JP2001073365A - Screwed type steel pipe pile and embedding construction method therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To efficiently embed a screwed type steel pipe pile with a blade having large bearing power. SOLUTION: A spiral blade 5 for screwing, having a broad width and a large diameter extending over the inside and outside of a steel pipe 1, is fixed at the lower end of the steel pipe 1, and a leading cylinder 7 is fixed onto the inner circumference of the spiral blade 5 and provided droopingly. When the steel pipe pile A is embedded at this time, an auger in which a screw having a small diameter is installed to a lower section is inserted into the steel pipe pile A, disposed upright on a ground, and the steel pipe pile A is rotational- pressed in, excavating the ground by the screw.

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 and a method of burying the pile.

[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 middle boring method, a method of screwing a rotary buried type with less vibration and noise is used. It has become. As the method of construction, Japanese Patent Publication No. Hei 2-62648 and Japanese Patent Laid-Open Publication No. Hei 8-226124 are known. The construction method of Japanese Patent Publication No. Hei 2-62648 uses a steel pipe pile with a spiral wing at the lower end of a main body with a bottom plate and an excavation blade at the lower end, and screw it into the ground to bury it. The construction method of Kaihei 8-226124 uses a pile with a spiral blade at the lower end of a steel pipe with an open end,
This is caused to settle by the application of a rotating force, and is characterized in that the sand provided in the lower portion of the steel pipe is closed with the earth and sand to form a support bottom.

[0003]

[Problems to be Solved by the Invention]
No. method has the advantage that steel pipe piles can be buried directly into the ground by rotary press-fitting.However, due to 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 00φ medium diameter and 700-1000φ. The method of Japanese Patent Application Laid-Open No. 8-226124 has the advantage that the penetration resistance is relatively small because a steel pipe pile with an open end is used, but the effect of closing the tip of the steel pipe pile is not sufficient, and a large support There is a problem that power cannot be expected.

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

[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. An outer diameter is larger than the diameter of the steel pipe, and an inner diameter is smaller than the diameter of the steel pipe. A protruding leading tube 7 is provided vertically.

In the steel pipe pile according to the present invention, a pair of semi-annular blades having an outer diameter larger than the diameter of the steel pipe and an inner diameter smaller than the diameter of the steel pipe are provided at the lower end of the steel pipe 1 forming the main body of the pile. 8, 8 and 8 are fixed to each other with the inclination directions thereof opposite to each other, and fixed to the inner periphery of the blades 8, 8, and a leading cylinder 7 protruding downward therefrom is vertically provided. It is.

In the burying method according to a third aspect of the present invention, a wide-width, large-diameter spiral blade 5 or a pair of wing plates 8, 8 having opposite directions of inclination are fixed to the lower end of the steel pipe 1. The steel pipe piles A and B having the leading cylinder 7 fixed to the inner periphery of the spiral wing 5 or the wing plates 8 and 8 and protruding downward therefrom are erected on the ground, and are inserted into the steel pipe piles A and B. A screw auger 10 having a small-diameter screw 12 attached to the tip of a rotating shaft 11 is provided by inserting the screw 12 into the leading tube 7 and projecting the leading end from the leading tube 7 to provide the steel pipe piles A and B and the screw auger. 10 is rotated and pressed, and following the excavation of the ground by the screw 12 and the penetration of the leading cylinder 7, the spiral blade 5 or the blade plate 8,
8 steel pipe pile by penetration promotion by screwing into the ground
A and B are buried.

[0008]

Embodiments of the present invention will be described below with reference to the drawings. 1 to 3 show a first embodiment of the steel pipe pile of the present invention, FIGS. 4 to 6 show other embodiments of the same, and FIGS. 7 and 8 show embodiments of the method of the present invention, respectively. Things.

1 to 3, reference numeral 1 denotes a steel pipe which forms the main body of the steel pipe pile A according to the first embodiment, the open lower end of which is formed on a single spiral surface 2a, and the spiral shape of the spiral pipe 2a. A step 3a having a height corresponding to the pitch of the spiral is formed between the start end and the end. The lower end surface 2a of the steel pipe 1 extends over substantially one turn, and has an outer diameter of approximately 1.5 times the diameter of the steel pipe 1.
A spiral wing 5 for screwing having a large wing width, whose inner diameter is approximately one half of the diameter of the steel pipe 1, is fixed by welding at an intermediate portion of the wing width, and is outside the steel pipe 1. Clearances 6a and 6b having a height corresponding to the pitch of the spiral blades 5 are formed between the start and end of the outwardly projecting outer wing 5a and the inwardly projecting inner wing 5b, respectively.

