Parametric assessment of pore pressure dynamics in hydrocarbon contaminated Guwahati sand using shake table test

Abstract

This paper presents a series of systematic shake table investigations to study the influence of hydrocarbon compounds on the pore pressure response of silty sand. The effect of degree of contamination in terms of crude oil content, ω (0, 2, 4, 6, 8 and 10% crude oil v/w), depth of contamination by varying the contamination depth ratio (β) from 0 to 1, and shaking history were extensively evaluated. A uniaxial scaled down model was subjected to three sequential horizontal base shaking (at a defined time interval) of peak ground acceleration 0.35 g. The results revealed a substantial improvement in the liquefaction resistance of the sand with an initial increase in crude oil content up to ω = 6%. With further increase in ω, the liquefaction resistance falloff sharply, resulting into a single-peaked profile with the highest resistance observed at ω = 6%, which has been regarded as threshold point. The microstructural mechanism believed to be responsible for such a behavior has also been discussed. Coupled effect of degree of contamination and depth of contamination has also been discussed in viewpoint of zero change point where no net change in the behavior was recorded.