Technical Reports

Postmortem Investigation Of The Kansas. Test Track Volume II

  • 19
  • Apr
  • 2017
AUTHOR: Homer C. Greer III, Mark A. Vispi, Melvin M. Carlson
KEYWORDS: Ballast, Embankments, Kansas Test Track, Railroad, tracks, Soil-track. interaction, Subgrades, Track performance, Tracks
ABSTRACT: The Kansas Test ~~rack (KTT) was comprised of nine .differen~tra'Cksystems, , which were built on a: designed embankment. The KTT subgrade experienced prema.ture failure in service, and KTT operations were terminated in June 1975 after six months of operation. A postmortem investigation of KTT was carried out in 1975 and 1976. Volumes I and'II document the structure, ballast, and embankment studies carried out by the u. S. Army Engineer Waterways Experiment Station in the postmortem investigation. Results presented in Volume I provide needed insight into track system behavior and are particul~rly descriptive of ballast and embankment performance. A rationale is presented to explain the mechar.ism of failure in the subgrade, and attention is drawn to' the'structure-ballast-subgrade interactidn processes which govern track· system performance. Inadequate drainage of the top of the KTT embankment led to moisture content increases in the top ofsubgrade from 1911 to 1974, when traffic commenced. The embankment clay was moderately to highly plastic, and moistureinduced loss of strength in the top few inches of subgrade was the principal cause ·of failure.