Document Type : Research Paper
Author
Soil Conservation and Watershed Management Research Institute, Tehran, Iran
Abstract
To evaluate the scour depth around cylindrical piles of coastal protection structures under wave impact pressure caused by wave breaking, an experimental study was designed. The study aimed to analyze how variations in wave characteristics, including wave height and period, influence scour depth. It is important to note that this research focuses on breaking waves that directly impact the structure.
In this study, a two-dimensional wave channel at the Coastal Engineering Laboratory of the Soil Conservation and Watershed Management Research Institute was used. To create shallow water conditions and ensure wave breaking at the pile location, as well as to assess the resulting scour depth, a sloped surface and a sediment reservoir were constructed in the middle section of the main channel. The sediment reservoir, with a depth of 0.35 meters, was installed upstream of the metal sloped surface and filled with sand sediments. A polycarbonate cylindrical pile was positioned at the center of the sediment reservoir.
The wave channel was filled with water to depths ranging from 0.4 to 0.5 meters, and waves of varying heights and periods were generated using a wave paddle system. Through trial and error, the exact wave breaking location and the pile’s position relative to it were identified. A total of 34 experiments were conducted under initial water depths ranging from 0.4 to 0.5 meters. Wave heights varied between 0.05 to 0.14 meters, and wave periods ranged from 2 to 7 seconds. After each experiment, scour depth at the pile location was captured and measured using imaging techniques.
The findings of this study revealed that wave breaking resulted in a 2.37-fold increase in scour depth and erosion compared to the passage of a regular wave near a cylindrical pile structure.
Therefore, marine structure designers must carefully consider this issue.
Keywords
)