Formation and evolution characteristics of dam breach and tailings flow from dam failure: an experimental study

The safety of tailings impoundments has long been a concern of academic researchers globally. The tailings dam breaks are extremely likely to induce secondary disasters such as mudflows, landslides and water and soil pollution, thus further aggravating the risk of accidents. On the basis of practical engineering, this study performed a dam-break physical model experiment and theoretical analysis to examine tailings dam overtopping and dam body collapse processes. It also discussed the leaked tailings flow evolution characteristics after dam failure, based on important parameters such as the dam-breach variation rules after dam break, flow velocity of the leaked tailings flow, particle deposition characteristics and submerged depth. Our research discovered that dam-breach development was mainly constituted by water current erosion-induced longitudinal downcutting and dam-breach slope instability-caused horizontal expansion. A large sand inrush amount resulted in a high downstream flow rate and large sediment depth after dam failure. In addition, when the sampling site was > 100 cm (model scale) away from the dam site, the discharged tailings flow size grading phenomenon was obvious during dam breach, and the particle size gradually decreased with increasing distance between the sampling characteristic sites and dam site.