3D Numerical Modeling of DMT Penetration and Membrane Expansion in Sand

This article presents a three-dimensional (3D) numerical modeling of the insertion and subsequent expansion processes of the flat dilatometer (DMT) conducted in sand. These processes are consecutively simulated considering an explicit finite-element numerical scheme that can cope with large deformations. The strain variation and stress fields around the DMT blade are determined during blade driving and following membrane expansion for different soil densities. It was found that the soil pushed by the blade wedge during penetration suffers a significant horizontal stress increase. However, the soil above and adjacent to the membrane recovers close to the original in situ stress level. This soil stress change caused by the blade penetration can be captured by the horizontal stress index KD. Finally, the numerical results show that KD follows the experimental data trend as a function of the soil relative density. The results of soil stiffness and friction angle obtained from numerical analyses were lower than the input values in the model (intact soil); however, they agree with experimental results.