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 fixed and suspended by welding. ing.

In order to bury the steel pipe pile A having the above structure, the steel pipe pile A is erected on the ground, and a driving device for rotating and pushing the steel pipe pile A is attached to the head thereof. And push it into the ground. As a result, first, the preceding guide cylinder 7 is pushed into the ground, and the sediment immediately below the guide cylinder 7 flows into the guide cylinder 7.

Next, the spiral wing 5 having a large diameter at the lower end of the steel pipe is cut into the outer ground of the penetrated leading tube 7 and is screwed by the reaction force of the ground acting on the upper surface of the spiral wing 5. It will be promoted. The earth and sand entering the gap 6a of the outer wing portion 5a of 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 earth and sand entering the gap 6b of the inner wing portion 5b flows into the inside of the steel pipe 1, merges with the earth and sand flowing from the lower end of the leading pipe 7, and is sent upward according to the penetration of the steel pipe pile A. Will go.

Next, in FIGS. 4 to 6, reference numeral 1 denotes a steel pipe which forms the main body of the steel pipe pile B in the second embodiment, and its open lower end has a mounting surface 2b, which is inclined by half a circle in the opposite direction to each other. 2b, and the welded portion of each mounting surface 2b, 2b is formed in a step 3b, 3b. At the lower end of the steel pipe 1, a large-diameter, wide-width semi-annular wing 11, 11 having an outer diameter of about 1.5 to 2 times the diameter of the steel pipe 1 and an inner diameter of about half the diameter of the steel pipe 1 is provided. However, the middle part of the span is in contact with the mounting surfaces 2b, 2b between the steps 3b, 3b, and is fixed by welding. As a result, gaps 12a, 12a due to a stagger in the height direction are provided between both end edges of the outer wing portion 11a projecting outward from the steel pipe 1 of the two wing plates 11, 11 and the inner wing portion 11b projecting inward. 12b
Are formed.

[0014] At the lower end of the steel pipe 1, the blade 1
A leading cylinder 7 having a diameter in contact with the inner circumference of each of the first and the eleventh protrudes a lower portion thereof considerably below the re-blade plates 11 and 11 and is fixed and suspended by welding.

In order to bury the steel pipe pile B having the above structure, as in the case of the previous case, the steel pipe pile B is erected on the ground, and is pushed into the ground while being rotated so as to be screwed in. The cylinder 7 is pushed into the ground, and the earth and sand immediately below the cylinder 7 flows into the leading cylinder 7.

Next, a pair of blades 11, 11 at the lower end of the steel pipe are
The steel pipe pile is cut into the outer ground of the penetrated leading tube 7 and screwed in by the ground reaction force acting on the upper surfaces of the wing plates 11.
The intrusion of B is being promoted. Then, in the gap between the pair of blades 11, 11, the sediment that has entered the gaps 12a, 12a between the outer wings 11a, 11a is compacted into the surrounding ground while sliding on the upper surface of the inclined outer wing 11a. I will go. On the other hand, the sediment that has entered the gaps 12b, 12b between the inner wing portions 11b, 11b flows into the steel pipe 1, merges with the sediment flowing from the lower end of the leading tube 7, and moves upward according to the penetration of the steel pipe pile B. Will be sent to

In the case of the steel pipe pile B, a pair of blades 11, 11
Cuts into the ground, the resistance at that time can be reduced, the rotation balance is good, and the straight running stability of the penetration is improved.

Next, a more preferable embedding method of the steel pipe pile A provided with the spiral blade 5 and the steel pipe pile B provided with the pair of blades 11, 11 will be described with reference to FIGS. Steel pipe pile
In the burial of A and B, a screw having a diameter small enough to pass through the leading tube 7 of the steel pipe piles A and B, and formed longer than the leading tube 7
A screw auger 10 having 12 attached to the tip of a rotating shaft 11 is used.

First, the steel pipe piles A and B are erected on the ground,
As shown in FIGS. 7 (a) and 8 (a), the screw 12 of the screw auger 10 is inserted into the leading tube 7, and the rotating shaft 11 is separated from the rotating pressing device (not shown) of the steel pipe piles A and B. (Not shown). Then, while keeping the tip of the screw 12 protruding from the lower end of the leading tube 7,
The steel pipe piles A and B and the screw 12 are rotated and pressed.

