Three Dimensional Seepage Analyses in Mollasadra Dam after Its Impoundments

Mollasadra dam is an earth fill dam with a clayey core and a height of 72 m from river bed, constructed on Kor River. pore water pressure in the dam was investigated following its construction and first and second impoundments. The dam was modeled by a finite element mesh. After the first and second dam impoundments, the overall trend in monitored pore water pressure was well modeled by the transient analysis. The result showed the six month time period between impoundments was long enough for the pore water pressure to reach equilibrium everywhere throughout the core, except where considerable initial construction- induced pore water pressure was observed. High values of construction-induced pore water pressure at elevation 2050 m did not dissipate completely during the 6 month period of almost constant reservoir level (el. 2098.3 m) and the pore pressures were still at the transient state throughout the core. Therefore, it was concluded that pore pressures in the core of earth fill dams may not achieve steady state conditions even several months after the dam construction and impoundments.