Prediction of Soil Properties from the Concepts of Energy Transfer in Dynamic Penetration Tests

Results from dynamic penetration tests are traditionally interpreted on the basis of empirical correlations, this being a frequent criticism to these tests. An alternative rational method of interpretation is proposed in this paper from which the energy delivered to the composition of rods is used to calculate a dynamic force that represents the reaction of the soil to the penetration of the sampler (Fd). Interpretation of soil properties both in sand and clay is based on this calculated dynamic force from which the internal friction angle and the undrained shear strength can be estimated. This is achieved from a simple combination of limit equilibrium analysis and cavity expansion theory. Case studies gathered from the Brazilian experience are reported in this paper to illustrate the applicability of the proposed approach.