JP2003034932A - Method of drawing out existing piles and excavation casing used for it - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a method for easily and reliably drawing out existing piles, without giving damages to the housing environment of neighboring inhabitants, etc., and also preventing subsequent existing pile cutting operations from becoming difficult due to the slime arising from cutting operations, and to obtain an excavation casing used for this method. SOLUTION: A casing 3 provided with a narrow strip of cutter 8 in a spiral form along its inner bottom circumferential surface in the way that the spiral may reduce its inner diameter as it goes up is inserted into ground while being rotated so as to cover an existing pile 1 to be drawn out. The outer circumference of the existing pile 1 is cut with the spiral cutter 8 located within the casing 3 to reduce the diameter of the existing pile 1, which is then cut off at the point where its diameter has been reduced, and the cut-off pile portion is drawn out. The operations are repeated to finally draw out the entire existing pile 1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for extracting an existing pile buried in the ground and a drill casing used for the method.

[0002]

2. Description of the Related Art Conventionally, as a method for pulling out an existing concrete pile 1 having a main bar 15 arranged as shown in FIG.
For example, connecting a vibro hammer suspended by a crane to the head of an existing pile with a chuck device, and using the vertical movement generated by the vibro hammer, a method of lifting the existing pile with a vibro hammer and pulling it out with a crane,
As shown in FIGS. 8 to 10, there is a method of using an auger casing 13 in which a casing bit 11 is attached to the tip and a plurality of pile breaking bits 12 are attached spirally inside the lower portion.

The method using the auger casing 13 is as follows.
Insert the auger casing 13 around the existing pile 1 so as to surround it while rotating, cut the outer peripheral surface of the existing pile 1 with the bit 12 for pile destruction, and cut the main bar 15 to reduce the diameter of the existing pile 1. Then, this reduced diameter portion is grasped with a hammer grab 16 or the like and folded and pulled up. By repeating such an operation, the existing pile 1 is sequentially cut from the upper portion to reduce the diameter, and then folded and pulled out.

[0004]

With the former method of using a vibro hammer, vibration and noise during operation are large, and it is difficult to carry out construction in urban areas, etc., considering the influence on neighboring residents and the like. The method of utilizing the latter auger casing 13, since a plurality of bits 12 for pile breakage are projected on the inner peripheral surface of the auger casing 13 at appropriate intervals,
A gap is created between the existing pile 1 and the inner peripheral surface of the auger casing 13, and this gap and the upper part of the existing pile 1 still remaining in the ground after cutting are formed by cutting with the bit 12 for pile destruction. Slime 14 drops and remains, auger casing 13
There is a risk that the inside of this will be clogged with this slime 14 and it will become difficult to cut as it goes to the lower part.

The object of the present invention is to eliminate the inconveniences of the above-mentioned conventional examples, there is no fear of damaging the housing environment of neighboring residents, and when cutting existing piles, the subsequent cutting is difficult due to the slime generated by cutting. It is intended to provide a method for extracting an existing pile that can be easily and surely extracted while preventing the occurrence of the occurrence of the problem, and an excavation casing used for the method.

[0006]

In order to achieve the above object, the present invention relates to a method of extracting an existing pile. Firstly, the inner diameter of the inner peripheral surface of the lower part is reduced as the band-shaped cutter is moved upward. Inserting into the ground so as to surround the existing pile while rotating the excavating casing provided in a spiral manner, and cutting the outer peripheral portion of the existing pile with a spiral cutter inside the excavating casing to reduce the diameter, The existing pile is cut at the reduced diameter part, the part above the cut part is pulled out, and this is repeated sequentially to pull out the entire existing pile. Secondly, the excavation casing is inserted by the erection device used in the all casing method. This is the summary.

Thirdly, as an excavation casing used in the method of extracting existing piles, thirdly, in an excavation casing which is rotated and propelled while being chucked at the outer periphery to be inserted into the ground,
The gist is that a strip-shaped cutter is provided in a spiral shape on the inner peripheral surface of the lower portion so that the inner diameter becomes smaller as it goes upward.

