Blast testing of explosive charges buried in frozen soil

Historically, most testing with shallow buried charges has focussed on soils which are predominantly quartz (silica) based. Particle size, moisture content and density have been previously investigated to ascertain the geotechnical parameters that govern the development of impulsive output. This has shown that in order of importance, moisture content, density and particle size drive the total impulse delivered. However, particle size does have a dramatic impact on the localised loading delivered to a target. The work in this paper presents testing done with frozen quartz sands, to investigate the difference that freezing the soil has on both the localised loading and the total impulses recorded using the University of Sheffield’s Characterisation of Blast Loading (CoBL) apparatus. Frozen soils have significantly different material properties, acting as a solid material instead of a cohesionless granular material. A process was developed for the preparation and blast testing of frozen soil samples and the results were then compared with the well-established Leighton Buzzard uniform sand to isolate the effect of freezing on the soil.