The international tunnelling community has lost one of its most innovative and productive personalities. Carlo Grandori, founder of Societa Esecuzione Lavori Idraulici (SELI), died on 17 September at the age of 91. I was privileged to attend the service in Rome where many of his friends and colleagues gathered to remember his life.
Carlo Grandori was a industrial engineer who specialised in hydroelectric construction and large dams. After World War ll, he concentrated on the tunnelling and underground aspects of this specialty and became known as an expert in traditional rock tunnelling. In the early 1960s he participated as a joint venture partner in machine tunnelling projects with his friend and TBM pioneer, Duri Prader, in Zurich, Switzerland.
I first met Carlo when he visited Seattle in 1967. He was planning a bid for the Orange-Fish project (T&TI, May 1969) in South Africa and was considering the possible application of a tunnelling machine. Although a machine was not chosen for this project, Carlo and his engineers continued to look for a machine tunnelling job they could sponsor.
After a complicated negotiation with ENEL, SELI was awarded the 4.5km Brasimone-Suviana Tunnel near Bologna, Italy, in about 1970. The rock in the 6.4m diameter tunnel was unstable and complicated and required immediate support. Carlo initiated the design of interspersing steel ribs with precast segments as close as possible to the front of the tunnelling machine. This started a trend in Europe of using precast segments in rock tunnels that would eventually extend to many other parts of the world. The unstable rock face led Carlo to suggest modifications to the cutterhead, which was the first attempt at rotary breasting or active support of the face while boring.
It was clear to Carlo Grandori that tunnel boring machines were in the early stages of development for bad rock conditions.
In-the-tunnel modifications would be required to adapt the machines to the rock, as it became apparent how the rock was reacting to the tunnel opening being bored. This initiated a life long collaboration for me with Carlo and his team.
In 1972 I brought to Carlo the idea of a telescoping shield machine with grippers located in the aft shield so that segments could be set while the boring was in progress. Carlo was intrigued and immediately began to sketch improvements to the concept. He realised that driving a machine through the rock was only one element of a successful job. Erecting supports, advancing infrastructure services and hauling out the muck were equally important tasks. The activities supporting the machine advance provided great potential for improving the efficiency of machine tunnelling.
In 1972 SELI secured the Orichella and Timpagrande tunnels in Calabria, a 4km long, 4.3m diameter, complex of tunnels in partly decomposed granite. This was to be the first application of a double shield tunnelling machine.
Carlo Grandori spent many days in his tunnels watching the machines and their trailing equipment perform. He was an active innovator and as a result the SELI double shield jobs performed with better results than could be achieved by other contractors.
After his son Remo had completed his engineering studies and military commitments he joined the SELI firm and gradually took on larger responsibilities in the machine and tunnel engineering work. Carlo shifted his concentration to unique designs of trailing or ‘backup’ equipment and segment installation.
Some years and many double shield machines later, SELI collaborated with Prader on the 7.5km long Langeten Relief Tunnel (1988-1991) in Switzerland where a double shield machine installed hexagonal segments for the first time. Carlo utilised this experience to design the backup system for the Yindaruqin Irrigation Project in China (T&TI, June 1991). This design proved to be a major step forward. The machine, operating in relatively favourable rock conditions, advanced 1,200m to 1,300m per month, while installing the hexagonal precast segmental lining. This job led to a long series of successful tunnel jobs in China.
Carlo remained active in the design of backup systems until quite recently. He designed a system for the Manabi project in Ecuador, which was only recently completed. The tunnel achieved an average advance of 64m per day.
Carlo’s technical contributions and leadership in the field of tunnelling will be missed by the entire industry. However, he was quite successful as a mentor and teacher to many people who can carry forward his design concepts and creative problem solving in tunnelling.
Carlo’s health had deteriorated in recent months, but he would recover to enjoy travel to the sea and beach walks with his family.
Son, Remo, continues leadership of the SELI company which is currently working on 16 TBM tunnel projects, from hard rock to large EPB TBMs, on five continents.
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