JP2001234533A - Pipe pile and method for rotatively press-fitting the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve a problem of insufficient strength of a pipe pile due to spiral twist of an excavating head of the pipe pile which is press-fitted into the ground by rotatively excavating the ground, the excavating head being of a spiral blade structure. SOLUTION: In the pipe pile 1 which has the excavating head 3 at a leading end of a pile main body 2 and is press-fitted into the ground by rotatively excavating the same. The excavating head 3 is constructed in the following manner. (a) The excavating head 3 is constituted of a support substrate 4 attached to the pile main body 2, a rotation fulcrum member 5 projected at the center of the support substrate 4, and excavating blades projected from the support substrate 4. (b) The excavating blades 6 are arranged one by one corresponding to evenly spaced radial lines L of the support substrate 4, and each blade is inclined an acute angle α with respect to the radial line L. Further, a front face of each blade is inclined an acute angle with respect to the support substrate 4. (c) The excavating blade 6 is projected to the outer periphery of the support substrate 4, to thereby form a soil discharging space 7 between a hole H and the support substrate 4. (e) The rotational direction of the pipe pile 1 is set to a direction that feeds soil excavated due to each inclination of the excavating blade 6 from the soil excavating space 7 onto the support substrate 4.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pipe pile buried underground for supporting a building or a structure, and a method of rotary press-fitting the pipe pile.

[0002]

2. Description of the Related Art Conventionally, there has been a pipe pile and a rotary press-fitting method for drilling and press-fitting the ground while a drilling head is provided at the tip of a steel pipe pile as a main body (JP-A-11-303069).
No. ). In most cases, the excavation head A has a spiral wing structure as shown in FIG. 4, and is screwed into the ground while the excavation head A excavates, and the pipe pile B is rotationally press-fitted.

[0003]

Since a pipe pile supports the foundation of a building or a structure, it must have a strength capable of withstanding a large load. However, in the conventional pipe pile B, sufficient strength cannot be obtained because the excavating head A to receive and support the load is spirally twisted. Further, since the spiral blade is difficult to weld, it must be welded to the pile main body C at the factory and then transported to the site. Since the spiral blade is bulky, the transport efficiency is poor.

SUMMARY OF THE INVENTION The present invention has been made in view of the above, and an object of the present invention is to provide a pipe pile which is easy to obtain accuracy and strength, and a method of rotary press-fitting the pipe pile.

[0005]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention relates to a pipe pile for excavating the ground and press-fitting it while rotating a drill head at the tip of a tubular pile main body. Are provided as in the following a to e. a. The excavating head is composed of a plate-shaped support substrate attached to the tip of the pile main body, a rotating fulcrum member projecting from the lower surface of the center of the support substrate, and an excavating blade projecting from the lower surface of the support substrate. b. The excavation blades are provided one by one in correspondence with a plurality of equally spaced radiations starting from the center of rotation of the support substrate, and have an acute angle to the radiations. c. The excavation blade has an acute inclination between the front of the blade and the lower surface of the support substrate. d. The shapes of the digging blade and the support substrate are set so that a discharge space is formed between the inner peripheral surface of the hole dug by the digging blade and the support substrate. e. The rotation direction of the pipe pile is set in a direction in which soil excavated by the inclination of the excavation blade is sent from the earth removal space to the upper surface side of the support substrate.

In the pipe pile of the present invention, a rotary fulcrum member is provided on the excavating head, and the pipe pile can be rotated around the fulcrum as accurately as a top. Therefore, it is possible to accurately perform the construction at the target point. In addition, since the excavation blade is inclined at an acute angle with respect to the radiation centered on the rotation center, the excavated soil moves toward the outer periphery of the excavation head, and the angle between the front of the blade and the support substrate becomes acute. Excavated soil moves upward. Therefore, the excavated soil comes out of the earth discharging space between the hole and the support substrate to the upper surface side of the support substrate and fills the hole.

In the pipe pile of the present invention, the support substrate is grounded to the bottom of the excavated hole via the excavation blade, and the load is supported on the entire surface of the support substrate, so that high strength is obtained. In addition, since the excavation head and the pile main body have a simple welding structure that does not require advanced technology, such as welding a plate to the end of a pipe, on-site welding is possible. Therefore, the pile main body and the excavation head can be separated and efficiently transported.

Further, after the pipe pile is pressed into the ground while rotating to reach a predetermined depth, the pipe pile is further moved to (36).
The present invention provides a rotary press-fitting method for pipe piles, which is repeatedly rotated within an angle of less than 0 degree / number of excavating blades, and press-fitted and fixed by an amount corresponding to the height of the excavating blade.

