Researchers from the University of Sydney have used bowls of puffed rice cereal to deliver insight into the collapse of rockfill dams, sinkholes and ice shelves.
The paper on Tracking time with ricequakes in partially soaked brittle porous media by University of Sydney researchers Itai Einav and François Guillard was published in Science Advances journal.
“When brittle porous media interact with chemically active fluids, they may suddenly crumble,” said Einav. “This has reportedly triggered the collapse of rockfill dams, sinkholes, and ice shelves. To study this problem, we used a surrogate experiment for the effect of fluid on rocks and ice involving a column of puffed rice partially soaked in a reservoir of liquid under constant pressure.
“We found localised crushing collapse in the unsaturated region that produces incremental global compaction and loud audible beats. These ‘ricequakes’ repeat perpetually during the experiments and propagate upward through the material. The delay time between consecutive quakes grows linearly with time and is accompanied by creep motion.
“All those new observations can be explained using a simple chemomechanical model of capillary-driven crushing steps progressing through the micropores.”
Through the experiments, Einav and Guillard identified a new form of incremental collapse and developed a numerical model to allow prediction of this type of failure.