JPH11247189A - Spliced pile structure made of steel pipe - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a spliced pile structure, in which large frictional force can be taken even to a weak ground in the vicinity of a ground surface and which has small penetration resistance and can be executed easily. SOLUTION: The spliced pile structure made of a steel pipe has a lower pile 1b, in which at least a bottom plate 2 and excavation pawls 3 are in stalled to a lowermost end section, at least one spiral collar 4 is mounted on an outer circumferential surface and the diameters of the spiral collars 4 and equalized and which is made of the steel pipe. The spliced pile structure is composed of the lower pile 1b and upper pile 1a, in which at least one spiral collar 4 is set up on the outer circumferential surface, the diameter of the spiral collar 4 is made the same as or lager than the that of the spiral collar 4 fitted to the lower pile 1b and the diameter of at least one of the spiral collars 4 is made larger than those of the spiral collars 4 installed to the lower pile 1b and which is made of the steel pipe.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a steel pipe pile used as a foundation pile for civil engineering and building structures,
In particular, the present invention relates to a joint pile structure of a steel pipe pile with a helical collar constructed by a twisting method.

[0002]

2. Description of the Related Art When constructing a pile, a method of statically twisting the pile is known to solve the problem of noise and vibration, and various pile materials have been devised. I have. A steel pipe is often used as a pile material because it has sufficient material strength against the torsional torque generated by the twisting. In order to improve the penetration of the steel pipe into the ground and to increase the frictional force with the ground,
There is an example in which a plurality of collars are provided in the middle of a pile. These are disclosed in, for example, Japanese Utility Model Publication No. 4-19080, Japanese Utility Model Publication No. 7-2677, and Japanese Patent Application Laid-Open No. Hei 5-31649.

The above-mentioned known technique will be briefly described. In Japanese Utility Model Publication No. 4-19080, an excavating blade is provided at a lower end, and is spaced from the lower end of the pile main body by a distance of 1/2 to twice the diameter of the pile main body. Helical wings of the same diameter with a large wing span, each having an outer diameter approximately twice as large as the outer diameter of the pile main body, are respectively wound around the outer peripheral surface of the pile main body at the upper position and at a predetermined distance above the pile main body. Are disclosed.

[0004] In Japanese Utility Model Publication No. Hei 7-2677, the outer diameter of the steel pipe pile main body to which the excavation blade is attached has an outer diameter that is approximately two to three times the outer diameter of the steel pipe pile main body over substantially the entire length thereof. A configuration is disclosed in which spiral wings having a pitch of approximately one-fourth and extending over substantially one turn are protruded at equal intervals of a multiple of the pitch of the spiral wings. JP-A-5-3116
In Japanese Patent Publication No. 49, a bottom plate and an excavating blade are provided at the lower end of the steel pipe pile main body, and the outer peripheral surface of the steel pipe pile main body is provided at substantially equal intervals in the length direction thereof, at least twice the outer diameter of the steel pipe pile main body. A spiral wing for screwing over approximately one turn with a diameter of
In addition, a configuration is disclosed in which the outer diameter of the separated spiral wings is increased at a constant rate toward the upper part.

In general, the ground near the ground surface has a younger geological age, and has a lower mechanical strength than a deeper stratum. In this regard, the above-described known technology has the following problems. That is, actual fairness 4-190080
In the technology disclosed in the publication, the spiral wings provided in the middle of the pile all have the same diameter, so that the frictional force near the ground surface becomes relatively smaller than the frictional force obtained at a position with a large depth, Speaking of the geological strata near the surface, it was hard to say that even with the spiral wings, the spiral wings were sufficiently effective.

The technique disclosed in Japanese Utility Model Publication No. Hei 7-2677 has a feature that the spiral blades are always twisted along the same trajectory because the interval between the spiral blades is a multiple of the pitch of the spiral blades. Since all the wings have the same diameter, the same problem as in the above-mentioned Japanese Utility Model Publication No. 4-19080 has occurred. JP-A-5-31164
In the technology disclosed in JP-A-9, the diameter of the spiral wing provided on the pile is
As the diameter increases as it goes upward, the friction force can be increased as it goes upward, but since the whole becomes wedge-shaped and penetrates into the ground, the penetration resistance is large, Sometimes it was difficult. further,
In order to increase the diameter of the spiral blade from the bottom to the top at a fixed rate, the dimensions of the spiral blade differ from one sheet to another, making the processing of the spiral blade and mounting to the pile complicated, which is impractical for practical use. It was appropriate.

[0007]

According to the present invention, a large frictional force can be taken even on a weak ground near the ground surface,
An object of the present invention is to provide a joint pile structure having a small penetration resistance and easy construction.

