| Abstract | Urbanizacijom i izgradnjom prometne infrastrukture javlja se potreba izvođenja opreznih
miniranja, odnosno miniranja koja s jedne strane, moraju razlomiti stijenu, a s druge strane, što
manje oštetiti stjensku masu te očuvati njena fizičko-mehanička svojstva izvan zone miniranja.
Primjena opreznih miniranja osigurava i smanjenje potencijalno štetnih utjecaja miniranja na
okolne objekte ili građevine.
Svojstva uobičajeno korištenih eksploziva u potpunosti ne zadovoljavaju tražene zahtjeve
što posebno dolazi do izražaja u uvjetima potrebe izvođenja opreznih miniranja. Istraživani
eksplozivi smanjene gustoće pretpostavljaju detonacijska svojstva i minersko-tehničke
karakteristike primjerene za uvjete opreznih miniranja.
Istraživanja su usmjerena ka izvedbi eksploziva smanjene gustoće proizvedenog na bazi
postojećih gospodarskih eksploziva, odnosno njihovih komponenata.
Provedena istraživanja odredila su sastav optimalne smjese eksploziva smanjene gustoće
na bazi emulzijske matrice s dodatkom ekspandiranog polistirena te njezina detonacijska i
minersko-tehnička svojstva. |
| Abstract (english) | Extended abstract: Due to urbanization and building of traffic infrastructure it is necessary to apply cautious
blasting, i.e. blasting which should fragment the rock mass, but on the other hand, it should also
cause the least possible damage of the rock mass in order to preserve its physical and
mechanical properties outside the blast area. Controlled blasting also reduces potentially
damaging effect of blasting on surrounding objects and structures.
The properties of explosives that are normally used do not fulfill the aforementioned
requirements, particularly when it is necessary to apply cautious blasting. Tested low density
explosives possess detonation properties and blasting and technical characteristics appropriate
for cautious blasting conditions. They are defined as explosives used for blasting operations in
mining engineering in order to achieve minimum fragmentation of crushed material, i.e. larger
fragment size, reduce blasting cost and obtain minimum damage outside the blast field.
Low-density explosives usually have densities below 0,80 g/cm3, and the explosives with
densities below 0,20 g/cm3 are called very low-density explosives.
Density of an explosive is decreased by adding materials that have substantially lower
density than explosive density. Materials that are added to explosives can be divided into two
groups: inert materials (perlite, vermiculite, glass microspheres, etc.) and materials with
combustion properties, i.e. materials that participate in oxidation reaction (polystyrene,
expanded polystyrene, polyurethane foam, coal dust, sawdust, sugar cane waste, peanut shells,
cereals, etc.).
The aim of this research is to obtain a low-density explosive manufactured by existing
explosives for civil uses, i.e. their components and other substances. That explosive will be
used for cautious blasting in order to reduce shock effect of energy released by detonation on a
borehole wall, reduce damage zone and reduce potentially damaging impact on the
environment.
The research includes laboratory and field tests. Laboratory tests include determining
borderline density of individual explosives for obtaining detonability. The decrease of density,
velocity of detonation and shock effect was done with blends of existing explosives for civil
uses with the addition of expanded polystyrene (EPS). Expanded polystyrene (EPS) was added
to explosives in different volume ratios, and different densities of new explosives that achieve
detonability were obtained. Field tests determine the effect of low-density explosive on the rock
mass, and the effect of detonation process on the environment. In order to determine the effect
of those explosives the following methods were used: crater test, determining methods for
measuring the velocity of detonation in a borehole, measuring oscillation velocities,
determining granulometric composition, etc.
Performed tests determined the composition of the optimal blend of a low-density
explosive on the basis of emulsion matrix with the addition of expanded polystyrene, and its
detonation properties and blasting and technical characteristics. |
