Analysis method for navigation control standards of non-sheltered approach channels

As a complex project built upon an existing hub, the reconstruction and expansion of ship locks are subject to boundary conditions such as flood discharge, ecology, geology, and the layout of existing structures. The approach channel often cannot be fully protected or arranged according to the specifications. There is ongoing debate about how to apply existing specification control standards to clarify the layout types of unprotected approach channels. Based on the flow condition control standards in the Code for Master Design of Shiplocks and the Design Code for Filling and Emptying System of Shiplocks, this paper analyzes the control principles of navigational and berthing conditions for entering and leaving the lock. It proposes an analytical method by which navigational control standards for unprotected ship lock approach channels can be managed in a zonal and segmented manner, according to the mode of lock operation and the division of navigable waters. This method is applied to the Hongjiang reconstruction and expansion ship lock project and verified through overall physical model flow field and ship model tests. The results show that the proposed zonal and segmented control method can effectively guide the layout of unprotected approach channels. Additionally, it may serve as a reference for the revision of relevant specifications. The proposed flow condition control standards can offer practical guidance for similar reconstruction and expansion ship lock projects.