Earth Structures Stability Under Rapid Drawdown Conditions

The paper presents the slope stability analysis of the unmodernised section of the Groszowice separation levee in the condition of water level changes, particularly after rapid drawdown.

Based on soils field and laboratory tests, the stability analysis of the construction was conducted with GEO5 software.

For the upper levee, the utilisation degree of slopes resistance was determined according to the Eurocode 7. Calculations were conducted for normal and high water level, as well as after rapid drawdown. The analysis was carried out with the use of five most commonly applied methods.

The results have shown that at normal and high water level, the structure was stable. However, it does not correspond with its existing damages. The loss of stability was proved only under rapid drawdown conditions.

Additionally, for the central part of the separation levee, the filtration curve position was conducted with the use of the Finite Elements Method (FEM). The water seepage on the slope above normal water level explains the suffosion displacement of soil particles that occurs due to damaged slope sealing and drainage.