JPH11310920A - Execution method of hollow pile by variable bit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To ensure safety while streamlining process of works when a hollow pile is inserted into the ground. SOLUTION: In the case a hollow pile 30 is inserted into the ground by an excavator 11 equipped with a variable bit 15, the variable bit 15 is widened larger than an outside diameter of the hollow pile 30, and the ground is excavated while inserting the hollow pile 30 from the rear of the excavator 11. After the hollow pile 30 is inserted down to a specific depth, the variable bit 15 is reduced in its diameter and is pulled out from the inside of the hollow bit 15. Concrete is cast downward of the hollow pile 30 to make protection of foundation.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of constructing a hollow pile using a variable bit, and more particularly to a method of constructing a hollow pile in which a pile is inserted while excavating the ground.

[0002]

2. Description of the Related Art
The pre-boring method and the Nakabori method are implemented as the pile driving method in urban areas to prevent noise and vibration. The pre-boring method is a method in which a boring hole is firstly excavated in the ground by an excavator, and then the excavator is raised and a pile is inserted. On the other hand, the Nakahori method is a method in which an earth drill is inserted inside a hollow pile and the pile is pressed in while excavating the ground with the earth drill.

However, in the pre-boring method, after excavating the ground to a predetermined depth, the excavator is pulled up and the pile is inserted, so that the work process is complicated and the construction period is long. Also, the boring hole may collapse before the pile is inserted, which makes it difficult to insert the pile. On the other hand, in the Nakahori method, the diameter of the earth drill is smaller than the inner diameter of the pile,
The diameter of the pile is larger than that of the excavated pile hole, and a large amount of press input is required to insert the pile.

Therefore, when constructing a hollow pile on the ground,
The technical problem to be solved arises in order to secure the safety while simplifying the work process, and the present invention aims to solve this problem.

[0005]

DISCLOSURE OF THE INVENTION The present invention has been proposed to achieve the above object, and is an excavator having a variable bit which can be radially expanded and contracted. While excavating the ground by expanding the bit to the outer diameter of the hollow pile or more, insert the hollow pile from the back of the excavator,
After inserting the hollow pile to a predetermined depth following the excavation of the excavator, the variable bit was reduced in diameter and pulled up from the inside of the hollow pile, and further formed at the lower part of the hollow pile. An object of the present invention is to provide a method of constructing a hollow pile using a variable bit for placing concrete in a diameter-enlarged hole and consolidating the concrete.

[0006]

An embodiment of the present invention will be described below in detail with reference to the drawings. FIG. 1 shows an excavator 11 used in the present invention, and a front end (a lower end in FIG. 1) of the excavator 11.
A head sleeve 13 having a guide bit 12 is provided, and a variable bit 15 is provided between a body 14 provided at an intermediate portion and the head sleeve 13. The variable bit 15 is composed of a plurality of wing bits 17, 17... Built in a plurality of slits 16, 16,. Is pivotally mounted at a pin 19. Each wing bit 17 is rotatable about the pin 19, but because the spring 20 is interposed between the clasp 18 and the wing bit 17, the wing bit 17 is pressed inward. In the illustrated state, the wing bit 17 is housed inside the slit 16 by the bias of the spring 20.

Here, the hollow portion 2 is provided inside the body 14.
As shown in FIG. 2, the opener plug 26 is lowered into the hollow portion 25 by a wire line from the ground, and the tip portion 26a is inserted from the insertion port 27. Is pressed by the tip 26a of the opener plug. Therefore, each wing bit 17 rotates outward against the bias of the spring 20, and the outer portion of the wing bit 17 projects from the slit 16.

On the other hand, when the opener plug 26 is pulled up, the tip 26a separates from the inside of the wing bit 17, and the wing bit 17 is returned by the bias of the spring 20. Therefore, the outer portion of the wing bit 17 enters the slit 16 and returns to the state shown in FIG.

As described above, the wing bit 17 moves up and down from the slit 16 by raising and lowering the opener plug 26, and the variable bit 15 can be expanded and contracted in the radial direction of the excavator 11. In FIG. 2, reference numeral 30 denotes a hollow pile buried in the ground, which is inserted from the rear of the excavator 11 with excavation as described later. A water passage 28 is formed in the shaft core of the opener plug 26, and water or muddy water is supplied from a high-pressure pump installed on the ground through the water passage 28 to the tip of the guide bit 12. To the department,
The excavated waste is formed to be collected together with water or muddy water along the outer peripheral surface of the excavator 11 and the inner and outer surfaces of the hollow pile 30 to the hole.

Next, a procedure for constructing a hollow pile by the excavator 11 having the variable bit 15 will be described. When inserting the hollow pile 30, an opener plug 26 is inserted into the hollow portion 25 of the excavator 11, as shown in FIG.
The variable bit 15 is expanded beyond the outer diameter of the hollow pile 30.
At the same time, the hollow pile 30 is inserted from the rear of the excavator 11 to immediately after the variable bit 25.

Then, as shown in FIG. 3, a boring rod 31 connected to a rear portion of the excavator 11 is rotated by a driving device (not shown) on the ground, and the hollow pile 30 is The hollow pile 30 is pushed in from a hole on the ground while excavating the boring hole 32 having an outer diameter of not less than.

In such a state, after the hollow pile 30 is inserted to a predetermined depth following the excavation of the excavator 11, the opener plug 26 is pulled up to move the variable bit 15 to an inner diameter of the hollow pile 30. Reduce diameter. Then, as shown in FIG. 4, the excavator 11 is pulled up from the boring hole 32 through the inside of the hollow pile 30. Thus, the enlarged diameter hole 33 is formed below the hollow pile 30, and concrete 36 is poured into the enlarged diameter hole 33 to consolidate the hollow pile 30 as shown in FIG. .

The present invention can be variously modified without departing from the spirit of the present invention, and it goes without saying that the present invention extends to the modified ones.

[0014]

As described in detail in the above embodiment, the present invention expands the variable bit of the excavator to pre-drill the ground and simultaneously inserts a hollow pile from the back of the excavator. Therefore, the construction period can be shortened compared to the conventional pre-boring method. In addition, since a hole having a diameter larger than the outer diameter of the hollow pile is excavated and the hollow pile is inserted, a large press input is not required for the insertion of the pile as compared with the conventional Nakahori method.

[0015] Thus, when the hollow pile is constructed on the ground, various effects are exerted, such as not adversely affecting noise and vibration, and also ensuring safety while simplifying the work process. It is an invention.

[Brief description of the drawings]

 The figure shows an embodiment of the present invention.

FIG. 1 is a longitudinal sectional view of an excavator in which a variable bit has a reduced diameter.

FIG. 2 is a longitudinal sectional view of an excavator in which a variable bit is in an expanded state.

FIG. 3 is an explanatory view of a construction procedure of a hollow pile roof method.

FIG. 4 is an explanatory view of a construction procedure of a hollow pile roof method.

FIG. 5 is a longitudinal sectional view of a hollow pile after construction.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Excavator 15 Variable bit 30 Hollow pile 32 Boring hole 33 Large diameter hole 36 Solidifying agent

Claims (1)

[Claims] An excavator having a variable bit that can be radially expanded and contracted, wherein the variable bit of the excavator is expanded to a diameter larger than the outer diameter of a hollow pile to excavate the ground. After inserting the hollow pile from the rear of the machine, and after inserting the hollow pile to a predetermined depth following the excavation of the excavator, the variable bit is reduced in diameter and pulled up from the inside of the hollow pile, A method of constructing a hollow pile using a variable bit, wherein concrete is cast into a diameter-enlarged hole formed below the hollow pile and solidified.