Requirements, concepts, and selected results for model tests on pile penetration

Designing and performing adapted model tests related to pile penetration is a major target of the central project of the research group GEOTECH. These tests shall allow to capture major aspects of pile penetration quantitatively and to obtain input data for numerical simulations. The tests are focused on the interaction of the pile and the soil in dry or saturated conditions. Guidelines are to keep the tests as simple as possible, realize boundary conditions that are convenient for numerical simulations, and to provide reliable information on the state of the soil at the beginning of and during the tests. Furthermore, implications induced by the measurements, e.g., lower stiffness of an instrumented pile or the use of glass walls enabling the application of digital image correlation have to be evaluated and considered in the numerical simulations as well. Examples demonstrate how the concepts have been implemented for the measurement of tip and friction force on model piles under monotonic, cyclic, and dynamic loading as well as for the evolution of pore water pressure. Based on selected results, size effects of the test devices and the role of the model material resp. its state are pointed out. The contribution includes a discussion on disturbing influences such as friction in the linear guiding system or between pile and glass wall. © Springer International Publishing Switzerland 2016.