As a result, the ground is excavated by the screw 12 and the leading cylinder is pushed into the excavated earth and sand. Then, as shown in FIGS. 7 (b) and 8 (b), the spiral blade 5 or The blades 8, 8 cut into the unexcavated ground outside the preceding leading cylinder and are screwed in by the ground reaction acting on the upper surface of the spiral blade 5 or the blades 8, and the penetration of the steel pipe piles A, B is promoted. Will go. In this case, the earth and sand excavated by the screw 12 is transported upward in the leading cylinder 7 and flows into the steel pipe 1. Also, the earth and sand entering the gap 6b of the spiral wing 5 enters the steel pipe 1 and merges with the earth and sand of the former, and the earth and sand entering the gap 6a slides on the inclined wing surface and consolidates to the surrounding ground. become.

The steel pipe piles A and B penetrate through the screw
When the tip of the gas 12 reaches the support layer, the screw 12
7 is lifted up into the leading tube 7 to perform the operation shown in FIG.
As shown in FIG. 8C, the process is performed until the spiral blade 5 or the wing plate 8 bites into or reaches the support layer B. After the penetration is completed, the screw auger 10 is pulled out to complete the construction. In this case, the excavated soil C is filled in the steel pipes A and B, and the effect of closing the pile bottom is sufficiently exhibited by the consolidation due to its own weight, but it is possible to add cement milk injection etc. as necessary. it can. In addition, the penetration of the steel pipe piles A and B does not need to necessarily reach the lower end portion of the support layer.

[0022]

As described above, according to the threaded steel pipe pile of the present invention, a wide-width, large-diameter spiral wing or a pair of wing plates whose inclinations are opposite to each other is provided at the lower end of the steel pipe. Since the guide tube is provided so as to protrude downward, many excellent effects can be obtained as follows.

(1) The penetration of the spiral wings and wing plates into the ground enables the pile to be propelled simply by rotating the pile with a small pressing force, and the pile can be buried without discharging the soil.

(2) Prior to the penetration of the steel pipe as the pile body,
Since the leading pipe is pushed in, the earth and sand below the steel pipe flows into the leading pipe and the steel pipe, so that the penetration resistance is reduced and the straightness at the time of penetration is improved.

(3) The pile after being buried can maintain a closed state due to the clogging of the lower portion of the steel pipe with the inflow of earth and sand, and a large supporting force can be obtained over a large area of the large-diameter spiral blades and blade plates.

According to the embedding method of the present invention, the screw of the screw auger is used to screw the steel pipe pile into the ground while excavating the ground below the guide tube. With low resistance, it can be installed efficiently with low power, and even in relatively hard ground, the steel pipe pile can be easily screwed and buried.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing one embodiment of the steel pipe pile of the present invention.

FIG. 2 is a perspective view of the main part.

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

FIG. 4 is a longitudinal sectional view showing another embodiment of the steel pipe pile of the present invention.

FIG. 5 is a perspective view of the main part.

FIG. 6 is a perspective view showing a lower end surface of the steel pipe.

7 (a), (b), (c) are longitudinal sectional views sequentially showing aspects of burying the steel pipe pile of FIG.

8 (a), (b), and (c) are longitudinal sectional views sequentially showing the embedding work of the steel pipe pile of FIG.

[Explanation of symbols]

 A, B Steel pipe pile 1 Steel pipe 5 Spiral wing 5a Outer wing 5b Inner wing 6a, 6b gap 7 Leader cylinder 8 Wing plate 8a Outer wing 8b Inner wing 9a, 9b Gap 10 auger

Claims (3)

[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 threaded steel pipe pile fixed to an inner periphery of a spiral wing and having a leading tube projecting downward therefrom. 2. A pair of semi-annular wing plates having an outer diameter larger 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 pile body, and the inclination directions thereof are opposite to each other. A screw-in type steel pipe pile, characterized in that a leading tube fixed to the inner periphery of the blades and protruding downward therefrom is vertically installed. 3. A wide-width, large-diameter spiral blade or a pair of wing plates whose inclination directions are opposite to each other is fixed to the lower end of the steel pipe and fixed to the inner periphery of the spiral blade or the wing plate. A steel pipe pile with a downwardly projecting leading cylinder is placed upright on the ground, and in the steel pipe pile, a screw auger with a small diameter screw attached to the tip of the rotating shaft is inserted into the leading cylinder. The tip is provided so as to protrude from the leading cylinder, and the steel pipe pile and screw auger are rotated and pressed,
Following excavation of the ground with a screw and penetration of the leading cylinder,
A method of burying a screw-in type steel pipe pile, wherein the steel pipe pile is buried by piercing the spiral wings or wing plates into the ground by screwing.