Long-term settlements induced by a large mat foundation

A facility was constructed near Trento (Italy) in 2011-2012 to house the medical equipment for proton-beam tumour therapy. The facility's most important building had a 46 x 30 m concrete mat and weighed approximately 370 MN. The site is characterized by the presence of post-glacial soils (Upper Pleistocene): a superficial 14 m thick layer of gravel and sand, a 4 m layer of soft clayey silt and a deep deposit of sand. A monitoring system with topographical measurements and deep extensometers was installed, and a number of 2D finite element analyses were conducted during construction to evaluate the soil response under the true load history over a long period. The comparison between the experimental observations over a 4-year period and the result of the simulations demonstrated the relevance of the consolidation process of the deep clayey soil layer to simulate the foundation response over time.