JP2003074054A - Steel pipe pile - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a steel pipe pile executable even to the hard gravel ground and the ground including debris. SOLUTION: This steel pipe pile is characterized by being constituted by having a vertical claw 5 suspended from an under surface of a spiral blade 2 in a starting end part of the spiral blade 2 arranged on the tip of the steel pipe pile 1.

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a spiral-shaped steel pipe pile with blades used as a foundation for a building such as a middle-floor house or a small-scale structure. . 2. Description of the Related Art Conventionally, a steel pipe pile having spiral blades on the tip of a steel pipe pile body or a pile body spaced apart from the tip by a fixed distance has been used as a foundation pile for a medium- to low-rise building. I have.
For example, in a steel pipe pile disclosed in JP-A-59-85028, a rotational torque is applied to a pile head, and the pile is buried underground by screwing. [0003] In such a steel pipe pile, the excavation blade provided at the tip of the steel pipe pile body excavates and softens the ground at the tip, extrudes soil corresponding to the pile volume to the side of the pile, and compresses the soil on the side of the pile to compress the ground. It is propelled and settled without consolidation and without earth removal. [0004] Therefore, the volume of the earth and sand compressed on the side surface of the pile acts as a frictional force by tightening the pile, and together with the spiral blade, a large supporting force can be developed. In addition, since the steel pipe pile can be buried simply by rotating, the construction time can be shortened and it is economical. [0005] When the steel pipe pile can be propelled and settled by the stroke of the spiral blade every one rotation, the above-mentioned effect can be exerted with almost no disturbance to the ground. However, in the case of a sandy gravel ground having an N value of 30 or more, or a ground containing waste, it is difficult to penetrate the ground. That is, 1
Since the helical blade cannot be propelled and settled by the rotation of the helical blade, the helical blade must be rotated many times to penetrate and settle the pile little by little. [0006] For this reason, there is a problem that the ground is agitated and disturbed by the spiral blades or the excavating blade provided at the tip of the steel pipe pile main body, so that a predetermined frictional force cannot be developed and the construction time is prolonged. there were. [0007] Further, in the ground containing sand, gravel, etc., the spiral blades are deformed by hitting with sand, gravel, etc., or are worn away by friction with sand, gravel, etc., so that a predetermined vertical supporting force is obtained. There was also a problem that it could not be expressed. Therefore, as shown in Japanese Patent Application Laid-Open No. Hei 7-11637, the present applicant superimposes a flat excavation and propulsion blade curved in accordance with a spiral blade on the starting end of the spiral blade. It was proposed to attach it, and the excavation and propulsion blade along the spiral blades could penetrate the ground without idling even on a rather hard ground, and a stable propulsion force could be obtained. [0009] Further, the ground disturbance due to idling can be prevented, which leads to an improvement in the supporting force, and the drilling and propulsion blade also has the effect of reinforcing the spiral blade, so that the deformation and deformation of the spiral blade can be prevented. It has become possible to prevent abrasion. [0010] However, the conventional example described above is not without its problems at all, and in the case of harder sandy gravel ground or ground containing waste, flat excavation and propulsion blades are required. Even if it is installed, it may be difficult to penetrate the ground. The present invention has been made to solve the above problems, and
An object of the present invention is to provide a steel pipe pile that can be constructed even on hard gravel ground or ground including waste. A steel pipe pile according to the present invention for achieving the above object is a steel pipe pile in which one or more spiral blades are fixed at the tip of the steel pipe pile, The helical blade has a vertical claw hanging from a lower surface of the helical blade at a starting end thereof. Since the present invention is constructed as described above, the vertical claw hanging down from the lower surface of the spiral blade at the starting end of the spiral blade excavates the ground where hard sand, gravel, etc. are present while excavating. Since the steel pipe pile does not run idle and the spiral blade is not deformed, worn down, or rolled up, a large tip supporting force can be exhibited. Clays having an N value of 10 to 30 have an adhesive property and therefore slip only with spiral blades. In particular, clays having an N value of 30 or more are hard and do not bite. In such a case, the above-mentioned vertical nail is effective. The "N value" is a weight of 622.7N.
