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Innovation in excavation equipment for tunnels

By Javier Sanz, construction director, ACCIONA Middle East.

Innovation in excavation equipment for tunnels
Innovation in excavation equipment for tunnels

When we think about transport infrastructure, we are thinking about nation’s development, as having a good infrastructure is synonymous of a country’s development and economic growth. Historically, the excavation of tunnels to break through mountain ranges or circumvent difficult passes facilitated the ferrying by rail and road of passengers and freight, with their subsequent social and economic benefits. Besides, the technological evolution of tunneling machines, which accelerated at the end of the 19th century and finally took off in the first half of the 20th, contributed greatly to the expansion of ground transportation worldwide.

In our region, in the case of the UAE, our leaders have developed a very detailed plan, known as Vision 2021, in which they want to ensure sustainable development to achieve a perfect balance between economic and social development while preserving the environment. The plan highlights the importance of infrastructure and aims for the UAE to be among the best in the world in the quality of airports, ports, roads and rail infrastructure.
Throughout our history, ACCIONA has participated alongside governments and users to put into practice its long experience as a sustainable solutions provider based in infrastructures, solving society’s needs. We have participated in several hundred projects that today form part of the infrastructure of many countries across the world, applying the most innovative and sustainable solutions to maximize their usefulness and minimize the environmental impact. In the past decade alone, the Company has built for example over 1,700km of roads corresponding to literally hundreds of projects.

In the construction sector, process improvement is a source of competitive advantages: innovation, quality, improved performance, cost reductions, among others; and we need to keep in mind that the excavation process during the execution of infrastructures is one of the biggest energy consumers and the correct guidance of the excavation section is vital. Sometimes the geology of the region complicates the subsoil excavation work. However, the technological evolution of tunneling machines has contributed greatly to the expansion of land transport worldwide and our leadership in the construction of roads, railway lines and suburban trains have become us in one of the leading experts in building every kind of tunnel.  

One of the critical factors in tunneling is selecting or adapting the right tunneling boring machine (TBM) and the actual need of it against a more traditional method. Selecting the specific equipment for each project is what makes ACCIONA a world leader in this sector. To meet all these challenges, in any location in the world, we own different types of TBMs: open-type main beams, single shield, double shield, earth pressure balance, hydro shield, to name a few. Our engineers and technicians are able to adapt them to any eventuality the project presents. These machines are colossal in size, worthy of admiration in themselves: they reach up to 100 meters long, with excavation diameters up to 18 meters and can weigh 2,800 tons. That is, they can be as long as nine buses, as high as a five-story building and heavy as 7 fully loaded Boeing 747s. Watching these huge cylinders open up the earth is a unique spectacle. No less astonishing is contemplating how they leave behind them a structure of perfectly assembled segments that hold up the tunnel safely. And, in production terms, our tunneling machines are powerful beasts, boring through over 1,000 meters of rock a month.

Of the more than 600 kilometers of tunnels that we have built throughout our recent history, TBMs have played a key role with more than a third of total production. These machines have participated in some of our most emblematic projects, such as the Dubai Route 2020 (Dubai Metro Red Line extension to the EXPO 2020 site); Legacy Way highway (Australia); Follo Line railway tunnels in Oslo (Norway); and Bologna (Italy), Fortaleza (Brazil) and Barcelona (Spain) metros. The use of TBMs has generated enormous benefits in these and other works that the company carries out in any location, since with its use, we are able to increase the safety, the soil stability and associated damages are reduced, a higher drilling performance is achieved and the tunnels are completed in a single phase with a higher quality finish.

Sustainability and digital transformation

The industry needs to ensure the best possible coexistence with the environment during a project; so, it is necessary to take a series of additional measures in order to avoid, for example, acoustic contamination or carbon emissions (the construction industry generates between 25 to 40% of the world’s carbon emissions). To deal with these problems, we take different measures depending on the project, like putting an acoustic ship to reduce the noise generated during the excavation work, for example. The carbon emissions issue can be solved by placing a material evacuation tape up to a kilometer long, which allows dispensing more than 180,000 trips of debris trucks to a nearby quarry. The result: we avoid the emission of more than 1,000 tons of carbon dioxide into the atmosphere, leading to a drastic reduction of the acoustic contamination in the area and the reduction of affectations to the local vegetation due to pollution and dust.

Apart from that, digital transformation plays a leading role in the applications of excavation and demolition equipment as the construction sector anticipates a technological surge: 100 billion euros is the combined value that the Davos forum has calculated for digitization from here to 2025. That is to say, the crossed effect of the industrial renewal through the emergence of the Internet will be equivalent to what the whole planetary economy generates today. A huge opportunity! The construction sector is starting to share this trend through leading digital applications that reach unprecedented levels of efficiency and boost the productivity above 150%. Besides, the gradual increase in the use of technology has a direct consequence in the improvement of the quality and safety of works and projects, reducing human errors and risk of accidents. For all this, the training of future professionals must be oriented, without further delay, towards this new paradigm.

At ACCIONA, we are working on several pilot projects on digitalization and currently applying them in large works around the world; they include augmented reality; solutions to develop pavements adapted to new challenges; and achieving an efficient, smarter and safer mobility while maintaining sustainability principles.
To sum up, we are witnessing an exciting time of increasingly accessible technologies where the construction sector cannot stay behind. That is why this new era is seen as a new opportunity based on regulation, technology and talent. We are immersed in the fourth industrial revolution that, like the previous ones, generates fear of the unknown and panic to the unprecedented. However, we have to live it in the key of opportunity, from a positive vision, adapting to development from the anticipation. Only then, we will be able to make the most of its advantages.