Tower crane pile head expansion pile

Abstract

To provide an expanded head pile for tower cranes, which uses a rotary press-fit steel pipe pile as the pile foundation for a tower crane, and ensures bending strength by expanding the pile diameter at the pile head, thereby reducing material costs. [Solution] A tower crane pile head expansion pile 1 is used as a pile foundation for a tower crane 10. The pile head of a rotary press-fit steel pipe pile 2 has spiral blades on the side of the steel pipe pile and is provided with an expansion head 4b with a diameter larger than that of the rotary press-fit steel pipe pile 2, and can be formed by joining a head expansion piece 4 to the pile head of the rotary press-fit steel pipe pile 2. The expansion piece 4 is composed of a connection part 4a made of a steel pipe with the same diameter as the rotary press-fit steel pipe pile 2, an expansion head 4b with a diameter larger than that of the rotary press-fit steel pipe pile 2, and a joint plate 4c welded between the upper end surface of the connection part 4a and the lower end surface of the expansion head 4b, and the lower end of the connection part 4a is connected to the upper end of the rotary press-fit steel pipe pile 2.

Description

[Technical Field]

[0001] This invention relates to a tower crane pile with an expanded head, which uses a rotary press-fit steel pipe pile as the pile foundation for the tower crane. [Background technology]

[0002] In the past, when installing a freestanding tower crane supported by pile foundations outside a building, H-shaped steel piles were often used as the pile foundation for the tower crane. However, due to various problems such as the generation of waste soil when excavating the pile hole, filling of the tip of the pile hole with foot consolidation liquid, poor foot consolidation due to liquid leakage, filling of the entire pile hole with cement milk, and vibration and noise when driving the pile, rotary press-fit steel pipe piles are increasingly being used instead of H-shaped steel piles.

[0003] Rotary press-in steel pipe piles are a construction method in which a steel pipe pile with spiral blades at the tip is rotated while being driven into the ground. This method allows for construction without soil removal, leaving no soil or sludge, and is environmentally friendly with low noise and vibration. It also reduces construction time by about one-third compared to H-beam piles, leading to reduced material costs. The action of the blades ensures high bearing capacity, and construction can be carried out in tight spaces using relatively small heavy machinery.

[0004] When used as pile foundations for tower cranes, steel pipe piles not only have a high axial force, but also have the advantage of not having a strong or weak axis like H-shaped steel piles, making them advantageous in terms of maximum bending moment underground. Also, because rotary piles can be removed, rotary press-fit steel pipe piles have come into use, as exemplified by the invention described in Patent Document 1. Other inventions related to rotary press-fit steel pipe piles include the invention described in Patent Document 2.

[0005] Patent Document 1 discloses a connecting fitting for a rotary press-fit steel pipe pile for connecting and fixing a rotary press-fit steel pipe pile having a generally cylindrical cross section with spiral blades on its side to a girder that constitutes a base. The connecting fitting includes an attachment portion for attaching to the side of the rotary press-fit steel pipe pile, a pair of holding members having support portions formed to extend from the attachment portion, a pair of lower fixing members formed to a length that allows the support portions of the pair of holding members to be supported from below, an upper fixing member that is placed on the upper part of the girder, and tightening bolts that connect and fix the upper fixing member to each of the pair of lower fixing members, thereby sandwiching the holding member via the girder member and fixing the rotary press-fit steel pipe pile to the girder member.

[0006] Patent Document 2 discloses an expanded head pile used as a foundation pile or bridge pier foundation in low-head areas, such as when renovating a station building, or in narrow areas. The expanded head pile has an expanded head constructed on-site at the head of a prefabricated pile, and the prefabricated pile is a rotary penetration pile with excavation blades or wings at the tip. The expanded head has a steel pipe inserted over its entire length, and the steel pipe doubles as a casing used when excavating underground and also absorbs reaction force when the rotary penetration pile is rotated and penetrated. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Japanese Patent Application Laid-Open No. 2015-232210 [Patent Document 2] Patent No. 4645091 Summary of the Invention [Problem to be solved by the invention]

[0008] The invention described in Patent Document 1 is a connecting fitting for rotary press-fit steel pipe piles, which are used to support and fix the base of a temporary platform on which a tower crane for suspending construction materials is installed, to rotary press-fit steel pipe piles that are rotated and driven into the ground. By using rotary press-fit steel pipe piles as the support piles for the tower crane, vibrations and noise during pile driving are reduced, and the generation of surplus soil is also significantly reduced. It is also possible to pull out and remove the steel pipe piles.

