黄河揭底冲刷现象的计算分析

Calculation and analysis of the bottom tearing scouring phenomenon in flood with hyperconcentration in the Yellow River

黄河中游的高含沙洪水常常引起黄河的"揭河底"冲刷。通过对黄河"揭河底"现象的分析,建立了"揭河底"冲刷的物理模式,进而导出了"揭河底"冲刷的力学方程和临界水沙条件,其计算结果与实测"揭河底"冲刷的水沙条件相一致。通过该方程与水沙条件的分析,进一步验证了散粒体泥沙起动的流速公式。这两个公式的导出对研究高含沙洪水引起的河床演变以及泥沙起动规律具有重要的理论价值。

The flood with hyperconcentration in the midstream Yellow River frequently causes the bottom tearing scouring.Based on the analysis of the bottom tearing scouring, this paper sets up the physical mode about the bottom tearing scouring and derives the mechanics equation of the bottom tearing scouring and the critical condition of the water and sediment, and the results of calculation agrees with the measured records. Based on the analysis of the equation and condition, the starting current velocity formula about the pill sediment is further proved. The two formulas derived possess important theoretical value to the research of river floor variation and sediments starting caused by the flood with hyperconcentration.