Comparison and analysis of experimental and virtual laboratory scale punch through tests

Laboratory scale punch through tests on floating rubble consisting of plastic blocks were conducted and simulated with a 3D discrete numerical model. The purpose was to analyse the experimental method and to validate the model. The motivation of using plastic blocks instead of ice was to simplify the interpretation of results as the plastic blocks do not freeze together. The indentor force and the lateral force induced by the rubble on one of the basin walls were recorded as a function of indentor penetration. Further, the experiments were recorded with a video camera and a motion tracking software was used to analyse the rubble deformation. The force records and deformation patterns from the experiments and simulations were in agreement. The evolution of the deformation patterns could be closely linked to the indentor force records, which demonstrates the need for the numerical model to correctly represent the rubble deformation. The experiments and the simulations showed, that the lateral force within the pile increased considerably during a punch through experiment. This makes the interpretation of punch through experiment results for material modelling challenging: the friction angle of the rubble can become overestimated making the punch through test unsuitable for achieving accurate values for friction angle. Consequently, no value for the rubble friction angle was derived here.

Comparison of rubble deformation patterns from experiments (left) and simulations (right).Figure optionsDownload as PowerPoint slideHighlights
► A discrete numerical model was compared to the experiments and validated.
► The evolution of the rubble deformation patterns was closely related to the load.
► The lateral force within the rubble was not constant during indentor penetration.
► Values for rubble friction angle are difficult to derive from punch through tests.