Thesis
The failure of Teton Dam: A new theory based on "state based soil mechanics"
Washington State University
Master of Science (MS), Washington State University
2003
Handle:
https://hdl.handle.net/2376/151
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 with highly compacted uniform clayey silt of low plasticity and therefore was prone to such a possibility. This thesis describes the details of the theory, the investigation, and the conclusions arrived at regarding the potential initiation of Teton failure. Furthermore, it critically evaluates the failure mechanisms proposed by previous investigations based on the results obtained and the framework of state based soil mechanics. 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. It is concluded 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
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Details
- Title
- The failure of Teton Dam
- Creators
- Navaratnarajah Sasiharan
- Contributors
- Balasingam Muhunthan (Degree Supervisor)
- Awarding Institution
- Washington State University
- Academic Unit
- Civil and Environmental Engineering, Department of
- Theses and Dissertations
- Master of Science (MS), Washington State University
- Publisher
- Washington State University; Pullman, Wash. :
- Identifiers
- 99900525185001842
- Language
- English
- Resource Type
- Thesis