摘要

The introduction of nitrogen and carbon dioxide gases into the ground during blasting increases pore fluid compressibility and thus affects the postblast mechanical behavior of densified sand. This study presents the techniques used to sample pore fluid in situ with the BAT probe at a full-scale blast densification site. Special emphasis is given to the importance of preparing sample containers prior to collecting pore fluid. In addition, a methodology to evaluate gas concentrations and the degree of saturation in situ is provided. Measurements of postblast gas concentrations reveal that gas generated by explosives significantly increases both nitrogen gas and carbon dioxide concentrations relative to preblast levels. In addition, groundwater flow is likely responsible for increased gas concentrations outside the zone after a blast. However, nitrogen gas is responsible, almost exclusively, for the saturation of groundwater with dissolved gas and introduction of free gas into the soil matrix.