EXPERIMENTAL AND NUMERICAL ASSESSMENT OF DYNAMIC SOIL-PILE-STRUCTURE INTERACTION

A reliable approach for studying the seismic soil-pile- structure interaction is the physical modelling of scaled models in 1-g or n-g devices. A comprehensive laboratory test campaign, performed on the 6-degree-of-freedom 1-g shaking table of the Bristol Laboratory for Advanced Dynamics Engineering (BLADE) of the University of Bristol (UK), is illustrated and discussed in the present thesis. The experimental campaign was carried out within the framework of the Seismic Engineering Research Infrastructures for European Synergies (SERIES). The physical model comprises a group of five piles embedded in a bi-layer deposit with several pile-head configurations and equivalent cantilever systems (single-degree of freedom, SDOF). To investigate the seismic soil-pile-structure interaction, the model was subjected to both dynamic and seismic input motions. The physical model was densely instrumented with accelerometers, Linear Variable Displacement Transformers(LVDTs), strain-gauges (along piles) and a contactless displacement transducer (Indikon) for the evaluation of the settlements. Typical results of free-filed, pile and system response analyses are discussed hereafter. In order to account for the inhomogeneous shear wave velocity profile in the bi-layer deposit, an analytical close-form solution has also been devoleped and validated using the experimental data. The outcomes of the experimental campaign were used to calibrate an advanced two-dimensions difference element model, which has been implemented in the computer program FLAC2D. The comparisons between the experimental and numerical results are satisfactory for case studies, i.e. considering different input motions (static, dynamic and seismic) and for a wide range of input accelerations.