泥石流与主河水流交汇的试验研究

Experimental Research on Confluence between Debris Flow and Main River

分析了泥石流与主河交汇试验的模型相似律并进行室内模型试验,探索了泥石流与主河水流的交汇规律.试验结果表明:交汇口支槽与主槽槽底之间的关系不同,泥石流入汇主槽后的运动形式也不同,大体可分为潜入式交汇和分层交汇2种形式.潜入式交汇中,泥石流龙头速度近似按线性关系衰减,龙头几何特征与异重流不同,它的高度与长度变化较小,横向宽度与长度可用线性关系表达;当支槽有回水时,泥石流头部受到水流的破坏,发生沙、石沉降,形成分层运动.

Model similarity-rules for confluence between a debris flow and the main river were analyzed, and a series of model experiments were performed to investigate the regularity of confluence between a debris flow and the main river. The experimental result shows that the movement patterns of a debris flow are different in the intersection region for different relationships between the branch and the main river and can be divided the submerging flow and the stratification flow. In the submerging flow, the velocity of the debris flow head, submerging into water, decreases approximately linearly, the changes in its height and length are very small, and there is a linear relationship between the width and the length. All these are quite different from a density current. Furthermore, when water flows into the branch, the debris flow head will be broken by water, resulting in the sedimentation of sand and stone. Under that condition, the debris flow entering into the river becomes a stratiform flow.