[0008]

Means for Solving the Problems The present inventor has made studies as a result of solving the above problems, and has accomplished the present invention. That is, the present invention provides (A) a bottom plate that closes at least the tip of a pile at the lowermost end, a drilling claw, and at least one spiral collar on an outer peripheral surface; A lower pile made of steel pipe having the same diameter of the brim, and (B)
At least one helical collar is provided on the outer peripheral surface, the diameter of the helical collar is equal to or larger than the diameter of the helical collar provided on the lower pile, and the helical collar is provided. A steel pipe joint pile structure comprising a steel pipe upper pile in which at least one diameter of the collar is larger than the diameter of the spiral collar provided on the lower pile.

In the present invention, it is necessary that at least one of the helical collars provided on the upper pile has a diameter larger than that of the helical collar provided on the lower pile. Usually, the diameter is preferably as large as about 10 to 50%. Further, an intermediate pile may be provided between (A) the lower pile and (B) the upper pile, and the intermediate pile may not be provided with a spiral collar. When a spiral collar is provided on the intermediate pile, a spiral collar having the same diameter as the lower pile is preferable.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an example of a joint pile structure according to the present invention will be described with reference to the drawings. FIG. 1 is an elevation view of an example of the joint pile structure of the present invention. The pile body 1 is made of a steel pipe. FIG. 1 shows an example in which an upper pile 1a and a lower pile 1b are configured. The piles are connected by a joint 6.
The connection of the piles is generally performed by arc welding, but a method of mechanically connecting with a threaded joint or the like has also been devised.

At the tip of the lower pile 1b, a bottom plate 2, an excavating claw 3, and a spiral collar 4 are attached. The bottom plate 2 is attached so as to close the tip of the pile in order to secure the tip supporting force of the pile. The outer diameter of the helical collar 4 is about twice the outer diameter of the pile body. Spiral collars 4 are attached at predetermined intervals in the middle of the pile. Spiral collar 4
The doughnut-shaped iron plate whose one end is open is twisted to form a substantially spiral shape, and is joined to the pile body by welding. The outer diameter of the spiral flange 4 attached to the lower pile 1b is the same. The diameter of the spiral collar 5 attached to the upper pile 1a is larger than the diameter of the spiral collar attached to the lower pile.

FIG. 2 shows another example.
An example is shown in which a part of the spiral collar attached to a has the same diameter as that attached to the lower pile. The helical collar attached to the upper pile 1a may be of various sizes as long as it is larger than the helical collar attached to the lower pile. FIG. 3 shows still another example.
An example in which an intermediate pile 1c exists between the upper pile 1a and the lower pile 1b is shown. A plurality of intermediate piles 1c can be used as necessary. Although not shown, the lower pile may be provided with a helical collar at only one position at the lowermost end. The spiral collar 4 of the upper pile may be omitted.

In constructing the pile having the structure of the present invention, the lower pile is erected at a predetermined center of the pile, and then a turning force is applied by a construction machine to twist the pile into the soil. Normal,
In order to connect and use a plurality of piles, as described above, the next pile is connected and buried by arc welding or a threaded joint. Finally, the upper pile used at the top is connected and buried, and the construction is completed. The helical collar attached to the upper pile has a larger outer diameter than the helical collar attached to the lower pile, but is also screwed into the ground by rotational force. It is.

[0014]

The joint pile structure of the present invention exhibits the following excellent effects. (1) The spiral collar of the upper pile installed near the ground surface,
Since it has a larger diameter than the spiral flange of the pile below it, it can take a large frictional force even near the ground surface. (2) It is sufficient that the diameter of the spiral collar is increased only in the upper pile portion, and there is no need to gradually increase the diameter from bottom to top. Therefore, the penetration resistance of the pile is reduced, and the construction is facilitated. Furthermore, the processing of the helical collar is simpler than the case where the helical collar is enlarged at a fixed rate, and the manufacture of the pile is simplified.

[Brief description of the drawings]

FIG. 1 is an elevation view of an example of a joint pile structure according to the present invention.

FIG. 2 is an elevation view of another example of the joint pile structure of the present invention.

FIG. 3 is an elevation view of an example of a joint pile structure having an intermediate pile in the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Pile main body 1a Upper pile 1b Lower pile 1c Intermediate pile 2 Bottom plate 3 Drilling claw 4 Helical collar 5 Helical collar (large diameter) 6 Joint part

Claims (2)

[Claims] (A) A bottom plate for closing at least a tip end of a pile and an excavation claw are provided at a lowermost end portion, and at least one spiral collar is provided on an outer peripheral surface, and the spiral collar is provided. Lower pile made of steel pipes having the same diameter, and (B)
At least one helical collar is provided on the outer peripheral surface, the diameter of the helical collar is equal to or larger than the diameter of the helical collar provided on the lower pile, and the helical collar is provided. A steel pipe joint pile structure comprising a steel pipe upper pile in which at least one diameter of the collar is larger than the diameter of the spiral collar provided on the lower pile. 2. The steel pipe joint pile structure according to claim 1, further comprising an intermediate pile between (A) a lower pile and (B) an upper pile.