Stability of Sloping Core Earth Dams

A series of tests on small scale embankments was conducted to give a better understanding of the mechanism of failure of sloping core earth dams, and to develop a rational method of stability analysis compatible with the observed sliding pattern. Six small earth dams with a range of core slopes varying from 2.45○ to 35○ were constructed and caused to fail in order to determine the consistency of the failure mechanism. Construction and testing procedures are described, and the results of plane strain tests and triaxial tests on the granular materials used in the construction of the upstream shells are presented. The conditions at failure for the earth dams tested are presented and analyzed. Observations of the deformations and features of the dams after failure indicated that failure occurred by a sliding block mechanism. An active block, a passive block, and an extensively sheared zone between the blocks participated in developing a catastrophic failure. An improved method for stability computations, using the developed failure mechanism and the plane strain strength parameters, is presented.