Accession Number : AD0696230

Title :   EFFECT OF A CHARGE IN OVERDRILLED HOLES,

Corporate Author : FOREIGN TECHNOLOGY DIV WRIGHT-PATTERSON AFB OHIO

Personal Author(s) : Turuta,N. U. ; Panchenko,D. F. ; Danilov,N. M.

Report Date : 04 SEP 1969

Pagination or Media Count : 20

Abstract : The effect of a charge in an overdrilled hole was studied in limestone, dolomitic limestone, and dolomite of the Yelenov deposit, with special attention being given to the fracture system. The investigation shows that radial displacement takes place by means of gas pressure on the walls of the hole because of compaction in the rock by closing of joints and, to a lesser degree, because of compaction through changes in microstructures of the material. In overdrilled holes, energy of the blast is spent on crumpling, destruction of rock structure next to the charge, forming slip planes, and developing cracks. Occurrence of natural fractures is an important factor in the amount and type of shattering. The difference between the effect of a charge in the overdrilled zone and the effect in the upper part of the hole is that development of slip planes in the upper part is a brief episode in the initial stage of the explosion, whereas in the overdrilled zone the development of slip planes is a continuous and fundamental part of the whole explosion process. (Author)

Descriptors :   (*SEDIMENTARY ROCK, DRILLING), (*EXPLOSIVE CHARGES, EXPLOSION EFFECTS), COMPACTING, FRACTURE(MECHANICS), MICROSTRUCTURE, CRACKS, STRESSES, PRESSURE, FORCE(MECHANICS), USSR

Subject Categories : Mining Engineering
      Ammunition and Explosives

Distribution Statement : APPROVED FOR PUBLIC RELEASE