Investigations of andesitic volcanic debris terrains: Part 2 — Geotechnical

Abstract

Here, results of geotechnical investigations for the proposed Dominica international airport are presented. The main geotechnical investigative method is comprised of boreholes to 30 m depth with standard penetrating testing (SPT) and undisturbed Shelby tube and disturbed split-spoon soil sampling. The geotechnical investigation confirms the findings of a companion geophysical investigation, which concludes that bedrock is not likely to be encountered within the proposed depths of excavation for the airport. Geophysical and geotechnical data correlations are developed. Seismic velocity and the number N of blow counts with SPT (SPT N) appear to be well correlated by a linear model. A model relationship between SPT and seismic dynamic elastic modulus is developed using seismic velocity. SPT N is better correlated with the dynamic elastic modulus than with seismic velocity. The study shows that the seismic velocity and the derived dynamic elastic moduli can accurately predict soil strength as measured by SPT blow counts.