Observed and predicted settlements induced by the construction of hydraulic tunnels in Buenos Aires

The paper deals with the main results of 3D numerical analyses carried out in order to simulate the tunnel construction for the real case of "Tuneles aliviadores del emisario principal del arroyo Maldonado" in Buenos Aires. Full 3D numerical analyses are also developed to study the interaction between tunneling excavation and a tall concrete building. The numerical models take into account the main features of excavation process with Tunnel Boring Machine (presence of shield, face pressure, tail void grout injection); a realistic structural model of the building is also used. Due to the very small level of deformation expected, a simply elastic perfectly plastic with Mohr Coulomb strength criterion is adopted; values of stiffness parameters are selected at very small deformation level. Soil parameters were determined by means of in situ and in lab experimental test results. Comparison between the monitoring data and numerical results shows the good forecast capacity of the geotechnical model developed and encourages utilizing of 3D analysis as a valuable tool in tunnel design in urban areas.