Italy’s record-breaking Riva tunnel achieved by dedicated engineers and workers
On the agenda of the President of the Republic, visiting Riva on July 8th, is a stop at the new Gardesana gallery among various commitments. Ciampi, it is said, is particularly keen on this visit because he wants to personally congratulate the workers of the construction site opened on March 8th.
The Head of State has learned that the Riva tunnel is a record-breaking tunnel, as confirmed by research from the Facoltà di Ingegneria di Trento. Never before in Italy had a tunnel longer than one kilometer been constructed in such a short time. Kudos to the Province – with its administrators, officials, and technicians – but especially to the men who, working day and night, challenged the millennia-old hardness of the dolomitic limestone.
The Construction Site and the Workers
When we tell the chief engineer about this «breakthrough», he smiles with satisfaction. Duilio Coatti, 50 years old, with eighty kilometers and 600 meters of tunnels completed (his personal record, gained both in Italy and abroad: Brazil, Panama, and Turkey), has a suntanned face furrowed by deep wrinkles and bloodshot eyes. The sun, the dust raised by trucks loaded with crushed rock… and above all, the hours of sleep lost.
To oversee a construction site open 24 hours a day, six days a week (Sunday is reserved for mechanical maintenance) for three months, requires people willing to sleep an average of 3-4 hours per night and possess a great passion for their work.
«The workers – he explains – feel more at ease knowing that the chief engineer is nearby. They are also more motivated; they work with great energy. And here, a united team was needed. Between 50 and 54 men divided into four crews, one for each entrance. Three shifts: from 6 am to 2 pm, from 2 pm to 10 pm, and from 10 pm to 6 am. Four people in the direction, a bookkeeper, and two surveyors».
Organization and Work Method
Not many when you think about it, considering the result. «Fundamental – adds Coatti – is the organization. A barbaric organization, thanks to which the construction site functions like a well-oiled gear. At the northern entrance, they start drilling the rock with the Jumbo, a kind of excavator with four arms, each making a 5-centimeter diameter hole three meters deep (for each «blast», the section of mountain being blown up with dynamite, 110 holes are required, ed).
Simultaneously, at one of the intermediate entrances, work is in a phase, the second, which begins with manually inserting the dynamite charges, and then proceeds to the next phase. That of the workers near the upstream entrance, while those in the south are engaged in the final phase. It was like having not just one, but four open construction sites.»
If it hadn’t been necessary to create a «window» 166 meters deep to work on four fronts simultaneously, Coatti affirms with modest pride, they could have completed such a tunnel in a month and a half.
Conclusions and Technical Aspects
The chief engineer adds that a bit of luck is also needed. None was lacking in the Sperone tunnel. The only, modest problems that slowed down the work were some small clay faults and water. Trivialities: in May alone, men and machinery from the Collini-Oberosler consortium excavated 465 meters of tunnel, as if using a roadheader.