滩地红树林引起的波浪衰减特性实验分析

The Laboratory Study on Wave Attenuation by Mangroves Forests

根据中国南海红树林的外形特征,将桧柏树枝按照一定几何比例修剪,在波浪水槽中测试在不同水深和波浪条件下,波浪通过不同宽度淤泥质滩地、平底有植物滩地和斜底有植物滩地的衰减率。结果表明有植物覆盖的滩地的消波效果约为淤泥质滩地的3~4倍；随着水深增加淤泥质滩地的波浪衰减率减小,而有植物覆盖的滩地的衰减率增加；植物带宽度为150cm的衰减率是宽度为45cm时的2倍,且坡度为1：25的斜底消浪效果略好于平底情况。选取影响波浪衰减的最主要因素水深、波高、波浪周期及植物带宽度等作为基本量,将其无量纲化,并根据实验数据进行多元回归分析,得到消浪系数公式。本实验结果对建设防浪林有一定指导意义。

The Chinese juniper was pollarded in a fixed geometric proportion according to the external physical characteristics of the mangroves in South China Sea. The experiments were conducted in the wave flume under different water depth and wave conditions. The wave attenuation was tested when the wave passed through the beach covered by the soft mud with and without the model trees, respectively. The results showed that the wave reduction after the wave through the model tresses is 2~3 times bigger than through the mud without trees. Besides, with the increasing of water depth, the wave attenuation decreased when the wave went through the soft mud, while it increased rapidly through the model trees. The wave reduction for the plant breadth of 45cm is about one time bigger than that of 165cm, and for the beach which had a gradient, the wave dissipating effect was slightly better than that of the flat one. The most important influence factors which included the water depth, wave height, mud thickness and wave period were chosen as the basic quantities and made dimensionless. After the multiple linear regression analysis for the experimental date, the wave attenuation equations for these three test condition were got, respectively. The results could provide some advice on planting vegetation on the bank to attenuate waves.