JPH08199568A - Foundation pile driving method and foundation pile - Google Patents

Abstract

PURPOSE: To obtain high ground bearing force/extraction force, reduce an amount of waste soil and to make it possible to lighten the disposal of waste soil. CONSTITUTION: A plurality of stages of spiral screw wings 3, 4 and 5 in the same progressing way are provided in the circumference of a steel pipe pile 2 at required intervals, and a foundation pile 1 with a diameter reduced with an outside diameter of the screw wings 3, 4 and 5 going downward is prepared. The foundation pile 1 is revolved by an auger device 8 to insert into the ground 7 from the ground with pressure, and most of the pile is buried into the ground 7 to use it as a footing member.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a foundation pile driving method for driving a pile into the ground to form a foundation of a building and a foundation pile therefor. This is a particularly useful technique on soft ground.

[0002]

2. Description of the Related Art Conventionally, there is known a foundation pile driving method in which a foundation pile having screw blades having the same outer diameter and continuously attached to the outer circumference of a steel pipe pile is rotated and driven deeply into the ground to drive the foundation pile. . In the foundation pile driving method using the foundation pile of the continuous screw blades, in the hard ground, the screw blades can bite into the ground and obtain a large anchoring force to withstand a high pulling force. However, in the ground with weak supporting force such as soft ground, ground support can be obtained only in the area of the outer diameter of the screw blade,
There is a problem that only a small pulling force and supporting force can be obtained and it cannot be used as a foundation. In addition, there is a problem that earth and sand are discharged to the ground by rotating the continuous screw blades, and the discharged earth and sand are treated and the pulling force and supporting force as a foundation pile become weaker because there is no earth and sand in the ground. is there.

[0003]

SUMMARY OF THE INVENTION The problems to be solved by the present invention are to solve these problems in the prior art, to obtain a strong bearing capacity, and to use a foundation pile driving method and foundation that can be used even on soft ground. To provide a stake.

[0004]

Means for Solving the Problems The constitution of the present invention which has solved the above problems is as follows: 1) A plurality of spiral screw blades of the same advance are provided on the outer circumference of a steel pipe pile at a predetermined interval and the outer diameter of the screw blades. A foundation pile whose diameter is reduced according to the downward direction is prepared, the foundation pile is rotated and pressed into the ground by an auger from the ground, and most of it is embedded in the ground to form a foundation member. Construction method 2) A foundation pile characterized in that spiral screw blades of the same advance are provided in a plurality of stages at required intervals on the outer circumference of a steel pipe pile, and the outer diameter of the screw blades is reduced downward.

[0005]

In the present invention, the foundation pile of the present invention is rotated on the ground by means of an auger or the like. When the foundation pile rotates, the screw blades at the bottom are press-fitted into the ground, and the foundation pile is embedded in the ground. Since a plurality of screw blades have the same advancing spiral, the foundation pile penetrates into the ground like a continuous screw blade. Since the screw blades are intermittently provided at predetermined intervals, the earth and sand carried by the rotation of the screw blades hit the ground where the screw blades are not present and stop rising, and are not sent to the ground. Since the outer diameter of the screw blades of the foundation pile used in the present invention decreases in the downward direction, the screw blades with a small outer diameter perform initial excavation with the ground where a large torque is required, and can be press-fitted without requiring an excessive torque. . As it is press-fitted, a large-diameter screw blade enters the ground to obtain a strong pulling force. Further, since the screw blades are reduced in diameter downward, the load acting on the foundation pile acts like a wedge against the ground to obtain a strong supporting force. This makes it possible to obtain a high supporting force even on soft ground such as soft ground.

[0006]

Embodiments of the present invention will be described below with reference to the drawings. This embodiment is to be applied to soft ground. FIG. 1 is an explanatory view showing a foundation pile driving method of an embodiment of the present invention, and FIG. 2 is a front view showing a foundation pile of an embodiment of the present invention. In the figure, 1 is a foundation pile of this embodiment, 2 is a steel pipe having a diameter of 140 mm and a diameter of about 5 m, and 3, 4 and 5 each have an outer diameter of 500.
Millimeters, 400 millimeters, and 300 millimeters of one-rotation screw blades have a distance of about 1.5 meters from each other. In the figure, 6 is a spiral blade provided at the lower end of the foundation pile 1, 7 is the ground, and 8 is an auger device. In this embodiment, the foundation pile 1 is attached to the auger device 8 on the ground, the foundation pile 1 is rotated by the auger device 8, and is pressed into the ground 7 by the spiral blade 6 at the lower end of the foundation pile 1 and the three-stage screw blades 3. When the foundation pile 1 is rotated, the spiral blade 6 and the screw blade 3 advance to press it into the ground. With the press-fitting, the screw blades 3, 4, and 5 lift the earth and sand of the ground 7,
Since there is an interval of about 1.5 m between the blades 4, 5, the earth and sand carried upward by the screw blades 4, 5 are screw blades 3,
The rise is stopped by hitting the earth and sand where there are no 4,5. As described above, in the foundation pile 1 according to the present embodiment, the soil in the ground 7 hardly rises to the ground. In addition, the pulling force and supporting load for the ground can be increased accordingly. When the foundation pile 1 of the present embodiment is driven into the ground, the load from above acts on the outer ground in a wedge shape due to the screw blades 3, 4, 5 that decrease in diameter as it goes downward, thereby obtaining a high supporting force. it can.

[0007]

As described above, according to the present invention, the supporting force can be increased by the screw blades that are reduced in diameter downward, and the ground is bited because there is a space between the screw blades. The pulling force and supporting force can be increased. As a result, sufficient supporting force and pulling force can be obtained even on soft ground such as soft ground. Further, since the screw blades are intermittently provided so as to be separated from each other, the earth and sand lifted up by the screw blades are stopped midway and are less likely to be discharged to the ground, which reduces the burden of processing the discharged land. At the same time, because the soil is not discharged, the pulling force and supporting force also increase.

[Brief description of drawings]

FIG. 1 is an explanatory view showing a foundation pile driving method according to an embodiment of the present invention.

FIG. 2 is a front view showing a foundation pile according to an embodiment of the present invention.

[Explanation of symbols]

 1 Foundation pile 2 Steel pipe pile 3 Screw blade 4 Screw blade 5 Screw blade 6 Spiral blade 7 Ground 8 Auger device

Claims (2)

[Claims] 1. A foundation pile in which a plurality of stages of spiral screw blades of the same advance are provided on the outer periphery of a steel pipe pile at a required interval apart from each other, and the outer diameter of the screw blades is reduced downward is prepared. A foundation pile driving method, characterized in that the foundation pile is rotated into the ground and press-fitted, and most of it is embedded in the ground to form a foundation member. 2. A foundation pile, characterized in that spiral screw blades of the same advance are provided in a plurality of stages on the outer circumference of a steel pipe pile at a required interval, and the outer diameter of the screw blades is reduced downward.