利用冲击力信号判断泥石流颗粒垂向分选的试验研究

Experimental Study on Vertical Sorting of Particles in Debris Flow with Impact Signals

分别提出根据冲击力数据的波动强度和峰值情况进行泥石流颗粒垂向分选研究的系统方法,并配置了三组不同容重(2 095 kg/m3、2 008 kg/m3和1 960 kg/m3)的粘性泥石流样品开展泥石流冲击试验。两种方法的分析结果基本一致,即容重为2 095 kg/m3的泥石流分选不明显,其他两组泥石流呈现出正粒序分布且容重越小分选越显著。量纲分析表明,开展的试验粘滞力在运动中起主导作用,颗粒之间作用力较小,不容易发生反粒序分选,这与通过冲击力分析颗粒垂向分选的结果一致,因此提出的利用冲击力信号判断泥石流颗粒垂向分选的系统方法具有适用性。

Studying vertical sorting of particles is important for understanding the complex mechanism of debris flow.In this paper we proposed two methods to judge vertical sorting of particles in debris flow.One is based on the standard deviation of impact signals,and the other is based on the peaks in impact signals.We carried out three groups of flume tests with debris densities of 2 095 kg/m3,2 008 kg/m3 and 1 960 kg/m3,respectively.Results of the two methods are similar.There is no significant vertical sorting with the first group of debris flows.There is normal sorting with the other two groups,and the normal sorting becomes more significant for debris flows with smaller density.Dimensional analysis indicates that viscous stress is dominant in debris flow movement.It is difficult for the smaller stress between particles to make a reverse sorting.This is consistent with the results using impact signals.Therefore,the methods proposed in this paper are applicable to judge vertical sorting of particles in debris flow.