沟谷泥石流运动过程模型试验

泥石流运动过程是泥石流运动力学核心内容之一.以新疆天山公路K630泥石流为原型,选取几何相似比1:650,推导了泥石流质量、固液两相流速和泥石流冲击力相似比,以流通区为核心,建造了沟谷泥石流试验模型.试验结果表明,泥石流运动具有显著的阵流特性,阵流间隔时间为10s左右,其间嵌套2~3次弱阵现象;阵流期间,泥石流流速和冲击力均较大;从流通区的源头至沟口,流速呈现非线性增大趋势,且泥石流体中固液两相流速变化趋势相似,弯道处泥石流超高现象显著;泥石流运动初期由于泥石流体中固相和液相混和搅拌不均匀而呈现稀性泥石流特征,随后粘性特性增强.这些现象与现场观测结果基本一致.

Model test of valley-shaped debris flow motion

Debris flow motion belongs to one key aspect in K630 studiy of debris flow dynamics. In this paper, taking the valley-shaped debris flow located at K630 of Tianshan Highway as an example,choosing 1/650 as the geometry similarity ratio, three similarity numbers for density, velocities of solid and liquid phases and impact force of debris flow were deduced. Further, physical model is established in laboratory, which focuses attention on covered area of the V-shaped debris flow. Based on the simulation, three results are concluded: (1) surges during debris flow motion are obvious, whose interval duration is about 10s, and at least there are two or three weak surges in one dominant surge. (2) during surging, both velocity and impact force of the debris flow are greater.(3) from source to mouth of the flow zone, debris flow velocities increase nonlinearly,and the variations both for solid phase and liquid phase are similar, and debris flow freeboard at tortuous valley is obvious.The debris flow during initial motion is thin fluid due to nonuniform mixing of loose materials by water, however, the mixture becomes viscous later. These phenomena are consistant basically with that observed in real time field.