Blast loading characteristics of shallowly buried explosive in In-Situ residual soil

Detonated landmine transfers blast load upwards above ground. However, the transmitted blast load magnitude depends on the type and condition of the soil where the detonation occurred. Although many studies have been carried out to investigate soil effects and quantify blast data regarding landmine detonation, no data on the effect of soils in natural conditions are available. Most of the previous shallow-buried blast experimental works were laboratory-based, involved large testing facilities and were mainly carried out in remoulded soil beds. In this study, a 1/10th scale test apparatus consisting of a 0.5 m x 0.5 m square steel jig and a five mm-thick steel target plate was used to quantify blast loading in in-situ residual soil. A high-speed video camera and a piezoelectric shock accelerometer were used to measure the blast loading parameter. The landmine explosion simulation was replicated using a 20- gram high-explosive charge detonated at a constant depth of burial (DOB). By using small-scale test setups, this study aims to measure blast loading intensities and the effect of ejecta on amplifying the velocity of translated above-ground-structure during blast events on in-situ soil. Test results showed that the average energy transfer in detonation in in-situ ‘Bentong’ residual soil was four times higher than silica sand. The second upsurge in plate acceleration was also detected during detonation in soils which emanated from the impact of ejecta. The upsurge amplified plate velocity to about 18% and 20% in in-situ soil and silica sand test, respectively. Correlation of test results observation and ‘detonation phases in soils’ with post-test crater profiles showed that unique crater properties and profiles in silica sand bed and in-situ ‘Bentong’ soil delivered distinct blast waves. Unique crater’s profile transmitted distinct ejecta characteristics that consequently amplify the magnitude of blast load.