JP2002167757A - Execution method of foundation pile - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an execution method of a foundation pile for wholly eliminating surplus soil discharged on the ground, and remarkably enhancing bearing power of the foundation pile. SOLUTION: In this execution method of the foundation pile, a screw blade 3 is projected on an outer peripheral surface, an expanding excavating head 2 having a pair of opening windows 4 bored in an outer peripheral wall is arranged on the lower end of the foundation pile 1, an agitating rod 5 having a pair of span expanding claws 7 expandably installed in a lower part is inserted into the foundation pile 1 and the expanding excavating head 2, span expanding claws 6 are inserted into the opening windows 4 of the expanding excavating head 2, the expanding excavating head 2 is connected to the agitating rod 5, boring is advanced in the ground while rotating the agitating rod 5 and the expanding excavating head 2, most of excavating earth excavated by the screw blade 3 is compacted to the inner periphery of an excavating hole 13, a small quantity of residual surplus soil is housed in a hollow part between the expanding excavating head 2 and the foundation pipe 1, and the foundation pile 1 and the expanding excavating head 2 are buried in the ground.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a construction method for burying a foundation pile in the ground, and more particularly to a method for excavating the ground and consolidating most of the excavated soil around a drilled hole. The present invention relates to a method for constructing a foundation pile capable of burying a foundation pile in the ground together with an enlarged excavation head capable of providing a large bearing capacity to the pile.

[0002]

2. Description of the Related Art As a conventional method of constructing a foundation pile of this kind, a middle moat method or an outer moat method, which is excellent in no vibration and no noise, has been generally carried out.

[0003] Since both the middle and outer excavation methods are construction methods in which the foundation pile is buried in the ground while excavating the ground and excavating the excavated soil on the ground, Since a large amount of soil is discharged, and such soil is turned into industrial waste, it is difficult to dispose of it, and it is difficult to secure a dump site, which has become a major social problem.

[0004] Furthermore, in these middle and outer moat methods, there is a problem that it is difficult to obtain a large supporting force on the basic pile because a head or the like cannot be attached to the tip of the basic pile.

[0005] In order to improve the drawbacks of the above-mentioned conventional middle and outer excavation methods, recently a method of rotating and burying steel pipe piles using a steel pipe pile and burying the steel pipe pile in the ground while rotating the steel pipe pile has been proposed. It has come to practical use.

[0006]

However, this method of rotating and burying steel pipe piles is a method of digging and embedding steel pipe piles in the ground while chucking the head of the steel pipe piles and rotating the steel pipe piles. Therefore, there is no excavated soil discharged to the ground. Therefore, there is a score that can solve all the problems of the above-mentioned middle moat method and outer moat method, but on the other hand, the following problems have occurred.

[0007] That is, the above-mentioned method of rotating and burying steel pipe piles is as follows.
Since the head of the steel pipe pile is chucked and a large force is applied to forcibly rotate the steel pipe pile, the steel pipe pile may be twisted, and eventually the steel pipe pile may be damaged or damaged. there were. In addition, when constructing steel pipe piles, there is no earth removal when excavating the steel pipe piles, so the ground resistance is extremely large,
Therefore, the reaction force due to the rotary burial of the steel pipe pile is increased, and there is also a problem that the construction cannot be performed unless an unnecessarily large construction machine is used.

The method for constructing a foundation pile according to the present invention is a completely new technique developed in view of the above-mentioned many problems in the prior art. Place the foundation pile on the enlarged excavation head with a large outer diameter, rotate the enlarged excavation head with a stirring rod, excavate the ground and consolidate most of the excavated soil to the peripheral surface of the hole, and after the consolidation It is an object of the present invention to provide a completely new foundation pile construction method capable of storing the remaining soil in the hollow portion of the enlarged excavation head and the foundation pile and burying the foundation pile together with the enlarged excavation head.

