
Prof. Laurent Briançon
KEYNOTE LECTURES – Geosynthetic reinforced soil : from the experimentation to design methods
BIOGRAPHY:
Laurent Briançon is a professor and researcher at the National Institute of Applied Sciences (INSA) of the University of Lyon in France. He received a PhD degree in Civil Engineering from the University of Bordeaux in 2001 and, later in 2024 the title of “Habilitation” in Civil Engineering. He worked for 9 years as an Assistant Professor at the Conservatoire National des Arts et Métiers, for 2 years at the engineering consultancy Antea Group, and since 2014 as an Assistant Professor at the National Institute of Applied Sciences.
His activities involve research, teaching, and consulting in the field of soil reinforcement and geosynthetics. Laurent’s research combines laboratory tests and field monitoring approaches to propose practical design methods. He specifically worked on the reinforced platforms by GSY on cavities and participated in the redaction of the French Standard XP G38-065 on this topic. He also participated in the French research project ASIRI on the pile-supported embankment and manages the new project ASIRI+ in this field since 2019.
So far, he has supervised over 17 PhD. He has published 30 journal papers and 3 books. He is the Vice president of the French Chapter of IGS and has been a member of the technical committee of the French chapter of ISSMGE.
ABSTRACT:
Construction on poor-quality soils or with a risk of loss of bearing capacity over time is a major challenge for the planning of land and economic development of a country. Environmental considerations imposed since the 2000s have strengthened economic choices on soil improvement and reinforcement solutions. Geosynthetic reinforcement has found a place of choice in structures to reduce the risk, improve load transfer and more generally control the settlements. Geosynthetic reinforcement of the granular layers also reduces their thickness and thus limits the extraction of natural material and its transport.
These innovative techniques are often the subject of research projects that propose rules for their design and setup. These studies require laboratory experiments to identify mechanisms and characterize the interactions between soils and geosynthetic sheets. They are often paired with numerical models calibrated on the experimental results to put into equations mechanisms and eventually propose design rules. Full-scale validations are also essential for a complete engineering transfer. The diversity of geosynthetic sheets and the complexity of interaction mechanisms require R&D actions to bring together researchers, producers, and designers.
This scientific and technical path will be detailed on three geosynthetic reinforcement applications:
- For granular platforms with cavity risk
In this field, French research began in 1997 with the project RAFAEL and went on for more 20 years with full-scale experimentations, laboratory tests, DEM simulations in the projects GEOINOV or PITAGOR to result in the French Standard XP G38-065 (2020).
- For load transfer platforms of pile-supported embankment
Several research projects have addressed this topic to study the role of the geosynthetic on the efficiency of this technique. In France, two research projects investigated pile-supported embankments (ASIRI, 2012; ASIRI+, 2025) and more particularly the role of the geosynthetic in the granular platform.
- For granular platform laid over weak soil subjected to traffic loading
Two French Thesis have recently investigated this problem by developing a traffic loading simulator, performing laboratory tests at a real scale, and DEM simulations (Khoueiry, 2019; Abou Chaz, 2024). The results of these studies will be compared to others to highlight the complexity and the variability of mechanisms depending on the type of geosynthetics, their location, and the compressibility of the subgrade soil.