Blast-Induced Stress Wave Propagation and Attenuation: Centrifuge Model Versus Prototype Tests
Charlie, WA
Colorado State Univ., CO

Dowden NA
Terracon, Inc., Albuquerque, NM

Villano, EJ
URS Corporation, Denver, CO

Veyera, GE
Univ. of Rhode Island, Kingston, RI

Doehring, DO
Emeritus of Geosciences, Colorado State Univ., Ft. Collins, CO

(Received 13 June 2003; accepted 5 August 2004)

Abstract
This paper presents results of centrifuge model studies and full-scale field (prototype) studies designed to provide insights into the influence of water content and the degree of saturation during compaction and testing on high-strain rate loading response of medium dense sand. Objectives of the study were to determine the influence of moisture content at the time of compaction on blast-induced ground shock and stress wave propagation and to compare centrifuge model explosive tests with prototype explosive tests. Model testing was conducted using a geotechnical centrifuge to simulate prototype testing conducted at a field explosives test site. Centrifuge models were constructed at scales of 1/26.3 and 1/18.9 and tested at acceleration levels of 26.3 and 18.9 times earth's gravity. Explosives consisting of 3.50×10^-4 kg (350 mg) and 1.031×10^-3 kg (1031 mg) of PBX 9407 were buried at depths of 76 mm and 54 mm, respectively. These scaled model tests simulated prototype tests in which 7-kg TNT equivalent explosive charges were detonated at a depth of 1.4 m. Specimens were compacted to a dry density of 1635 kg/m³ at degrees of saturation ranging from 0 to 60 % (water contents from 0 to 14.4 %). Centrifuge model tests and the prototype tests showed similar results. Peak particle velocity, peak stress, and peak scaled acceleration were found to be a function of the degree of saturation with the lowest values at 0 % saturation. Lowest attenuation coefficients occurred in the sand compacted at degrees of saturation of 13 % for the centrifuge tests and 20 % for the prototype tests. Highest attenuation coefficients occurred in the sand compacted dry and at 60 % saturation for all the prototype tests and most of the centrifuge tests. Attenuation coefficients generally decreased with increasing seismic velocities.

Keywords:
centrifuge, centrifuge modeling, compaction, explosives, ground shock, instrumentation, matric suction, moisture, prototype, sand, saturation, soil dynamics, transient loading, unsaturated sand

Paper ID: GTJ12007
DOI: 10.1520/GTJ12007

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Author Charlie, WA Affiliation Colorado State Univ., CO Author Dowden NA Affiliation Terracon, Inc., Albuquerque, NM Author Villano, EJ Affiliation URS Corporation, Denver, CO Author Veyera, GE Affiliation Univ. of Rhode Island, Kingston, RI Author Doehring, DO Affiliation Emeritus of Geosciences, Colorado State Univ., Ft. Collins, CO Author Charlie WA, Dowden NA, Villano EJ, Veyera GE, Doehring DO Title Blast-Induced Stress Wave Propagation and Attenuation: Centrifuge Model Versus Prototype Tests Symposium , Committee on