بررسی تأثیر وزن سد بر رفتار وابسته به زمان پی ساختگاه سد گتوند

Abstract
Gotvand rock fill dam is being constrcted on Karun river located in Khoozestan province south of
Iran. The dam is foung on Aghagari formation which is consisted of mudstone and sandstone layers.
These layers are intermittent of weak to medium strength with uniaxial compressive strength 15 and
25 MPa respectibely. Some regional factors as continuous unloading caused by river flood washed off
and horizontal tectonic loading have created a local anticline in the foundation of dam. According to
previous analyses, results have shown that this folding will continue over the time. In this research
effect of the dam weight on time d- dependant deformation of the dam foundation has been studied.
Ration of horizontal to vertical stresses (K) was estimated to be 0.4 to 0.7 by in-situ tests, so dam site
numerical models were executed (numerical analysis wity the FLAC3D code) with K equal to 0.4,0.55
and 0.7. First, the models were executed statically. Maximun settlement of foundation due to the dam
weight was estimated a bout 37cm. Ihen for time dependent analysis, the behavior of rocks is assumed
to obeay Maxwell creep viscousplastic rheological model and the models were executed for 100 years
equal to the dam life time. The results of numerical analysis show that upward deformations of the
foundation with K=0.55 and 0.7 is continuously, even in the central region of dam where the dam
weight is maximum. But in the model with K=0.4, in the first 60 years after the construction, creep
deformation are downward and after this time, directions of deformation were changed to upward.