Modeling the Influence of Soil Characteristics on the Blast Intensity of Buried Explosive Charges

Abstract

Geotechnical soil parameters and soil moisture content in particular, were found to have a significant effect on the total impulse inflicted on a structure by a buried explosive charge [1, 2, 3]. Previous research conducted by Plasan [6] quantified the blast intensity of a buried explosive charge in graded gravel by two measuring routines: steel plate deformation and flying plate. In the study, which was presented in previous IBS conference [7] an additional soil types and soil parameters where examined while utilizing improved measuring apparatus. The experimental study was conducted on three different soils: sand, clayey sand and graded gravel with silt. The blast intensity was measured by mine impulse pendulum (MIP). Results obtained indicate that saturation ratio is the most dominant factor influencing buried- charge blast impulse magnitude. Sequential to experiments, a numerical investigation was performed in order to characterize the blast and to relate its characteristics to soil type and properties. Finite element (FE) explicit simulation was conducted using Ls-Dyna. In the numeric model, impulse load was inflicted to the MIP by implementing both software embedded blast subroutines, i.e. *LOAD_BLAST_ENHANCED and *INITIAL_IMPULSE_MINE, by Arbitrary Lagrangian Eulerian (ALE) formulation and DES with Particle Blast method. In order to accurately simulate buried charge impulse load, it is required to use either ALE formulation Particle Blast or to scale reflected pressure pulse duration. The correlation of the different blast modeling methods to the test results for the different soil types and saturation degree will be presented and discussed.