Study of acoustic response of an object buried in sand with different water contents

The work is aimed at solving the problem of humanitarian demining by creating a laser-acoustic complex using a laser Doppler vibrometer for detecting landmines buried in the ground. The parameters of the acoustic response of a plastic mine simulant buried in sand at different depths were investigated. Dry sand and sand with various moisture degrees (5, 10 and 15%) were used in the studies. Soil vibrations were excited by acoustic white noise. It was found that the vibration spectra of the object buried in soil exhibit several resonances, the amplitude and frequency of which depend on burial depth and soil humidity. Specifically, immersion of the object in the sand resulted in a decrease in the vibrational amplitude and a shift of the resonance frequency. The latter demonstrated non-monotonic dependence on the burial depth. It was established that the nature of the acoustic vibration spectra of the soil surface allows for an unambiguous conclusion about the presence or absence of an object in the soil. The research results make it possible to increase the accuracy of object detection and identification.