JP6180854B2 - How to remove existing piles - Google Patents

Description

  The present invention relates to a method for removing an existing pile.

  When constructing a new structure by dismantling an existing structure, in general, after dismantling the ground part of the existing structure and dismantling the underground part including the foundation, a new underground part (foundation) and Build the ground part.

When removing the foundation when dismantling the foundation, it is common to cut the periphery of the pile from the ground with a casing and crush and remove the inside of the casing.
Moreover, when the pile diameter of the existing pile is comparatively small, after cutting a pile outer periphery and cutting off with the ground, the existing pile is also pulled out directly.

  For example, in Patent Document 1, after inserting a casing so as to surround the outer periphery of the existing pile and cutting the existing pile and the ground, the existing pile is raised by injecting mortar into the casing from the lower end of the casing. A method for removing an existing pile while pulling it out (while pushing up) is disclosed.

  In addition, Patent Document 2 discloses a drilling operation for drilling a core portion of an existing pile for a predetermined length, a cutting operation for cutting a lower end portion of a cylindrical outer peripheral portion left by the drilling operation, and a cutting operation. The removal method of the existing pile which removes the existing pile by repeating the raising operation | work which pulls up the cylindrical outer peripheral part made from underground is disclosed.

Japanese Patent Application Laid-Open No. 06-207412 JP 2012-102559 A

Since the existing pile removal method of Patent Document 1 is pulled out while maintaining the original shape of the existing pile, the apparatus and equipment used for pulling out the existing pile become large, and the construction cost may be expensive.
In addition, it was not possible to employ when it was not possible to secure the space necessary for pulling out existing piles, such as when there was another structure above the work site.

The existing pile removal method of Patent Document 2 uses a special machine such as a cutting device that can be inserted into a drilling hole in a cutting operation, or a lifting device that grips and lifts a cylindrical outer peripheral portion from the ground in a lifting operation. There was a need.
In addition, since the drilling operation, the cutting operation, and the pulling operation are repeatedly performed, it is necessary to replace the apparatus for each operation, which may be time-consuming.

  The present invention solves the above-mentioned problems, and proposes a method for removing an existing pile that can easily remove an existing pile even when the height above the construction site is limited. Let it be an issue.

Removing method of the existing pile of the present invention performs a coring drilling to form the cavity in consideration of the buoyancy acting on its own weight and the existing pile of the existing pile bottomed the existing pile to solve such problems ground and coring step of forming into a tubular shape, wherein a drilled the outer periphery of the existing pile to edge cutting and the existing pile and the surrounding ground edge switching process, is raised the existing pile, a portion of the existing pile And a cutting step of cutting a protruding portion protruding above the ground of the existing pile .

According to removing method such existing pile performs coring drilling to form a cavity of a predetermined size, to increase by utilizing the buoyancy upon which is lighter existing piles, when increasing the existing pile It is possible to reduce the scale of the equipment (lifter) used for the operation. In addition, since the existing pile is cut every predetermined length, it is possible to perform work even when the sky is limited.

In addition, since the existing pile after core drilling has a bottom, the buoyancy due to groundwater, etc. is greater than when centering over the entire length of the existing pile, so a device (lifter) that supports the existing pile, etc. It becomes possible to reduce the load on the.
The order of the centering process and the edge cutting process is not limited.

If a casing is arranged around the existing pile in the edge cutting step, and a liquid such as water or muddy water is injected into the casing in the pile rising step (water injection), even if there is no groundwater, Since buoyancy comes to act, it becomes possible to perform the removal work of the existing pile more efficiently. Moreover, even when groundwater exists, you may increase the buoyancy of the existing pile by pouring muddy water with a density larger than water.

Moreover, in the said pile raising process, you may adjust the raising amount and raising speed of an existing pile by inject | pouring (water injection) liquids, such as water and muddy water, into the said cavity. By doing this, even if the pile mass of the existing pile is smaller than the buoyancy, it can be prevented that the existing pile protrudes more than necessary, and safety during construction can be ensured. .

According to the method for removing an existing pile of the present invention, it is possible to easily remove the existing pile even when the height above the construction site is limited.
Moreover, since there are many work from the ground compared with the removal method of the conventional existing pile, it is excellent in workability | operativity.
Furthermore, the construction period can be shortened compared to the case of crushing existing piles with a hammer grab or the like.

(A)-(c) is sectional drawing which shows each process of the existing pile removal method which concerns on this embodiment. (A)-(c) is sectional drawing which shows each process of the existing pile removal method following (c) of FIG.

This embodiment demonstrates the case where the existing pile 1 made from reinforced concrete with a pile diameter of 2.0 m and a pile length of 50 m is removed. In addition, the shape dimension of the existing pile 1 is not limited.