According to the first aspect of the present invention, by inserting the excavation casing into the ground while rotating the excavation casing so as to surround the existing pile, the spiral cutter inside the excavation casing is simultaneously inserted into the outer peripheral portion of the existing pile. To cut. As a result, the cut portion of the existing pile is reduced in diameter, and the existing pile is broken at the reduced diameter portion. Therefore, if the existing pile is cut and the existing pile above the cutting point is pulled out and such work is repeated sequentially, the lower portion of the existing pile is also pulled out. In this case, the vibration and noise unlike the vibro hammer do not occur, and the pulling out can be performed without using a large-scale crane.

According to the second aspect of the present invention, in addition to the above-mentioned action, since the digging casing is inserted by using the erection device used in the all-casing construction method, the device does not become large-scale and the construction site is There are less restrictions and the excavation casing can be used to reliably pull out existing piles.

According to the third aspect of the present invention, as the excavation casing, a strip-shaped cutter is provided in the lower part of the excavation casing in a spiral shape so that the inner diameter becomes smaller as it goes upward. The slime generated when cutting an existing pile with this cutter is pulled up along the spiral cutter. Therefore, the slime does not fall inside the excavating casing and does not clog the gap between the existing pile and the existing pile, and it is not difficult to cut the lower part of the existing pile.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described in detail below with reference to the drawings. FIG. 1 is a perspective view of an erection device and an excavation casing used in the method for extracting an existing pile of the present invention, and FIG. 2 is a vertical cross-sectional front view of a lower portion of the excavation casing, which is a main part of the same. To explain, the built-in device 2 is, as is well known, a press-fitting machine used in, for example, an all-casing construction method, and a chuck device 4 for tightening the outer periphery of the casing 3 in a rattle shape, and a motor and a speed reducer for rotating the chuck device 4 And the like, and an elevating cylinder 6 by a hydraulic cylinder that vertically moves the chuck device 4 and the driving device 5.

Reference numeral 7 in the drawing denotes an outrigger which is a horizontal jack for horizontally installing the building device 2.

The casing 3 is inserted into the ground by being rotatably propelled while being chucked on the outer periphery by the erection device 2, and is inserted into and removed from the main body tube which is replenished at an appropriate length to a required length and the tip of the main body tube. It is a combination with a casing head that is freely fitted, and the fitting portion is fastened with bolts. Then, a casing bit 11 as an excavating blade was provided at the tip of the casing head at the tip. This casing bit 11 sets the angle of the blade so that the cutting soil is pushed outward.

In the present invention, in addition to this configuration, FIG. 2 and FIG.
As shown in FIG. 5, the strip-shaped cutter 8 is spirally provided on the inner peripheral surface of the tip of the casing head at the tip of the casing 3 such that the inner diameter becomes smaller as the cutter 8 goes upward. The cutter 8 is made of a cemented carbide that is harder than the metal of which the casing 3 is made, and is formed by continuous peaks and valleys in the lengthwise direction of the strip. It is desirable to let it adhere.

Next, a method for pulling out the existing pile 1 using the casing 3 will be described with reference to FIGS. The building device 2 is installed above the existing buried pile 1, the casing 3 is clamped and fixed at its outer periphery by the chuck device 4, and the chuck device 4 is rotated by the drive device 5 while the lifting cylinder 6 is free. The casing 3 is inserted into the ground of the outer peripheral portion so as to surround the existing pile 1. The existing pile 1 is made of concrete in which the same main bars 15 as those described with reference to FIG. 7 are arranged.

In this case, since the casing bit 11 is projectingly provided at the tip of the casing 3, even the hard ground can be easily inserted.

As shown in FIG. 4, if the casing 3 is inserted while rotating to a predetermined depth, that is, the pile head, and further, as shown in FIG. 5, the casing 3 is rotated and inserted around the existing pile 1, A strip-shaped cutter 8 protruding in a spiral shape on the inner peripheral surface of the casing 3 bites into the outer peripheral surface of the existing pile 1 and sequentially cuts from the upper side to the lower side with rotation.

