JP2002167759A - Execution method of foundation pile - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an execution method of a foundation pile for remarkably reducing 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, a screw auger 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, the span expanding claws 7 are inserted into the opening windows 4 of the expanding excavating head 2, the expanding excavating head 2 is connected to the screw auger 5, boring is advanced in the ground while rotating the expanding excavating head 2 by the screw auger 5, 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 discharged on the ground via the screw auger 5, cement milk is injected from a lower part of the screw auger 5, and the foundation pile 1 and the expanding excavating head 2 are joined.

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 screw auger and excavate underground while consolidating most of the excavated soil to the surrounding surface of the hole, and after the consolidation An object of the present invention is to provide a completely new foundation pile construction method capable of discharging residual soil to the ground by a screw auger and burying the foundation pile together with an enlarged drilling head in the ground.

[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 screw auger inserted in the part to the enlarged excavation head, the excavated soil is excavated on the peripheral surface of the excavation hole with the screw blade while rotating the enlarged excavation head through the screw auger to excavate underground. This is a method for constructing a foundation pile, which comprises compacting and discharging a small amount of residual soil after compaction to the ground by a screw auger, and burying the foundation pile together with an 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 protrudes from an outer peripheral surface of the enlarged excavation head, and the enlarged excavation head excavates underground while rotating with a screw auger. Most of the excavated soil generated during the drilling can be compacted to the peripheral surface of the drilled hole with a screw blade, and only a small amount of residual soil not compacted to the peripheral surface of the drilled hole can be discharged to the ground by a screw auger. I can do it. Therefore, the amount of residual soil discharged to the ground can be extremely reduced.

[0012] The gist of the second invention of a method for constructing a foundation pile according to the present invention is to cover a steel pipe casing around the foundation pile and connect a lower portion of the steel pipe casing to the enlarged excavation head. A method for constructing a foundation pile according to the first invention, characterized in that the enlarged drilling head and the foundation pile are buried in the ground while excavating underground by rotating the enlarged drilling head.

In the method for constructing a foundation pile according to the second 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.

The gist of the third aspect of the method for constructing a foundation pile according to the present invention is that the enlarged drilling head and the foundation pile are buried in the ground, and then cement milk is injected into the drilled hole to perform the enlarged drilling. A method for constructing a foundation pile according to the first invention or the second invention, characterized in that a head and a foundation pile are integrally connected and a root is fixed around a lower end portion of the foundation pile.

In the method for constructing a foundation pile according to the third aspect of the present invention, cement milk is injected into an excavation hole and solidified after the enlarged excavation head and the foundation pile are buried in the ground. The foundation pile and the enlarged excavation head can be integrally connected to each other via the cement milk.
As a result, the lower end of the foundation pile can be solidified and the bearing capacity of the foundation pile can be significantly improved.

[0016]

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.
(A) and (b) are simplified explanatory views of a main part when a steel pipe casing is used in carrying out the method for constructing a foundation pile according to the present invention, and FIGS. 3 (a) to 3 (e) respectively show the present invention. It is a simplified explanatory view showing a process of a construction method of a foundation pile.

1 (a), 1 (b) to 3 (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 (outer diameter including the screw blade 3) of the enlarged excavating head 2 is, for example, 1 mm per 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 screw auger, which has a diameter capable of being inserted into the foundation pile 1 and the enlarged excavation head 2 and through which oil, air or cement milk flows. And a screw blade 6 protrudes from the outer peripheral surface thereof.

Further, at the lower portion of the screw auger 5, expansion pawls 7 which can be freely expanded and contracted by a hydraulic device or the like (not shown) are provided on both sides to protrude. Further, a tip screw blade 8 is attached to the lowermost end of the screw auger 5.

In connecting the lower portion of the screw auger 5 and the enlarged excavating head 2 to each other, particularly, FIG.
As shown in (b), the pair of expansion pawls 7 are inserted into the enlarged excavation head 2 in a contracted state, and then the above-described hydraulic device or the like is operated to extend the expansion pawls 7 outward. Through the opening window 4 provided in the enlarged excavation head 2. As a result, the enlarged excavating head 2 is connected to the screw auger 5
Can be combined with

In the basic method for constructing a foundation pile according to the present invention, the screw auger 5 is rotated by using an apparatus configured as shown in FIG.
The excavation head 2 and the tip screw blade 8 excavate underground to form a drill hole, and most of the excavated soil excavated with the screw blade 3 of the enlarge drill head 2 is compacted on the inner peripheral surface of the drill hole 13. In addition, a small amount of soil remaining during the consolidation is discharged to the ground via the screw auger 5.

By continuing the work described above,
With the foundation pile 1 and the enlarged excavation head 2 excavated to a certain depth in the ground, the expansion nail 7 provided at the lower portion of the screw auger 5 is contracted and pulled out from the opening window 4 to remove the screw auger. 5 and the enlarged excavation head 2 are released.

