JP7709632B2 - Method for toppling a tower-like structure using an anchor ring as a toppling axis - Google Patents

Description

The present invention relates to a method for toppling a tower-like structure such as a power-generating wind turbine, in which the tower-like structure is toppled for dismantling by using an "anchor ring" that is embedded in a concrete foundation, located about 500 mm to 800 mm above the ground, and firmly connected to the tower-like structure above it as a toppling axis.

Structures are demolished due to deterioration over time or to replace equipment, but if the structure in question is a tall, so-called tower-like structure, the standard procedure is to set up scaffolding, begin by dividing the structure into smaller pieces at the top, then use a crane or other device to lower it down to the lower sections, and finally remove the foundation.

In order to reduce the amount of work at height during the above-mentioned demolition, thereby increasing the safety of workers and reducing the amount of labor required to complete the demolition quickly, known techniques for knocking down tower-like structures for demolition include those disclosed in Patent Document 1 (Method of knocking down a regenerative furnace for a hot air stove) and Patent Document 2 (Method of knocking down a tower-like structure using its foundation).
The technology disclosed in Patent Document 1 relates to a technique in which the base of a structure is reinforced in some way to ensure an axis of toppling, and then the direction of toppling is controlled by cutting into the structure itself, thereby ensuring safe toppling.
The technology disclosed in Patent Document 2 has been developed from the issues with the technology in Patent Document 1, and relates to a technology that realizes safe toppling by forming a strong axis of toppling by cutting out the concrete foundation and controlling the toppling direction. The bottom of the tower-like structure and the concrete foundation are fixed with flanges and bolts, and it is a so-called "anchor bolt type" structure.
The notches in Patent Documents 1 and 2 are less than half the size of the bottom, and even with the notch, the center of gravity is still on the safe side of the tipping axis, so an external force must be applied to start the tipping, resulting in a forced tipping. For example, Patent Document 2 describes a method of using a jack to push up the device.

Patent No. 4790357 Relisted No. 2018/189852 (Assessment date 2021/08/10)

In Patent Document 1, the axis of overturning is created by reinforcing the base, and in Patent Document 2, the axis of overturning is created by utilizing the strength of the concrete foundation. The most important issue in the overturning method is where to find a strong axis of overturning.

According to Patent Document 1, there is a method for dismantling a tower-shaped structure, a "hot air stove regenerative furnace," in which filler is packed into the bottom of the cylindrical regenerative furnace to increase its strength, and this part is cut out to prevent buckling due to insufficient strength when the furnace is overturned. This limits the direction of overturning, allowing the furnace to be overturned safely.

However, the process of filling the concrete with filler requires time and waiting time while the filler hardens. In addition, the filler becomes industrial waste at the final stage of demolition.

According to Patent Document 2, without using the "reinforcement of the cylindrical lower part" as in Patent Document 1, a concrete foundation buried in stable ground is utilized, digging down to the concrete foundation, cutting into the concrete foundation to create a strong axis of toppling, limiting the direction of toppling and ensuring safe toppling. However, the work of digging down to the concrete base requires a lot of man-hours.

In this invention, an "anchor ring" that is embedded in a concrete foundation and is located about 500mm to 800mm above the ground and is firmly connected to the tower-like structure above it is used as the tipping axis. The upper and lower parts of the anchor ring have flanges with a thickness of 100mm, and the top and bottom are bound by tightening nuts on bolts inside the tower. It can be said that the thickness and circular structure form a strong plate. The lower part of this anchor ring is cut in the tipping direction to create a notch larger than half of the bottom of the plate, and the center of gravity of the entire plate is on the tipping axis side, and a state is created in which the stationary state is maintained by the "resistance of the anchor ring" and the "resistance of the remaining bolts (although the bolts that were in the cutout part are removed) ," and then, while holding the bolts on the tipping axis, the remaining bolts are cut from the inside to the outside (or cut from the outside to the inside), and at some point, the remaining bolts cannot withstand the tipping force and are torn off, causing the tower-like structure to naturally tip over and topple.

The invention described in claim 1 to achieve the above object is:
The method includes a horizontal cutting step of cutting the lower part of the anchor ring horizontally to a position larger than half of the bottom and determined by a pre-calculated method, a notch creating step of cutting the lower part of the anchor ring diagonally upward from the lower part toward the central cross section of the horizontal cut, an attachment step of welding an iron material to the notch portion to protect the tipping axis (to prevent it from spreading), and a tipping step of tipping the tower-like structure by the tipping axis on the anchor ring, with the meeting line of the horizontal cutting step and the notch creating step as the tipping axis.

With this configuration, there is no need to "fill with filler and then dispose of it later" as in Patent Document 1, nor is there a need to "dig down to the huge base buried in the ground" as in Patent Document 2.The tower-like structure can be easily, safely and quickly toppled using the anchoring, a strong part of the tower-like structure, as the axis of toppling.

In this type of toppling, the anchoring, a strong part that is part of the original structure, is used as the strength of the toppling axis (toppling fulcrum), which makes it possible to resist buckling and the tower-like structure can be toppled in the planned direction, making it safe.

The invention of claim 2 is characterized in that the center of gravity of the entire structure is moved to the tipping side of the tipping axis, and the bolts are sequentially cut from a state in which the structure is restrained by the resistance of the anchor ring and the tension of the remaining bolts, allowing the structure to tip naturally without applying a large external force.

