Investigation of the dynamic properties of coral sands with different water contents under planar impact

Abstract

Flyer plate impact tests were carried out on three water content (dry, 10 % and 30 %) coral sands using one-stage gas gun device. Based on the time course curve of particle velocity at the free surface of the specimen, the interaction between coral sand with different water content and shock wave propagation was analyzed, and the impact adiabatic relationship and equation of state of coral sand with different water content under one-dimensional strain conditions were determined. The results demonstrate that there are discernible discrepancies in the dynamic response of coral sand across varying water content conditions. The dielectric elastic wave velocity is observed to decrease with increasing water content. Conversely, the slope of the shock wave velocity-particle velocity (D_s-u_s) curve is seen to increase with increasing water content. The attenuation rate of shock wave propagation in coral sand is significantly affected by water content, up to 50 % in dry and 10 % water content coral sand. However, there is almost no attenuation for water content up to 30 %, and enhanced shock wave pressure may occur in the presence of reflecting boundaries.