  The removal method of the existing pile of this embodiment is provided with the centering process, the edge cutting process, the pile raising process, and the cutting process.

As shown in FIG. 1A, the centering step is a step of forming a centering hole in the existing pile 1 and forming the existing pile into a bottomed cylindrical shape.

Coring drilling of existing pile 1, so as not to cut the existing pile 1 rebar (reinforcing bar cage) 2, and drilling along the central portion of the existing pile 1 in the axial direction.

In the present embodiment, a cavity 3 having a diameter of 1.6 m is formed with respect to an existing pile 1 having an inner diameter of a reinforcing bar of 1.8 m. The cavity 3 is formed to a depth of 46 m with the bottom left in the existing pile 1. Incidentally, the geometry of the cavity 3 is set in consideration of the buoyancy acting on its own weight and the existing pile of the existing pile.

Although the drilling method of the existing pile 1 is not limited, For example, what is necessary is just to perform using an all casing excavator (not shown).
The cavity 3 is filled with a stabilizing liquid such as mud used for drilling. In addition, concrete pieces and the like generated along with the drilling are removed from the cavity 3.

Edge switching step, as shown in FIG. 1 (b) is a step of edge cutting of the existing pile 1 and the surrounding ground G by excavating an outer periphery of the existing pile 1.

In the present embodiment, by arranging the casing 4 to the outer periphery of the existing pile 1, for edge cutting and existing pile 1 and the surrounding ground G.

Edge cutting (arrangement of the casing 4) is performed using an all-casing excavator (not shown) or the like while circulating fresh water or muddy water (stabilizing liquid) or the like around the outer periphery of the existing pile 1.
In the present embodiment, as the casing 4, the casing 4 is used whose inner diameter is larger than the outer diameter of the existing pile 1 and whose length is longer than the length of the existing pile 1.

A pile raising process is a process of raising the existing pile 1 and projecting a part of the existing pile 1 to the ground, as shown in FIG. In addition, in the pile raising process, the height (projection length) of the existing pile 1 to be projected to the ground is not limited.

Existing pile 1 raises utilizing buoyancy by reducing the specific gravity of the apparent existing pile 1 by draining the stabilizing solution remaining in the interior of the existing pile 1. At this time, if necessary, the existing pile 1 is lifted by a lifting machine or the like.

Here, as the specific weight of the reinforced concrete 25 kN / ^{m 3,} stable liquid-full level in the cavity 3 of the existing pile 1 Datosuruto, the weight of existing pile 1 is 2724KN (see equation 1). The density of the stabilizing liquid is 12 kN / m ³ .

1614kN + 1110kN = 2724kN Equation 1
here,
Weight of existing pile before drilling: 3927kN = 157.1m ³ (volume of existing pile ) x 25kN / m ³
Weight of existing pile removal part: 2313kN = 92.5m ³ (volume of removal part) × 25kN / m ³
Weight of existing pile after drilling: 1614kN = 3927kN-2313kN
Weight of stable liquid at full water: 1110 kN = 92.5 m ³ (cavity volume) × 12 kN / m ³

Meanwhile, the buoyancy acting on the existing pile 1 by stabilizing solution or the like around the existing pile 1 is 1885KN (see Equation 2).
157.1m ³ × 12kN / m ³ = 1885kN Equation 2

Thus, if draining all the stabilizing solution from the cavity 3 of the existing pile 1, the buoyancy is greater than the weight of the existing pile 1 (see Equation 3). That is, the existing pile 1 is lifted in the process of draining the stabilizing liquid from the cavity 3.
2724kN-1110kN = 1614kN <1885kN Equation 3

In the present embodiment, high-density muddy water is poured into the inside of the casing 4 (around the existing pile 1) so as to obtain a large buoyancy.
Incidentally, only the buoyancy in the case of do not float existing pile 1, raise existing pile by using the crane or a jack or the like (increase). Further, as compared with the buoyancy in the case pile the mass of the existing pile 1 is small, and water injection Shimizu like into the cavity 3 of the existing pile 1, by balancing the buoyancy, increase the amount and rate of increase of the existing pile Adjust.

A cutting process is a process of cutting the protrusion part which protruded on the ground of the existing pile 1, as shown to (a) and (b) of FIG.

In the cutting step, first, as shown in FIG. 2 (a), the temporary receiving member 5 is installed on the protruding portion of the existing pile 1 and temporarily received on the ground portion.
When the existing pile 1 protrudes above the ground by a predetermined height, a liquid such as a stabilizing liquid or fresh water is injected into the cavity 3 in order to stop further lifting.
Next, the protruding portion of the existing pile 1 is cut above the temporary support member 5. At this time, the suspension member 6 is installed on the protruding portion. In addition, the apparatus used for the cutting of the existing pile 1 is not limited.

