A time-domain nonlinear formulation for the numerical prediction of groundborne vibrations due to pile driving

In this work, a time-domain nonlinear finite element model, considering an effective semi-explicit/explicit time integration procedure, is proposed to analyse ground-borne vibrations. In this approach, stabilized calculations and reduced governing systems of equations are enabled, eliminating the typical restrains of explicit time-marching algorithms, and providing a reduced computational effort solution procedure. In this sense, the present methodology combines the best features of both explicit and implicit standard formulations. In addition, iterative computations are not necessary in the discussed semiexplicit/explicit strategy, further greatly improving the efficiency of the proposed procedure when nonlinear models are regarded. To demonstrate the effectiveness of the discussed formulation, first, the classical Lamb's problem is studied and the obtained results, regarding accuracy and efficiency, are compared to those provided by the Newmark and Bathe methods, illustrating the much better performance of the proposed approach. In the sequence, ground-borne vibrations arising from pile driving are analysed, following a parametric study. In this case, a nonlinear hyperbolic model is employed to describe the soil behavior, and an axisymmetric finite element formulation is considered to describe the coupled soil-structure model. Comparisons with standard numerical approaches and previously reported results, available in the literature, are also provided for this problem, once again illustrating the excellent performance of the proposed formulation to effectively analyse complex wave propagation models.