Preliminary Numerical Simulation of Centrifuge Tests on Tunnel-Building Interaction in Liquefiable Soil

This paper shows the results of preliminary numerical analyses performed to simulate centrifuge tests that will be carried out for the project STILUS within the framework of the European funded network SERA (Seismology and Earthquake Engineering Research Infrastructure Alliance for Europe). The aim of the project is to investigate the problem of tunnel-structure interaction in liquefiable soil through a series of centrifuge tests and to assess an effective mitigation technique. Two models will be tested in centrifuge, in the first one only the tunnel is modelled while in the second one a simplified structure on strip foundations is added. In order to analyze a cut-and-cover tunnel in an urban environment a rectangular section has been assumed. The tests were simulated by means of Plaxis 2D and the soil was characterized by PM4Sand model. The results were evaluated in terms of pore pressure build up, accelerations and settlements. The distribution of excess pore pressure induced around the tunnel and the building basement may also be useful to identify where mitigation techniques that may locally reduce pore-pressure build-up would be most effective against the effects of soil liquefaction and should be implemented in the forthcoming tests