Award-winning papers in 2022

The Crampton Prize, presented for the best paper on geotechnics practice, was awarded to Royston et al. (2022).

Large-diameter open caissons are a widely used construction solution for deep foundations, underground storage and attenuation tanks, pumping stations, and launch and reception shafts for tunnel boring machines. The sinking phase presents a number of challenges during construction, including maintaining caisson verticality, controlling the rate of sinking and minimising soil resistance through the use of lubricating fluids. This paper describes the instrumentation and monitoring of a large-diameter caisson on a UK construction site. The caisson was instrumented for the measurement of settlement and tilt, soil–structure interaction contact stresses and structural performance. A key objective for the monitoring project was to provide real-time feedback to the site engineering team to inform the construction process. The monitored data revealed the occurrence of complex soil–structure interactions during sinking that are not readily captured by existing prescriptive design approaches. This case history provides valuable information for the development of an improved basis for design as well as an important frame of reference for future monitoring projects.

The Tso Kung Hsieh Award, presented for the best paper on earthquake engineering, seismic effects and structural dynamics, was awarded to Williams (2022).

Liquefaction assessments for tailings facilities have significant uncertainty, yet their results are typically presented as single-value deterministic factors of safety (FoSs) to compare against standard practice guidance. Some of the uncertainty is due to inherent material variability or measurement error associated with in situ testing techniques. There is also a considerable – and often ignored – contribution from the transformation models used to convert in situ measurements to design parameters. For seismic liquefaction assessments, the key sources of transformation model uncertainty are from the empirical relationships relating standard penetration testing or cone penetration testing (CPT) results to cyclic resistance and residual undrained strength. While the uncertainties associated with the material variability and measurement error will vary by site and can usually be reduced through additional investigation, the model uncertainties are constant and irreducible without further work. This paper shows how the transformation model uncertainties associated with CPT-based liquefaction assessments can be incorporated into design practice to estimate probabilities of failure and lead to very different outcomes than simply considering FoS alone.