Effect of gas on shear wave velocity of sandy soils densified with explosives

Abstract

Context: Shear wave velocity tests (Vs) are commonly used to estimate the increase in resistance of explosive densified soils. In some historical cases, Vs tests performed after the soil improvement process do not show a significant increase in soil resistance, even though the soil surface sits more than 0.50 m. It is believed that this response is due to the presence of gas on the soil mass. Method: This paper presents the results of monotonic triaxial tests performed on samples of dense gaseous sandy soils to evaluate the effect of occluded gas on the response to the shear wave velocity in densified sands with explosives. For sand sampling, it was collected from a loose sand deposit located in South Carolina, USA. These samples were densified in-situ with explosives, and consolidated to the in-situ effective stress conditions, which are considered representative in the conditions of effort at the moment of the densification with explosives. Results: Triaxial tests were performed under global non-drained conditions. The results of these tests show that gas causes the shear wave velocity values obtained for the gaseous sands to approximate the shear wave velocity values obtained in the saturated samples tested under drained conditions. In addition, behavior tends to be more pronounced as the soil is denser. Conclusions: These response may offer some insights as to why the shear wave velocity does not increase significantly in densified soils with explosives, even though the density increases considerably.

Keywords

• arenas sueltas, densificación con explosivos, licuación, mejoramiento de suelos, velocidad de onda de corte