[0009]

SUMMARY OF THE INVENTION The method for constructing a foundation pile according to the present invention is an invention which fundamentally improves on the problems of the conventional method for constructing a foundation pile described above, and the gist of the first invention is as follows. ,
Placing the foundation pile on an enlarged excavation head having an outer diameter of 1.5 to 2.5 times the outer diameter of the foundation pile and projecting a screw blade on the outer peripheral surface, and hollowing the foundation pile After connecting the stirring rod inserted into the section to the enlarged excavation head, the excavated soil is drilled on the peripheral surface of the excavation hole with the screw blade while excavating underground by rotating the enlarged excavation head via the stirring rod. A method for constructing a foundation pile, comprising compacting and storing a small amount of remaining soil in a hollow portion between the enlarged excavation head and the foundation pile, and burying the foundation pile together with the enlarged excavation head in the ground.

The method for constructing a foundation pile according to the first aspect of the present invention is characterized in that the foundation pile has an outer diameter of 1.5 to 2.5 mm below the foundation pile.
Since it is buried in the ground in a state where the enlarged excavating head having a double outer diameter is connected, a large supporting force can be given to the foundation pile.

Further, a screw blade is protruded from the outer peripheral surface of the enlarged excavation head, and the enlarged excavation head excavates in the ground while rotating with a stirring rod. Most of the excavated soil generated during the drilling can be compacted to the peripheral surface of the excavated hole by the screw blade. In addition, only a small amount of soil remaining unconsolidated on the peripheral surface of the excavation hole can be stored in the hollow portion between the enlarged excavation head and the foundation pile. Therefore, it is possible to completely prevent the excavated soil from being discharged to the ground.

The gist of the second invention of the method for constructing a foundation pile according to the present invention is that the foundation pile has an outer diameter 1.5 to 2.5 times the outer diameter of the foundation pile, and a screw blade protrudes from the outer peripheral surface. The foundation pile is placed on the enlarged drilling head, and a downhole hammer is attached to the lower part of the stirring rod, which can excavate the ground while rotating and compact the excavated soil, and is inserted into the foundation pile. After connecting the downhole hammer to the enlarged digging head, while rotating the downhole hammer and the enlarged digging head via a stirring rod, excavating underground,
The excavated soil is compacted to the peripheral surface of the excavated hole with the screw blade, and a small amount of remaining soil is compacted in the enlarged excavation head and the ground below it with a downhole hammer, and the enlarged excavated head and the foundation pile are placed underground. This is a method of constructing a foundation pile characterized by being buried.

In the second embodiment, the downhole hammer is attached to the lower portion of the stirring rod, and the downhole hammer is connected to the enlarged excavating head. Therefore, the downhole hammer is connected via the stirring rod and the downhole hammer. By rotating the enlarged excavating head, it is possible to excavate while excavating underground by the screw blade of the enlarged excavating head and the downhole hammer.

As described above, most of the excavated soil excavated by the screw blade and the downhole hammer can be compacted on the inner peripheral surface of the excavation hole by the screw blade. In addition, a small amount of soil remaining unconsolidated on the inner peripheral surface of the excavation hole can be finally compacted by the downhole hammer in the enlarged excavation head and on the ground below.

Therefore, when the construction method of the second invention is carried out, similarly to the construction method of the first invention, the excavated soil can be completely prevented from being discharged to the ground and buried in the ground. The ground around the enlarged excavation head can be compacted more firmly, and the bearing capacity of the foundation pile can be further strengthened.

The gist of the third invention of the method for constructing a foundation pile according to the present invention is to cover a steel pipe casing around the foundation pile and to connect a lower part of the steel pipe casing to the enlarged excavation head. A method for constructing a foundation pile according to the first invention or the second invention, characterized in that an enlarged excavation head and a foundation pile are buried in the ground while excavating underground by rotating an enlarged excavation head.

In the method for constructing a foundation pile according to the third aspect of the present invention, a steel pipe casing is coated around the foundation pile,
The steel pipe casing is connected to the enlarged drilling head, and the steel pipe casing is excavated in the ground while rotating together with the enlarged drilling head. Can be smoothed.

