered tip portion of the reinforcing member 40 may be provided inside the steel pipe 10 and may not protrude from the opening of the opening portion 20, or may be provided outside the steel pipe 10 and may protrude from the opening of the opening portion 20.
[0074] As shown in FIG. 13B, the reinforcing member 40 is welded to the inner surface 1c of the steel pipe 10 by welding. In FIG. 13B, welding portions 41 are formed at the tip portion and the back side portion of the reinforcing member 40. Note that the fixing method of the reinforcing member 40 is not limited to welding, and for example, alternative connecting means such as an adhesive or a bolt can be used alone or in combination with welding.
[0075] 2-2. Operational effects of the second embodiment 2-2-1. Regarding the opening area In the second embodiment, even if the inclination angle of the first wing portion 3a is suppressed from the viewpoint of reducing resistance in excavation, for example, the inclination angle of the second wing portion 3b is ensured to be larger than the inclination angle of the first wing portion 3a. Therefore, the second opening area Ar2 is ensured to be larger than the first opening area Ar1. For this reason, it is suppressed that the object to be excavated is difficult to be taken into the steel pipe 10, and it is suppressed that the penetrability of the steel pipe pile 100 is impaired.
[0076] 2-2-2. Regarding the inclination angle When the steel pipe pile is rotationally penetrated, the tip of the wing part excavates the ground, and the excavated material is moved upward along the wing part. As a result, the wing part receives a downward force and the steel pipe pile penetrates. At the lower end of the wing part that excavates the new ground, a large reaction force is received during excavation. However, once the excavated earth and sand are plasticized, the downward reaction force decreases while moving upward along the wing part. For this reason, if the angle of the wing part is constant in the spiral direction (substantially spiral direction), there is a concern that the upper part of the wing part cannot appropriately receive the reaction force from the excavated material. In the second embodiment, the second inclination angle θ2 of the second wing part 3b is larger than the first inclination angle θ1 of the first wing part 3a. Thereby, first, the resistance during excavation can be suppressed by the first wing part 3a with a relatively small inclination angle. Since the first wing part 3a is the part that first contacts the ground, it goes without saying that a downward reaction force is ensured. Second, when the excavated material moves on the upper surface of the second wing part 3b, the second wing part 3b has a relatively large inclination angle, and can receive a large downward reaction force from the excavated material. That is, the steel pipe pile 100 can also appropriately receive a downward reaction force at the second wing part 3b, and the penetrability is improved.
[0077] 2-2-3. Regarding ensuring the supporting force When the excavation part (wing part) is viewed from the central axis direction of the steel pipe, if an opening, a notch, etc. are formed in the excavation part, the area of the lower surface of the steel pipe pile (excavation part) is reduced accordingly, and when an up-and-down direction force acts on the steel pipe pile, there is a concern that the reaction force from the ground cannot be obtained and the supporting force decreases. In the second embodiment, when the excavation part 30 is viewed from the direction of the central axis C of the steel pipe 10, the range where the excavation part 30 (wing part 3) is provided is 70% or more of the total area of the circular region Rg (almost 100% in the second embodiment). Thereby, the area of the lower surface of the excavation part 30 can be ensured more widely, and it becomes easier to ensure the supporting force of the steel pipe pile 100.
[0078] 2-2-4. Reinforcement of the opening part It is conceivable to attach a flat reinforcing member to the opening part 20 instead of the reinforcing member 40 to reinforce the opening part 20. However, with this method, since the earth and sand hit the reinforcing plate during earth and sand intake, the resistance increases. Furthermore, with a flat reinforcing member, it is difficult to secure an area where the excavated material does not contact the area 42 behind the reinforcing member, and there is a concern that the opening part 20 is likely to be blocked. On the other hand, in the second embodiment, since the reinforcing member 40 formed to taper toward the opening part 20 is provided, the resistance during intake of the excavated material can be reduced. Also, in the second embodiment, since the width of the portion on the back side of the reinforcing member 40 is wider than the portion on the tip side of the reinforcing member 40, it is easy to secure an area where the excavated material does not contact the area 42 behind the reinforcing member 40, and it is possible to make the area where the excavated material does not contact the inner surface 1c of the steel pipe 10 large, suppress the closing of the opening part 20, and suppress the resistance during penetration.
[0079] 2-3. Modification of the second embodiment 2-3-1. Other shapes of the reinforcing member 40 In the second embodiment, the cross-sectional shape of the reinforcing member 40 has been described as triangular, but it is not limited to this. As shown in Fig. 15A, the cross-sectional shape of the reinforcing member 40 may be circular. In this case, the welded part 41 is preferably formed to taper toward the opening part 20. Thereby, it is possible to obtain the same effects as the reinforcing member 40 described in the second embodiment. Also, as shown in Fig. 15B, the cross-sectional shape of the reinforcing member 40 may be trapezoidal. Also in this case, by forming the welded part 41 to taper toward the opening part 20, it is possible to obtain the same effects as the reinforcing member 40 described in the second embodiment.
