Chaiyuth Chinnarasri creator Gupta, Ashim Das Examination Committee Noppadol Phien-Wej Examination Committee Sutat Weesakul Examination Committee Ackermann, Norbert L. Examination Committee Tawatchai Tingsanchali Chairperson The Royal Thai Government (Ministry of University Affairs) Scholarship Donor text series technical report th Bangkok Asian Institute of Technology 2000 continuing eng 192 leaves 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. A Dissertation Submitted in Partial Fulfillment of the Requirements for the Degree of Doctor of Engineering, School of Engineering and Technology Thesis (Ph.D.) - Asian Institute of Technology, 2000 Dam failures Investigation Asian Institute of Technology. http://203.159.5.9/ait-thesis/detail.php?q=B06553 http://203.159.5.9/ait-thesis/detail.php?q=B06553 280101 20260818113040.0