As a result, the diameter of the cut portion of the existing pile 1 is reduced, and if the reduced diameter portion is grasped and bent by a hammer grab 16 or the like as shown in FIG. Be disconnected. Therefore, if the existing pile 1 having a reduced diameter in the upper part of the cut portion is pulled out and such work is repeated in sequence, the lower part of the existing pile 1 is also pulled out, and the existing pile 1 is pulled out over the entire length.

When the outer peripheral portion of the existing pile 1 is cut by the cutter 8, a large amount of slime 14 is generated by the cutting,
The slime 14 is pulled up along with the rotation of the spiral cutter 8. Therefore, the slime 14 does not fall inside the casing 3 and clog the gap between the slime 14 and the existing pile 1, and it is not difficult to cut the lower part of the existing pile 1. In this case, the vibration and noise unlike the vibro hammer do not occur, and the pulling out can be performed without using a large-scale crane.

[0020]

As described above, the existing pile extracting method of the present invention and the excavating casing used for the same do not generate vibration and noise as in the case of a vibro hammer, and thus may harm the residential environment of neighboring residents and the like. Moreover, when cutting an existing pile, it is possible to prevent the slime generated by cutting from falling inside the casing, and prevent the falling slime from clogging inside the casing and making subsequent cutting difficult. Can be pulled out easily and surely. In addition, since it can be pulled out without using a large-scale crane, there are less restrictions on the construction site.

[Brief description of drawings]

FIG. 1 is a perspective view of an erection device and an excavation casing used in a method for extracting an existing pile according to the present invention.

FIG. 2 is a vertical sectional front view of a lower portion of the excavation casing used in the existing pile extracting method of the present invention.

FIG. 3 is a cross-sectional plan view of the lower portion of the excavation casing used in the existing pile extraction method of the present invention.

FIG. 4 is a vertical cross-sectional front view of a cutting start state by an excavation casing showing a method of extracting an existing pile of the present invention.

FIG. 5 is a vertical sectional front view showing a method of extracting an existing pile of the present invention during cutting by an excavating casing.

FIG. 6 is a vertical cross-sectional front view showing a state at the time of cutting showing a method for extracting an existing pile of the present invention.

FIG. 7 is a vertical sectional front view of an existing pile to be pulled out.

FIG. 8 is a vertical cross-sectional front view at the start of cutting in a conventional method of extracting an existing pile with an excavating casing.

FIG. 9 is a vertical cross-sectional front view of a conventional method of extracting an existing pile using an excavating casing during cutting.

FIG. 10 is a vertical cross-sectional front view showing a state at the time of cutting according to a conventional method of extracting an existing pile with an excavating casing.

[Explanation of symbols]

1 ... Existing pile 2 ... Building device 3 ... Casing 4 ... Chuck device 5 ... Drive device 6 ... Elevating cylinder 7 ... Outrigger 8 ... Cutter 11 ... Casing bit 12 ... Pile breaking bit 13 ... Auger casing 14 ... Slime 15 ... Main bar 16 ... Hammer grab

Claims (3)

[Claims] 1. An inner peripheral surface of a lower part is inserted into the ground so as to surround an existing pile while rotating an excavating casing provided in a spiral shape so that the inner diameter thereof becomes smaller as the cutter goes upward. The outer peripheral portion of the existing pile is cut by the spiral cutter inside the excavation casing to reduce the diameter, the existing pile is cut at the reduced diameter portion, and the upper portion is pulled out from the cut portion, which is sequentially repeated to remove the existing pile. A method for extracting existing piles, which is characterized by pulling out the whole. 2. The method for extracting an existing pile according to claim 1, wherein the excavation casing is inserted by a building device used in the all-casing construction method. 3. An excavating casing which is rotatably propelled while being chucked at its outer periphery and is inserted into the ground, is provided with a strip-shaped cutter on the inner peripheral surface of the lower portion in a spiral shape so that the inner diameter becomes smaller as it goes upward. A drilling casing characterized in that