JP2001073363A - Screwing steel pipe pile - Google Patents

Abstract

PROBLEM TO BE SOLVED: To lessen the insertion resistance of a steel pipe pile by fixing a spiral wing over substnaitally one winding on the lower end of the steel pipe making the body of the pile, fixing it on the inner periphery to overlap a leading cylinder projected downward, and providing a small diameter spiral wing over substantially one winding on the lower end of the leading cylinder. SOLUTION: A steel pipe is pushed into ground while rotating it, an inner diameter spiral wing 8a is cut into the ground, and soil and sand are made to flow from a through hole 9 and a gap 10 into the leading cylinder 7 to be pumped upward. Next, the spiral wing 5 is cut into the outside ground of the leading cylinder 7, screwed by the reaction force of the ground acting on the upper face of the spiral wing 5, and insertion is promoted. Soil and sand entering the gap 6a of the outer wing part 5a of the spiral wing 5 is consolidated while sliding the wing upper face of a spiral inclination. The soil and sand entering the gap 6b of the inner wing part 5b is made to flow into the steel pipe, merged with the soil and sand made to flow in from the lower end of the leading cylinder 7 to be pumped upward. Thus, the insertion of the pile can be promoted only by rotating the pile by slight push pressure, and burying can be performed without removing soil.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a winged steel pipe pile which is rotatably buried underground without vibration.

[0002]

2. Description of the Related Art When burying steel pipe piles, instead of the general impact method, press-fitting method, pre-boring method, and digging method, a rotary buried method with less vibration and noise is used. It has become. The method is disclosed in Japanese Patent Publication No. 2-62848,
No. 24 is known. Tokiko 2-626
The construction method of No. 48 uses a steel pipe pile provided with a spiral blade at the lower end of a main body having a bottom plate and a digging blade at the lower end, and screwing it into the ground to bury it.
The construction method of No. 4 uses a pile with a spiral blade provided at the lower end of a steel pipe with an open end, which is settled by the application of rotational force. The ribs provided in the lower part of the steel pipe block the sediment. It is characterized in that the support bottom is formed by using the support bottom.

[0003]

Problems to be Solved by the Invention
The construction method of No. 48 has the advantage that steel pipe piles can be buried by rotary press-fitting directly into the ground, but because of the high penetration resistance, they are mainly intended for small diameter steel pipe piles.
There is a problem in targeting large-diameter steel pipe piles such as a medium diameter of 0 to 600φ and 700 to 1000φ. In addition, Japanese Patent Application Laid-Open No. H8-2261
The construction method of No. 24 has the advantage that the penetration resistance is relatively small because it uses a steel pipe pile with an open tip, but the effect of closing the tip of the steel pipe pile is not sufficient and a large bearing capacity cannot be expected. There's a problem.

The present invention has been made in order to solve the above-mentioned conventional problems. The present invention can be applied to medium-diameter and large-diameter steels having low penetration resistance, and is excellent in the obstruction at the tip of a pile.
An object of the present invention is to provide a steel pipe pile capable of obtaining a large supporting force.

[0005]

The construction of the present invention for achieving the above object will be described with reference to the drawings. A steel pipe pile according to claim 1 is provided at the lower end of a steel pipe 1 constituting a main body of the pile. A spiral wing 5 for screwing over approximately one turn, having an outer diameter larger than the diameter of the steel pipe 1 and an inner diameter smaller than the diameter of the steel pipe 1.
Is fixed to the inner periphery of the spiral wing 5, and a leading tube 7 projecting downward therefrom is superposed. The lower end of the leading tube 7 has an outer diameter substantially equal to that of the leading tube 7. In addition, the small-diameter spiral blades 8a and 8b extending over substantially one turn are provided.

In the steel pipe pile according to the present invention, a semi-annular blade plate 11 having an outer diameter larger than the steel pipe diameter and an inner diameter smaller than the steel pipe diameter is provided at the lower end of the steel pipe 1 forming the body of the pile. A pair of the guide tubes 7 are fixed to the inner periphery of the wing plate 11 so as to be opposed to each other with the inclination directions thereof being opposite to each other, and are protruded downward therefrom.
At the lower end of the leading tube 7, a pair of small annular blades 13a, 13b having an outer diameter substantially equal to the leading tube 7 and having a semi-annular or semi-circular shape are opposed to each other and inclined in the direction of inclination. It is characterized by being fixed in the opposite manner.

[0007]

Embodiments of the present invention will be described below with reference to the drawings. 1 to 4 show the first embodiment, and FIGS. 5 to 8 show the second embodiment.