[0009] However, the invention described in Patent Document 1 does not take into consideration the bearing capacity of the rotary press-fit steel pipe piles on which the tower crane is installed. Also, the expanded head piles described in Patent Document 2 were not envisioned as pile foundations for tower cranes.

[0010] The present invention aims to solve the problems described above, and aims to provide an expanded head pile for tower crane piles that uses rotary-pressed steel pipe piles as the pile foundation for tower cranes, ensures bending strength by expanding the pile diameter at the pile head, and reduces material costs. [Means for solving the problem]

[0011] The expanded head pile for tower crane piles of this invention is characterized by the fact that, as a pile foundation for a tower crane, the head of a rotary-pressed steel pipe pile has spiral blades on the side of the steel pipe pile and is provided with an expanded head with a diameter larger than the diameter of the rotary-pressed steel pipe pile.

[0012] In the head expansion pile for tower crane piles of the present invention, an expansion piece including the expansion head is joined to the pile head of the rotary press-fit steel pipe pile, and the expansion piece is composed of a connection part made of a steel pipe of the same diameter as the rotary press-fit steel pipe pile that is connected to the pile head of the rotary press-fit steel pipe pile, the expansion head, and a joint plate welded between the upper end surface of the connection part and the lower end surface of the expansion head, and the lower end of the connection part can be connected to the upper end of the rotary press-fit steel pipe pile.

[0013] In addition, in the expanded head pile for tower crane piles of the present invention, a water injection hole with a diameter of less than 1 / 4 of the diameter of the connection part may be provided in the center of the joint plate.

[0014] The lower end of the connecting portion and the upper end of the rotary press-fitted steel pipe pile can be joined by welding or mechanical joining.

[0015] In addition, in the head expansion pile for tower crane piles of the present invention, an extension piece may be provided above the head expansion pile, and the upper end of the head expansion pile and the lower end of the extension piece may be joined using welding or mechanical joining. [Effects of the Invention]

[0016] The expanded head pile for tower cranes of this invention expands the pile head diameter of rotary press-fit steel pipe piles used as the pile foundation for tower cranes, thereby ensuring the bending strength of the tower crane pile and providing more stable support for the tower crane. It also reduces material costs. [Brief explanation of the drawings]

[0017] [Figure 1] 1 is a schematic diagram showing one embodiment of an expanded head pile for tower crane piles according to the present invention. [Figure 2] FIG. 2 is a partially enlarged cross-sectional view of the head expansion piece in the embodiment of FIG. 1. [Figure 3] 1 is a front view showing an example of the installation of a tower crane base using an expanded head pile for tower crane piles of the present invention. [Figure 4] FIG. 4 is an elevation view of the embodiment of FIG. 3 up to the tower crane. DETAILED DESCRIPTION OF THE INVENTION

[0018] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below with reference to the accompanying drawings, but the present invention is not limited to the following embodiments.

[0019] Figure 1 shows a schematic diagram of one embodiment of the tower crane pile head expansion pile 1 of the present invention. The rotary press-fit steel pipe pile 2 that constitutes the general part of the pile has a pile diameter D0 and a pile thickness t, and in this example, excavation wings are provided at four locations on the side of the pile.

[0020] The first blade 2a1 has an outer diameter D W1 and the plate thickness t W1 The second blade 2a2 has an outer diameter D W2 and the plate thickness tW2 The third blade 2a3 has an outer diameter D W3 and the plate thickness t W3 The fourth blade 2a4 has an outer diameter D W4 and the plate thickness t W4 It was decided.

[0021] The outer diameter of each drilling blade is D W1 <D W2 <D W3 <D W4 The outer diameter of the excavation blades increases as the position of the rotary press-fit steel pipe pile 2 increases. w and set at the same intervals.

