DYNAMIC ANALYSIS OF KARKHEH EMBANKMENT DAM IN IRAN

Karkheh dam project is located at a high seismic potential region at the south western of Iran. The owner of the dam, still in construction stage, is Iranian Water and Power Company ۱WPC, the Engineer is Mahab Ghodss consulting engineers and the contractor is Sepasad Company. The seismic stability analysis of the dam being necessary, seismic hazard studies and response analysis of the embankment-foundation system to the applied base rock motions was per-formed by-The Engineer [۵]. The corrected Tabas and Manjil earthquake records, scaled to M.C.E. level, were. used as input base rock acceleration. Dynamic laboratory tests were per-formed by resonant column and dynamic triaxial testing apparatus on core (clay & mixed mate-rial), shell and foundation materials in Iran (BEES [۲] & SHRC [۳}) and China (IWHR [۴]). The test results provided the variation of shear modulus and damping ratio with respect to shear strain amplitude as well as dynamic strength of materials. After selection of appropriate acceleration time history and proper dynamic characteristics of soil materials, dynamic response analysis was carried out using different computer programs. Permanent displacement of dam crest was calculated based on slope failure, seismic induced deformation and settlement dbe to dissipation of excess pore water pressure. Finally, the men-tioned seismic stability analysis of Karkheh dam showed that the design earthquakes have no significant effect on the stability of the dam body [۵]. In another dynamic analysis of Karkheh dam, which has been done in parallel, natural frequencies and mode shapes of the darn body were evaluated [۶].