If the protrusion part of the existing pile 1 is cut | disconnected, as shown to (b) of FIG. 2, a wire etc. will be attached to the suspension member 6, and the cut cylindrical body 7 will be removed using a lifting machine etc. FIG. In addition, the removal method of the cylindrical body 7 is not limited. Moreover, what is necessary is just to install the suspending member 6 as needed, and does not necessarily need to install.

When the cylindrical body 7 is removed, as shown in FIG. 2 (c), the stabilizing liquid is discharged from the cavity 3 and the existing pile 1 is levitated, or the existing pile 1 is further removed using a lifting machine or the like. Pull up and make the upper part of the remaining part of the existing pile 1 protrude above the ground (pile raising process). And as shown to (a) and (b) of FIG. 2, the protrusion part of the existing pile 1 is cut | disconnected and removed (cutting process).
Thus, the whole existing pile 1 is removed by repeating a pile raising process and a cutting process.

According to removing method of the existing pile of the present embodiment, since the cored drilling to existing pile 1, it is possible to raise the existing pile 1 in a state of being lightweight, the pulling means of the crane or the like The burden can be reduced.

Since the core punching hole of the existing pile 1 is performed so that the existing pile 1 becomes a bottomed cylindrical body, a larger buoyancy acts on the existing pile 1 than in the case where the bottom is not left.
Therefore, it reduces the load on the pulling means when raising the existing pile 1, or it is possible to float the existing pile 1 only buoyancy (rise).

Moreover, the existing pile 1 is cut off from the peripheral ground by the casing 4 being provided around, and the peripheral frictional force acting on the existing pile 1 is removed or reduced. The load on the pulling means when raising the existing pile 1 is further reduced.

The water injection or drainage stabilizing solution or the like into the cavity 3 formed in the existing pile 1, aims to balance the weight and buoyancy of the existing pile 1, it is made possible to ensure safety during construction.

Since the pile ascending process and the cutting process enable work from the ground, the work in each process can be performed by combining existing machine tools and simple equipment, so it is necessary to use a special machine. The existing pile 1 can be removed relatively inexpensively.

After removing the existing pile 1, cast-in-place piles can be formed by laying reinforcing bars (reinforcing rods) and placing concrete, so the process from removal of existing piles 1 to construction of new piles is integrated. Can be carried out and is excellent in workability.

To remove an existing pile 1, utilizing buoyancy acting on the existing pile 1 with reducing the weight of the existing pile 1, without using a large crane and the like, it is possible to perform removal of existing pile 1 . For this reason, construction can be performed even when the construction is under the restriction of the empty head or when the construction space is relatively small.

The embodiment of the present invention has been described above. However, the present invention is not limited to the above-described embodiment, and the above-described components can be appropriately changed without departing from the spirit of the present invention.
For example, in the embodiment, the case where the edge cutting process is performed after the centering process has been described, but the order of the centering process and the edge cutting process is not limited, and the centering process is performed after the edge cutting process is performed. You may implement.

Although the said embodiment demonstrated the case where the casing 4 was arrange | positioned around the existing pile 1 in an edge cutting process, the casing 4 does not necessarily need to be arrange | positioned.

Existing bottom of pile 1 cavity 3 formed in a through hole is formed, by injecting the grout between the lower end and the natural ground of the existing pile 1 from the through-holes may be pushed existing pile 1.

The existing pile 1 may be unreinforced concrete, and is not necessarily reinforced concrete. Moreover, the cross-sectional shape of the existing pile 1 is not limited.

DESCRIPTION OF SYMBOLS 1 Existing pile 2 Reinforcement 3 Cavity 4 Casing 5 Temporary receiving member 6 Hanging member 7 Cylindrical body

Claims (3)

A coring process performed coring drilling, molding the existing pile into a bottomed cylindrical shape to form the cavity in consideration of the buoyancy acting on its own weight and the existing pile of the existing pile,
An edge switching step of edge cutting and the existing pile and the surrounding ground by excavating an outer periphery of the existing pile,
Said existing pile was elevated to a pile increasing step to protrude a portion of the existing pile on the ground,
Characterized in that it comprises a cutting step of cutting a protruding portion protruding on the ground of the existing pile removing method of the existing pile. In the edge cutting step, a casing is arranged around the outer periphery of the existing pile ,
The method for removing an existing pile according to claim 1, wherein in the pile raising step, a liquid is injected into the casing.   The method for removing an existing pile according to claim 1 or 2, wherein a liquid is injected into the cavity.

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