An explosive is a set of compounds or a mixture of chemicals that are capable of rapid spreading and chemical transformation, followed by the release of a certain amount of heat and gas formation. There are two groups of such substances:
- Pyrotechnic.
- Initiating, throwing, brisant.
An explosive charge is the amount of chemical or nuclear substances concentrated in a vessel (metal or plastic) having special sockets for an explosive means.
For peaceful purposes, charges are used to destroy barriers, dilapidated buildings, etc. When performing military tasks, such devices are used to destroy bridges, damage to the road surface, fragments of excavations.
The most commonly used subversive substance is pressed TNT in checkers. The latter serve for the further manufacture of charges according to the specified parameters.
The shape distinguishes:
- elongated;
- cumulative;
- concentrated;
- curly.
Each form has its own purpose. For example, curly are used to undermine various designs. Therefore, the form and thickness of the substance itself are selected individually.
The main parameters in the calculation of blasting
The essence of calculating explosive charges in the planning of subversive work or operations is the correct selection of their quantity, mass and proper location.
The volume of the affected medium directly depends on the excess pressure. Therefore, the whole calculation begins with the definition of this parameter:
D p = p - p 0.
In this case, p is the pressure at the front of the shock wave; p 0 - atmospheric pressure.
The difference between these parameters depends on the distance between explosives, the environment and the amount of charge.
The amount of overpressure is calculated in several stages: first, the estimated radius of the explosion is found, then, based on the number obtained, the actual overpressure is determined.
Having received all the necessary data, you can tentatively assess the degree of destruction of the object (complete, strong, medium or weak).
Explosion methods and charge components
The manufacture of explosive charges takes place in production, and in finished form they arrive at the warehouse, and it is also possible to manufacture them immediately before use.
There are four ways to charge explosion:
- fire;
- chemical;
- mechanical;
- electric.
In the first case, an incendiary tube is used, which is used even for underwater undermining. During manufacture, a clamping device, a special rope, and a detonator are used. Used to undermine both single and mass charges.
The electrical method of driving an explosive charge is effective for detonating an entire group of charges at a specific time. For its manufacture, a number of measuring instruments, an electric power source and an electric detonator are required.
Features of undermining various elements
Explosive material is selected individually for each structure and volume of an element. For instance:
- To undermine wooden structures, logs, beams, contact and non-contact charges of various shapes are used. In this case, non-contact charges should be only concentrated.
- Steel and other metal structures can only be undermined by contact external elongated, also the explosive charge can be concentrated or figured.
- Concrete and reinforced concrete structures are undermined by contact and non-contact external and internal charges.
Marking of concentrated charges
Each explosive charge package is marked with a waterproof paint. For most stocks, the symbols are standard and consist of:
- Product code (for example, SZ-1 stands for "concentrated charge").
- Next, 3 digits are indicated by a dash. Such numbers indicate the factory code, batch number and year of manufacture (in order from left to right).
- The code for the explosive is indicated below (for example, T - TNT). If the substance is educational, instead of marking, a long white strip is affixed.
