Aiming at the problem of increasing port erosion under the background of global warming, in order to improve the protection effect of dikes on ports, a new type of perforated caisson dike is proposed in this paper. The reflection coefficient, transmission coefficientand the maximum flow velocity in front and behind the dike are analyzed by the indoor wave flume test of the new type of perforated cai-sson dike and the traditional rectangular caisson dike under different incident wave conditions and different water depth of the dike. The test results show that the new perforated caisson dike has stronger wave energy dissipation capacity than the traditional rectangular caisson dike when used in non-large dike top water depth. Compared with the rectangular caisson dike, the transmitted wave height can be reduced by 5.5%~32.2%, the reflected wave height can be reduced by 3%~37.9%, and the maximum velocity in front of the dike can be reduced by 6.3%~19%. The maximum velocity behind the levee can be reduced by 4%~52.2%. On the whole, it shows excellent performance of reducing wave reflection and reducing current.

In order to investigate the effect of lateral extrusion generated by the pressure difference between the peak and valley on seabed liquefaction, this paper used a self-designed hydraulic cyclic loading device to study the liquefaction differences of soil under uniformly distributed and planar wave cyclic loads with and without lateral extrusion. The results indicate that the planar wave cyclic load with lateral extrusion can accelerate the occurrence of soil liquefaction compared to the uniformly distributed cyclic load without lateral extrusion, with acceleration rates ranging from 23% to 60%. Moreover, the larger the peak value and shorter the period of the cyclic load, the more likely the soil is to liquefy.

To address the issues of wave dissipation and stability when gravity-based or piled submerged breakwaters are deployed on soft soil foundations, this paper proposes a snake-curved submerged breakwater structure that balances wave dissipation, stability, and material savings. A numerical wave flume model was established using Flow 3D software to study the interaction between waves and the snake-curved submerged breakwater, and to examine its wave dissipation characteristics and structural performance. The simulation results show that the structure's size affects its wave dissipation characteristics. When the crest width is smaller than half the wavelength of the incident wave, as the width increases, the transmission coefficient of the snake-curved breakwater initially increases and then decreases. However, increasing the crest width has limited effect on enhancing energy dissipation. As the curvature increases, the transmission coefficient decreases first and then increases. Excessive curvature may lead to scouring pits and concentrated wave pressure, reducing the structural stability. Additionally, the horizontal wave force on the snake-curved breakwater is significantly smaller than that on a rectangular breakwater, especially when the crest width is large, leading to better load performance. However, considering economic factors, appropriately reducing the crest width and optimizing the curvature can also improve energy dissipation and reduce structural load.