Tunnel Construction Professionals
Shield Tunneling
General Manager, Shield Tunnel Engineering Department, Civil Engineering Technology Division, Obayashi Corporation Atushi TAKEDA
“The power of machines and the power of people as two wheels”
Development of shield tunneling method in Japan
The shield tunneling method, characterized by the process which takes place mostly underground with minimal impact on the environment, was developed in 19th century Europe.
Its full-scale adoption in Japan was in 1936, for the construction of Kanmon undersea tunnel, connecting Shimonoseki in the main island and Moji in Kyushu. In the 1970s and 1980s, the uniquely Japanese “earth pressure balanced” shield construction method was developed. Today, the technology is adopted around the world for roads, railroads, multi service tunnel for gas and water, and more.
Passing on the technology in the future
With the graying of society, labor shortages have become a major issue in Japan, and our department is no exception. While fewer young workers are joining our company, retiring are the experts with the knowledge and experience of the method which has been developed over 50 years. It has become increasingly difficult to pass on the knowledge and techniques of shield tunneling to the next generation.
To tackle this urgent issue, we have started business improvement and technological development incorporating ICT and AI. We are creating the environment where those with limited experience and knowledge can continue to build on the work of their predecessors.
Expectations for automated shield construction system OGENTS ®
As a concrete measure for labor shortages, we have focused on the development of the automated shield construction system OGENTS ®︎.
OGENTS ®︎ is for the automation of all six processes of shield tunnel construction, namely, automatic survey of shields, shield autonomous driving technology, automatic removal of excavated soil, automatic backfill grouting, shield facilities automation and automatic assembly of segments. It is expected to reduce the number of engineers and workers involved in shield construction by half.
Automation of each process is almost complete, and we are currently in the process of integrating them. We could say that automated construction of shield tunnels is within reach.
Development of human resources in parallel with technology development
Automation of construction work alleviates workforce shortages, but it is not a panacea for all issues, and not all automation leads to greater efficiency. It is crucial to selectively use different technologies and methods depending on different cases.
Tunnel construction deals with nature, and we cannot rely solely on machines. Responding to unforeseen accidents requires the experience and expertise of people. We strongly feel that it is necessary to develop cutting-edge technologies such as ICT, AI and automation, while at the same time to develop human resources to pass on the knowledge and skills that have been cultivated over the years.
To this end, Obayashi holds a training session every two years for each type of construction work, bringing together expert engineers of the work from all over the country. It is a chance to not just cram in knowledge, but also an opportunity for people to interact and exchange information in person.
Latest technologies and trouble case studies are also shared with field workers on site. A system for accumulating knowledge and experience as an organization has taken root.
Human resources as the foundation
While technology such as the automation of construction is advancing rapidly, I personally feel that "power of the people" is becoming increasingly important.
Shield tunneling deals with nature. Also, in recent years, remarkable technologies have been developed in the world,
especially in China. Therefore, we must not only accumulate knowledge but also humbly learn and engage in our work with global perspective and willingness to confront the challenges of nature.
Our work relies heavily on machines. We should rely on machines for the parts we need to rely on, but in the end, I believe it is important for the workers on site and their supporters to share the same sense of purpose in facing challenges.
Obayashi's corporate culture, which values people, provides the groundwork for each individual’s motivation and brings them together as “organizational strength.” We will continue to improve the power of our people as well as our machines.
