Study on the impact characteristics of debris flow under the check dam

Local erosion downstream of the check dam affects the stability of the project, and overflow of debris flow in the spillway is closely related to erosion. Establishing a connection between the impact of the dam and overflow of the spillway is crucial for the design of energy dissipation and erosion prevention projects. The relationship between the empirical coefficient, Froude number, and discharge coefficient is established through theoretical analysis, and a formula for calculating the jet distance is developed using jet theory. Furthermore, conducting a series of flume experiments to analyze spatial distribution characteristics of maximum impact pressure, and five factors are selected, including bulk density, scale, slope, effective opening width of spillway, and effective height of dam, to analyze their impact on the maximum impact pressure. Finally, considering the impact of overflow of the spillway on the impact pressure of debris flow, the impact pressure coefficient is modified, and the discharge coefficient of the spillway is added to the formula. A calculation method for the maximum impact pressure is established, and the results are compared with previous research models. The effect of the discharge of the spillway on the impact force has been discussed. Research results can provide a basis for the design of protective measures, enabling them to better serve the prevention and control of debris flows.