Predicting the role of geotechnical parameters on the output from shallow buried explosives

Experiments have been conducted to quantify the effect the geotechnical conditions surrounding a buried charge have on the resulting output. From the results obtained the critical importance of moisture content in governing the magnitude of impulse delivered is highlighted. This has led to the development of a first-order predictive model for the impulse delivered from a buried charge, based on bulk density and moisture content, allowing rapid assessment of the effect of varying the geotechnical conditions. The work utilised a half-scale impulse measurement apparatus which incorporated a deformable target plate. Impulse, peak and residual target deflections were recorded for each test. No variations the charge geometry, mass of explosive, burial depth or stand-off were considered, with the focus solely being on the effect of the geotechnical conditions on the magnitude of loading and structural response. Five different types or grades of soils were used in the work, with both cohesive and cohesionless soils represented. The effect of air voids on the impulse generated was also investigated which showed that while strongly correlated, air voids alone is a poorer predictor of impulse than moisture content.