Experimental study on formation characteristics and influence of ice jam in melting period

Abstract

Ice problem widely exists in the north rivers, especially the ice disaster of the water elevation rise triggered by local ice jam in melting period caused by flowing ice. Therefore, it is of great significance to study the formation and influence of ice jam during the melting period. In this paper, the characteristics of ice flow in Yumenkou reach of the Middle Yellow River during the melting period is studied by laboratory physical model tests using paraffin as model ice. The results showed that: The formation of ice jam is controlled by flow rate and ice density during the melting period. When the flow rate is small and the density of flowing ice is high, there are enough ice cubes in a certain space who have enough time to combine with each other to form an ice jam. An ice jam is made up of at least two ice cubes stacked on top of each other vertically whose backwater influence is at least greater than the maximum height of one ice cube. An ice jam is more likely to form in the wider reaches of the river. The reason for that is, when the flow ice density reaches a certain level, the flow velocity is reduced more due to the wider river width, and the ice cubes are more likely to collide, squeeze and combine with each other, which are not easily transported by water with low flow intensity.