The report submitted herein is a case history describing observations and in-depth analyses made at a highway site involving a massive, unstable side-hill embankment located on I-64 in Boyd County. The in-depth study was initiated in January 1973. The I-64 site was selected for study because it contained several design, construction and maintenance features as well as soil types that are typical of many highway embankments in Kentucky. Side-hill fill situations are common design problems and oftentimes have required extensive maintenance after construction. Major objectives of the study were to 1) determine the causes of instability of the I-64 embankment, 2) check a remedial solution previously reported for the I-64 site and present alternative solutions if necessary, 3) determine short-term (initial) and long-term safety factors of the embankment slopes, and 4) compare theoretical shear surfaces obtained from a slope stability program based on Bishop\u27s simplified method of slices with actual failure points obtained from slope indicators and surface observations. All slope stability computations were carried out in terms of effective stress using shear strength parameters obtained from consolidated, isotropic, undrained triaxial tests with pore pressure measurements
