基于能量守恒理论的波浪侵蚀土质岸坡范围预测方法

波浪对三峡库区土质岸坡的侵蚀极大影响了库区生态与地质环境安全，预测波浪对岸坡的侵蚀范围将是库区防灾减灾工作的重要措施，然而现有的侵蚀预测主要是以经验方法为主，难以获得准确的结果。为此，采用能量守恒理论，考虑波浪上爬过程中的层厚及流速变化，分别构建波浪上爬势能方程与摩擦耗能方程，最终联立建立波浪作用土质岸坡侵蚀范围预测方程。为获取预测方程的关键参数，开展波浪上爬岸坡模型试验，研究波浪上爬岸坡时的流速、层厚及爬高变化规律；为验证侵蚀范围预测方程的可靠性，开展波浪侵蚀岸坡模型试验，获取土质岸坡侵蚀演化进程。波浪上爬模型试验结果表明：岸坡坡度越大，则波浪爬高越大，爬坡水流厚度也随之增大，但爬坡水流流速随之减小；根据试验结果获取了水流厚度参数与流速参数的分布区间，构建了水流厚度参数、流速参数与岸坡坡度间的关系方程。波浪侵蚀岸坡模型试验结果表明：土体干密度越大，岸坡的抗侵蚀能力越强，且岸坡达到最终稳态所需的时间越长；碎石含量越多，岸坡的抗侵蚀能力越强，由于碎石护面作用使得岸坡侵蚀稳定的时间缩短；将岸坡侵蚀稳定终态结果与预测方程结果进行了对比，验证了本文提出的侵蚀范围预测方程是可靠的。本文提出的波浪侵蚀范围预测方程可广泛应用于国内外水库土质岸坡的侵蚀灾害防治工作中。

Prediction Method of Wave-induced Erosion Range on Soil Bank Slopes Based on Energy Conservation Theory

The erosion of the soil bank slope by waves in the Three Gorges Reservoir Area (TGRA) significantly affects the ecological and geological environment safety of the reservoir area. Predicting the erosion range of the bank slope by waves will be an important measure for disaster prevention and mitigation in the TGRA. However, the existing erosion prediction is mainly based on empirical methods, and it is difficult to obtain accurate results. Therefore, using the energy conservation theory, considering the wave layer thickness and wave velocity changes during the wave run-up, the wave run-up potential energy equation and the friction energy consumption equation were respectively established, and finally the prediction equation for the erosion range of the soil bank slope caused by waves was established simultaneously. In order to obtain the key parameters of the prediction equation, the model test of the wave run-up bank slope was carried out, and the flow velocity, layer thickness and run-up law were studied; in order to verify the reliability of the prediction equation, the wave erosion bank slope model test was carried out to obtain the erosion evolution process of the soil bank slope. The results of wave run-up model test shown that the greater the slope of the bank slope, the higher the wave run-up, and the thickness of the water flow increases, but the velocity of the water flow decreases; according to the test results, the distribution interval of the water flow thickness parameter and the flow velocity parameter was obtained, and the relationship equation between the water flow thickness parameter, the flow velocity parameter and the slope of the bank slope was constructed. The model test results of wave erosion bank slope shown that the greater the dry density of soil, the stronger the erosion resistance of the bank slope, and the longer the time required for the bank slope to reach the final steady state; the more gravel content, the stronger the anti-erosion ability of the bank slope, and the stable time of bank slope erosion was shortened due to the effect of gravel protection; by comparing the final steady state results of bank slope erosion with the results of the prediction equation, it was verified that the prediction equation of erosion range proposed in this paper is reliable. The wave erosion range prediction equation proposed in this paper can be widely used in the prevention and control of erosion disasters on soil bank slopes of reservoirs.