Nuclear explosions offer a means of reducing both costs and time for some types of major civil construction projects. Hardrock can be rapidly and predictably reduced to high-quality aggregate. Linear craters resulting from five or more simultaneous explosions can be connected to form cuts for use in highway, railroad, and canal construction. Broken rock for aggregate is produced in maximum amount by burial of the nuclear explosive deeper than for normal cratering; the result is a mound of rubble rather than a depression. The size distribution of the rubble depends primarily on the physical properties of the pre-explosion rock, especially the natural fracture characteristics. Costs are estimated at 10found per ton for a 10-kt explosion. Multiple charges produce linear craters whose shape, depth, and width depend on charge yield and spacing. Optimum conditions result in a trench with scalloping of less than 10 percent of the average width, and rubble at the trench ends of less than 3 percent of the total ejecta. Seismic shock problems are minimized by blasting the cut in separate connecting sections. Current research efforts are directed to obtaining experience and to gaining better understanding of variable (such as those resulting from surface topographic irregularities and variable geologic conditions) as they pertain to problems of crater slope stability and the use of crater fallback as foundation material. Significant recent cratering experiments in hard rock include three with nuclear explosives and eight with large chemical high explosives. /AUTHOR/

Media Info

  • Pagination: p. 18

Subject/Index Terms

Filing Info

  • Accession Number: 00263980
  • Record Type: Publication
  • Report/Paper Numbers: Proceeding
  • Files: TRIS
  • Created Date: Dec 31 1974 12:00AM