JP2886365B2 - Construction method of pile - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for constructing a pile by a digging method.

[0002]

2. Description of the Related Art As a conventional method of constructing a pile by a middle excavation method, as shown in FIGS. 5 to 7, an earth auger is inserted into a hollow portion of a pile to excavate just below a tip of the pile, and excavation is performed by a spiral blade. A method of inserting a pile while discharging the soil, stopping the impact at the planned depth, or expanding the excavation by expanding the expansion bit of a special structure, injecting cement milk, and consolidating to create an expanded bulb. Generally done.

However, in the conventional construction method, an earth auger provided with spiral blades over the entire length is used, so that excavated soil is discharged from the tip of the auger. If it is not soiled, it may be difficult to set it down.

[0004] In addition, when the excavated soil at the tip is scooped, placed on a spiral blade, and pushed up and carried, the excavated soil is not kneaded sufficiently, so that the soil adheres to the blades and shafts depending on the soil quality, and the motor has Although it is a load, and efficient soil removal is not possible, water is injected to improve it.
The work management for that was complicated.

[0005] Further, when the auger is pulled up, almost no soil remains in the hollow portion, so that the tip is treated (hitting or consolidation).
At that time, it was necessary to inject water into the hollow part of the pile or to return the soil, and the work management for that purpose was complicated.

Further, in the case of the compaction work, there is a problem that the auger is moved up and down to carry sand or gravels which may be aggregates of the support layer upward, thereby reducing the incorporation into the compacted bulbs.

[0007]

The object of the present invention is to remove the excavated soil directly from the tip of the conventional auger by using a spiral blade, so that a large amount of soil is removed and it is difficult to perform the soil removal smoothly. An object of the present invention is to solve a problem that no soil remains in a hollow portion.

[0008]

According to the present invention, there is provided a drilling rod 2 having a cutting blade 3 at a tip thereof, a plurality of stirring blades 4 at a predetermined interval above the cutting blade 3, and a spiral blade 5 above the blade. Into the hollow part of the pile, and pile 1
In the course of submerging, the excavating rod 2 is repeatedly moved up and down while rotating the excavating rod 2 as needed, and the surrounding excavated soil is agitated by the agitating blades 4 to be muddy. The present invention proposes a method of constructing a pile to be discharged according to No. 5.

[0009]

The soil excavated by the excavating blade 3 at the tip is sent into the pile hollow where the agitating blade 4 at the tip of the auger is located, the excavation is temporarily suspended during excavation, and the excavating rod 2 is rotated forward and backward appropriately. By repeatedly moving up and down, the excavated soil is agitated by the agitating blades, and becomes mud 6 sufficiently kneaded.

Thereafter, when the excavation is started again, the mud 6 is sequentially pushed up by the excavated soil from below as the excavation progresses, and is placed on the spiral blade 5 above the excavating rod 2, and is upward without adhering to the spiral blade 5 or the shaft. It is smoothly discharged, and the rotational load of the drill rod 2 is reduced.

If the pile is pressed in while repeating such excavation and stirring processes as necessary a plurality of times, the mud 6 always remains below the hollow portion of the pile 1 to prevent the support layer from loosening due to boiling. At the same time, when the excavation is performed at the planned depth and the root consolidation liquid (cement milk) is injected, the gravel as an aggregate is sufficiently left, and the expanded bulb 8 having high strength provides a sufficient supporting force.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An excavating rod 2 inserted into a hollow portion of a pile 1 has an enlarged excavating blade 3 which is radially expandable and contractable at the tip thereof. Is attached, and the spiral blade 5 is attached above the stirring blade portion.

In the excavation work, the pile 1 is press-fitted while excavating the ground immediately below the pile 1 with the excavation blade 3 at the tip of the excavation rod 2 inserted into the hollow portion of the pile 1, and the installation length of the stirring blade 4 Each time the excavation is performed to the extent, the excavation is suspended, and the excavation rod 2 is repeatedly moved up and down while rotating the excavation rod 2 forward and backward.
The excavated soil in the vicinity of is stirred to obtain mud 6 sufficiently kneaded.

After excavating to the required depth, the excavated soil is agitated by the impeller 4 in the same manner as described above, and if necessary, the same excavation and agitation steps are repeated a plurality of times to set the pile 1 to the design depth. .

The mud 6 generated by appropriately stirring as described above is newly excavated as the excavation progresses, and is pushed up from below into the excavated soil sent into the hollow portion of the pile 1, and is sequentially placed on the upper spiral blade 5. And is discharged smoothly upward.

In this case, since the excavated soil and the mud 6 always remain below the hollow portion of the pile 1, it is possible to prevent the support layer from being loosened due to boiling.

After the pile 1 reaches the planned depth, while expanding and digging with the expanding digging blade 3, a root consolidation liquid (such as cement milk) is injected from an injection hole 7 at the tip of the digging rod 2 to form an expanded bulb 8. I do.

At this time, a sufficient amount of gravel as an aggregate remains in the remaining mud 6, and a sufficient supporting force can be obtained by the expanded bulb 8 having high strength.

In order to improve the stirring of the stirring blade 4, air, water, bentonite muddy water or the like may be injected into the hollow portion of the pile 1.

[0020]

As described above, according to the present invention, the excavated soil is agitated by the agitating blades, and is discharged after being sufficiently kneaded into muddy soil. The load is also reduced.

Since the mud is always left below the hollow portion of the pile, the amount of discharged soil is small, the support layer can be prevented from loosening due to boiling, and the labor for backfilling and filling with water can be reduced.

When the root compaction liquid is injected by enlarging excavation, a sufficient amount of gravel as an aggregate remains, and a sufficient supporting force can be obtained by the expanded bulb having high strength.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing a construction mode of the present invention.

FIG. 2 is a longitudinal sectional view showing a construction mode of the present invention.

FIG. 3 is a longitudinal sectional view showing a construction mode of the present invention.

FIG. 4 is a longitudinal sectional view showing a construction mode of the present invention.

FIG. 5 is a longitudinal sectional view showing a conventional construction mode.

FIG. 6 is a longitudinal sectional view showing a conventional construction mode.

FIG. 7 is a longitudinal sectional view showing a conventional construction mode.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Pile 2 Drilling rod 3 Drilling blade 4 Stirrer blade 5 Spiral blade 6 Mud 7 Injection hole 8 Enlarged bulb

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) E02D 7/00 E21B 7/28 E21B 7/30 E21B 10/32

Claims (2)

(57) [Claims] An excavating blade is provided at a tip, a plurality of agitating blades are provided at required intervals in a required area above the excavating blade, and a drilling rod having a spiral blade is inserted above the excavating blade into a hollow portion of the pile. While the pile is being set aside, the drilling rod is repeatedly moved up and down while rotating the drilling rod forward and backward as appropriate, and the surrounding excavated soil is agitated by the agitating blades to be muddy. A pile construction method characterized in that the pile is discharged by a spiral blade. 2. The pile construction method according to claim 1, wherein an enlarged excavating blade is used as the excavating blade, the excavating blade being radially expandable and contractable, and excavated at a required depth to inject a root solution.