[0018]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view showing a construction method of a foundation pile according to the present invention.
FIGS. 1 (a) and 1 (b) are simplified explanatory diagrams of a main part of an apparatus used for carrying out the method for constructing a foundation pile according to the present invention, respectively.
FIGS. 3 (a), 3 (b) and 3 (c) are explanatory views of a case where a downhole hammer is attached to a lower portion of a stirring rod and used, and FIGS. 4 (a) to 4 (e) are simplified explanatory diagrams showing steps of a method for constructing a foundation pile according to the present invention, respectively.

1 (a), 1 (b) to 4 (a) to
In (e), 1 is a concrete foundation pile (pile)
And is formed in a hollow shape. Reference numeral 2 denotes a hollow enlarged excavating head, and a screw blade 3 is provided on an outer peripheral surface of the enlarged excavating head 2.

The outer diameter of the enlarged excavating head 2 (the outer diameter including the screw blade 3) is, for example, 1 mm for 600 mm.
It has an outer diameter of 1.5 to 2.5 times that of the foundation pile 1 so as to be 200 mm. A pair of opening windows 4 through which an enlarging nail, which will be described later, can be inserted is formed at an outer wall of the enlarged excavation head 2 at a corresponding position.

In the figure, reference numeral 5 denotes a stirring rod having a diameter capable of being inserted into the foundation pile 1 and the enlarged excavation head 2 and having a hollow inside for allowing air or oil to flow therethrough. Is formed.

Further, at the lower part of the stirring rod 5, expansion pawls 6 which can be freely expanded and contracted by a pneumatic device or a hydraulic device (not shown) are provided on both sides so as to protrude. Further, a tip screw blade 7 is attached to the lowermost end of the stirring rod 5.

In connecting the lower portion of the stirring rod 5 and the enlarged excavation head 2 to each other, particularly, as shown in FIG. 2 and then by operating the above-described pneumatic device or the like, the extension pawl 6 is extended outward and inserted into the opening window 4 provided in the enlarged excavation head 2.
The enlarged excavating head 2 can be connected to the stirring rod 5.

In the basic method of constructing a foundation pile according to the present invention, an enlarged excavating head 2 is rotated by rotating a stirring rod 5 using an apparatus configured as shown in FIG. To excavate underground to form excavation holes,
Most of the excavated soil excavated by the screw blade 3 of the enlarged excavation head 2 is compacted on the inner peripheral surface of the excavation hole 13, and a small amount of residual soil remaining during the consolidation is discharged to the ground via the stirring rod 5.

By continuing the work described above,
With the foundation pile 1 and the enlarged excavation head 2 dug to a certain depth in the ground, the expansion nail 6 provided at the lower part of the stirring rod 5 is contracted and pulled out from the opening window 4 to remove the stirring rod. 5 and the enlarged excavation head 2 are released.

In the above embodiment, an example was described in which a pair of expanding nails 6 and a tip screw blade 7 were attached to the stirring rod 5, but as shown in FIGS. 2 (a) to 2 (c), The construction method of the present invention is also carried out when a downhole hammer 8 is attached to the lower end of the stirring rod 5 and the downhole hammer 8 is provided with a pair of expanding claws 6 as described above. I can do it.

This downhole hammer 8 is manufactured and sold by Kowa Sangyo Co., Ltd. (Nishi-Kasugai, Aichi Prefecture). The downhole hammer 8 is rotated by a stirring rod or a motor, and the bottom of the hole is formed at the tip pit by compressed air. It is a tool that can excavate while hitting. In the embodiment of the present invention, the pair of expanding nails 6 are assembled at predetermined positions of the downhole hammer 8 so that the expanding nails 6 can expand and contract.

When the downhole hammer 8 is attached to the lower portion of the stirring rod 5 and the downhole hammer 8 is connected to the enlarged excavating head 2, the enlarged excavating head 2 is rotated while the stirring rod 5 is rotated. The underground is excavated with the screw blade 3 and the tip of the downhole hammer 8, and the excavated soil excavated with the screw blade 3 and the downhole hammer 8 is forcibly compacted into the inner peripheral surface of the excavation hole. You can excavate while digging.

Therefore, most of the excavated soil excavated as described above can be compacted on the inner peripheral surface of the excavation hole, and a small amount of unreacted soil is finally excavated by the downhole hammer 8. It can be compacted in the head 2 and the ground below it.

