Wave Generation from Explosions in Cavities in Rock

Abstract

We have developed a measurement mehtod to monitor P- and S-waves generated from laboratory-scale explosions in meter-sized rock media at a series of stations, and invented a unique device to drill spherical cavities with diameters of up to 10 cm in rock. We have also conducted laboratory experiments in which spherical/cylindrical charges of 0.2 to 1.9 g mass were detonated at the center of spherical/cylindrical cavities with radii from 0.6 to 1.5 cm in Bedford limestone and the waves generated by the explosions were recorded in the near field within 250 mm. The reccords and post-explosion studies clearly demonstrate the P-waves generated from both explosions in cavities and crack propagation in rock. The peak particle displacement induced by P-waves ranges from 9 to 15 um at 150 to 210 mm from the source for the spherical cavity experiment with 1.9 g explosives, and 8 to 4 um at 150 to 220 mm from the source with 0.8 g explosives, 35 to 10 um at 150 to 240 mm for the tamped cylindrical cavity experiment with 1.2 g explosives and 7 to 2 um at 150 to 190 mm from the source for the decoupled cylindrical cavity experiment with 0.24 g explosives.

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Document Details

Document Type
Technical Report
Publication Date
Jun 30, 1998
Accession Number
ADA406747

Entities

People

  • Cangli Liu
  • Thomas J. Ahrens

Organizations

  • California Institute of Technology

Tags

Communities of Interest

  • Counter IED
  • Energy and Power Technologies
  • Sensors

DTIC Thesaurus Topics

  • Air Force Research Laboratories
  • Crack Propagation
  • Cracks
  • Diameters
  • Doppler Effect
  • Earth Sciences
  • Explosions
  • Explosives
  • Materials
  • Measurement
  • Nuclear Explosions
  • Oceanography
  • Secondary Waves
  • Seismology
  • Shock Waves
  • Strain Gages
  • Underground Explosions

Fields of Study

  • Physics

Readers

  • Explosive Engineering.
  • Marine Propulsion Engineering and Naval Architecture
  • Seismology