01 columnary prismial object

It refers to a component that is always larger in size than the other two dimensions. Such as beams, columns, etc.

02 block block object

A structure in which the three-way size is generally large is called a block. Such as foundation, pier and so on.

03 thin wall structure

Structures that are always much smaller in size than the other two-way dimensions, such as walls, floors, and the like.

04 all demolition blast clean demolishing blast

All demolition blasting requires that all the exploded bodies be broken. If the machine is shipped, the block size may be appropriately larger; if manual slag is used, the broken block size should not be too large.

05 cutting and blasting joint-cutting blast

1) Cutting and blasting are divided into two situations, one is to disassemble the component, the other is to remove a part of the component, retain a part, and the retained part is not destroyed, and must use pre-cracking or smooth blasting.

2) In engineering, the plane-symmetric long-shaped shaped energy pack is mainly used for cutting metal sheets and pipes, and it is a promising process for cutting hull steel sheets.

06 Principle of cutting and blasting principle of joint-cutting blast

The cutting blasting method uses the blasting method to form a crack in the direction of the connection of the blasthole, so as to achieve the purpose of removing a part of the retaining part. According to the rock blasting mechanism, when the explosive is exploded inside the rock, it is divided into the crushing zone, the fracture zone and the vibration zone according to the degree of rock damage. The principle of cutting and blasting is to eliminate the crushing zone and control the crack zone.

07 presplit blasting

Pre-cracking blasting is to arrange a row of pre-cracking holes along the cutting joint. After the first detonation, a pre-crack is formed along the pre-cracking hole, and then the non-retained part is blasted and dismantled. Due to the pre-crack, the retained part needs to be protected.

08 smooth wall blasting

The difference between smooth cut blasting and pre-splitting blasting is that the light face is finally detonated. It is not only responsible for the formation of cracks, but also for the crushing of concrete in front of the light face.

09 thin-wall structure demolition blasting of thin wall structure

Due to the thin plate structure, it can only be drilled along the smallest dimension. Its characteristics are as follows: 1) The minimum resistance line is consistent or oblique to the direction of the blasthole, and no lateral free surface can be used; 2) The blasthole is shallow and the minimum resistance line is small. Therefore, it is very easy to produce flying stones; 3) the blasthole is shallow, the hole spacing and the row spacing are small, thus increasing the drilling and charging workload, and the blasting cost is increased.

10 floor blasting hard ground blasting

Floor refers to a pavement or site constructed of artificial materials. Demolition of concrete paved roads or sites by blasting is called floor blasting.

11 wide hole blasting of wide ground blasting of hard ground

Because the conventional floor blasting is difficult, in the engineering practice, a wide-pitch blasting technique different from conventional blasting is summarized. The key of wide-pitch floor blasting is that the depth of the blasthole is equal to the thickness δ of the floor. Generally, the hole spacing of the blasthole is 2 to 4 times that of conventional blasting, and the consumption of unit explosive is 1.5 to 2 times that of conventional blasting.

Demolition blasting of stand high buildings

High-rise structures generally refer to structures with large ratios of height and diameter, such as chimneys and water towers. They are characterized by high center of gravity and small support area, so they are very easy to destabilize and collapse or collapse under gravity to disintegrate, so the destruction of the structure is As a result of gravity, blasting is only a means of destabilizing the structure.

13 structure of water towers

The water tower is divided into two types: truss type support and cylindrical support according to its support type. The truss type support is a reinforced concrete structure, and the removal method is similar to the reinforced concrete frame structure; the cylindrical support is generally a brick structure, and the removal method is similar to the chimney removal. The top tank is generally a reinforced concrete structure.

14 chimney structure chimney structure

The shape of industrial and civil chimneys is mostly cylindrical, and a few are square. According to the materials used, it is divided into two types: reinforced concrete structure and brick structure chimney.

15 chimney removal methods demolishing methods of chimneys

There are many types of demolition methods commonly used at home and abroad, which can be broadly summarized into the following three categories:

1) mechanical removal method; 2) manual removal method; 3) blasting removal method.

16 directional blasting demolition of slim and high buildings

The main principle of the directional collapse design is to blast a blasting gap larger than 1/2 of the bottom circumference at the bottom of the dumping side, thereby destroying the stability of the structure, resulting in the instability of the overall structure and the shift of the center of gravity. The overturning moment is formed by the weight. Force it to collapse in a predetermined direction within a certain range.

17 towering buildings collapsed collapsed blasting demolition of slim and high buildings

The tall buildings are folded first and then collapsed to touch the ground. Folding collapse can be divided into two ways: one-way folding collapse and two-way folding collapse. It is preferred according to the size of the surrounding area.