(63.5 kgf) The number of hits required to drop a hammer freely from a height of 75 cm and drive a standard penetration test sampler into a 30 cm length. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of a steel pipe pile according to the present invention will be specifically described with reference to the drawings. 1 (a) and 1 (b) are explanatory side views showing the configuration of a steel pipe pile according to the present invention, FIG. 2 is a bottom view showing the configuration of a steel pipe pile according to the present invention, and FIG. 3 is a configuration of various vertical claws. FIG. 1 and 2, the main body of the steel pipe pile 1 is a steel pipe, usually having an outer diameter of 100 mm to 500 mm and a thickness of 4 mm to 4 mm.
20 mm, length 3 m to 10 m. A spiral blade 2 is attached to the outer peripheral surface of the tip of the steel pipe pile 1 by about one turn. If the number of the blades 2 is one turn or less, a sufficient supporting force cannot be obtained when the steel pipe pile 1 is buried in the ground. The spiral blade 2 is made of steel, and its outer diameter is preferably about 1.5 to 3 times the outer diameter of the steel pipe pile 1 main body.
More preferably, it is about twice. The above range is preferable because the construction efficiency does not decrease while the supporting force increases. The spiral blade 2 preferably has a thickness of 6 mm to 40 mm, and its stroke L is preferably about 50 mm to 200 mm in terms of workability. The spiral blade 2 is attached to the steel pipe pile 1 usually by welding. The tip of the steel pipe pile 1 may be closed by attaching a bottom plate 4 or may be left open. At the beginning of the spiral blade 2, a flat extended blade 3 having the same width as the blade 2 is mounted obliquely in the propulsion direction. The extension blade 3 is made of a rigid material, and a material having high strength is preferably selected. It is important from the viewpoint of rigidity that the extension blade 3 is attached to the start end of the spiral blade 2 and the outer peripheral surface of the steel pipe pile 1 by welding or the like. The skew angle of the extension blades 3 is about 45 degrees to 60 degrees with respect to the horizontal plane, and is provided so as to protrude from the tip of the steel pipe pile 1, whereby the steel pipe pile 1 penetrates into the ground. It is easy to do. The height of the extension blades 3 is a number from the tip of the steel pipe pile 1.
The height protrudes about 10 cm from cm. The thickness of the extension blades 3 depends on the thickness and the outer diameter of the steel pipe pile 1 and the spiral blades 2 as well as the size and the mixing ratio of the gravel and the rag, but in consideration of the workability and the bearing capacity. About 10 mm to 40 mm is appropriate. At the beginning of the spiral blade 2, two vertical claws 5 hanging from the lower surface of the spiral blade 2 are provided side by side. It is important in terms of rigidity that the vertical claw 5 is attached to the lower surface of the spiral blade 2 and the lower surface of the extension blade 3 by welding or the like. Thereby, the vertical claw 5 also serves as a reinforcing material for preventing the spiral blade 2 from being deformed. The shapes of the vertical claws 5 are shown in FIGS.
As shown in (a), a rhombus is preferable, and its skew angle is preferably about 45 degrees to 60 degrees with respect to the horizontal plane similarly to the extension blade 3. The height of the vertical claws 5 is preferably not less than the height of the extended blades 3 as shown in FIG. 1, but may be not more than the height of the extended blades 3. The thickness of the vertical claw 5 is suitably about 10 mm to 40 mm similarly to the extension blade 3. The shape of the vertical claw 5 is not limited to the rhombus, as shown in FIG.
Various shapes are applicable as shown in (b), (c), and (d). In FIG. 3, the upper side (upper side in FIG. 3) of each figure is a side fixed to the spiral blade 2 and the left side (left side in FIG. 3) of each figure is spiral blade 2 Is located on the side of the starting end. With the above-described configuration, even on a hard ground including gravel and rags, the vertical claws 5 excavate and protrude the hard ground containing gravels and gulls, and the spiral blades 2
Can penetrate the ground without idling, can obtain stable propulsion, and can also prevent ground disturbance due to idling, leading to an improvement in support capacity. Further, since the extension blade 3 and the vertical claw 5 have the effect of reinforcing the spiral blade 2, it is possible to prevent the spiral blade 2 from being deformed or worn down, and to further improve the supporting force. Can contribute. In this embodiment, an example in which the extended blade 3 is provided will be described. However, the same applies to a case where the extended blade 3 is omitted and the vertical claw 5 is attached to the lower surface of the spiral blade 2 by hanging. Effect can be obtained. Clays having an N value of 10 to 30 have an adhesive property and therefore slip only with the spiral blades 2. Clays (Dotan) having an N value of 30 or more are hard and slip and do not bite. In such a case, the vertical nail 5 is effective. <Example> The present invention will be described in detail below with reference to examples. The steel pipe pile 1 according to the present invention has an outer diameter of 26.
