A new shared miniature cone penetrometer for centrifuge testing

Abstract

Cone penetrometers (CPTs) are commonly used for characterising the soil properties of centrifuge models; CPT data is useful for interpretation and quality control. This paper describes the development and design of a new robust CPT device for centrifuge testing. The new device consists of a 6mm cone, an outer sleeve, and an inner rod that transmits cone tip forces to a load cell above the ground surface. The design eliminates the need for a custom submerged strain gauge bridge near the tip, significantly reducing cost. A direct comparison was performed between this CPT device and another similar device developed at the University of Cambridge. CPT's were manufactured using the new design and then shipped to eight different centrifuge facilities, for quality control of similar experiments performed for LEAP (Liquefaction Experiments and Analysis Projects). All the centrifuge tests simulated a 4 m deep deposit of soil, all consisting of Ottawa F-65 sand with relative densities ranging between about 45 to 80%. The results obtained have been extremely valuable as an independent assessment of the density calculated from mass and volume measurements at different laboratories.