Density is the most important parameter of debris flow. This work looks into the typical debris flow and mountain torrent occurred in Longmen Mountains in the past 20 years and compares the calculation results of the density using various methods. It shows that the mean deviations of result are in the range of 20–30%, and the static model is only suitable to the occurred debris flow event but not the forecast. Based on the analysis of typical rainfall debris flow, the influence factors of density are revealed; it shows that the density is controlled by the form conditions and the soil-water coupling process of debris flow. A function is introduced to describe the activity of material source, which defined by volume and relative elevation of materials, and the watershed area. The forecast model is established by the relationship between the density and its influence factors. When the new method is applied to the Longmen mountain area and the upper basin of the Minjiang River, although there are still few discretization errors, the results still can explain nearly 95% of the evolution trend, which shows that the new method is not compromised by regional differences.

中文翻译：

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西南地区降雨泥石流密度预测计算方法研究

密度是泥石流的最重要参数。这项工作研究了过去20年中龙门山的典型泥石流和洪流，并比较了使用各种方法计算密度的结果。结果表明，结果的平均偏差在20％至30％的范围内，静态模型仅适用于发生的泥石流事件，而不适用于预测。在分析典型降雨泥石流的基础上，揭示了密度的影响因素。结果表明，密度受泥石流形成条件和土水耦合过程的控制。引入了一个函数来描述物料源的活动，该活动由物料的体积和相对高度以及分水岭面积定义。通过密度及其影响因素之间的关系来建立预测模型。当新方法应用于龙门山区和the江上游盆地时，尽管离散误差仍然很少，但结果仍可以解释近95％的演化趋势，这表明新方法并未受到损害。通过地区差异。