Artificial reef (AR) can be regarded as a perforated breakwater when it performs as an auxiliary structure in beach nourishment. In this paper, a kind of artificial reefs made of cuboid reinforced concrete blocks, which has already applied practically in beach nourishment projects in Beidaihe, has been experimentally investigated on the wave attenuation process in terms of small and destructive waves. Regular waves with five sets of wave height and period were used. The reflection coefficient, transmission and dissipation coefficients were obtained from measurements. Wave and velocity processes near the reef were compared and analyzed. The reflection coefficient (Kr) is 0.10~0.29, with transmission coefficient (Kt) of 0.31~0.65 and the dissipation coefficient (Ki) of 0.05~0.59. It is a definite and stable regime that the AR attenuates the incident wave. The AR performs as a submerged breakwater for small wave. But it impacts on moderate waves by more dissipation than reflection, when the porosity character highlights. As for big incident wave, the dissipation and reflection effects of the AR can reach the limit due to the extra energy loss, which maybe in large proportion, caused by the natural breaking of big incident wave.
Coastal erosion is a worldwide problem and now largely intensified due to human activities. The available options of shoreline management to deal with erosion problems are: to accept retreat in areas where beaches and dunes are wide and high; to maintain the coastline at a fixed position by of hard structures and/or by soft nourishment (Van Rijn, 2011). If a long term erosion trend is captured at the problem area by profile analysis versus time, it may consider to nourish the area, either as beach or shoreface nourishment or both. Although beach nourishment often is regarded as the most effective method for shoreline stabilization, it is not economically or environmentally suitable for some sites or even the ‘hot spots’ in a successful nourishment project (Harris, 2003).