The management of the soil conditioning process for the excavation of the Rome Metro C line

Tunnel excavations in urban areas are often performed with TBM and Earth Pressure Bal-ance technology which requires the continuous injection of chemicals in the soil condi-tioning process. Several advantages can be achieved by performing laboratory activities prior to starting the excavation in order to predict risks such as clogging in fine grained soils or severe cutter-head wear in coarse soils and to define an optimal range of values for injection parameters. Since the in-lab reproduction of all the conditions occurring dur-ing the excavation is hardly possible, measurement performed directly on site and TBMs monitoring data analysis are relevant tools to improve the knowledge on soil conditioning process and chemicals management. For the project of the Rome Metro C line, laboratory tests and on-site measurement were performed and useful information on excavation were drawn from the analysis of the recorded data. The results provided insights on ad-vantages, limits and differences of results between laboratory-scale and on-site soil condi-tioning.