JPH073791A - Method and device for extracting existing pile - Google Patents

Abstract

PURPOSE:To extract and remove an existing pile without causing vibration and noise. CONSTITUTION:An extracting jack 4 is installed on the ground above a dry- excavated portion 2 to which the head 1a of an existing pile 1 is exposed. A tightening frame 12 is lowered by a hydraulic cylinder 8 and tightened at a position below the existing pile 1 and then pulled up by the hydraulic cylinder 8. When the tightening frame 12 is extracted by a substantial amount, the tightening is released and the frame is lowered and tightened again at the position below the pile and then pulled up. By repeating these operations the existing pile 1 is gradually extracted and pulled up through a through hole 7a at the center of a top board 7. Then under almost no earth pressure the pile can be completely extracted and removed by a hoisting device such as a crane.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a construction method and apparatus for extracting and removing existing piles (steel pipe piles, concrete piles, H steel, cast-in-place piles, etc.) that are constructed underground in a building.

[0002]

2. Description of the Related Art Conventionally, as a method for extracting the existing piles, a method of using a vibro device and pulling out while removing earth pressure with high-pressure water has been most often used. Further, in Japanese Patent Laid-Open No. 2-58628, a pressure water jetting member composed of a ring-shaped pipe having a diameter larger than the pile diameter of an existing pile is provided at the lower end of a column, and a pulling device having a vibrating device at the upper end is provided by a lifting device. Suspend, the pressure water jetting member is fitted to the pile head of the existing pile, and the pressure water jetting nozzle of the jetting member jets pressure water to the outer circumference of the pile head, and gives a vibration to the ground by a vibration generator. On the other hand, an invention of a construction method for penetrating an existing pile by penetrating an existing pile to the lower bottom portion of the existing pile and an apparatus therefor is known.

[0003]

The above-mentioned conventional drawing method is unsuitable for construction in urban areas or at night because it involves vibration and noise, and even if the soil pressure is relieved by pressure water, it is not suitable for the ground. Since the earth pressure is restored in a short time, it takes time to complete the work with pressure water.

[0004]

SUMMARY OF THE INVENTION Therefore, the present invention provides a method and an apparatus for extracting existing piles, which is vibration-free, noise-free and requires only a short working time. Exposing the head of the existing pile to the empty excavation part by excavating, and on the ground above the empty excavation part, a tightening mechanism that tightens or unfastens the head of the existing pile by a lifting mechanism from the main body standing on the ground. Repeat the procedure of installing a pulling device that is vertically movably suspended, moving the tightening mechanism downward by the elevating mechanism, tightening the existing pile, raising it as it is by the elevating mechanism, and releasing the tightening upward. It is characterized by gradually pulling out the existing pile from the ground to eliminate the earth pressure, and then pulling it out from the ground by a lifting device.As an optimum device for carrying out the construction method, the head of the existing pile is Exposed sky A plurality of columns are erected on the ground above the section and a top plate is provided above the columns, a through hole is provided in the center of the top plate, and the head of the existing pile penetrates and is tightened below the through hole. A tightening frame capable of tightening or releasing the tightening of the head by a hydraulic cylinder for use is supported by a plurality of lifting hydraulic cylinders suspended from the periphery of the through hole so as to be movable up and down. It is intended to provide a pulling device set below the ground.

[0005]

[Operation] The extraction device is installed on the ground above the hollow excavation part where the head of the existing pile is exposed. First, the elevating mechanism (hydraulic cylinder for elevating) lowers the tightening mechanism (clamping frame) to tighten the lower position of the existing pile, and the elevating mechanism pulls it up. When it is pulled out to some extent, the tightening mechanism is released, lowered again, tightened at the lower position, and pulled up. By repeating this procedure, the existing pile is gradually pulled out, and in the above-mentioned pulling device, it penetrates through the through hole in the center of the top plate and is pulled upward. When it is pulled out to some extent and the earth pressure is almost eliminated, it can be completely pulled out and removed by a lifting device such as a crane.

[0006]