18 high-rise buildings collapsed vertical blasting demolition of slim and high buildings

Destroy the bottom structure of the towering building so that it can disintegrate itself in the in-situ state by the gravity acceleration generated during the downward movement of the center of gravity and the impact force when falling on the ground under the action of its own weight.

Orientation method of directional blasting

The orientation of the chimney and water tower directional collapse is determined by its height and its horizontal distance to surrounding buildings.

20 notched shape gap shape

The blasting gap is to create good instability conditions. Therefore, the shape of the blasting gap will directly affect the accuracy of the collapse of the towering structure. At present, when the chimneys and water towers are demolished in the country, the commonly used notches have six basic shapes: rectangular, trapezoidal, inverted trapezoidal, oblique, anti-oblique, and anti-human. Among them, trapezoids and rectangles are used more.

21 notch height gap height

The gap height day is an important parameter in the design of the chimney and water tower demolition blasting. The height of the blasting gap (day) should be greater than 1.5 times the wall thickness δ of the blasting part. Usually take:

H = (1.5 ~ 2. O) δ

22 notched arc length gap arc length

The notch arc length L is the unfolded length of the notch including the length of the orientation window. According to engineering experience, the blasting gap arc length should be:

Guizhou Runde blasting

Where D is the diameter of the bottom of the chimney or water tower.

23 orientation window orientation opening

In order to ensure that the chimney or water tower can collapse in the collapse direction of the design, in addition to the correct selection of the form and parameters of the blasting gap, a window is sometimes excavated by wind or blasting at both ends of the blasting notch. This window is called a directional window. The purpose of the orientation window is to separate the remaining portion from the blasting notch portion so that the blasting does not affect the retained portion to ensure proper collapse direction.

24 blasting demolition principle of buildings

The principle of building blasting demolition is to make full use of the gravity of the building itself, according to different demolition requirements, blow up the main supporting members, so that the building loses stability or loses support in an instant, in the "sudden application" of gravity Dump, collapse, disintegrate, and destroy. Therefore, the essence of blasting and demolition of buildings is gravity removal, which is only a means of destabilizing buildings.

25 directional blasting demolition of buildings

When the surrounding site of the demolished building has a relatively open space in one direction, and the horizontal distance from the boundary of the building to the boundary of the site is greater than the height of 2/3 to 3/4 of the building, a directional dumping scheme may be adopted, that is, the building along the The intended direction collapsed.

26 destabilization condition of bearing reinforced concrete load-bearing column

When the controlled blasting method fully breaks the concrete at a certain height above the foundation of the column and makes it break away from the steel frame, the isolated steel frame cannot form the overall bending section. When the static load on the top of the steel frame exceeds its compressive strength limit or When the critical load of instability is reached, the steel bar is plastically deformed, and the column collapses and collapses.

27 building in situ collapse scheme vertical blasting demolition of building; vertical collapse of building

For general low-rise buildings and factory buildings, whether it is brick-concrete structure or reinforced concrete frame structure, as long as the horizontal distance of the building around the building is about 1/2 of the height of the building, and the aspect ratio of the building is less than 1.0, no one has an open space. At this time, it is most appropriate to adopt the in-situ collapse scheme, that is, the building (structure) collapses in the original position.

28 inward folded folding method; building inward folded method

This solution is to let the middle part of the building first collapse, and the surrounding part is then closed to the collapsed middle part to achieve complete collapse. This scheme is actually a combination of in-situ paste and directional dumping.

29 unidirectional successive folded collapse method

This solution is derived from the directional dumping program. The essence is to detonate each floor from the top to the bottom in a directional dumping manner, so that each layer of structure is continuously folded and collapsed in one direction. This blasting scheme can significantly reduce the collapse distance of the building. Generally, the horizontal distance of the collapsed site is equal to or greater than half of the height of the building.

30 two-side alternate folded collapse method

This scheme is more suitable for demolition blasting when the horizontal distance of the ground around the high-rise building is narrower, and the blasting collapse accumulation range can be controlled within the distance range of H/n (H——the height of the building, n——the number of floors of the building) ). The scheme is similar to the one-way folding scheme, except that when the top-down sequence is detonated, the upper and lower layers are alternately detonated and collapsed continuously.

31 rear seat bock ward collapse

When a building collapses under blasting, the bottom portion of the building is difficult to support the collapse of the building.

32 deflection deviation

The direction in which the building collapses deviates from the predetermined direction.

33 forward punching-up

The phenomenon of the centroid point moving forward when the building collapses.

34 towering building explosion size muckpile area of ​​slim and high buildings

The size of the towering building collapse refers to the length and width of the collapse of the chimney and water tower when it collapses.

35 base reaction force

When the blasting is dismantled, the building (structure) rotates around the fulcrum, and the reaction force generated at its support is called the bearing reaction force.