G. R. Rakhshandehroo - Associate Professor, Dept. of Civil Eng., Shiraz University, Shiraz, Iran
A. A. Hekmatzadeh - Dept. of Civil Eng., Islamic Azad University, Eghlid Branch, Eghlid, Iran

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, and 3-D transient and steady state analyses of pore pressures were performed and the results were compared to monitored data. According to the monitored heads, pressures across the core dropped considerably, reflecting good performance of the core. After the first and second dam impoundments, the overall trend in monitored pore water pressure was well modeled by the transient analysis. Therefore, it was concluded that pore pressures in the core of earth fill dams may not achieve steady state conditions even months after the dam construction and impoundment. It was also concluded that conductivity behavior as a function of negative pore water pressure in unsaturated zone does not play an important role in modeling results.

pore water pressure, transient analysis