Controlled Perimeter Blasting in Cold Regions.

• Main Author: Mellor,Malcolm
• Other Authors: COLD REGIONS RESEARCH AND ENGINEERING LAB HANOVER N H
• Format: Text
• Language: English
• Published: 1975
• Subjects: Civil Engineering; Ammunition and Explosives; *EXPLOSIVE CHARGES; *COLD REGIONS; *EXPLOSIVES; *DETONATIONS; CONTROL; ROCK; SOIL MECHANICS; ROCK MECHANICS; EXPLOSION EFFECTS; SOILS; CONSTRUCTION; ICE; HOLES(OPENINGS); BLAST; HARBORS; ANTARCTIC REGIONS; ROCK DRILLING; ICE ISLANDS; McMurdo Sound; Presplit blasting; Smooth blasting; Controlled perimeter blasting; PE62710A; AST32; Antarctic; Antarc*; Iceberg*
• Online Access: http://www.dtic.mil/docs/citations/ADA047367; http://oai.dtic.mil/oai/oai?&verb=getRecord&metadataPrefix=html&identifier=ADA047367

The general principles of pre-split blasting and smooth blasting are described, and practical procedures that have been developed for work in common rocks are reviewed systematically. The topics covered include shothole spacing, charge weight per unit length of shothole, decoupling ratio, adjustments for explosive type and rock type, and weight of explosive per unit face area. Relevant properties of frozen rocks, frozen soils, and ice are compared with those of common unfrozen rocks, and appropriate adjustment of blast design is discussed. Interim relationships for the design of controlled perimeter blasting in frozen soils and massive ice are put forward, recognizing that additional experimentation is required. Special problems in controlled blasting of ice are discussed. These include effects of wet holes, delayed removal of burden, and submerged burden. Special attention is given to the cutting of ice islands and icebergs. An Appendix describes an operation in which the face of the ice wharf at McMurdo Sound was trimmed by pre-split blasting. (Author)