非均质泥石流形成过程动力学特征

非均质泥石流是产生于山坡与沟谷中的一种典型固液两相流,具有颗粒级配宽、容重大、流动阻力与流速分布的不均匀性等特征,致灾影响深远。本文通过在云南省蒋家沟泥石流观测研究站实施48组泥石流形成动力过程模拟试验,首先分析非均质泥石流起动方式,将模拟泥石流起动划分为常遇型、溃坝型及滑坡型三种类型,并进一步将泥石流形成过程划分为固体颗粒起动、固体颗粒加速混掺及固液两相流形成的三个不同阶段;基于孔隙水压力及水力因子等测定数据,分析揭示了泥石流形成的三阶段的动力学特征,表明三类泥石流形成后流速较大,均呈急流状态,而且水流强度以溃坝型泥石流为最大,常遇型泥石流次之,滑坡型泥石流最小。本项研究成果对丰富泥石流学科内容以及提高泥石流灾害预测水平具有重要意义。

Dynamical characteristics of formation processes for non-homogeneous debris flow

As a kind of typical two-phase flow, non-homogeneous debris flow behaves some basic properties such as grain size distribution with a large scale, more specific gravity, and non-uniformity of both flow resistance and velocity,which results in heavy natural disasters. As for this,48 runs simulation experiments for non-homogeneous debris flow were carried out at Debris flow Observation and Research Station at Jiangjia Gully in Yunnan Province. It has been shown by experimental results that the ways of particle starting were stated as individual, common and generous particle starting, and types of particle starting includes three types such as common-encountered type, dam-break type and landslide type. Furthermore, the formation processes may be divided into three kinds of the stage, such as solid particle starting stage, refined and accumulated mixture stage and formation stage of two-phase flows. Therefore, the dynamical characteristics responding to three kinds of the stages have been revealed, and the sequencings for water flowing intensity are dam-break type''s debris flow, common-encountered type''s debris flow and landslide type''s debris flow. These results not only enrich the subject of debris flow dynamics, but also benefit the disaster prevention and mitigation of debris flows.