A STUDY ON RESIDUAL DEFORMATION OF ROCKFILL DAM BASED ON DYNAMIC CENTRIFUGE MODEL TEST

A dam model with reservoir was placed in a centrifugal field of 50 to 60G and was strongly excited in the actual seismic-wave along stream direction. Impervious central earth core rockfill dam (ECRD) and the concrete facing rockfill dam (CFRD) were modeled and applied maximum base acceleration of up to about 700gal. During the tests, installing two or more accelerometers, displacement gauges and pore pressure meters at the dam base and several parts of the dam body precisely monitored the behavior of the rockfill dam. The main damage of the dam model was settlement and the rock fall from upstream and downstream slope surface, and no circular slip failure was observed. The settlement concentrated at the crest of the dam body and near the upstream and downstream slope surfaces, and settlement was larger at the rock zone than in the core and was larger in the upstream-side rock zone than the downstream zone due to the effect of water storage. The settlements of dam models were compared with the observed settlements of actual dams, which had been exposed to big ground motions. From the tests results and lessons learnt from past incidents, the safety of rockfill dams is discussed from the viewpoint of residual deformation.