Abstract:
Embankment dam should be stable under all loading conditions and operations due to its
susceptibility to hydraulic, seepage and structural failures. Aguat wuha embankment dam
has been affected by high water loss through the dam body especially around the periphery
of the out let and downstream slope face erosion. This study was conducted to evaluate
seepage, slope stability, and stress deformation performances under all loading condition.
In this study, field measured data and GeoStudio2012 model was used to analyse seepage,
slope stability and stress deformation of the dam under different cases of reservoir operation conditions. Leakage flow rate, pore water distribution and location of the phreatic line
were determined using the finite element (FE) software, SEEP/W. The slope stability evaluation utilizes limit equilibrium (LE) based software (SLOPE/W). The stress-deformation
was analysed using the FE models, SIGMA/W software. The stability analysis results indicated that the critical upstream and downstream slope of the dam is safe within the prescribed USACE range of factors of safety for all loading causes and operations. In addition
the stress deformation results of vertical settlement and horizontal strain showed that the
impervious core material is safe against the inside cracking due to the vertical and horizontal displacement and the dam could not be affected by overtopping problem due to vertical
settlement .But, in cause of seepage the result showed that the simulated results of SEEP/W
software show that the average flow rate of leakage for the entire length of the dam at
Elevations 2874 m a.m.s.l and 2868m a.m.s.l reservoir level was equal to 1.17*10-5 m3
/s
and 5.51*10-6 m3
/s respectively; whereas the actually measured seepage at the downstream
of the dam body was 6* 10-3 m3
/s and 4*10-3 m3
/s at elevations 2874 m and 2868 m reservoir water level respectively which is much higher than the simulated one. From this we
can conclude that the dam is exposed to seepage and downstream face erosion and may the
dam lead to failure. Therefore, remedial measures should be taken before the dam fail and
cause damage of life, property and investment of the downstream.
