Citation

Kyfor ZG, Gemme RL. Transp. Res. Rec. 1994; 1462: 17-27.

Copyright

(Copyright © 1994, Transportation Research Board, National Research Council, National Academy of Sciences USA, Publisher SAGE Publishing)

DOI

unavailable

PMID

unavailable

Abstract

Embankment instability that occurred along several completed sections of a major interstate highway located in the western part of New York State is described. The affected embankments ranged in height from 4.6 m (15 ft) to 9.15 m (30 ft) and were constructed of silty clay over a silty clay foundation. Field investigations revealed that movements were taking place within the embankments and were not a result of the foundation soil. These movements were consistent with an undrained mode of failure. The embankment material was obtained from borrow excavations made outside the project limits and classified as a medium to highly plastic clay. The moisture contents of the borrow ranged from 25 to 55% and the plasticity index ranged from 15 to 32%. Drill holes progressed through the affected fills indicated that the embankment moisture contents at the time of distress exceeded the optimum moisture content (20%) by 5 to 10% based on a standard Proctor compactive effort. The undrained shear strengths at these moisture contents were not sufficient to provide for internal stability of the embankments. The results of the field and laboratory investigations are presented. They consist of inclinometer results of embankment monitoring, compaction curves for material used, and moisture contents and densities of fills obtained during construction and after movement began. A relationship between moisture content and undrained shearing strength is also shown. Stabilization consisted of flattening all embankments greater than 4.6 m (15 ft) from a 1 (vertical) on 2 (horizontal) to a 1 (vertical) on 3.5 (horizontal) side slope.

Language: en

Keywords

Embankments; Shear strength; Foundations; Highway systems; Failure analysis; Clay; Compaction; Excavation; Geomorphology; Moisture; Plasticity; Soils; Stabilization