Novel approach for investigating soft soils using the Medusa DMT

The majority of invasive geotechnical investigations through soil stratigraphy in Australia typically fall into one of two categories: conventional drilling (auger/wash-boring/mazier) with Standard Penetration Tests (SPTs) and undisturbed tube sampling, or direct push static probing (Cone Penetrations Tests, Flat Dilatometer Tests). Conventional drilling methods rely on visual, tactile logging and rudimentary penetration tests, whereas push probe methods capture continuous geotechnical data whilst often omitting sampling. Whilst both methods typically capture the necessary data, they are most often used exclusively, due to the additional time and costs incurred when used in conjunction. SMEC Australia recently undertook a geotechnical investigation in a soft soil environment and derived a methodology to incorporate both investigation methods at a singular investigation point, therefore increasing data reliability in a time and cost-effective manner.

This paper describes this methodology in detail, discussing how it optimises geotechnical investigations. It also includes a comparison between DMT test results and laboratory results.