Accession Number : AD0663830

Title :   PROCEDURES FOR PREDICTION OF GROUND SHOCK PHENOMENA BASED ON ONE-DIMENSIONAL SHOCK PROPAGATION CONSIDERATIONS. REPORT 2. EXPERIMENTAL STUDY OF LOADING-UNLOADING STRESS WAVE INTERACTIONS IN A SOIL SHOCK TUBE,

Corporate Author : URS CORP BURLINGAME CALIF

Personal Author(s) : Zaccor,J. V. ; Walter,D. F. ; Davis,V. W.

Report Date : MAY 1967

Pagination or Media Count : 200

Abstract : The report describes a definitive experimental study in which shock-induced square-wave pulses in soil were observed to give way to decaying pulse shapes, as in a gas shock tube, and rapid attenuation of peak stress occurred thereafter due to nonlinear propagation in the rarefaction. In the study three different duration pulses were applied to an 8-ft vertical column of granular material confined under boundary conditions leading to a stress-strain (Sigma - Epsilon) behavior described by d to the 2nd power Sigma/d Epsilon to the 2nd power > 0, i.e., a strain-hardening type of response. Applied stresses ranged from 50 to 500 psi. The report describes a simple modification to be applied to the prediction procedure described in the first report of this series in order to take into account, to a first approximation, the nonlinear propagation of unloading waves that occurs in real media because of nonlinear stress-strain behavior in the unloading branch. The procedure which predicts stress and motion histories based on the conservation laws, a measured constitutive relationship, and the applied pressure-time profile, is demonstrated by predicting the entire sequence of an experimentally observed square-wave pulse transformation into a decaying pulse. (Author)

Descriptors :   (*SOIL MECHANICS, STRESSES), SHOCK WAVES, INTERACTIONS, SHOCK TUBES, PREDICTIONS, STRAIN(MECHANICS), PRESSURE, STRAIN GAGES, MEASUREMENT, ATTENUATION, MOTION, LOADS(FORCES), SOILS, TABLES(DATA), INSTRUMENTATION, UNDERGROUND STRUCTURES, NUCLEAR WARFARE, PROTECTION

Subject Categories : Soil Mechanics
      Mechanics

Distribution Statement : APPROVED FOR PUBLIC RELEASE