Formation of front part in multigranular debris flow affecting the intermittent fluidity

通过试验与计算结果的对比，研究了单颗粒和双粒径混合颗粒泥石流中前缘形成对泥石流流动力学特性的影响。单颗粒泥石流的实验结果与计算结果一致，而混合颗粒泥石流的实验结果与计算结果不一致。这种不一致被认为是由于较小的泥沙颗粒所产生的主导剪切应力引起的，这是由于在泥石流的流体内检测到的逆级配所导致的。此外，还发现，由于多颗粒泥石流前部的粒度偏析并不影响发育阶段的流动性，因此计算流速低估了实际流速。

Characteristics of flow mechanics affected by formation of front part in debris flows consisted of sediment particle with monogranular and two diameter mixed was examined by comparison between experimental and calculated results. Both experimental and calculated results were corresponded with monogranular debris flows, whereas disagreement was shown in debris flow with mixed particle size. The disagreement was considered to be induced by the dominant shear stress due to smaller sediment particles, resulting from inverse grading detected in flow body of the debris flows. In addition, it was indicated that the calculated velocity was underestimated than actual velocity, as the particle size segregation in the front part of multigranular debris flows did not affect the fluidity in the developing phase.