[0022] The head expansion piece 4 is provided to expand the pile diameter of the pile head of the rotary press-fit steel pipe pile 2. The head expansion piece 4 has a connection part 4a with the same pile diameter D0 as the rotary press-fit steel pipe pile 2, and a connection part 4b with a pile diameter D0 larger than the pile diameter D0 of the rotary press-fit steel pipe pile 2. X The thickness of the pile is t1, and the enlarged head 4b is provided between the connection part 4a and the enlarged head 4b. The enlarged head 4b has the same diameter D X and a joint plate 4c.

[0023] It is advisable to ensure the quality of the expansion piece 4 by welding and processing the upper end of the connection portion 4a to the lower surface of the joint plate 4c, and the upper surface of the joint plate 4c to the lower end of the expansion piece 4b in advance in a factory or the like.

[0024] The upper end of the rotary press-fit steel pipe pile 2 and the lower end of the connecting portion 4a can be joined by welding or mechanical joining. As shown in Figure 1, an extension piece 3 can be further provided on the enlarged head portion 4b, and the upper end of the enlarged head portion 4b can also be joined to the lower end of the extension piece 3 by welding or mechanical joining.

[0025] Figure 2 is a partially enlarged cross-sectional view of the expansion piece 4 in the embodiment of Figure 1. The joint between the upper end of the connection portion 4a and the lower surface of the joint plate 4c may be achieved by, for example, providing a groove on the steel pipe side of the connection portion 4a and groove welding using a backing metal. Similarly, the joint between the lower end of the expansion head portion 4b and the upper surface of the joint plate 4c may be achieved by providing a groove on the steel pipe side of the expansion head portion 4b and groove welding using a backing metal.

[0026] 2, the plate thickness t of the connecting portion 4a of the expansion piece 4 and the plate thickness t1 of the expansion head portion 4b are approximately the same. Here, as an example of the dimensions and tolerances of the joint plate 4c, an example using 490 material is shown in Table 1.

[0027] [Table 1]

[0028] Table 1 shows the pile diameter of the rotary press-fit steel pipe pile 2, the pile diameter D0 of the connection part 4a of the expansion piece 4, and the pile diameter D of the expansion head part 4b of the expansion piece 4. X The thickness of the joint plate 4c can be set depending on the N value of the ground.

[0029] For example, the pile diameter D0 of the rotary press-fit steel pipe pile 2 and the connecting portion 4a of the head expansion piece 4 is 267.4 mm, and the pile diameter D X If the N-value is 355.6 mm and the N-value is 15 or less, the thickness of the joint plate 4c should be 22 mm. In this way, the specifications of the expansion piece 4 can be determined depending on the applicable ground (sandy or clayey) on which the tower crane will be installed.

[0030] As shown in Figure 2, a water injection hole 5 may be provided in the center of the joint plate 4c. By passing a water injection pipe inside along the center line of the pile and injecting water from the tip of the tower crane pile head expansion pile 1, the ground directly below the pile can be softened, reducing frictional resistance and promoting smooth excavation and installation. This is particularly effective when installing piles in hard ground or dense sandy soil, reducing the number of times the pile is struck and suppressing noise and vibration during construction. For example, the diameter d of the water injection hole 5 is his preferably equal to or smaller than 1 / 4 of the pile diameter D0 of the connecting portion 4a.

[0031] Figure 3 is a front view of an embodiment in which a tower crane base 12 is installed using the tower crane head expansion pile 1 of the present invention. The tower crane head expansion pile 1, which is a rotary press-fit steel pipe pile 2 with an expanded head 4b, is rotary pressed into the ground and penetrated.

[0032] The upper end of the tower crane pile head expansion pile 1 is connected to a base connection part 14 via a tower crane pile joint 11. The upper part of the base connection part 14 is connected to a base 12 on which a tower mast 15 for installing the tower crane 10 is provided, and a support beam part 13.

[0033] A tower mast 15, which serves as the bottom of the tower crane 10, is provided in the center of the base 12. An arm 12a of the base 12 extends from the tower mast 15 as a center.

