Study the Infiltration and Stability of the Earthfill dams (Proposed Kashkan dam as a Case study)


This paper performed two steps of analysis. The first step used Soil Conservation Service (SCS) method to estimate surface water infiltration rates from the earth fill dams (proposed Kashkan dam north of Duhuk city as a case study). In the second step, a two dimensional finite element seepage analysis using (Seep/w) software was employed to determine seepage rates. The main purpose of constructing Kashkan dam is to store the rainfall water during rainy season and use it during summer season to provide the human requirements of water as well as to performed the agricultural requirements. Mean monthly rainfall data recorded for selected watersheds during the period (1986-2008) was used. The maximum infiltration rate during the depended period asymptotically tends to the value of the saturated permeability. The computed infiltration rates were used as input data for the seepage analysis by assigning the ground surface boundary condition. Finally, positive and negative pore water pressure distributions obtained from the seepage analysis are used as input data to calculate the variations in the factor of safety during the event . It is concluded from that the Kashkan dam is safe against the danger of slope failure due to slippage under the operation heads.