泥石流堆积形态分析

ANALYSIS ON ACCUMULATION STATE OF DEBRIS FLOW

泥石流体的力学性质一般属宾汉(Bingham)体,其运动要克服极限切应力,因此在斜槽中会堆积下来,并在沟口形成扇形地。以往多认为在均一斜面上堆积形态是等厚的,因而就推论出存在不淤坡度等观点。根据实际观测和模型试验,实际上堆积厚度沿程是不等的。根据不等厚度的假定,导出了泥石流的堆积方程式,不仅对堆积形态的计算更接近实际,而且对泥石流运动有了新的看法:泥石流在任何坡度下都能够流动,在任何坡度下都会产生堆积,仅仅是其堆积形态和数量不同而已。

The mechanical behaviour of debris flow agrees with Bingham pattern in general. The movement of debris flow requires overcoming the ultimate shearing force. Thus the debris may be accumulated in the valley and form a fan at the mouth. It used to be believed that the accumulation is the same in thickness and non-silting slope bases exist. But according to observation,survey and model experiment,in fact,the thickness along the accumulation is different. An accumulation equation of debris flow is established according to the assumption of different thickness. The computation is made of accumulation state approximate to the fact,and new viewpoints on debris flow is formed,that is,debris flow may move and be accumulated on any slopes,with different state and quantity.