According to this rotary press-fitting method, the strength of the pipe pile is the highest since the excavating blade is fixed in a state of being cut into the bottom of the hole.

[0010]

Embodiments of the present invention will be described below with reference to the drawings. 1 (a) is a front view showing a main part of the pipe pile, FIG. 1 (b) is a bottom view of the pipe pile, FIG. 2 is a front view showing a used state, and FIG. 3 is a partially enlarged view showing the main part. It is a front view.

The pipe pile 1 of the present invention is formed by welding a drill head 3 to the tip of a steel pipe pile main body 2. The excavating head 3 has a disk-shaped support substrate 4 attached to the tip of the pile main body 2, a triangular plate-shaped rotation fulcrum member 5 projecting from the lower surface of the center of the support substrate 4, and a projecting surface provided on the lower surface of the support substrate 4. And a digging blade 6.

The excavating blades 6 are provided one by one corresponding to a plurality of equally spaced radiations L (three at 120 ° intervals in the embodiment) starting from the center of rotation of the support substrate 4 and the radiations thereof are provided. L is inclined such that the angle α becomes an acute angle. In the embodiment, the angle α is about 60 degrees, but the angle may be appropriately increased or decreased according to the soil properties. Needless to say, the radiation L does not need to be written on an actual product.

As shown in FIG. 3, the excavating blade 6 is inclined such that the angle β between the front surface of the blade (the surface receiving the earth pressure) and the lower surface of the support substrate 4 is an acute angle. The angle β of the embodiment
Is about 60 degrees, but the angle may be appropriately increased or decreased according to the soil quality, similarly to the angle α.

The excavation blade 6 has a size protruding outside the outer peripheral edge of the support substrate 4, and the diameter of the hole H excavated by the excavation blade 6 exceeds the diameter of the support substrate 4. Accordingly, a discharge space 7 is formed between the inner peripheral surface of the hole H excavated by the excavation blade 6 and the support substrate 4. Needless to say, such a discharge space 7 can be formed by devising the size and arrangement of the excavating blades 6 even if the support substrate 4 has a shape other than a circle. Therefore, the shape of the support substrate 4 is not limited to a circle. For example, the support substrate 4 may be provided with a notch for forming a discharge space on the outer periphery of a polygonal or elliptical shape of a triangle or a circular plate.

The cutting edge of the digging blade 6 has a shape combining a horizontal portion 6a and a tapered portion 6b. At the beginning of the digging, the digging is performed only on the horizontal portion 6a, and the tapered portion 6b is gradually added to dig the entire cutting edge. It is supposed to. By doing so, the torque required at the start of excavation can be reduced, so that the rotation driving means and the pile main body 2 described later are not overloaded.

Next, a method of burying the pipe pile 1 of the present invention will be described. First, the pile main body 2 and the excavation head 3 are transported separately, and the excavation head 3 is welded to the tip of the pile main body 2 on site. The pile 1 in which the pile main body 2 and the excavation head 3 are integrated is like an unfolded umbrella and the loading efficiency on the bed is low. However, since the single pile main body 2 is a simple steel pipe, it is worn separately from the excavation head 3. If this is the case, many books can be loaded efficiently.

Next, as shown in FIG.
Upright to the ground Z through the steady rest 8. At this time, the rotation fulcrum member 5 is inserted into the center of the pile driving point. Then, a rotary joint 9 directly connected to a rotation driving means (not shown) is fitted to the upper end of the pipe pile 1 to rotate the pipe pile 1 counterclockwise in FIG. 1B. Then, the excavating head 3 rotates around the rotation fulcrum member 5, the horizontal portion 6 a of the excavating blade 6 cuts the ground Z, and the tapered portion 6
With the addition of b, the ground Z is excavated by the entire excavation blade 6. The excavated soil is sent to the outside of the excavation head 3 according to the inclination of the angle α of the excavation blade 6, so that the excavated soil is raised around the excavation head 3 at the beginning of excavation.

Next, when the excavation proceeds and the excavation head 3 goes underground, the inner periphery of the hole H excavated and the support substrate 4
A discharge space 7 is formed between the two. Since the excavated soil is sent upward according to the inclination of the angle β of the excavating blade 6 as shown in FIG. 3, the excavated soil is summed up with the moving direction due to the inclination of the angle α and passes through the earth discharging space 7. It goes out to the upper surface side of the support substrate 4. Therefore, the upper surface side of the support substrate 4 is sequentially backfilled with the excavated soil, and the pipe pile 1 is gently pressed in while being buried as shown by the two-dot chain line in FIG. If the length of the pile main body 2 is not enough, the rotation joint 9 is removed, another pile main body 2 is added by welding, and the operation is continued.

