Deep Penetration Into Frictional Ductile And Brittle Materials

The mooring of offshore platforms and tension piles may involve deep penetration into rocks. This research was intended to study the phenomena and mechanisms of deep penetration, first through experimentation and then, based on the experimental results, by developing models for frictional, ductile/brittle materials. Penetration and pullout tests were performed under varying conditions including brittleness of the material, confining conditions, joint conditions (orientation and spacing), nose shape of penetrator and penetration velocity. By measuring the acceleration history in rapid penetration tests, the energy required to achieve a particular penetration depth was obtained. Through comparison with the results of slow penetration tests, it was also possible to assess the effect of penetration rate. In the modelling effort, the Strain Path Method (SPM) was used to analyze the deep penetration problem. The resultant model for a brittle material was validated by comparing the prediction to the experimental results. Grant no. NA86AA-D-SG089