HERRENKNECHT Mighty breakthrough for Europe's biggest boring machine

In Italy, the largest tunnel boring machine ever used in Europe successfully completed its drive in June. The supersize borer (Earth Pressure Balance Shield, diameter 15.87 meters) made by Herrenknecht in Schwanau, Baden/Southern Germany, dug 7.5 kilometers of highway tunnel through the Apennines. In cooperation with the customer, Herrenknecht designed a new system for the machine, to protect particularly the site crew from the expected methane gas deposits in the ground.

On June 8, 2020, the largest tunnel boring machine (TBM) built and used in Europe crowned its tunnelling mission with a mighty breakthrough. With this project milestone, the machine from the Schwanau TBM manufacturing plant with an XL diameter of 15.87 meters completed 7.5 kilometers of particularly complex tunnelling through the Italian Apennines.

Following the specifications of customer Pavimental S.p.A., Herrenknecht designed and manufactured an EPB machine (Earth Pressure Balance Shield). Working closely with the contractor, the Herrenknecht engineers tailored the tunnel boring machine to the specific requirements of the project. Among other things, they implemented a comprehensive warning and protection system to reliably protect the site crew against potential dangers from the methane gas deposits predicted underground during the advance. This foresight paid off.

The large three-lane "Santa Lucia” tunnel newly excavated by the Herrenknecht EPB Shield is a key project in the expansion of the A1 highway between Bologna and Florence. Thanks to optimized routing on the previously winding highway, the efficient tunnel will reduce the likelihood of accidents as well as travel times and thus the gasoline and diesel consumption of tens of thousands of cars and trucks a day.

Following just 12 months of design and assembly, in August 2016 the EPB Shield was punctually ready at Herrenknecht in Schwanau for formal acceptance by the contractor and representatives of the client, Autostrade per l’Italia S.p.A. After the start of tunnelling in July 2017, the Pavimental miners drove up to 122 meters of tunnel per week through the Apennine mountain range with the 4,800 tonne colossus. During the long drive over 7.5 kilometers, the EPB machine with its large diameter of 15.87 meters excavated a total of around 1.5 million cubic meters of soil and rock. This corresponds to almost two thirds of the volume of the Cheops pyramid.

Italian contractors and infrastructure projects are known and respected worldwide for very large tunnel boring profiles and complex tunnel geologies. Herrenknecht is areliable pioneer partner to them with matching expertise and innovative ability. With the production of the Santa Lucia machine, Herrenknecht beat the existing European record for TBM diameters of 15.55 meters. It had been held since 2010 by the Herrenknecht EPB Shield for the Sparvo tunnel, also for the expansion of the A1 motorway in Italy.