DEM modelling of dynamic penetration in granular material

Abstract

Dynamic penetration has been widely employed in some site investigation procedures and for the installation of driven piles. A 3-dimensional discrete element method model has been developed to simulate dynamic rod penetration into a calibration chamber. The chamber has been filled with a scaled analogue of Fontainebleau sand. A novel method for simulating the physical rod as boundary condition is presented. It is shown that the method leads to a good agreement in static penetration comparisons. A parametric study of involved variables shows that penetration increases with force magnitude and impact time but tip resistance is quite insensitive to them. The tests are then extended to six conditions that combine two density levels and three confining stresses. It is found that increasing the confining stress does increase tip resistance, whereas it reduces penetration distance. As expected, penetration in dense sand results in larger penetration resistances and smaller penetration distances.