According to the present invention, the lower part of the anchor ring is cut horizontally, and then a notch is made diagonally upward from the lower part and removed, and the tower-like structure is toppled using the meeting line between the horizontal cut and the diagonally upward cut as the axis of toppling. This makes it possible to easily overturn the tower-like structure.

By making the notch larger than the radius of the tower and bringing the center of gravity of the tower toward the tipping side rather than the tipping axis, the tower can be kept stationary using the resistance of the anchor ring and the tension of the remaining bolts, and then the bolts can be cut off from that state, allowing the tower to tip naturally without the need for a large external force.
The overturning can be carried out without the need for "extra reinforcement" or "large-scale excavation of the ground" as in Patent Documents 1 and 2.

FIG. 1 is a side view showing a tower-like structure according to an embodiment of the present invention. FIG. 1 is a diagram showing the anchor ring according to the present embodiment and the surrounding cuts, notches, and overturning axes.

Figure 3 - Figure 5

11A and 11B are diagrams illustrating bolt cutting in a down-setting process according to the present embodiment;

FIG. 6

This is an external view of the fallen object.

Figure 7-Figure 8

A diagram showing the difference between the "anchor ring method" and the "anchor bolt method"
be

Next, an embodiment of the present invention will be described in detail with reference to the drawings.
A method for knocking down a tower-like structure for dismantling it will be described with reference to Figs.
FIG. 1 is a side view showing a tower-like structure according to an embodiment of the present invention, FIG. 2 is a diagram showing the anchor ring and the surrounding cuts, notches, and overturning axis in the method of collapsing a tower-like structure, and FIGS. 3 to 5 are diagrams showing the bolt cutting in the collapse process according to this embodiment.

As shown in Fig. 1, in this embodiment, the tower-like structure 10 is a wind turbine for generating electricity, but the tower-like structure of the present invention is not limited to a wind turbine for generating electricity. For example, even if it is not a single tower, a similar structure may be used for a pillar supporting a heavy object.

The term "anchor ring" is a general term for "a strong plate built above a concrete base for connecting to a structure above it," and its shape is not limited to that shown in Figure 2.

The tower-like structure 10 is connected via a tower 12 with an anchor ring and fixed to a foundation 13 .

Next, each step of the method for collapsing a tower-like structure of the present invention will be described. The method for collapsing a tower-like structure of the present invention includes a horizontal cutting step, a notch forming step, an installation step, and a collapsing step.

[Horizontal cutting process]
Next, a horizontal cut is made under the anchor ring while holding the bolt, up to a pre-calculated distance 21, which is greater than the radius of the bottom. The cut can be made by, for example, melt cutting or by using a wire saw or the like.

[Notch creation process]
Next, a cut is made from below the cut surface obliquely upward toward the central cutting line 22 to form a notch. The cutting can be performed by fusion cutting, or a wire saw or the like may be used.

[Installation process]
Next, the cutout portion made in the cutting process is reinforced. Reinforcement can be achieved, for example, by welding a steel material (not shown) in the same direction as the tipping axis 22. This prevents the cut from opening up when the structure is toppled, causing the tipping direction to deviate from the plan.

[Falling process]
Next, in the process of toppling, since the center of gravity is on the tipping side in this invention, no external force strong enough to prevent tipping is required as described above. In order to prevent the tipping axis from shaking and maintain its strength by holding the bolt 31 (two bolts are held on each side in the figure, but any number can be used depending on the situation), the bolt is cut horizontally from the inside to the outside (or from the outside to the inside) under the anchor ring while avoiding the bolt (see Figure 3), and the remaining bolts are cut one by one. This can be done remotely using a wire saw (not shown in the figure), so it can be achieved even if the worker is not near the site just before the tipping, which is also beneficial for ensuring the safety of the worker.

In the above embodiment, a power-generating wind turbine is used as an example of a tower-shaped structure, but this is not limited thereto, and any tower-shaped structure that is constructed using an anchoring method may be used.
The difference between the anchoring method for fastening tower-like structures in this invention and the anchor bolt method, in which the bottom part of the tower-like structure is fastened to the concrete foundation, is shown in schematic diagrams and photographs in Figures 7 and 8.

10 Tower-like structure 12 Tower 13 Base 20 Anchor ring 21 Distance determined by calculation 22 Center cutting line (= overturning axis)
23 Notch portion 31 Bolt 32 Wire saw (only wire is shown)

Claims (2)

A method for performing toppling while utilizing anchoring of a tower-like structure, comprising the steps of:
A method for knocking down a tower-like structure comprising: a horizontal cutting step of cutting the lower side of the anchor ring horizontally to a position larger than half of the bottom and determined by a pre-calculated method; a notch creating step of cutting diagonally upward from below the base flange of the anchor ring toward the central cross section of the horizontal cut ; an attachment step of welding a support material to protect the tipping axis to the notch portion; and a toppling step of using the meeting line of the horizontal cutting step and the notch creating step as the tipping axis to topple the tower-like structure by the tipping axis on the anchor ring, characterized in that the anchor ring is used to create a strong tipping axis and topple the structure. The method for toppling a tower-like structure described in claim 1 is characterized in that the center of gravity of the entire structure is moved to the tipping side of the tipping axis, and the bolts are sequentially cut from a stationary state caused by the resistance of the anchor ring and the tension of the bolts connecting the upper and lower flanges that were not cut off in the notch forming process, and at a certain point the remaining bolts are unable to withstand the tipping force and are torn off, causing the structure to tip naturally without applying a large external force.