Steel pipe pile 1 of 7.4 mm, thickness 8 mm, length 15 m (connecting steel pipe pile 1 of 6 m + 5 m + 4 m), outer diameter 500 m
m, a spiral blade 2 having a thickness of 19 mm, and a stroke L of 120 mm as shown in FIG.
Spiral blade 2 with extension blade 3 having a height of 50 mm and a thickness of 16 mm
At the starting end of the steel pipe pile 1 at an inclination angle of 45 degrees so as to protrude from the tip of the steel pipe pile 1. Further, a diamond-shaped vertical claw 5 having a width of 80 mm, a height of 80 mm, and a thickness of 16 mm is hung from the lower surface of the spiral blade 2 on the starting end of the spiral blade 2 at two locations at substantially equal intervals. 4
The steel pipe pile 1 was attached at a tilt angle of 5 degrees so as to protrude from the tip of the steel pipe pile 1. Further, the tip of the steel pipe pile 1 was closed by attaching a bottom plate 4. The bottom plate 4 was provided with a normal digging blade and an auxiliary digging blade (not shown). When the steel pipe pile 1 is GL-0 to 14 m (distance from the ground surface), the ground is soft ground having an N value of 7 or less.
The ground deeper than -14 m was constructed on the gravel ground having an N value of 40 to 50. The steel pipe pile 1 was sunk to GL-15m, and the tip of the steel pipe pile 1 was made to penetrate 1 m into the gravel ground. Thereafter, the steel pipe pile 1 was pulled out and observed. On the other hand, as a comparative example, a conventional steel pipe pile was constructed under the same conditions and pulled out and observed. Conventional steel pipe piles have vertical claws 5
And the steel pipe pile 1 of the present invention described above except that the extension blades 3 are omitted.
The configuration was the same as described above. The machine used for the construction is DHJ-12 manufactured by Nippon Sharyo Co., Ltd. The machine weight is about 13 t and the rotation torque is 6 tm. The size of the machine is 5m long,
The width of the reader is 2.3 m, and the height of the reader is 9 m, which is generally adopted for narrow land. As a result, the actual construction time for the steel pipe pile 1 of the present invention and the conventional steel pipe pile was the same as about 10 minutes up to GL-14m, but between GL-14m and 15m, The conventional steel pipe pile took about 30 minutes, while the steel pipe pile 1 took about 10 minutes. Thereafter, both were pulled out and the shapes were observed. As a result, in the steel pipe pile 1 of the present invention, the spiral blade 2 was not deformed at all, and there was no abrasion. On the other hand, in the conventional steel pipe pile, the tip of the spiral blade 2 was turned up by gravel. It was observed that it was raised and deformed, and the beginning of the spiral blade 2 was worn and sharpened. As described above, the present invention has the above-described configuration and operation, so that even when the ground is hard, including sand and gravel, the vertical claws excavate the ground and the spiral blades idle. No stable propulsion can be obtained. Further, the construction can be performed without deforming or abrading the spiral blade, and since the spiral blade does not roll up, a large tip supporting force can be exhibited. Clays having an N value of 10 to 30 have an adhesive property and therefore slip only with spiral blades. In particular, clays having an N value of 30 or more (Dotane) are hard and slip and do not bite. In such a case, the above-mentioned vertical nail is effective. Further, as compared with the conventional steel pipe pile, the number of rotations of the spiral blades at the time of penetrating into the hard ground can be reduced, so that the ground is less disturbed and the appearance of peripheral friction can be expected.
Also, the construction time can be shortened.

BRIEF DESCRIPTION OF THE DRAWINGS FIGS. 1 (a) and 1 (b) are side explanatory views showing a configuration of a steel pipe pile according to the present invention. FIG. 2 is an explanatory bottom view showing a configuration of a steel pipe pile according to the present invention. FIG. 3 is a perspective explanatory view showing the configuration of various vertical claws. [Description of Signs] 1 ... steel pipe pile 2 ... spiral blade 3 ... extended blade 4 ... bottom plate 5 ... vertical claw

Claims (1)

Claims: 1. A steel pipe pile in which one or more spiral blades are fixed at the tip of the steel pipe pile, and the lower surface of the spiral blade is provided at the start end of the spiral blade. A steel pipe pile having a vertical claw suspended from a steel pipe pile.