Debris flow is a natural phenomenon that requires appropriate structural measures such as detention dams to reduce hazards resulting from it. The objective of this paper is to present a two-dimensional numerical model to investigate debris flow deposition in the reservoir of the detention slit dams. The governing equations include shallow water equations considering the bed level variation, sediment continuity, and debris-flow transport equations. Shallow water equations were discretized using the MacCormack scheme and then Banihabib Scheme was applied for solving sediment continuity equation. The governing equations were solved in an iterative procedure and as a result, flow properties and bed level variations were obtained in silt dam reservoir. The model performance was evaluated against experimental and numerical models in two aspects including the outflow hydrograph and reservoir bed level variations or trapping efficiency. The model performed quite well in outflow hydrograph simulation, and the comparison of the bed level variations or trapping efficiency illustrated that the simulated values were acceptable. A sensitivity analysis of the parameters was carried out to analyze the influence of parameters variation on outflow and sedimentation volume. The results of this sensitivity analysis revealed sedimentation is more sensitive to the parameter variation than outflow hydrograph. Generally, the proposed numerical method can provide insights on the debris flow deposition in slit dam reservoir, which could be useful for slit dam design.

泥石流是一种自然现象，需要采取适当的结构措施，例如拦水坝，以减少泥石流带来的危害。本文的目的是提出一个二维数值模型，研究滞留缝坝水库中的泥石流沉积。控制方程包括考虑床位变化，沉积物连续性和泥石流输送方程的浅水方程。使用MacCormack方案离散浅水方程，然后将Banihabib方案用于求解沉积物连续性方程。通过迭代程序求解了控制方程，结果获得了淤泥坝水库的水流特性和水位变化。根据实验模型和数值模型在两个方面对模型性能进行了评估，包括流出水文图和储层床位变化或捕集效率。该模型在流出水文模拟中表现很好，对床位变化或捕集效率的比较表明，模拟值是可以接受的。对参数进行敏感性分析，以分析参数变化对流出量和沉降量的影响。敏感性分析的结果表明，沉积物对参数变化的影响比流出水文曲线更敏感。通常，所提出的数值方法可以为裂隙水库中的泥石流沉积提供洞察力，这对于裂隙水坝的设计可能是有用的。