Design and instrumentation of a novel centrifuge container for fly-ash run-out experiments

Abstract

Debris flow, landslides and material run-outs have significant environmental and economic consequences for numerous industries. High-quality experimental data with controlled boundary conditions can help validate and calibrate the predictive capabilities of mechanistic and semi-empirical numerical models. A novel centrifuge container to model dewatering and run-outs induced by a rapid loss of confinement is presented. The design features a pair of vertical doors opened in-flight to simulate failure of the containing structure. Illustrative centrifuge results investigating the run-out characteristics of a fully saturated, densely deposited class-F fly ash are presented. Modified soil moisture probes to monitor the distributions and time-varying fly-ash water content throughout the testing are explored. Furthermore, the successful use of depth-sensing cameras to reconstruct progressive deformations of the material front at various time scales is demonstrated. Combined water content, pore pressure and deformation measurements provide insight into the material behaviour during the run-out, revealing two time scales at which the deformations occur. However, discrepancies between water contents inferred from the dielectric measurements and electrical conductivities highlight the need for independent verification of the bulk material water content when using the modified probes. Overall, the potential of these innovative instrumentation techniques to complement traditional geotechnical instrumentation is shown.