砾石堤坝和多孔方型鱼礁消浪护滩的试验研究--以北戴河西海滩为例

Experimental Study on Wave Dissipation and Beach Protection by Gravel Dam and Porous Square Reef:Taking Beidaihe West Beach as the Example

本文通过物理模型试验,研究了砾石堤坝、多孔方型鱼礁、堤坝+鱼礁等不同防护措施对岸滩的保护作用。通过测量不同防护措施的波浪透射系数、输沙率、水下坡度角及床面地形变化,并与无防护措施的工况进行对比,结果发现:不同试验条件下堤坝+鱼礁工况的透射系数仅为0.21~0.36,对波浪具有显著的消减作用;同一水位不同防护措施下的输沙率由大变小依次为:堤坝、堤坝+鱼礁、无工程、鱼礁;堤坝迎浪面的水下坡度角随极限波高呈现先增大、后减小的趋势,堤坝工况的水下坡度角约是堤坝+鱼礁工况的2~4倍;对于近岸的地形恢复,堤坝+鱼礁工况的效果比较明显,且对岸滩附近的侵蚀较少。堤坝+鱼礁的防护措施可明显减小波浪的透射系数,增加向岸输沙率,对恢复近岸地形、保护岸滩有显著作用。

The wave transmission coefficient,sediment discharge rate,underwater slope angle and seabed topography under the cases of different protective measures are measured by using physical model and compared with those under the cases of no protective measures.It is revealed that under different experimental conditions the transmission coefficient in the case of gravel dam and reef is only 0.21—0.36,indicating that the combination of gravel dam with reef has a significant dissipation effect on the waves.The change law of sediment discharge rate under the same water level but different working conditions is gravel dam>gravel dam+reef>no project>reef.The underwater slope angle of the wave-ward surface of the dam tends to increase first and then reduce with the increase in extreme wave height.The underwater slope angle under the case of gravel dam is about 2—4 times that under the case of gravel dam+reef.For the recovery of nearshore terrain,the case of gravel dam+reef has obvious effect and can also reduce the erosion of coastal beach.Therefore,it is concluded that the protection measure of the combination of gravel dam with reef can significantly reduce the wave transmission coefficient and increase the sediment discharge rate landward,and can also play a significant role in restoring the nearshore topography and protecting the coastal beach.