In the above embodiment, the construction method of the present invention was implemented without using a steel pipe casing. Next, an embodiment in which the construction method of the present invention is implemented using a steel pipe casing will be described in detail.

FIGS. 3A and 3B and FIGS.
In (e), reference numeral 9 denotes a steel pipe casing capable of covering around the foundation pile 1, and a pair of key grooves 10 are formed at corresponding positions on the lower end edge of the steel pipe casing 9. At a predetermined position on the outer peripheral surface of the enlarged excavation head 2, a pair of protrusions 11 that can be inserted into the key groove 10 are respectively provided at predetermined positions.

When the method for constructing a foundation pile according to the present invention is carried out by using the above-mentioned steel pipe casing 9, as shown in the figure, the steel pipe casing 9 covered around the foundation pile 1 is lowered and the steel pipe casing 9 is lowered. While covering the lower end portion of the casing 9 around the upper end portion of the enlarged excavation head 2, the key groove 10 of the steel pipe casing 9 and the projection 11 of the enlarged excavation head 2 are aligned with each other. By inserting the projection 11 into the bent innermost part of the key groove 10 by rotating the steel pipe casing 9 or the enlarged excavation head 2 in a predetermined direction, the steel pipe casing 9 and the enlarged excavation head 2 are rotated. Can be combined with each other.

Subsequently, as shown in FIGS. 4A to 4C, the enlarged excavation head 2 is excavated in the ground while rotating, so that the enlarged excavation head 2, the steel pipe casing 9 and the foundation pile 1 are fixed to each other. , That is, the lower part of the foundation pile 1 and the position where the enlarged excavation head 2 is inserted into the support layer ground 12. When the steel pipe casing 9 is used as described above, the steel pipe casing 9 can be excavated while being rotated together with the enlarged excavation head 2, so that the relationship between the steel pipe casing 9 and the soil on the peripheral surface of the excavation hole 13 can be cut off. Excavation between the enlarged excavation head 2 and the foundation pile 1 can be performed more smoothly.

As described above, when the construction method of the present invention is carried out, the screw blade 3
And the enlarged drilling head 2 is
Drilling underground while rotating with a screw blade 3
Most of the excavated soil excavated in the above can be compacted in the inner peripheral portion of the excavation hole 13.

The remaining small amount of excavated soil not compacted in the excavation hole 13 can be stored in the hollow portion of the enlarged excavation head 2 and the hollow portion of the foundation pile 1. Further, when the downhole hammer 8 is attached to the lower part of the stirring rod 5 as in the second embodiment, a small amount of soil that could not be compacted on the inner peripheral surface of the excavation hole is enlarged. It can be compacted in the hollow portion of the excavation head 2 and the ground below it.

Therefore, when the present invention is implemented, the excavated soil excavated by the screw blade 3, the tip screw blade 7 or the downhole hammer 8 of the enlarged excavating head 2 is not discharged to the ground at all, and The excavated soil can be compacted on the inner peripheral surface of the excavation hole 13 or can be stored inside the enlarged excavation head 2 and the foundation pile 1.

[0037]

According to the method for constructing a foundation pile according to the present invention, a ground excavation head having an outer diameter of 1.5 to 2.5 times the outer diameter of the foundation pile is connected below the foundation pile. Since it is buried inside, there is an effect that a large supporting force can be given to the foundation pile.

Further, a screw blade is projected from the outer peripheral surface of the enlarged excavating head, and the enlarged excavating head excavates underground while rotating with a stirring rod. Most of the excavated soil generated during the drilling can be compacted to the peripheral surface of the excavated hole by the screw blade. In addition, only a small amount of soil remaining unconsolidated on the peripheral surface of the excavation hole can be stored in the hollow portion between the enlarged excavation head and the foundation pile. Therefore, there is also an effect that the excavated soil can be completely prevented from being discharged to the ground.

In the construction method of the present invention, when the downhole hammer is attached to the lower part of the stirring rod and this downhole hammer is connected to the enlarged excavating head, the downhole hammer is connected via the stirring rod and the downhole hammer. By rotating the enlarged excavating head, it is possible to excavate while excavating underground by the screw blade of the enlarged excavating head and the downhole hammer.