Subsequently, using a hollow portion of the screw auger 5, cement milk (not shown) is filled into the excavation hole 13 from the lower portion thereof, and the cement milk is solidified to thereby form a foundation pile via the cement milk. 1 and the enlarged excavation head 2 can be integrally connected to each other.

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

FIGS. 2 (a) and 2 (b) 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 FIG. 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. 3 (a) to 3 (c), the enlarged excavation head 2 is excavated in the ground while rotating, and the enlarged excavation head 2, the steel pipe casing 9 and the foundation pile 1 are fixed to each other. , That is, a position where the lower part of the foundation pile 1 and the enlarged excavation head 2 are 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.

In the state shown in FIG. 3C, the cement milk is poured into the excavation hole 13 from the lower part of the screw auger 5. After the pouring of the cement milk is completed, FIG.
As shown in (d) and (e), by raising the steel pipe casing 9 while rotating the steel pipe casing 9 or the enlarged excavation head 2 in a predetermined direction, the protrusions 11 from the key grooves 10 are formed.
And the steel pipe casing 9 and the screw auger 5 are removed from the foundation pile 1 to complete the construction method according to the present invention.

As described above, when the construction method of the present invention is carried out, the screw blade 3
In addition, since the excavation head 2 is excavated in the ground while rotating the enlarged excavation head 2 with the screw auger 5, most of the excavated soil excavated with the screw blade 3 can be compacted in the inner peripheral portion of the excavation hole 13.

A small amount of the remaining excavated soil not compacted in the excavation hole 13 is discharged to the ground through the foundation pile 1 by the screw auger 5. Therefore, when the construction method of the present invention is carried out, the remaining soil is discharged to the ground in a very small amount, so that the processing of the remaining soil can be carried out without much trouble and cost.

Further, when the present invention is implemented, an enlarged excavation head 2 having a larger outer diameter than the foundation pile 1 can be installed at the lower end of the foundation pile 1, so that the supporting force of the foundation pile 1 is increased. You can do it. Furthermore, when cement milk is injected into the drill hole 13, the cement pile allows the foundation pile 1 and the enlarged excavation head 2 to be integrally connected to each other, whereby the bearing capacity of the foundation pile 1 is increased. Can be greatly enhanced.

[0033]

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.

A screw blade protrudes from an outer peripheral surface of the enlarged excavation head. The enlarged excavation head excavates underground while rotating with a screw auger. Most of the excavated soil generated during the drilling can be compacted to the peripheral surface of the drilled hole with a screw blade, and only a small amount of residual soil not compacted to the peripheral surface of the drilled hole can be discharged to the ground by a screw auger. I can do it. Therefore, there is also an effect that the amount of residual soil discharged to the ground can be extremely reduced.

In practicing the present invention, a steel pipe casing is coated around the foundation pile, and the steel pipe casing is connected to the enlarged drilling head. In the case of excavation, the resistance of the earth and sand around the excavation hole can be cut off by the steel pipe casing, which has the effect of making excavation smooth.

Further, when cement milk is injected into the excavation hole and solidified after the enlarged excavation head and the foundation pile are buried in the ground, the foundation pile and the foundation pile are connected via the cement milk. The enlarged drilling head can be integrally connected to each other. This has the effect of solidifying the periphery of the lower end of the foundation pile and significantly improving the support force of the foundation pile.

[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) and 2 (b) are simplified explanatory views of a main part when a steel pipe casing is used in carrying out a method for constructing a foundation pile according to the present invention, respectively.

FIGS. 3A to 3E 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 ... Screw auger 6 ... Screw blade 7 ... Expansion nail 8 ... Tip screw blade 9 ... Steel pipe casing 10 ... Key groove 11 ... Projection 12 ... Support layer Ground 13… Drilled hole

 ──────────────────────────────────────────────────の Continuing on the front page (72) Inventor Takahiro Hayashi 5-27-9 Sendagaya, Shibuya-ku, Tokyo F-term in Toyo Asano (reference) 2D041 AA02 BA12 BA13 BA35 CA05 DB03 FA14 2D050 AA07 AA16 BB02 BB05 CA05 CB05 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 screw auger inserted into the hollow portion 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 screw auger. A method of constructing a foundation pile, comprising compacting the periphery of a hole, discharging a small amount of soil after compaction to the ground by a screw auger, and burying the foundation pile together with an enlarged excavation head. 2. 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 expand while drilling in the ground. 2. The method according to claim 1, wherein the excavating head and the foundation pile are buried underground. 3. Injecting cement milk into the drilling hole after burying the enlarged drilling head and foundation pile in the ground,
3. The method for constructing a foundation pile according to claim 1, wherein the enlarged excavation head and the foundation pile are integrally connected and the periphery of the lower end of the foundation pile is solidified.