Numerical Stady of Pore Pressure Development and Dissipation in Core of Masjed-Soleyman Rockfill Dam

The main role ofcore in earth dams is to reduce and control the seepage flow through the dam. In order to achieve this purpose، the core material is usually selected from pure or mixed clays. Due to very small coefficient of permeability، the clay cores can prevent water leakageeasily. However، pore water pressures developed inside the core during construction، can not be dissipated quickly. As a result، increasing the rate of embankment filling during the construction stage، may lead to large development of the pore pressure inside the core. In this study،based on a hardening elasto-plastic constitutive model، the total stresses and pore pressures inside the core of MASJED-E-SOLEYMAN rockfill dam، are calculated using the PLAXIS software during the construction and first reservoir filling stages. The analysis is in term of effective stress coupled with consolidation analysis. In order to verify the result of the numerical analysis، the measurment data from installed instruments intherockfill dam have been compared with the numerical results. This comparsion shows that the numerical analysis results are in a good agreement with the instrument results. Excess amount of pore pressures in the core of this dam is due to very small coefficient of permeability and high rate of embankment filling.