[0080] 2-3-2. Forms with different opening areas In the second embodiment, the inclination angles of the first wing portion 3a and the second wing portion 3b were different, so that the first opening area Ar1 and the second opening area Ar2 were different, but the present invention is not limited to this. That is, in making the opening areas different, it is not essential that the inclination angle of the second wing portion 3b is larger than the inclination angle of the first wing portion 3a. For example, even if the inclination angles of the first wing portion 3a and the second wing portion 3b are the same, the first opening area Ar1 and the second opening area Ar2 can be made different depending on the shape of the vertical edge portion 1f.
[0081] 2-3-3. Regarding the shape of the edge of the wing portion 3 In this modification example, the edge of the first wing portion 3a has a tapered shape, and it is a form in which the biting into the ground is good. Specifically, as shown in FIGS. 16A and 16B, the edge t1 of the first wing portion 3a may have a tapered shape. The edge t1 extends linearly and is disposed at the formation position of the opening portion 20. Since the edge t1 has a tapered shape and is angled like a blade tip, the resistance during excavation can be reduced, it is easy to bite into the ground, and the object to be excavated can be easily taken into the pipe. Similarly, the edge t2 of the first wing portion 3a may also have a tapered shape. The edge t2 is provided at the peripheral edge portion of the first wing portion 3a and extends in an arc shape (circular arc shape in this modification example). Since the edge t2 has a tapered shape and is angled like a blade tip, the biting property into the ground can be improved, the penetration resistance can be reduced, and the penetrability can be improved. Note that the second wing portion 3b also has the same configuration as the first wing portion 3a, and its edge may have a tapered shape.
[0082] 3. Other embodiments The first embodiment, modification examples 1 and 2 of the first embodiment, the second embodiment, and modification examples of the second embodiment can be appropriately combined. For example, as in the first embodiment, after the plate-like portions of the first wing portion 3a and the second wing portion 3b are overlapped, as in the second embodiment, the second opening area Ar2 may be larger than the first opening area Ar1, or the second inclination angle θ2 may be larger than the first inclination angle θ1. Also, on the premise of the form in which the plate-like portions of the first wing portion 3a and the second wing portion 3b are overlapped as in the first embodiment, the reinforcing member 40 described in the second embodiment or its modification may be provided in the opening portion 20.
Explanation of Reference Numerals
[0083] 100: Steel pipe pile 10: Steel pipe 1a: Tip 1b: Tip surface 1c: Inner surface 1d: Outer surface 1e: Steel pipe edge 1e1: First steel pipe edge 1e11: First tip 1e12: First terminal 1e2: Second steel pipe edge 1e21: Second tip 1e22: Second terminal 1f: Vertical edge 20: Opening portion 30: Excavation portion 3: Wing portion 3a: First wing portion 3b: Second wing portion 3c1: First plate-like portion 3c2: Second plate-like portion 3c11: Outer edge 3c12: Inner edge 40: Reinforcing member 41: Welded portion 42: Region C: Central axis О: Center p: Furthest position P1: First virtual plane P2: Second virtual plane tp: Tip t1: Edge t2: Edge
Claims
1. A steel pipe pile having an excavation part at the tip of the steel pipe, wherein the excavation part has wing parts, the wing parts have overlapping first and second plate-like parts, the first plate-like part is connected to the steel pipe edge part of the tip surface of the steel pipe in a region overlapping the second plate-like part, the second plate-like part is connected to the first plate-like part, the steel pipe pile.
2. The steel pipe pile according to claim 1, wherein the thickness of the second plate-like part is larger than the thickness of the first plate-like part, the steel pipe pile.
3. The steel pipe pile according to claim 1 or claim 2, wherein when the wing parts are viewed in plan, the first plate-like part is arranged inside the edge of the second plate-like part, the steel pipe pile.
4. The steel pipe pile according to claim 3, wherein the first plate-like part has an outer edge part and an inner edge part, the outer edge part is arranged outside the connection part between the first plate-like part and the steel pipe edge part in the radial direction of the steel pipe, the inner edge part is arranged inside the connection part in the radial direction, the second plate-like part is connected to both the outer edge part of the first plate-like part and the inner edge part of the first plate-like part, the steel pipe pile.
5. The steel pipe pile according to claim 1 or claim 2, wherein the first outer protrusion width is 30% or more and 70% or less of the second outer protrusion width, the first outer protrusion width is the width by which the first plate-like part protrudes from the outer surface of the steel pipe in the radial direction of the wing part, the second outer protrusion width is the width by which the second plate-like part protrudes from the outer surface of the steel pipe in the radial direction of the wing part, the steel pipe pile.
6. The steel pipe pile according to claim 1 or claim 2, wherein the first inner protrusion width is 30% or more and 70% or less of the second inner protrusion width, the first inner protrusion width is the width by which the first plate-like part protrudes from the inner surface of the steel pipe in the radial direction of the wing part, the second inner protrusion width is the width by which the second plate-like part protrudes from the inner surface of the steel pipe in the radial direction of the wing part, the steel pipe pile.
7. The steel pipe pile according to claim 1 or claim 2, wherein the first and second plate-like parts are flat plates, the steel pipe pile.
Citation Information
Patent Citations
Winged steel pipe piles
JP4267489B2