Hard rock subsea tunnels - investigation, planning, excavation and rock support & Design of underground excavations and the significance of Eurocode 7  

The NTU-JTC Industrial Infrastructure Innovation Centre organised two seminars on Wednesday, 20th February 2013.  The speaker was Professor Bjørn Nilsen, Professor of Geological Engineering from the Norwegian University of Science and Technology.

The first seminar was titled “Hard rock subsea tunnels - investigation, planning, excavation and rock support”.  Norway has more than 15 subsea tunnels for oil and gas pipelines, water supply and sewage and the deepest of such tunnels goes down to almost 300 meters below sea level. This seminar discussed the characteristics of the Norwegian subsea tunnels, the geological conditions and the main methodology regarding geological investigations, design and excavation. Professor Nilsen also presented interesting plans for a 25 km long road tunnel going down to 400 meters below sea level.

The second seminar was titled “Design of underground excavations and the significance of Eurocode 7”. The first part of this seminar focused on the basic design procedure for underground openings, covering factors such as location, orientation, shaping and dimensioning. The second part of the seminar covered the significance of the new European Standard for geotechnical design: Eurocode 7. The concepts of Reliability Class, Degree of difficulty and Geotechnical categories was discussed, as well as the four alternative design principles that may be used according to Eurocode 7.

Professor Bjørn Nilsen has 40 years of extensive experience in engineering geology, rock mechanics and rock engineering, including field investigations, planning and design of underground excavations and high rock slopes, stability analyses, preparation of specifications/tender documents and construction control. His current projects consist of subsea tunnelling, engineering geological aspects of mechanical excavation, hydropower projects and slope stability. He has been involved in preparing national code and guidelines for road tunnels and other types of rock engineering in Norway.

The seminar was well attended with more than 80 participants from NTU, industrial partners and statutory boards. After the seminar, NTU-JTC I3C’s Co-Director, Professor Lu Ming presented a token of appreciation to Professor Nilsen.