Seepage and stability analyses of a zoned earth dam subjected to variable water heads: numerical simulations with Abaqus

The behaviour of a zoned earthen dam is analysed by means of a finite element model implemented in Abaqus. The analysed dam was built in Slovenia at the end of the 1980s for irrigation and flood protection purposes. In 2007, detection of a wet stain on the downstream slope forced the drawdown of the reservoir to carry out remedial works. Transient fully coupled hydro-mechanical analyses under partially saturated conditions have been conducted to investigate the behaviour of the dam from its construction to present. Available in-situ measurements have been exploited to calibrate the model and to assess the reliability of the predictions. To address the effects of the wet stain and of the remedial works on the dam body, stability analyses have been performed at significant times. Future scenarios have been analysed, using provided information on the time schedule of the reservoir impounding after completion of the remedial works. The results show that the high pore water pressures measured inside the dam body may be explained by damage experienced by the irrigation pipelines and that remedial works are necessary to restore the dam functionality.