Typhoons, extratropical cyclones, and cold fronts cause strong winds leading to storm surges and waves in the Bohai Sea. A wave–flow coupled numerical model is established for storm events observed in 2022 caused by three weather systems, to investigate how storm waves are modulated by wave–tide–surge interaction (WTSI). Wave response is basically controlled by water level change in coastal areas, where bottom friction or breaking dominates the energy dissipation, and determined by the current field in deep water by altering whitecapping. Wave height increases/decreases are induced by positive/negative water level or obtuse/acute wave–current interaction angle, leading to six types of field patterns for significant wave height (Hs) responses. For the three storm events, Hs basically changed within ±5% in central deep water, while the maximum increase/decrease reached 160%/−60% in the coastal area of Laizhou Bay/Liaodong Bay. Based on maximum Hs and its occurrence time, WTSI modulation is manifested as the superposition effect of wave–tide and wave–surge interactions in both space and time scales, and occurrence time depends more on tide than surge for all three storms. The enhancement/abatement of WTSI modulation happens for consistent/opposite changing trends of wave–tide and wave–surge interaction, with the ultimate result showing the side with a higher effect.

The strength of water exchange capacity serves as a proxy for the self-purification capacity of water bodies, thereby playing a pivotal role in enhancing the overall water environment. This study focuses on the secondary outfitting area of the immersed tube tunnel within the Shenzhen–Zhongshan Link, utilizing either the substances transport model or the particle tracking model. This framework is designed to delve into the similarities, differences, and appropriateness of the Eulerian and Lagrangian methods in appraising the water exchange capacity of semi-closed water areas. The following key insights have been derived: (1) The spatial distribution patterns of water exchange capacity computed using both methods align, indicating a congruency in their fundamental principles. However, in our case study, the average water transit time determined by the Lagrangian method is 1.6 times higher than the average water residence time calculated by the Eulerian method, suggesting a more conservative approach by the Lagrangian method. (2) The results obtained from varying particle release times or initial concentration release times within a tidal cycle in the case exhibit notable disparities, highlighting the sensitivity of the system to these factors. (3) The Lagrangian method exhibits a significant 12% difference in average water transit time, compared to the mere 0.9% difference observed in the average water residence time calculated by the Eulerian method. This underscores the Lagrangian method’s heightened sensitivity to the timing of particle release. Conversely, the Eulerian method offers more stable simulation outcomes in assessing the water exchange capacity of semi-closed water bodies, making it a preferred choice for such studies. However, if a comprehensive understanding of water exchange capacity, material transport trajectories, and final destinations is sought, the Lagrangian method would be the more appropriate approach. The research outcomes presented in this paper can serve as a valuable reference for selecting appropriate evaluation techniques for water exchange capacity in semi-closed water areas, encompassing not just immersed tube outfitting zones but also lagoons and harbor basins.

The application of non-excavation construction technology, such as the pipe jacking method, has obvious advantages in building urban underground space engineering projects, which can effectively reduce the occupation of ground surfaces and the migration of obstacles above or below the ground. However, pipe jacking machines with a rectangular cross-section can easily encounter great difficulty due to the significantly increased jacking resistance while it is jacked in hard rock strata, which are often influenced by large blind spots on the working face of pipe jacking machines with a rectangular cross-section. The aforementioned blind spots belong to areas that cannot be cut by the cutter heads due to the circular cutterhead and rectangular outer frame of pipe jacking machines with a rectangular cross-section. Therefore, the effective pretreatment of the aforementioned blind spots should be implemented prior to operating pipe jacking machines with a rectangular cross-section in hard rock strata. This paper presents a case study of employing horizontal-directional drilling as a multi-pilot heading pretreatment for breaking large blind spots on the working face of pipe jacking machines with a rectangular cross-section, which was implemented prior to operating a pipe jacking machine with a rectangular cross-section in shallow buried rock strata. In particular, this multi-pilot heading pretreatment is expected to be used to safely construct a rectangular comprehensive pipe gallery using pipe jacking machines with a rectangular cross-section in shallow buried rock strata and when passing underneath existing light rail lines, which can effectively save the precious land resources required for sustainable development. The study was implemented by employing a numerical simulation, focusing on the safety of the adjacent existing light rail line and the stability of the surrounding rocks, which are influenced by the variation in the distribution positions and sizes of the drilling holes used when implementing the horizontal-directional drilling. The results demonstrate that the horizontal-directional drilling applied for the multi-pilot heading pretreatment could effectively break the blind spots on the working face of the pipe jacking machine with a rectangular cross-section, in which the safety of the adjacent existing infrastructure was significantly influenced by the distribution positions and sizes of the drilling holes used when implementing the horizontal-directional drilling. This study can provide a reference for carrying out pipe jacking construction using pipe jacking machines with a rectangular cross-section, in which horizontal-directional drilling is employed as the multi-pilot heading pretreatment for breaking the large blind spots on the working face. Moreover, the distribution positions and sizes of the drilling holes used when implementing the horizontal-directional drilling could be appropriately optimized by utilizing the method of numerical analysis. Meanwhile, the study is also expected to eliminate the hazards of safely running the aforementioned adjacent existing light rail line during implementing the multi-pilot heading pretreatment of horizontal-directional drilling.

The study of mechanisms and the accurate simulation of riprap movement caused by complex hydrodynamics are significant for harbor, channel and coastal engineering. Field measurement of current and riprap drift distance was conducted for a dike project in the port of Lianyungang, Jiangsu Province, China. Meanwhile, a well-validated three-dimensional hydrodynamic model was developed to study and analyze the riprap movement process and the influence of project position combined with the theoretical movement equation of riprap. At the moment of maximum flood, the riprap drift distance is greater than at the moment of maximum ebb. The riprap drift distance increase as the tidal inlet width decreases, which follows a second-order exponential distribution. The riprap mass reduces the riprap drift distance, and the magnitude of the reduction diminishes gradually as the riprap mass increases. Therefore, heavy riprap can reduce the horizontal drift distance in a construction.