| Author | Chaiyuth Chinnarasri |
| Call Number | AIT Diss. no. WM-99-02 |
| Subject(s) | Dam failures--Investigation
|
| Note | A Dissertation Submitted in Partial Fulfillment of the Requirements for the Degree of Doctor
of Engineering., School of Engineering and Technology |
| Publisher | Asian Institute of Technology |
| Series Statement | Dissertation ; no. WM-99-02 |
| Abstract | Failure of a dam is a major event, which may cause great suffering and damage. Since
most dam failures are due to overtopping and concern mostly embankment dams, there is a
need to understand embankment dam failure behavior. A one-dimensional numerical model
for embankment dam breaching due to flow overtopping is developed. The model consists of
three modules: a module of unsteady flow over steep bed slopes, a dam surface erosion
module, and a slope sliding failure module.
The Maccormack explicit finite difference scheme is used to solve the one-dimensional
equations of continuity and momentum for unsteady rapidly varied flow over steep bed slopes.
For dam surface erosion, the governing equations are a one-dimensional equation of sediment
mass conservation and a sediment transport formula. The equations are solved by using an
explicit finite difference technique of the modified Lax scheme. Five sediment transport
formulas namely Meyer-Peter & Mueller (1948), Smart (1984), Bagnold-Visser (1988),
Rickenmann (1991), and Takahashi (1991) were selected for calculating the erosion process
along the dam surface due to overtopping. During an overtopping event, two types of dam
surface stability are involved, i.e. erosional stability and sliding stability. In the computation of
sliding stability, the simplified ordinary method of slices is applied based on effective stress.
Three sets of experiments were carried out, the first one under a fixed dam bed condition,
the second one under dam surface erosion, and the third one under dam surface erosion and
sliding. The model was calibrated and verified using experimental data. The calibrated model
shows very good results in predicting reservoir water surface level, dam height, overtopping
discharge, and propagation of dam crest which are very important parameters in the
computation of flood and inundation area downstream of the dam. The model also predicts
reasonably well the erosion and failure of the dam surface profiles and their corresponding
water surface profiles.
Sensitivity analysis showed that the model accuracy depends largely on the sediment
transport formula and coefficient of pore water pressure under the dam surface downstream of
the dam crest.
Moreover, the present model was verified with the actual dam breach outflow data of the
Buffalo Creek Dam, North Carolina, U.S.A. and also with the existing models namely
BREACH model and MIKE-1 ldam break model. The present model is found to give the
nearest prediction of the observed peak breach outflow and its time of occurrence compared to
the BREACH model and the MIKE-11 model. |
| Year | 2000 |
| Corresponding Series Added Entry | Asian Institute of Technology. Dissertation ; no. WM-99-02 |
| Type | Dissertation |
| School | School of Engineering and Technology |
| Department | Department of Civil and Infrastucture Engineering (DCIE) |
| Academic Program/FoS | Water Engineering and Management (WM) |
| Chairperson(s) | Tawatchai Tingsanchali; |
| Examination Committee(s) | Gupta, Ashim Das;Noppadol Phien-Wej;Sutat Weesakul;Ackermann, Norbert L.; |
| Scholarship Donor(s) | The Royal Thai Government (Ministry of University Affairs); |
| Degree | Thesis (Ph.D.) - Asian Institute of Technology, 2000 |