游艇波浪侵蚀长港河河岸的计算分析

Calculation and analysis of bank erosion of Changgang River caused by yacht-generated waves

  • 摘要: 船行波导致的河岸侵蚀对土地资源和堤防构成威胁。游艇体量小,其危害往往被忽视,然而快速航行的游艇会对河岸产生严重损坏。目前量化评估船行波侵蚀河岸的文献很少。建立船行波引起河岸侵蚀后退的估算模型,并结合鄂州市长港河侵蚀进行实例计算。研究过程由三部分组成:一是现场勘测和调研,包括采集河岸土样,测量河道特征参数,调查长港河船舶类型、船舶技术参数及各类船舶每天航行频次;二是开展室内土工试验,测定土样颗粒级配曲线和临界剪应力,以评估河岸的抗侵蚀性;三是开展河岸侵蚀的数值计算,包括计算游艇船行波要素,采用侧向侵蚀模型计算河岸侵蚀率。计算结果表明,在游艇船行波侵蚀作用下,长港河河岸年平均侵蚀后退54.4 cm,与现场调研结果基本相符。

     

    Abstract: River bank erosion induced by ship waves can be a serious threat to the land resources and the dykes. Dangers given by the yacht-generated waves usually are neglected because of yacht's small sizes, however, the high speeds of yachts can result in significant damages to the river banks. As there is generally little quantitative information available to assess the magnitude of erosion, the objective of this paper is to establish an available model for estimating the recession of the river bank caused by ship-generated waves and provide an application example of the model. The study includes three main components: field measurement and investigation, laboratory experiment, and numerical modeling. The field measurement consists of soil sampling from banks of the Changgang River in Ezhou city and measurement of the river characteristics; site investigation includes learning about the types of recreational yachts sailing on the Changgang River and their parameters, as well as daily navigation frequencies. The laboratory experiments of the soil samples were carried out to determinate the soil particle size distribution curves and the critical shear stresses, so as to estimate the riverbank erodibility. Finally, the yacht-generated wave factors were calculated, and the numerical modeling of the bank erosion rates of the Changgang River was conducted by using a lateral erosion model, from which, an annual bank recession of the Changgang River was obtained as 54.4 cm, approximately consistent with the field survey result.

     

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