ABSTRACT
The new Milan Metro Line 4 requires the treatment of alluvial soil by permeation grouting, in order to allow stations and service shafts excavation. The Line stretch underpassing the city involves the careful scheduling of site activities for minimizing the impact on the city life. An efficient grouting work management has been planned from the beginning. For each working site, geotechnical investigations have been executed, detecting stratigraphy and granulometric composition of the soil layers to be treated, showing their variability along the Line. First grout mixtures were set up in laboratory, and work organization tested on site. During the work, actually in progress, tube-a-manchette (TAM) meshes and grouting parameters are optimized for each site. Regular checks on mixture, daily examination of injection parameters and of surrounding buildings structural monitoring allow to implement a real-time management of the grouting activities tailored on each site, respecting the general work development and scheduling.
