Ricerc@Sapienza

Earth Pressure Balance (EPB) technology is currently the most widely used technique in mechanized tunnelling with Tunnel Boring Machines (TBMs) and particularly in urban en-vironments, because of several advantages, as the possibility to excavate in different geo-logical conditions and effectively controlling the induced effects on the pre-existing struc-tures. EPB technology requires the continuous injection of chemicals during the advance-ment: this may induce the accumulation of xenobiotic compounds in the excavated debris.

In the mechanized tunnelling with Tunnel Boring Machines (TBM), the filling process of the tail void that is created simultaneously to the advancement of the TBM between the excavation profile and the extrados of the precast concrete segments of the final lining takes on particular importance. The effectiveness of this operation depends on the injection methods and the mechanical characteristics of the injected material, which is crucial for the success of the excavation, the correct positioning of the lining elements and the reduction of the effects induced on the surface (settlements).