Effect of lime-treatment on earthen embankment failure processes

ABSTRACT ONLY - Lime treated soils are increasingly utilized in earthen structures to reduce shrink and swelling of expansive clays and improve slope stability. In this study, failure of an untreated earthen embankment due to overtopping will be compared to failure of an earthen embankment treated with lime. Prior to embankment construction, lime treatment methods will be optimized to reduce soil erodibility as measured by jet erosion tests conducted on standard proctor samples prepared with varying levels of moisture content and percent lime. The cross-section of the embankments will be trapezoidal with a 3:1 (H:V) side slope. The embankment height, width at crest, and length will be approximately 1.3 m, 1.8 m, and 15 m, respectively. Flow during overtopping will be near 3.0 m3/s for each test. To simulate an embankment repair after construction, only the downstream slope of the lime-treated embankment will be treated with lime and overlain by a 0.5 m thick layer of untreated compacted soil. Breach widening rates will be quantified using digital video monitoring and water levels in the forebay and tailwater will be monitored using pressure transducers. This research will provide critical tests needed to inform earthen dam design.