A Methodology for Field Testing Shock Wave Propagation through Soils for the Validation of Finite Element Computational Models

Abstract

The study of blast waves propagation in soil is complicated by the variety and randomness of soil composition making modeling difficult. Current measurement methods during blast events are expensive, and sensors are expended after one use when within blast proximity. This study proposes a repeatable alternative, low-cost, material characterization test method of in-situ soil prior to conducting blast tests, confirming soil stress wave velocities and sensor functionality at a lower loading. These results can be used to tune numerical models for elastic wave propagation through the desired soil sample. The study method focuses on soil material, compaction rate, and moisture content. The method measured shock waves initiated by a piezoelectric modal hammer striking a ¾-inch thick, 7.96 in average diameter, A-36 steel plate, optimized the proposed sensor array, and compared test results to a computational finite element model in LS-DYNA, with physical soil properties ascertained from the test setup. Results of the test method and LS-DYNA models demonstrated and validated three separate geomaterial models and a simplified finite element model. Statistically significant predictions, within ±1 standard deviation of the experimental mean velocity, were determined for the three computational models. The Deployable Impulse-based Soil Characterization (DISC) Method thus improves the effectiveness of blast research both in laboratory and remote conditions and indicates the value of further development of the technique for broader and more refined applications.