First, a first embodiment will be described.
1 to 3, reference numeral 1 denotes a steel pipe which forms a main body of the steel pipe pile of the present invention, and an open lower end surface thereof is formed in a spiral shape 2 a, and a spiral pitch is provided between a start end and an end of the spiral. Is formed at a height corresponding to the height. The helical 2a of the steel pipe 1 has a lower end formed substantially spirally and having an outer diameter of about 1.5 to 2 times the diameter of the steel pipe 1 and an inner diameter of about 1/2 of the diameter of the steel pipe 1. A spiral screw blade 5 having a large width is fixed by welding at an intermediate portion of the blade width, and an outer blade portion 5a protruding outward from the steel pipe 1 and an inner blade portion 5b protruding inward are formed. Gaps 6a, 6 each having a height corresponding to the pitch of the spiral blade 5 are provided between each start and end.
b is formed.

At the lower end of the steel pipe 1, a leading cylinder 7 having a diameter in contact with the inner periphery of the spiral blade 5 projects downward from the lower part of the spiral blade 5 by a considerable length, and is fixedly provided by welding. .
At the lower end of the leading tube 7, a small-diameter spiral blade 8a having an outer diameter substantially the same as the diameter of the leading tube 7 is provided so as to extend over substantially one turn, and a small-diameter spiral blade 8a is provided on the inner periphery of the small-diameter spiral blade 8a. Through hole 9
Is formed, and a gap 10 having a height corresponding to the pitch is formed between the start end and the end of the small diameter spiral blade 8a.

When the steel pipe pile is buried, the steel pipe pile is erected on the ground, and a drive device (not shown) for rotating and pushing is attached to the head of the steel pipe pile. And push it into the ground. Thereby, first, the internal spiral blade 8 at the leading end of the leading cylinder 7 cuts into the ground and excavates, and the earth and sand flows into the leading cylinder 7 through the through holes 9 and the gaps 10 and is sent upward. Will be.

Next, the large-diameter spiral wing 5 at the lower end of the steel pipe is cut into the ground outside the leading tube 7 and is screwed by the reaction force of the ground acting on the upper surface of the spiral wing 5, so that the penetration is promoted. . The earth and sand entering the gap 6a of the outer wing portion 5a in the gap between the start end and the end of the spiral wing 5 is compacted to the surrounding ground while sliding on the spirally inclined wing upper surface. On the other hand, the sediment that has entered the gap 6b of the inner wing portion 5b flows into the steel pipe 1, merges with the sediment that has flowed in from the lower end of the front pipe 7, and is sent upward.

FIG. 4 shows another embodiment in which a small-diameter spiral blade is provided. In this embodiment, a small-diameter spiral blade 8b having no through hole 9 as in the small-diameter spiral blade 8a is used. That is, the spiral blade 8b is formed in a disk shape, a cut is formed at one location from the center to the outer periphery in the radial direction, and both ends are staggered up and down to form a gap 10. Therefore, the same function as the spiral wing occurs as a whole, and the ground is excavated by rotation, and the earth and sand flows into the cylinder 7 from the gap 10,
Will be sent.

Next, a second embodiment will be described. In FIGS. 5 to 7, reference numeral 1 denotes a steel pipe which forms a main body of the steel pipe pile, and its open lower end is formed in a stepped portion 3b, 3b with a connecting portion of the mounting surfaces 2b, 2b inclined in opposite directions each other at half a circumference. Have been. The outer diameter of the steel pipe 1 is
A large-diameter, wide-width semi-annular blade plate 11, 11 having an inner diameter of approximately 1.5 to 2 times the diameter of the steel pipe 1 is approximately 1.5 to 2 times the diameter of the steel pipe 1, and an intermediate portion of the blade width is provided with steps 3a, 3a. It is fixed by welding in contact with the mounting surfaces 2b, 2b therebetween. As a result, the two wing plates 11,
Gaps 12a and 12b are formed between both ends of an outer wing portion 11a protruding outward from the steel pipe 1 of 11 and an inner wing portion 11b protruding inward due to a stagger in the height direction.

The lower end of the steel pipe 1 has two wing plates 11, 11.
A leading cylinder 7 having a diameter in contact with the inner periphery of the upper part projects downward from the blade plate 11 by a considerable length below the lower part thereof, and is vertically provided by welding. At the lower end of the leading tube 7, a pair of semi-annular wing plates 13a, 13a are opposed to each other and are fixed to each other inclining in the body direction. Holes 14 are formed, and gaps 15, 15 are formed between the ends of the two wing plates 13a, 13a due to staggers in the height direction.

When the steel pipe pile is buried, the steel pipe pile is erected on the ground, and a drive device (not shown) for rotating and pushing is attached to the head of the steel pipe pile. And push it into the ground. Thereby, first, the small wing plate 13a at the leading end of the leading cylinder 7 is cut into the ground and excavated, and the earth and sand flows into the leading cylinder 7 from the through holes 14 and the gaps 15 and is sent upward. Will go.

