Numerical Analysis of Dynamic Contact during Dynamic Compaction with Large Deformation

AbstractThe calculation of dynamic contact between the bottom of a hammer and the surface of soil is the key technical issue in dynamic compaction. In this paper, a large deformation hypothesis is used based on the relationship between strain and displacement. Then, nonlinear governing equations of soil, based on a finite-element approach, are established and an iterative calculation form is presented. According to the contact and separation processes of the hammer and soil, the dynamic contact conditions are given in the calculation of the dynamic contact stress. Finally, according to the energy conservation law, an optimization model is used and an additional energy equation is established. Furthermore, a specific algorithm for optimizing the model is given. The calculation results show both the time-interval changing features and spatial distribution features of the stress and displacement. The numerical results and field test comparisons of the rammed pit demonstrate that this method is effective.