## 1 Introduction  
At present, most port sites with superior coastal and near-shore natural conditions have been developed and utilized, and offshore deep water will be the development direction of large-scale port and wharf construction in the future. However, a series of problems, including large horizontal forces of external loads such as wave and current force, ship crowding force, and construction difficulties, have always been difficult problems in wharf construction [1]. At present, traditional gravity and pile foundations are the main two forms of wharf structure, but when facing the offshore deep-water environment, these display many deficiencies. In order to solve the problem of the surface facing large waves and strong currents in the open sea, (1) for the traditional gravity structure, the overall stability of the structure is affected by excessive waves and current force on the wave-facing surface; (2) the traditional pile foundation structure faces difficulties in pile sinking construction, so a new barrel-pile foundation composite structure wharf is proposed. The structure is as follows: the foundation is a box barrel, the upper part is a high-pile beam-slab composite structure, and the external load and structural self-weight of the wharf panel are transmitted to the box barrel and foundation bed through piles. Compared with the design in [2], a pile foundation square caisson gravity structure, the new structure has the advantages of a coordinated structure, fast dispersion under the wave load, a wide range of applicable geological foundations, and a simple construction process, saving project progress and cost. Specifically: (1) the pile adopts the combination of straight piles and inclined piles, and the pile diameter ranges from \(\diameter\) 0.8 m to \(\diameter\) 2.5 m, so it can quickly disperse the external load and has little influence on wave reflection; (2) the box barrel foundation is a multibarrel combination type, and the top elevation is designed to be 1.25 times the incident wave height of the lowest tide level. The foundation treatment is simple and less affected by waves; (3) the new cylindrical foundation is prefabricated on land, with air floatation haulage, negative-pressure pumping sinking, and bottom installation. The upper high pile is reserved by the foundation and can be directly inserted. The construction process is simple; (4) the overall structure is flexible at the top and rigid at the bottom, which is suitable for different complex geological conditions. Based on the deep-water wave impact environment in the open sea, the hollow pile foundation and bottom box foundation in the new structure have little impact, but the wharf superstructure is vulnerable to wave attack and serious damage due to the limitation of the wharf's elevation. There have been a large number of cases of damage to structures located in unprotected sea areas due to the wave impact load [3]. For example, in 1972, the rise of water level and huge waves caused by Typhoon No. 3 destroyed the approach bridge decks of many wharves in North China. In September 2004, Hurricane Ivan hit Pensacola, Florida, in the USA, resulting in the collapse of the bridge deck of Escambia Bay Bridge [4]. In order to prevent such accidents, one must accurately calculate the crest height and panel wave impact force under extreme sea conditions, which can be used as the basic design data for reasonably determining the wharf elevation. At present, in the research field of wave crest height, the technical code for design and construction of an open wharf (JTJ295-2000) [5] stipulates that the wharf surface will not be submerged under the action of waves. Generally, it is considered that the beam and slab on the upper part of the wharf will not be affected by wave uplift force, and the water surface blocking height caused by the interaction between waves and the high-pile wharf is considered by using the surplus height, which is arbitrary.