Next, the large-diameter vane plate 11 at the lower end of the steel pipe is cut into the ground outside the leading tube 7, and is screwed by the reaction force of the ground acting on the upper surface of the vane plate, whereby the penetration is promoted. The outer wing portion 11 of the pair of wing plates 11
The earth and sand entering the gaps 12a, 12a between the a, 11a are compacted to the surrounding ground while sliding on the upper surfaces of the inclined outer wings 11a, 11a. On the other hand, the sediment that has entered the gaps 12b, 12b between the inner wings 11b, 11b flows into the steel pipe 1,
It merges with the earth and sand that has flowed in from the lower end of the front pipe 7 and is sent upward.

FIG. 4 shows another embodiment in which a small wing plate is provided. In this embodiment, the small wing plate 13
a, small wing plate with no through hole 14 as in 13a
13b, 13b. That is, the small wing plate 13b has a substantially semicircular shape and is provided so as to oppose each other so that they are in contact with each other at the center with their inclination directions being opposite to each other. Is formed. In this case, the earth and sand excavated by the small blade plates 13b, 13b due to the rotation flows into the leading cylinder 7 through the gap 15 and is sent.

[0018]

As described above, the screw-in type steel pipe pile according to the present invention has a large-diameter spiral wing having a large wing width extending inside and outside the steel pipe, or extending inside and outside the steel pipe at the lower end of the steel pipe as the pile body. A pair of large-diameter semi-annular blades having a wide wing width are provided in opposite inclination directions to each other, and are fixed to the inner periphery of the spiral blades or the blades, and a lead having a small-diameter spiral blade or a pair of blades is provided. Since the tube is vertically provided, there are many excellent effects as described below.

(1) By penetrating the spiral wings or wing plates into the ground, the pile can be penetrated and propelled by simply rotating the pile with a small pressing force, and the pile can be buried without soil removal.

(2) Prior to the penetration of the steel pipe as the pile body,
Notch and excavation into the ground by the inner wing of the leading cylinder and inflow of the earth and sand into the leading pipe are performed, and the earth and sand excavated by the incision of the inner wing of the spiral wing flows into the steel pipe. And can be buried reliably and easily even on hard ground.

(3) Since the leading tube projects below the spiral blade, the straight running stability at the time of penetration is good.

(4) Since the lower end after embedding can be kept almost closed by the inner wing portion and the small-diameter spiral wings or vane plates of the leading cylinder, the large-diameter spiral wings or A large bearing capacity corresponding to the entire area under the outer diameter of the blade is obtained.

(5) The spiral blade or blade plate is fixed to the steel pipe at the center of the blade width, and the leading tube is fixed to the inner periphery thereof, so that the overall strength and rigidity are increased. Is large, and sufficient resistance to screw penetration and pile supporting force can be obtained.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a first embodiment of a steel pipe pile of the present invention.

FIG. 2 is a longitudinal sectional view of the main part.

FIG. 3 is a perspective view showing a lower end surface of the steel pipe.

FIG. 4 is a perspective view of a main part showing another embodiment.

FIG. 5 is a perspective view showing a second embodiment of the steel pipe pile of the present invention.

FIG. 6 is a longitudinal sectional view of the main part.

FIG. 7 is a perspective view showing a lower end surface of the steel pipe.

FIG. 8 is a perspective view of a main part showing another embodiment.

[Explanation of symbols]

 Reference Signs List 1 steel pipe 2a spiral surface 2b inclined mounting surface 3a, 3b step 5 spiral blade 5a outer blade 5b inner blade 6a, 6b gap 7 leading cylinder 8a, 8b small diameter spiral blade 9 through hole 10 gap blade plate 11a outer blade 11b Inner wing 12a, 12b Clearance 13a, 13b Small diameter blade

Claims (2)

[Claims] At least one spiral wing having an outer diameter larger than the diameter of the steel pipe and an inner diameter smaller than the diameter of the steel pipe is fixed to a lower end of the steel pipe forming the main body of the pile. A small-diameter spiral blade that is fixed to the inner periphery of the spiral blade and protrudes downward therefrom is overlapped, and the outer diameter of the spiral tube is substantially the same as that of the leading tube at the lower end thereof. Screw-in type steel pipe pile characterized by having provided. 2. A pair of semi-annular blades having an outer diameter greater than the diameter of the steel pipe and an inner diameter smaller than the diameter of the steel pipe are opposed to each other at the lower end of the steel pipe forming the main body of the pile, and the inclination directions thereof are opposite to each other. And a leading cylinder fixed to the inner periphery of the wing plate and projecting downward therefrom, and a semicircular ring having an outer diameter substantially equal to that of the leading cylinder at the lower end of the leading cylinder. Alternatively, a screw-in type steel pipe pile is characterized in that a pair of small-diameter blades having a semicircular shape are fixed to face each other with their inclination directions opposite to each other.