本文以研究泥石流运动的均衡浓度为目的，进行了一系列高浓度的泥石流实验、泥石流均衡浓度公式已被广泛引用，但该公式中的动摩擦角却很难确定。本文通过实验确立以颗粒浓度和颗粒最大体积浓度的动摩擦角的函数关系式。实验中的液体为水和浆。
将泥石流样品中的粗颗粒分开是非常困难的。本文用D50分界线方法将泥石流样品中的粗细颗粒分开并得到粗颗粒在细颗粒浆体中的浓度。泥石流样品选自云南东川蒋家沟和大盈江浑水沟，这两条泥石流沟的泥石流包括了除水石流外的所有类型泥石流。用本文的动摩擦角与静摩擦角的函数关系式计算的泥石流运动的均衡浓度与泥石流资料很接近。

The paper presents experimental data concerning the uniform flow of highly concertrated mixture of debris flow. As we  know, the equilibrium concentration of solid particles in water is function of the slope of moving, the density of solid particales and the kinetic friction angle of the particles. The kinetic friction angles is the function of the internal friction angle, the concentration of solid partcles and the maximum possible concentration. To determine the function between the kinetic friction angle and internal friction angles is the aim of this research.
Flume experiments to determine equilibrium concentration in water and slurry was performed, indicating that a high density slurry makes the coarse particles able to move angle was given by these experiments. However, demarcation between the coaeses particles proved very difficult. Any fixed demarcation line of coarse particles and fine particales is good for either high concentration or low concentration debris flow. The D50 demarcation line was suggested in this paper to demarcate the coarse particales and fine particles of debris flow. The equilibrium concentration of debris flow was calculted by D50 demarcation for the debris flow in a field. The equilibrium concentration of debris flow calculated by the funcation between the kinetic friction angle and internal friction angle is quite close the equilibrium concentration date of debris flow in field.