Interactions at the front face of EPB and slurry shield when drilling in sand

Prof. Adam Bezuijen

The construction of a tunnel with a tunnel boring machine (TBM) influences the soil in front of the TBM. Excess pore pressures are measured in saturated sand in front and around the approaching TBM, which influences the stability of the soil. The magnitude of these pressures depends among others on the soil layering, drilling velocity, permeability of the soil and the pressure in the mixing chamber. The pressure buildup when drilling starts and the decay when drilling stops depends on the plastering properties of the slurry or the foam mixture in a layer at or just in the front face. Laboratory tests have shown that the permeability of that layer depends on the slurry or foam properties, the applied gradient, but also on the amount of sand in the slurry or foam mixture. For a slurry shield, the so-called filter cake at the front face is important for stability of the front face, also when elevated air pressure is used in the excavation chamber for maintenance. Most laboratory experiments on slurry and foam infiltration are performed on saturated sand. However, partly saturated conditions occur regularly. Recent tests show the influence of saturation.
The paper presents an overview of older and recent research with respect to the slurry and foam interactions at the front face. Measurement results are explained with theoretical models.

Smart Monitoring of Tunnels

Prof. Wout Broere

Dr. Broere is a professor of Underground Space Technology at Delft University of Technology, where he obtained his PhD in 2001, and a Fellow of the International Society of Trenchless Technologies ISTT. His research interests range from trenchless technologies, large diameter tunnelling and the use of underground space to site investigation, physical modeling and offshore foundation engineering. He has been involved as a consultant in various offshore, foundation engineering and major tunnelling projects in the Netherlands and abroad and advised several municipalities on the integration of underground space in urban development.

Dr. Broere is currently Editor-in-Chief for Tunnelling and Underground Space Technology. He is a board member of the NSTT and the ISTT, a member of ISSMGE TC204 and ITA-AITES Commitee on Operational Safety in Underground Facilties and past-Animateur of ITA-AITES WG20 on `Urban Problems – Underground Solutions’. Dr. Broere currently chairs the Steering Board on Structural Aspects of Tunnels of the Dutch Centre for Underground Construction COB and is secretary for the European Tunnelling Forum EuTF working group on Preventive Maintenance and Refurbishment.

Dr. Broere has published extensively on a wide range of geotechnical engineering and underground space related topics and supervised over 250 BSc and MSc students and has been involved in multiple PhD projects. He currently leads the research programmes Futureproof Tunnels and Talking Assets 2025, both aimed at tackling the challenges in monitoring, maintaining and refurbishing aging underground infrastructure.

Deformation of Shield Tunnels Induced by Adjacent Excavation

Prof. Ren-Peng Chen

Prof. Ren-Peng Chen currently works as a professor in College of Civil Engineering and the head of Research Center for Advanced Underground Space Technologies, at Hunan University, China. His research focuses on the soil arching effect, transportation geotechnics, urban underground construction and maintenance. Prof. Chen has served as an investigator on over 50 research projects with grants received from national government agencies including Natural Science Foundation of China (NSFC), Ministry of Science and Technology (MOST), Ministry of Education (MOE), province government agencies, numerous design institutes and construction companies. He has published more than 300 peer-reviewed journal articles, and one of which won the Outstanding Journal Paper Award of ASCE. He is the nominated member of Geotechnical Infrastructure for Megacities and New Capitals (TC305), and Asian Regional Technical Committee of Urban Geotechnics of ISSMGE.

Exploiting the Renewable Energy Resources of Our Cities’ Underground

Prof. Lyesse Laloui

Prof. Lyesse Laloui is an active scientist at the Swiss Federal Institute of Technology, EPFL. He is a member of the Swiss Academy of Engineering Sciences and the vice-president for Europe of the International Association of Soil Mechanics and Geotechnical Engineering. He has a strong focus on sustainability and geo-energy topics. Prof. Laloui’s efforts to help meet society’s needs in areas such as climate change, renewable energy and the optimisation of natural resources have been recognized and awarded by the European Research Council with an Advanced ERC Grant, received Honorary Doctorate Causa Degrees from Heriot Watt University (UK) and Cluj Technical University (Romania), the “Excellent Contributions Award” of the International Association for Computer Methods and Advances in Geomechanics, the “Roberval Award”, the “RM Quigley Award” and delivered the “Vienna Terzaghi Lecture”, the “Vardoulakis Lecture”, the “G.A. Leonards Lecture”, and the “Kersten Lecture”. He is the Founder and Honorary Editor-in-Chief of the Elsevier Geomechanics for Energy and the Environment journal. His research portfolio includes 13 written and edited books and over 350 peer reviewed papers; resulting in more than 18000 citations. Two of his papers are among the top 1% in the field of Engineering. Prof. Laloui has given keynote and invited lectures at more than 40 leading international conferences.

The Reduction in Geotechnical Risk on Underground Projects Using Information Engineering and AI

Prof. Michael Mooney

Michael is the Grewcock Chair Professor of Underground Construction & Tunnel Engineering at Colorado School of Mines. He directs the Center for Underground as well as the post-graduate degree program and post-graduate online certificate in Underground Construction & Tunnel Engineering. Michael’s research involves pressure balance TBM tunneling, large diameter liner design, AI and the digital underground, and control of ground and building deformation. He has authored over 200 peer-reviewed publications. Michael was born in the UK and moved to the USA as a child. He received a doctorate in geotechnical engineering from Northwestern University and a masters in structural engineering from the University of California. Michael is a registered Professional Engineer and a consultant on numerous tunneling projects in the US and internationally.

Learning from Failures in Tunnelling

Prof. Wei Wu

Prof. Wu is director of the Institute of Geotechnical Engineering at the Universität für Bodenkultur (BOKU), Vienna, Austria. He received his PhD from Karlsruhe University, Germany in 1992. Afterwards, Dr. Wu entered the cut-and-thrust world of engineering consulting. He joined Lahmeyer International Ltd in Frankfurt, Germany in 1992. In 2002, Dr. Wu moved to Electrowatt Infra Ltd in Zurich, Switzerland. During his time at Frankfurt and Zurich, Dr. Wu had worked on some major tunnel projects of the world, e.g. Metro Athens, Greece and Gotthard Base Tunnel, Switzerland. In 2003, he was offered the chair professor at BOKU. Prof. Wu is the editor-in-chief of Acta Geotechnica, and has coordinated some large research projects funded by the European Commission.