基于物理模拟试验的库岸滑坡冲击涌浪

Impulse wave generated by reservoir landslides based on physical model experiments

以三峡库区的滑坡规模和典型河道为原型,以1:200为正态相似比进行滑坡涌浪三维物理模拟试验。在对比分析试验结果的基础上,考虑滑坡涌浪的产生过程中发生在近源区以内的水舌和首浪2种水体雍高,并分别阐述两者的特征和区别,完善冲击涌浪的概念。将水舌的最大高度和水舌长度作为2个特征量,分别运用方差分析法和逻辑回归分析法,得出其影响因素的显著性并拟合经验公式;以抛物线型作为水舌运动的轨迹方程,在已知水舌高度和水舌长度的情况下,预测水舌拍打到一定宽度河道对岸的高度。以大堰塘滑坡和千将坪滑坡涌浪分析为例,对比本文冲击涌浪公式和潘家铮公式。计算结果表明:潘家铮公式计算结果较首浪高度偏大,较水舌高度偏小;而本文公式计算的冲击涌浪高度以及抵达至对岸的爬坡浪高度与实际情况较一致,充分验证了应用本文公式进行三峡库区库岸滑坡涌浪预测分析具有较好的适应性和较高的准确性。

The three dimensional experiment of landslide triggered waves was conducted by modeling landslides and a river channel in Three Gorges Reservoir, and the similarity ratio is 1：200 in normal. Based on the experiment data, the characteristics of both water tongue and initial wave during the generation of the waves in the near source field were considered, and the concept of impulse wave was discussed. Taking the max water tongue height and the max distance （maximum horizon distance from the entry point to the highest water tongue point） to describe water tongue＇s shape and movement, the variance analysis method and multiple logistic regression analysis method were used to analyze the significance of influence factors and fit formula respectively. After analyzing the mechanics of water tongue＇s movement, a parabola equation was approved as the motion profile of the water tongue, then the highest point on the opposite hill of the river that the water tongue fly to impact was predicted. Taking the already existing Dayantang landslide on Qingjiang River and Qianjiangping landslide in three gorges reservoir for example, the max water tongue height, initial wave height and the calculation height by Panjiazheng formula were compared. The results show that the wave height calculated by Panjiazheng formula is higher than the initial wave height and lower than the max water tongue height as to landslides in Three Gorges Reservoir. The wave height calculated by formulas in this paper is consistent with the fact, which approves that formulas based on our experiment are appropriated to predict landslide triggered waves in Three Gorges Reservoir.