JPH0370068B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) This invention dismantles a concrete chimney by overturning it. It concerns a method of dismantling a chimney.

(Problem to be solved by the invention) Conventionally, reinforced concrete chimneys have been dismantled by manually lowering the height by dropping the walls inward from the top, or by securing the safety of the site and around the chimney, and then removing the walls from the base. This is done by lifting concrete and overturning it.

By the way, in this latter method of overturning, the lifting is usually carried out manually or mechanically, and the workers are quickly evacuated after the last lift is done, the reinforcing bars are cut, and the start of overturning is confirmed while monitoring for signs of overturning. Demolition is carried out in this manner, but the reality is that demolition work is dangerous because it begins to fall before workers can evacuate.In recent years, chimneys have become enormous, reaching over 100 meters in height. It is not uncommon for this to happen, and as the scale of the evacuation increases, the area over which debris is scattered also expands, making the danger even greater than the time required for evacuation.

This invention was made with the aim of streamlining the demolition work and improving safety in light of the above-mentioned actual state of demolition methods that involve overturning.This invention was achieved by adopting a method of overturning after the workers have completely evacuated. This is what I am trying to do.

(Means for Solving the Problems) The present invention aims to streamline the dismantling work and improve safety and precision by using gunpowder to perform the final stage of chipping, which conventionally relied on human power.

Before blowing up a chimney with gunpowder, only a designated part of the base is pricked, and after loading the gunpowder, workers are evacuated to a safe area, and the gunpowder is ignited to topple the chimney.

The wall of the base is symmetrically suspended with respect to a predetermined falling direction from the front to the rear in a U-shape and at a required height.

The central angle and required height of the U-shaped part with respect to the center of gravity axis of the chimney are calculated based on the total weight of the chimney, the cross-sectional performance of the base section, etc.

Gunpowder is loaded at the front of the wall in the direction of overturning and at both ends of the hanging point, and the gunpowder at both ends of the hanging point located at the rear of the falling direction releases the compressive force of the main reinforcement placed in that part, and also releases the compressive force due to the explosive force. The gun is ignited slightly later than the gunpowder at the front in the direction of overturning to provide upward impact force and overturning force and to overturn efficiently and accurately.

(Example) The present invention will be described below based on drawings showing one example.

In this invention, a chimney A made of reinforced concrete as shown in FIG.
This is a method of dismantling it. 1, , , indicate cross sections taken along the WW line, the X-X line, the Y-Y line, and the Z-Z line.

Figure 2 shows an example of a chimney A with a typical height of 65 m.

The hatched parts in the figure are the cutout parts,
The dotted portions a and b indicate the charging portions of the gunpowder 2, respectively. Further, the arrow indicates the set falling direction of the chimney A, the center thereof, and the dashed line indicates the center of gravity axis.

As shown in , the hanging part is set in a U-shape symmetrically around the center of gravity axis from the front to the rear in the direction of fall, and the center angle θ is determined by the weight of chimney A, the cross-sectional performance of the base section, and the size of opening c. It is determined by calculations based on various conditions such as the height and reinforcement state of the surrounding area. It is desirable that this central angle θ is a dominant angle as shown in the figure to ensure that the device does not fall over.

Further, as shown in , the height of the suspended portion is set gradually smaller from the front toward the rear in the direction of the fall. The heights h to h' are also determined according to various conditions like the central angle θ.

The width and height of the charging portions a and b of the gunpowder 2 are also determined taking into account the above-mentioned conditions and a certain safety factor. a
The gunpowder 2 loaded in parts 2 and 3 is ignited after a certain period of time during detonation. That is, part a is ignited first, and then part b is ignited several seconds later, and the wall 1 is blown up.

Fig. 3 shows an example of a large-scale chimney A with a height of 100 m, especially when a steel frame 3 is placed around the opening c for reinforcement.

In this case as well, the central angle θ and the heights h to h' of the suspended portion are determined in the same way as in the embodiment shown in FIG. be exposed.

Next, the working procedure will be explained with reference to FIG.

First, markings are made on the wall 1 according to values such as the central angle θ and the heights h to h' of the chisel portion and the two gunpowder loading portions, which are determined based on detailed calculations (). At this time, the direction of the overturning is determined by fully considering the situation around the chimney A, the wind direction, and the wind force. In addition, for example, perform core boring at key points of chimney A such as in Figure 1, check the current concrete strength at the time of dismantling each wall 1, compare it with the above value, and correct it if necessary. .

Following marking on the wall 1, holes 1b for inserting the gunpowder are drilled in the determined gunpowder 2 loading portions a and b ().

Next, the marked portion is chiseled using a breaker 4 or the like while maintaining balance in the left and right directions of falling (), and the gunpowder 2 is loaded into the drilled hole 1d ().
At this time, the necessary number of reinforcing bars for the suspended portion are cut, and a buffer material 5 is installed at the tipping position of the chimney A to soften the impact.

After preparing to explode Gunpowder 2, all workers will be evacuated immediately and this will be confirmed.

Next, parts a and b of the two gunpowder parts are ignited one after another, and the base is exploded ().

After the chimney A falls over (), the chimney A is further broken down and dismantled using the breaker 4, and disposed of to complete the demolition work.

(Effects of the Invention) This invention is as described above, and only necessary parts of the base of the chimney are pierced in advance, and the rest is blown over after the workers have completely evacuated, which simplifies the work and reduces the work time. It is possible to shorten the time and at the same time improve safety.

In addition, since concrete chiseling is carried out based on careful calculations, it is possible to increase the certainty and precision of tipping.

[Brief explanation of drawings]

Figure 1 is an elevation view showing the entire chimney.
, , are their respective W-W lines, X-X lines, Y-Y
Figure 2 shows the implementation of chiseling and drilling of the base of the chimney, Figure 3 shows a plan view, Figure 3 shows an elevation view, and Figure 3 shows another example. 4 is a plan view, is an elevation view in the direction of overturning, is a side view, and FIGS. A... Chimney, C... Opening, 1... Wall, 1d...
...Drilling, 2...Gunpowder, 3...Steel frame, 4...Breaker, 5...Buffer material.

Claims (1)

[Claims] 1. The wall at the base of the reinforced concrete chimney is symmetrically arranged in a U-shape from the front to the rear in the direction of fall with respect to the specified direction of fall, and the required height is connected to the front of the wall in the direction of fall and both ends of the hanging point. After drilling an extinguishing hole for inserting gunpowder, load gunpowder into the extinguisher hole, ignite the gunpowder at the front in the direction of the fall, and after a certain period of time, ignite the gunpowder at both ends of the tipping point to explode the base of the chimney. A method of dismantling a chimney that is characterized by overturning it.