Next, after the excavating head 3 reaches a predetermined depth, the pipe pile 1 is further repeated within an angle smaller than (360 degrees / number of excavating blades), that is, an angle smaller than 120 degrees in the embodiment. While rotating (preferably in small increments), the excavating blade 6 is press-fitted corresponding to the height. If the excavating head 3 is press-fitted while being repeatedly rotated as described above, the excavating blade 6 is in a state of biting rather than shaving the bottom surface of the hole H.
When the press-fitting is performed to the height equivalent to the height of the support substrate 4, the support substrate 4 is in a grounded state, and the strength is dramatically improved.

Next, the rotary joint 9 attached to the upper end of the pile main body 2 is removed, and the construction of the pipe pile 1 is completed.

Although the present invention has been described with reference to the embodiment, it is needless to say that the present invention is not limited to the above embodiment. For example, in the embodiment, the pipe pile 1 is repeatedly rotated at the final stage to press-fit the excavation blade 6 by an amount corresponding to the height, but the operation may be finished in a state where the pipe pile 1 reaches a target depth. . Although the strength in that case is inferior to the construction method of the embodiment, practically sufficient strength can be secured. The number of blades of the excavation head 3 is optimally three in the embodiment from the viewpoint of cost and strength, but need not be limited thereto.

[0022]

According to the pipe pile of the present invention, since the excavating head has a rotating fulcrum member and rotates accurately around the fulcrum, the pipe pile can be press-fitted with high precision into a point aimed at. Also, the excavated blade is inclined at an acute angle with respect to the radiation, so that the excavated soil moves toward the outer periphery of the excavating head. Further, since the angle between the front of the blade and the support substrate is acute, the excavated soil is sharp. Moves upwards. Therefore, the excavated soil smoothly exits from the earth discharging space between the hole and the support substrate to the upper surface side of the support substrate and refills the hole, so that the efficiency and workability are very good.

Thus, in the pipe pile of the present invention, the support substrate is grounded to the bottom of the excavated hole via the excavation blade, and the load is supported on the entire surface of the support substrate, so that high strength is obtained. In addition, since the excavation head and the pile main body have a simple welding structure that does not require advanced technology, such as welding a plate to the end of a pipe, on-site welding is possible. Therefore, the pile main body and the excavation head can be separated and efficiently transported.

According to the second aspect of the present invention, since the excavation blade can be fixed by being cut into the bottom of the hole, the strength of the pipe pile is greatly improved.

[Brief description of the drawings]

FIG. 1A is a front view showing a main part of a pipe pile, and FIG. 1B is a bottom view of the pipe pile.

FIG. 2 is a front view showing a use state.

FIG. 3 is a partially enlarged front view showing a main part.

FIG. 4 is a front view showing a conventional pipe pile.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Pipe pile 2 ... Pile main body 3 ... Drilling head 4 ... Support substrate 5 ... Rotating fulcrum member 6 ... Drilling blade 7 ... Draining space Z ... Soil L ... Radiation H ... Hole

Claims (2)

[Claims] An excavating head is provided at a tip of a tubular pile main body, and is excavated and press-fitted while rotating the ground, wherein the excavating head is configured as in the following a to e. A pipe pile characterized by becoming. a. The excavating head is composed of a plate-shaped support substrate attached to the tip of the pile main body, a rotating fulcrum member projecting from the lower surface of the center of the support substrate, and an excavating blade projecting from the lower surface of the support substrate. b. The excavation blades are provided one by one in correspondence with a plurality of equally spaced radiations starting from the center of rotation of the support substrate, and have an acute angle to the radiations. c. The excavation blade has an acute inclination between the front of the blade and the lower surface of the support substrate. d. The shapes of the digging blade and the support substrate are set so that a discharge space is formed between the inner peripheral surface of the hole dug by the digging blade and the support substrate. e. The rotation direction of the pipe pile is set in a direction in which soil excavated by the inclination of the excavation blade is sent from the earth removal space to the upper surface side of the support substrate. 2. After the pipe pile according to claim 1 is pressed into the ground while rotating to reach a predetermined depth, the pipe pile is further rotated at an angle smaller than (360 ° / number of excavating blades). A rotary press-fitting method for pipe piles, characterized in that the pipe pile is press-fitted and fixed by an amount equivalent to the height of a drilling blade while being repeatedly rotated within the pipe.