D.H. Trollope Medal presentation – Soil arching in piled embankments

Dr. Louis King

Geosynthetic reinforced piled embankments (GRPEs) utilise soil arching and membrane actions to transfer embankment loads towards pile heads, and in turn, to a deeper founding stratum. These mechanisms reduce the stress acting on the soil directly beneath the embankment (subsoil). When designing GRPEs, the most common design approach is to assume a single state of soil arching develops, which is independent of subsoil settlement and pile head settlement. However, results from field trials, physical modelling and numerical modelling does not support the assumption that arching develops independent of settlement. 

Louis will present his research on physical and numerical modelling which was undertaken to gain further understanding of soil arching and how it develops as the subsoil undergoes consolidation. Small-scale model piled embankments were constructed to simulate the progressive development of soil arching while being imaged using synchrotron produced X-rays. Results from X-ray imaging show that failure surfaces develop in the granular material overlying pile heads as subsoil undergoes consolidation. These failure surfaces indicate that the soil arching mechanism above a pile head is analogous to the failure mechanism that develops beneath shallow foundations, although vertically mirrored.

A design method is proposed that accounts for the progressive mobilisation of both arching stresses within the embankment and membrane actions as subsoil undergoes consolidation by utilising an interaction diagram approach, which is shown to match the results from centrifuge modelling closely.

About the speaker

Dr. Louis King Senior Associate, FSG Geotechnics & Foundations

Dr Louis King is a Senior Associate Geotechnical Engineer with FSG Geotechnics & Foundations. Louis commenced his industry career in 2011 at Golder Associates before returning to Monash University in 2015 to complete his PhD on the topic of geosynthetic reinforced piled embankments. 

Louis’ research focused on physical modelling of the soil arching response in piled embankments, resulting in the publication of more than 10 journal and conference papers. His journal paper titled “Kinematics of soil arching in piled embankments” published in Géotechnique won the 2020 D.H. Trollope Medal. 

Since returning to industry, Louis has lead the geotechnical design of several large infrastructure and building projects, specialising in soil-structure interaction and the design of retention systems, deep foundations and ground improvement. 

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