CPT and T-bar Penetrometers for Site Investigation in Centrifuge Tests

Geotechnical design is based on site investigations which provide a reasonable overview of the soil profile and a realistic estimate of the geotechnical properties of each component layer. Nevertheless, when centrifuge modelling is involved, in situ tests become an additional challenge mainly because of limitations of in-flight procedures, but also due to the miniaturization of regular tools. As centrifuge modelling is becoming widespread, mostly as a result of decreasing electronic and computer costs, miniature site investigation tools are being designed to provide proper geotechnical information about model layers. This paper examines the development of site investigation tools to assess the strength of models during centrifuge tests. These tools are a T-bar penetrometer and a Cone Penetration Test (CPT) apparatus capable of measuring the resistance of clay and granular soils, respectively. These tools were used in a number of centrifuge tests on clay soils and silty tailings respectively. Both tools were tested and the results compared with centrifuge tests, in situ conventional tests, triaxial and direct shear laboratory tests showing an overall consistency and reliability of the measured data.