Accession Number : AD0738779

Title :   Preshot, In situ Site Investigation Vibratory and Seismic Techniques, Pre-Gondola II, Fort Peck, Montana.

Descriptive Note : Final rept.,

Corporate Author : ARMY ENGINEER WATERWAYS EXPERIMENT STATION VICKSBURG MISS

Personal Author(s) : Curro,Joseph R. , Jr

Report Date : FEB 1968

Pagination or Media Count : 36

Abstract : An in situ site investigation consisting of vibratory and refraction seismic tests was conducted prior to the Pre-Gondola II cratering event near Fort Peck, Montana. The refraction seismic tests indicated existence of two subsurface zones. The near-surface soil exhibited a compression wave velocity range of 1100 to 1670 fps and extended from the ground surface to depths varying from 9 to 28 ft. The second zone encountered, shale bedrock, exhibited a velocity range of 5700 to 6000 fps and extended to an undetermined depth. Numerous irregularities were detected in the surface of the bedrock layer. The vibratory tests indicated initial shear wave velocities to increase uniformly with depth, from 250 fps at a depth of about 2.5 ft to 1140 fps at approximately 74 ft. (Author)

Descriptors :   (*SOIL MECHANICS, ECHO RANGING), (*UNDERGROUND EXPLOSIONS, *CRATERING), SHALE, COMPRESSIVE PROPERTIES, VIBRATION, ELASTIC PROPERTIES, SHEAR STRESSES, REFRACTION, TERRAIN, SEISMIC WAVES, SEISMOMETERS, MONTANA, NUCLEAR EXPLOSIONS, SIMULATION

Subject Categories : Soil Mechanics
      Explosions

Distribution Statement : APPROVED FOR PUBLIC RELEASE