[0034] A support beam 13 is provided below the base 12, and a fixing member 13b is provided at the end of the support beam 13a made of H-shaped steel. Tightening bolts 12c are passed vertically through both ends of fixing member 12b provided at the end of arm 12a of base 12, and are then passed through support beam 13a and fastened by nuts 12d.

[0035] The tower crane 10 is constructed by passing a fastening bolt 13c vertically through a fixing member 13b provided at the end of the support beam 13, connecting the base connection part 14 provided below the support beam 13a, and tightening it with a nut 13d. Also, while Figure 3 shows an example in which the support beam 13 is provided below the base 12 of the tower crane 10, there is also a case in which the support beam 13 is not provided.

[0036] Conventionally, H-shaped steel piles have often been used instead of steel pipe piles as the pile foundation for tower cranes 10, and tower crane manufacturers only stock pieces that connect the traditionally used H-shaped steel piles to tower cranes. When using the tower crane pile head expansion pile 1 of the present invention, the tower crane pile joint 11 for connecting the expansion head 4b or the top of the extension piece 3 to the base connection part 14 for the H-shaped steel pile may be, for example, the tower crane pile joint 11 disclosed in Patent Application No. 2025-106361 by the present applicant.

[0037] FIG. 4 shows an elevational view of the tower crane 10 installed in the embodiment of FIG. By installing the base 12 of the tower crane 10 using an expanded head pile 1 for the tower crane pile as the pile foundation for the tower crane 10 and installing the tower crane 10 on the tower mast 15, the bending strength of the tower crane pile is ensured and the tower crane 10 can be supported more stably than before. [Industrial Applicability]

[0038] This invention converts the pile foundation of a tower crane into an expanded head pile for tower crane piles, and by enlarging the pile diameter at the pile head, the stress applied to the joint between the pile and the tower crane base can be efficiently transmitted, improving the allowable load capacity of the tower crane pile and creating a safer structure. [Explanation of symbols]

[0039] 1. Tower crane pile head expansion pile 2 Rotary press-fit steel pipe piles 2a1, 2a2, 2a3, 2a4 drilling blades (spiral blades) 3 Extension Pieces 4. Expanding piece 4a Connection 4b Head expansion 4c Joint plate 5 Water injection hole 10. Tower Crane 11 Tower crane pile joints 12 base 12a Arm 12b Fixing member 12c Fastening bolt 12d nut 13 Beam bearing part 13a Support beam 13b Fixing member 13c Fastening bolt 13d Nut 14 Base connection 15 Tower Mast

Claims

1. A tower crane pile with an expanded head is used as a pile foundation for a tower crane.The expanded head pile is a rotary-pressed steel pipe pile with spiral blades on the side of the steel pipe pile, and the head of the rotary-pressed steel pipe pile has an expanded head with a diameter larger than the diameter of the rotary-pressed steel pipe pile.

2. The tower crane pile head expansion pile according to claim 1, An expansion piece including the expansion head is joined to the pile head of the rotary press-fit steel pipe pile, The expansion piece is A connection portion made of a steel pipe with the same diameter as the rotary press-in steel pipe pile connected to the pile head of the rotary press-in steel pipe pile; The enlarged head portion; a joint plate welded between the upper end surface of the connection portion and the lower end surface of the expansion head portion, The lower end of the connecting portion is connected to the upper end of the rotary press-fit steel pipe pile. A tower crane pile with an expanded head.

3. 3. The head expansion pile for tower crane piles according to claim 2, characterized in that a water injection hole having a diameter of less than 1 / 4 of the diameter of the connection portion is provided in the center of the joint plate.

4. 3. The head expansion pile for tower crane piles according to claim 2, characterized in that the connection between the lower end of the connection portion and the upper end of the rotary-pressed steel pipe pile is a welded or mechanically joined joint.

5. An expansion head pile for tower crane piles as described in claim 1 or 2, characterized in that an extension piece is provided above the expansion head, and the upper end of the expansion head and the lower end of the extension piece are joined by a welded joint or a mechanical joint.

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