As described above, most of the excavated soil excavated by the screw blade and the downhole hammer can be compacted on the inner peripheral surface of the excavation hole by the screw blade. In addition, a small amount of the remaining soil not compacted on the inner peripheral surface of the excavation hole has an effect that the downhole hammer can finally be compacted in the enlarged excavation head and the ground below the enlarged excavation head.

Therefore, when the downhole hammer is used in this manner, the excavated soil can be completely prevented from being discharged to the ground and buried in the ground, similarly to the above-mentioned basic construction method. Since the ground around the enlarged excavation head can be compacted more firmly, there is an effect that the supporting force of the foundation pile can be further strengthened.

When the steel pipe casing is covered around the foundation pile and the steel pipe casing is connected to the enlarged drilling head, and the steel pipe casing is excavated in the ground while rotating with the enlarged drilling head, the excavation is performed by the steel pipe casing. It can cut the resistance of the earth and sand around the hole,
This has the effect of making excavation smooth.

[Brief description of the drawings]

FIGS. 1 (a) and 1 (b) are simplified explanatory views of the main parts of an apparatus used for carrying out a method for constructing a foundation pile according to the present invention.

FIGS. 2 (a), (b) and (c) are explanatory views in the case where a downhole hammer is attached to a lower portion of a stirring rod and used.

FIGS. 3 (a) and 3 (b) are simplified explanatory views of main parts when a steel pipe casing is used in carrying out the method for constructing a foundation pile according to the present invention, respectively.

FIGS. 4A to 4E are simplified explanatory views showing steps of a method for constructing a foundation pile according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Foundation pile 2 ... Enlarged excavation head 3 ... Screw blade 4 ... Opening window 5 ... Stirring rod 6 ... Expansion jaw 7 ... Tip screw blade 8 ... Downhole hammer 9 ... Steel pipe casing 10 ... Key groove 11 ... Protrusion 12 ... Support Layer ground 13… Drilled hole

Continued on the front page (72) Inventor Takahiro Hayashi 5-27-9 Sendagaya, Shibuya-ku, Tokyo F-term in Toyo Asano Corporation (reference) 2D041 AA02 BA12 BA13 CA05 DB02 DB03 FA03 FA14 2D050 AA03 AA07 BB05 CA02 CB05 CB06 CB10 CB34 EE03

Claims (3)

[Claims] 1. The foundation pile is placed on an enlarged excavation head having an outer diameter of 1.5 to 2.5 times the outer diameter of the foundation pile and having a screw blade protruding on the outer peripheral surface, and After connecting the stirring rod inserted into the hollow part of the foundation pile to the enlarged excavation head, excavating excavated soil with the screw blade while excavating underground by rotating the enlarged excavation head via the stirring rod. The foundation pile is characterized in that it is compacted on the peripheral surface of the hole, and a small amount of remaining soil is stored in the hollow portion between the enlarged drilling head and the foundation pile, and the foundation pile is buried in the ground together with the enlarged drilling head. Construction method. 2. The foundation pile is mounted on an enlarged excavation head having an outer diameter of 1.5 to 2.5 times the outer diameter of the foundation pile and having a screw blade protruding on the outer peripheral surface. At the bottom of the stirring rod, a downhole hammer that can excavate the ground while rotating and compact the excavated soil is installed, and after connecting the downhole hammer inserted into the foundation pile to the enlarged excavation head, stirring is performed. While drilling in the ground by rotating the downhole hammer and the enlarged drilling head via a rod, the excavated soil is compacted to the peripheral surface of the drilled hole with the screw blade, and a small amount of remaining soil is left downhammer. A method for constructing a foundation pile, wherein the foundation pile is buried underground with the expanded drilling head compacted in the ground below the expanded drilling head. 3. A steel pipe casing is covered around the foundation pile and a lower portion of the steel pipe casing is connected to the enlarged drilling head, and the steel pipe casing and the enlarged drilling head are rotated to excavate while excavating in the ground. 3. The method according to claim 1, wherein the excavating head and the foundation pile are buried underground.