Open AccessEvaluation of the upstream slope stability of earth dams based on drawdown conditions - Khassa Chai Dam: a case study
Author(s) -
Thair Jabbar Mizhir Alfatlawi,
Yahyea K. Al-temimi,
Zeena M. Alomari
Publication year - 2020
Publication title -
iop conference series. materials science and engineering
Language(s) - English
Resource type - Journals
eISSN - 1757-899X
pISSN - 1757-8981
DOI - 10.1088/1757-899x/671/1/012072
Subject(s) - drawdown (hydrology) , geotechnical engineering , finite element method , geology , water level , piezometer , instability , safety factor , slope stability , pore water pressure , hydrology (agriculture) , groundwater , engineering , mechanics , structural engineering , aquifer , physics , cartography , geography
Sudden drawdowns may cause instability in slopes without adequate levels of protection against failure. In this paper, a numerical approach utilising the finite element method (FEM) was employed to examine the seepage and slope stability of a typical earth fill dam. Finite element software (GEOSTUDIO 2012) was used to carry out both steady-state and transient seepage analyses on Khassa Chai Dam in Iraq to study the seepage and upstream slope stability after various upstream drawdown scenarios. To include water levels during evacuation, variable linear water heads with time were identified as boundary states in the transient seepage analysis. The quantity and direction of water flux, existing gradient, and safety factor were calculated for all scenarios. The results revealed that the stability of the slope during drawdown is highly impacted by how fast its pore water pressure dissipates. The results also showed that a minimum F.S. was achieved within 10 hr in the case of a 1-day water drawdown, with the F.S. reduced by 60.66%; this becomes critical when the water level in the basin drops by about 41.67% of its original height.