EXPERIMENTAL INVESTIGATION OF THE FAILURE MECHANISM OF THE ZONED COHESIVE EARTHFILL DAMS
Keywords:
Breaching; Earthfill Dams; Headcut; Overtopping; CohesiveAbstract
Earthfill dams are the common manmade hydraulic structures constructed all over the world. Breaching of
an earthfill dam can leads to catastrophic damage to downstream communities, substantial loss of life, environmental
damages, and momentous property damages. This research paper aims to investigate the breach pattern of the zoned
cohesive earthfill dams due to overtopping. Two small-scale laboratory experiments with different mode of initiation of
breaching process, flat crest top level and an initial pilot channel erected at middle of crest were conducted. The
dimensions of placed model were, 12 inches crest width, 30 inches crest length, 20 inch crest height, and 1:2 upstream
and downstream side slopes. The results indicated that headcut erosion has a vital role in the breach development
process of cohesive zoned embankments. The breach cross section has almost a trapezoidal shape. The final breach
section width reached to the full width of the dam in case of flat top crest level test while it was confined to the middle of
the dam in case of test performed with initial pilot channel at middle of the crest. Also, the presence of relatively high
cohesive soil in the central impervious core strongly slow down the breach growth process.