Embodiments of the present invention will be described below with reference to the drawings. As shown in FIG. 1, first, an area around the head of an existing pile is excavated to obtain an empty excavation portion 2. Next, the laying material 3 is laid on the ground except for the empty dug portion 2, and the extraction jack 4 is installed on the laying material 3.
(FIG. 2) This withdrawal jack 4 has four columns 6, 6 ... As a main body 5 and a top plate 7 having a through hole 7a for extracting an existing pile in the center, and further, inside the main body 5, Four hydraulic cylinders 8, 8 ... Are hung vertically around the through hole 7a,
The tip of the piston rod 9 of each hydraulic cylinder 8 is pin-coupled to the outer periphery of a tightening frame 12 formed of a pair of half members 10, 11. As shown in FIG. 3, each half member 10 and 11 is
The flange portions 10a, 10b and 11a, 11 are provided at both ends, respectively.
b, and the flange portions 10a, 11b and 10 of each other.
The inner diameter created by the tightening frame 12 when the b and 11a are in contact with each other is the same as the existing pile 1
Is smaller than the outer diameter of. Further, in each flange portion, the flange portion 10a of the half member 10 and the half member 1
The piston rods 14, 14 of the tightening cylinders 13, 13 are attached to the first flange portion 11a, and the other flange portion 10b,
Cylinder parts 15 and 15 are fixed to 11b, respectively, and the inner diameter of the tightening frame 12 can be enlarged or reduced by the operation of the tightening cylinders 13 and 13. Further, the main body 5 is connected with a hydraulic unit for operating the hydraulic cylinder 8 and the tightening cylinder 13, and a generator (not shown).
The maximum extraction capacity of the extraction jack 4 is 320 t, and the maximum inner diameter of the tightening frame is 2000 mm. Next, the hydraulic cylinder 8 is operated from the state shown in FIG. 2 to lower the tightening frame 12 below the ground, and the head 1a of the existing pile 1 protruding to the hollow excavation portion 2 is inserted into the tightening frame 12. Then, the tightening cylinders 13, 13 are operated to bring the two half members 10, 11 close to each other, and the head 1a of the existing pile 1 is tightened. (FIG. 4) After that, the hydraulic cylinder 8 is operated again to operate the piston rod 9 in the direction of contracting, that is, in the direction of extracting the existing pile. When the existing pile 1 is pulled out to some extent, the tightening cylinder 13 is actuated this time to loosen the tightening frame 12, and only the tightening frame 12 is lowered by the hydraulic cylinder 8. Then, the tightening frame 12 is tightened again at the lowered position, and the hydraulic cylinder 8 pulls it out. By repeating this, the drawing operation is performed several times as shown in FIG. In the present embodiment, the stroke of the hydraulic cylinder 8 is 700 mm. The existing pile 1 is gradually pulled out by the above work, and the head portion 1a penetrates the through hole 7a of the top plate 7 and projects upward as shown by the chain double-dashed line in FIG. Then, after confirming that the earth pressure has disappeared, the existing pile 1 is completely pulled up by the crane, and the pulling out work is completed. In this series of operations, there is almost no vibration or noise, and the operations can be completed in a short time.

If the earth pressure around the existing pile can be eliminated by the above work procedure, there is no problem, but if the earth pressure is relatively high, bentonite is injected by a boring machine before using the extraction jack 4, If the circumference of the existing pile 1 is loosened to some extent, the subsequent pulling out work will be easy.

In the above-described embodiment, the tightening frame composed of the two-divided half-divided members has been described. For example, as shown in FIG. , 18 are connected with a universal joint, etc.,
The tightening cylinder 13 may be provided only between the half members 17 and 18. In the above embodiment, the tightening frame applied to the existing columnar pile is explained.
In the case of an existing steel pile, it is natural that the shape of the fastening frame can be arbitrarily changed according to the shape of the existing pile, for example, by using a fastening frame having a square shape into which the outer shape of the same shape steel penetrates.

[0009]

As described above, according to the present invention, since there is no vibration and no noise, it is possible to finish the drawing work in a short time without being affected by the place or time. Construction work can be started quickly, which in turn shortens the overall construction period.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing a state in which an empty excavation portion is provided by excavating the periphery of an existing pile head.

FIG. 2 is an explanatory diagram showing a state in which a pull-out jack is installed on the upper part of the hollow excavation portion.

FIG. 3 is an explanatory diagram showing details of a fastening frame.

FIG. 4 is an explanatory diagram showing a work of pulling out an existing pile using a pulling jack.

FIG. 5 is an explanatory diagram showing a work of pulling out an existing pile using a pulling jack.

FIG. 6 is an explanatory view showing another embodiment of the fastening frame.

[Explanation of symbols]

1 ・ ・ Existing piles 2 ・ ・ Empty excavated parts 3 ・ ・ Laying materials 4 ・ ・ Pulling jacks 5 ・ ・ Main body 6 ・ ・ Supporting posts 7 ・ ・ Top plate 8 ・
・ Hydraulic cylinders, 9 ・ ・ Piston rods, 10, 11,
16, 17, 18 ... Half split members, 12 ...
..Tightening cylinders, 14 ... Piston rods, 15 ...
Cylinder part.

Claims (2)

[Claims] 1. A tightening mechanism which exposes the head of an existing pile to an empty excavated portion of the ground, and tightens or releases the head of the existing pile on the ground above the empty excavation portion. Installed a pulling device suspended from the main body by an elevating mechanism so that it can be moved up and down, moving the tightening mechanism downward by the elevating mechanism, tightening the existing piles, raising it as it is by the elevating mechanism, and releasing the upper tightening. A method of extracting existing piles, in which the existing piles are gradually pulled out from the ground to eliminate the earth pressure by repeating the above procedure, and then the piles are pulled out from the ground by a lifting device. 2. A plurality of columns are erected on the ground above the hollow excavation part where the head of the existing pile is exposed, and a top plate is provided above the columns.
A through hole is provided in the center of the top plate, and below the through hole,
A head frame of an existing pile penetrates and a tightening frame capable of tightening or releasing the tightening of the head by a tightening hydraulic cylinder is supported movably up and down by a plurality of lifting hydraulic cylinders suspended from around a through hole, Further, the lowermost position of the fastening frame is set lower than the ground, and the existing pile extracting device is characterized in that.