Partitioning of shallow buried near-field blast

Buried blast continues to present a threat to military and humanitarian operations. Burying an explosive device simultaneously hides and has the potential to enhance the subsequent blast loading. Although widely published and accepted that a buried blast load consists of a number of temporally separated elements most research instruments quantify resultant load in terms of a single impulse value. Over-pressure sensors have been used to temporally research buried blast loading, however these provide only a single point measurement to a three-dimensional loading. Understanding the temporal loading from a buried blast will support the development of more effective and innovative protection systems. In recent years there have been a number of published research efforts providing new methods and results on temporal blast loading, however how these results relate to the blast loading has not been presented in the public domain. Using a combination of computational modelling and a specifically designed scaled test rig that enabled both free-field as well as intermediate and near-field target response measurements, this research explored the quantification and the temporal phasing of a shallow-buried blast load. The target force-time response, the target side-on and face-on pressure and the target assembly displacement-time confirmed a phased free-field blast load, phased target pressure loading and a phased temporal target response. Based on published work and the computational modelling and test results from this work, three shallow buried blast load phases were identified comprising: 1. An initial soil ejecta and blast overpressure impact (Phase One); 2. Followed by gas expansion (Phase Two) and; 3. Last reflected pressure combined with afterburn (Phase Three) loading. For this research the soil ejecta primarily contributed to the blast load as part of the first phase impact and had limited contribution thereafter. The percentage phase contribution to the total blast loading is dependent on the measurement system and its characteristics. The identified three loading phases were verified ii through comparison to secondary data from both scaled and full blast load test rigs