July will see the start of construction of the $29M, 2.2km long Quattro Venti rail tunnel in Rome, Italy.
The Quattro Venti contractor consortium of Astaldi/Impregilo will drive the single bore, twin track tunnel from existing stations Roma Transtevere to Roma San Pietro using a Herrenknecht 7.9m diameter EPB shield.
The geology comprises a variety of tuff, silt-clay alluvial deposits, gravel-sand and clay over the first 300m and Pliocene marine deposits of clayey silt and silty clay over the remaining 1.9km.
Groundwater pressure of 1.0-1.5 bar in the first 300m increases to 3-3.5 bar above the crown for the rest of the alignment. Overburden ranges from 2-6m for the length of the tunnel. The machine will erect a uni-ring formation of prefabricated segments bringing the final tunnel id to 7.7m.
The alignment runs under the Monteverde and Trastevere districts, a complex and highly populated urban area that has existing underground railway and municipality works. Client Ferronie dello Stato SpA has imposed stringent monitoring using a range of extensometers to gauge possible settlement. Construction detailed design has been undertaken by Italian consultant Rocksoil.
The tunnel section has been designed to double the capacity of the Rome to Viterbo line between the two stations and is considered essential for the expansion of the Rome Metropolitan railway service.
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Roma Transtevere and Roma San Pietro
