Centrifuge model study on the influence of desiccation cracks on the seepage behavior of upstream clay anti-seepage system subjected to abrupt flood

The influence of desiccation cracks on the performance of upstream anti-seepage systems subjected to abrupt flood was investigated using centrifuge experiments of scaled-down embankment dam models. Desiccation cracks were introduced in the sloping core and the upstream blanket by simulating solar radiation. Both intact and cracked models were subject to 100×g centrifuge acceleration. Pore water pressure was monitored using pore pressure transducers placed at preselected locations within the model, and the opening width and length of the dominant cracks were manually measured. The crack number was lower on the blanket surface than on the sloping core, but the crack opening width and length developed rapidly. The intact anti-seepage system, which lowered the infiltration surface and effectively dissipated the pore water pressure, showed good performance, whereas the cracked anti-seepage system suffered seepage failure owing to high pore water pressure at the crack tip under the abrupt flood condition. The results indicate that desiccation cracks on the blanket surface provide the essential material condition for hydraulic fracturing, and abrupt flood provides the favorable mechanical condition. Desiccation cracks on upstream anti-seepage systems pose a major hidden danger and should be excavated and backfilled in a timely manner to prevent dam accidents.