Ground deformation and blast wave propagation in dry sand subjected to buried explosion: a centrifuge modelling study

A series of centrifuge model tests of buried explosions in dry sand were designed and performed to investigate the blast effects in diverse underground explosion (UE) scenarios. The typical ground deformation pattern and blast wave propagation in different types of UE events were modelled. The excavated cratering was observed in shallow-buried excavation explosion tests. Surface collapse and subsidence craters were formed in the partially contained explosion tests, in which the initial ground motion direction turned from upward to downward with the increase of burial depth. The scaling law for centrifuge modelling of blast wave propagation was derived and examined. The critical burial depth for complete coupling of ground shock energy is within the range of 0.4 m/kg1/3 and 0.8 m/kg1/3, and the gravity effect on blast wave propagation can be disregarded under centrifugal accelerations of 62 g and 106 g (g is the Earth's gravity). The elastic blast wave velocity in dry sand was determined in the model test, and it increased with the burial depth. The attenuation laws for peak pressure and peak scaled acceleration in dry sand were calibrated, and the scaling coefficient for peak pressure estimation increased with the medium's acoustic impedance, while the attenuation coefficient showed a contrasting trend.