This project involves the technical field of land and water transportation management.
Floating transportation of pipe sections is a key link in the construction of immersed tube tunnels, and its difficulties are mainly reflected in the following: 1) The huge size of the pipe sections (180 meters in length, 78,000 tons in displacement), poor streamlined shape, easily affected by water flow, no power, and coordinated control of multiple tugboats makes it difficult to control pipe sections;2) Long-distance towing, complex sea conditions and environment, Busy water traffic, fragile concrete structures, narrow channel width and shallow water areas and other unfavorable conditions make safety guarantee difficult; 3) The window time to meet the floating transportation conditions is very limited. In this limited time, the processes such as lifting, undocking, towing, mooring, sinking, and docking of pipe sections must be completed, making the floating transportation time requirements high. At the same time, the project is expensive. The pipe section costs about 100 million yuan, the floating work boat costs about 200 million yuan, and the watertight rubber is worth millions of dollars. Improper pushing position or displacement during floating transportation can lead to cracking of the pipe section or damage to the watertight rubber. Any grounding or collision can destroy pipe sections and work boats, block navigation channels, affect construction periods, and cause hundreds of millions of losses.
Therefore, the research on key technologies for floating control of ultra-large pipe sections has important application and promotion significance for ensuring safe navigation during floating transportation, improving floating efficiency of pipe sections, and reducing consumption and waste of human resources and funds.
The main innovative achievements of the project include:

1. Comprehensively analyze the water flow resistance characteristics of ultra-large immersed pipe sections, analyze the control response relationship between pipe sections and tugboats through parameters such as cycle time, track band width, and tugboat power, so as to overcome the problem of multi-tugboats coordinated control of ultra-large pipe sections in complex water conditions and achieve successful long-distance floating transportation of the world's largest pipe section;
2. Aiming at the characteristics of pipe sections such as high inertia, poor anisotropy, and easy deflection, a unique tugboat equipment and towing method is proposed, and control technology for floating transportation of ultra-large pipe sections in channels, foundation trenches, and steering areas is established, and emergency control in situations such as sudden cable breaks, current diversion, etc., control the risk of towing and floating transportation, and ensure the safety and efficiency of floating transportation of pipe sections;
3. For the first time in China, a simulation experiment and training platform for pipe section floating operators was established; integrating satellite navigation and water flow meteorological data, designing floating management software for tugboat power distribution and control, and accurately and efficiently guiding each tugboat to designated locations, predicting pipe section dynamics through trajectory reckoning, monitoring pipe section positions and providing yaw warning.
   This project is applied to the floating transportation of pipe sections, making the floating transportation length of pipe sections reach 180 meters for the first time, and the displacement has increased to 78,000 tons. The floating transportation scale of pipe sections has been significantly improved, making it the largest scale in the world at present. The floating transportation technology of ultra-large pipe sections has reached the international first-class level.
   The results of this project and related technologies have been widely used in a series of projects such as the Hong Kong-Zhuhai-Macao Bridge, Shanghai-Tong Railway Bridge, navigation safety, port and shipping demonstration and transportation of major parts. A total of 93.97 million yuan has been created in economic benefits and a new breakthrough in floating transportation of pipe sections has been achieved., creating a new record for floating transportation of ultra-large pipe sections.