Operation Dial Pack. Project LN305, Earth motion and stress measurements in the outrunning region
Murrell, Donald W.
Technical reportAbstract: The objective of this project was to measure and analyze ground shock in the outrunning region produced by the 500-ton Dial Pack detonation. Motions and stresses were measured at 645- and 840-foot ground ranges at depths of 1. 5, 5, 10, and 20 feet. Thirty-one of thirty-two gages produced good records; time histories are included in Appendixes A and B, and frequency response spectra are presented in Appendix C. Peak outrunning accelerations and velocities showed little attenuation over the instrumented range. The vertical peaks did not show any consistent relationship with depth, but the horizontal motions increased with depth. Since the deeper gages were close to the refractive layer, the motions emanating therefrom were stronger at depth. Vertical accelerations were greater than horizontal accelerations by a factor of 4, and vertical velocities showed a tenfold increase over horizontal velocities. Similar patterns of attenuation were noted for the displacements. However, due to additive effects of the airblast-induced motion, horizontal displacements were greater than vertical displacements by a factor of 1.9. Airblast induced accelerations and velocities were compared with the outrunning motions and were found to be depths dominant at the 1. 5- and 5-foot. At the 10- and 20-foot depths, accelerations and velocities from the two sources were about equal.
Weapons Effects Laboratory (U.S.)Engineer Research and Development Center (U.S.)
Dial Pack (Operation); Earth movements; Explosive effects; Ground shock calculations; Stress measurement
Technical report (U.S. Army Engineer Waterways Experiment Station) ; N-73-4.
Approved for public release; distribution is unlimited.