4th Keiichi Fujita Lecture: Interactions at the front face of EPB and slurry shield when drilling in sand

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The fourth “Keiichi Fujita Lecture” at the 11th International Symposium on Geotechnical Aspects of Underground Construction in Soft Ground (IS-Macau 2024) | Interactions at the front face of EPB and slurry shield when drilling in sand

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 of 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 build-up 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 lecture 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.

Presenter

Adam Bezuijen, Emeritus Professor, Department of Civil Engineering, Ghent University

Prof. Adam Bezuijen, an Emeritus Professor at Ghent University, boasts over 40 years of expertise in geotechnical engineering. He has been a member of TC28/TC204 since 2002, serving as the vice-chair and chair of TC204 for a decade (2012 – 2022). Additionally, he is a member of TC 104 Physical Modelling and has played roles in CEN-TC189 Geosynthetics, contributing to the standardization of test methods for geosynthetics and CE-marking. His significant contributions include advancing knowledge in face stability (emphasizing groundwater flow for slurry and EPB machines), tail void grouting, slurry properties, infiltration, cake formation, and foam properties and behavior. Bezuijen served as the promotor for 8 PhD projects and participated 19 times as a member of PhD juries. With a career spanning over 40 years at Deltares and its predecessors, as well as almost 10 years at Ghent University as a professor in soil mechanics and geotechnics, he has left an indelible mark on the field. Adam Bezuijen’s impact is further highlighted by his contribution to over 400 publications.

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