Validation of Medusa DMT test procedures in Fucino clay

The Medusa DMT is a self-contained, fully automated cableless probe able to autonomously perform dilatometer tests using a blade of standard dimensions. The pressurization is applied using a hydraulic motorized syringe which actuates a volume controlled expansion of the membrane. This procedure is highly repeatable, operator-independent and capable to impose a programmable pressurization rate for achieving the DMT pressure readings. The motorized syringe, controlled by the electronic board, is also able to maintain the membrane in equilibrium with negligible displacement, allowing to implement alternative test procedures. This paper illustrates the results of a field-testing campaign specifically planned to validate/compare different Medusa DMT test procedures at Fucino-Telespazio (Italy), a well-documented benchmark test site constituted by a geologically NC, cemented, quite homogeneous soft lacustrine clay of high plasticity. The comparison of results obtained by Medusa DMT adopting three different test procedures (Standard, Repeated A-readings, A-reading while penetrating) and by traditional pneumatic DMT indicates substantial accuracy and consistency of measurements provided by all test procedures.