Location
New York, New York
Date
13 Apr 2004 - 17 Apr 2004
Abstract
Teton Dam failed during its first filling on 5 June 1976. The 405-ft high dam was designed and built using modern standards; therefore its failure received considerable scrutiny from engineering experts. Failure mechanisms suggested, included hydraulic fracture, internal erosion, wet-seam theory, and defects in the abutment rock. None of the investigations, however, were able to explain satisfactorily why the dam breached when the reservoir reached EL.5301.7 ft and only in the vicinity of Sta. 14+00 on the right abutment. The investigation here is focused on this crucial aspect of the failure using the modern framework of fundamental “state based soil mechanics”. According to this framework highly compacted soils of low plasticity in an environment of low liquidity index and low confining stress would crack in the presence of high shear stresses. The impervious core (Zone-1) of Teton was constructed of uniform clayey silt of low plasticity and highly compacted and therefore was prone to such a possibility. This paper describes the details of the theory, the investigation, and the conclusions arrived at regarding the potential initiation of Teton failure. Finite element analysis carried out using state based parameters indicate the presence of deep open transverse vertical crack(s) in the core (Zone-1) to a maximum depth of about 32 ft from the crest only in the right abutment and in the vicinity of Sta. 14+00. We conclude that once the water level in the reservoir rose above El 5300.0 ft in the early hours of 5 June 1976 water flowed through the open vertical crack(s), which slowly eroded the crack into a large tunnel leading to the major breach of the dam hours later.
Department(s)
Civil, Architectural and Environmental Engineering
Meeting Name
5th Conference of the International Conference on Case Histories in Geotechnical Engineering
Publisher
University of Missouri--Rolla
Document Version
Final Version
Rights
© 2004 University of Missouri--Rolla, All rights reserved.
Creative Commons Licensing
This work is licensed under a Creative Commons Attribution-Noncommercial-No Derivative Works 4.0 License.
Document Type
Article - Conference proceedings
File Type
text
Language
English
Recommended Citation
Pillai, V. S.; Muhunthan, V.; and Sasiharan, N., "The Failure of Teton Dam – A New Theory Based on "State Based Soil Mechanics"" (2004). International Conference on Case Histories in Geotechnical Engineering. 15.
https://scholarsmine.mst.edu/icchge/5icchge/session00g/15
The Failure of Teton Dam – A New Theory Based on "State Based Soil Mechanics"
New York, New York
Teton Dam failed during its first filling on 5 June 1976. The 405-ft high dam was designed and built using modern standards; therefore its failure received considerable scrutiny from engineering experts. Failure mechanisms suggested, included hydraulic fracture, internal erosion, wet-seam theory, and defects in the abutment rock. None of the investigations, however, were able to explain satisfactorily why the dam breached when the reservoir reached EL.5301.7 ft and only in the vicinity of Sta. 14+00 on the right abutment. The investigation here is focused on this crucial aspect of the failure using the modern framework of fundamental “state based soil mechanics”. According to this framework highly compacted soils of low plasticity in an environment of low liquidity index and low confining stress would crack in the presence of high shear stresses. The impervious core (Zone-1) of Teton was constructed of uniform clayey silt of low plasticity and highly compacted and therefore was prone to such a possibility. This paper describes the details of the theory, the investigation, and the conclusions arrived at regarding the potential initiation of Teton failure. Finite element analysis carried out using state based parameters indicate the presence of deep open transverse vertical crack(s) in the core (Zone-1) to a maximum depth of about 32 ft from the crest only in the right abutment and in the vicinity of Sta. 14+00. We conclude that once the water level in the reservoir rose above El 5300.0 ft in the early hours of 5 June 1976 water flowed through the open vertical crack(s), which slowly eroded the crack into a large tunnel leading to the major breach of the dam hours later.
