Development and application of a new ballast water system for immersed tunnel installation: A case study of the Yuliangzhou tunnel in Xiangyang, China

Ballast water systems are an indispensable part of the installation immersed tunnels and utilized to increase or reduce total weight tunnel elements in processes floating transportation, mooring sinking. Traditional ballast generally utilize rigid tanks, which consist retaining walls made steel-wood parts, for supply discharge. However, there many drawbacks traditional system based on tanks. For example, construction tanks is a complex process that not very efficient but costly. In addition, installing dismantling steel panels involve substantial welding work fire operations, result amount smoke dust inside elements, resulting environment harmful human health. Based Yuliangzhou Immersed Tunnel, extends across Hanjiang River Xiangyang, China, new type with flexible water-filled containers was developed address abovementioned problems. The equivalent volume method proposed determine geometric size containers. Field stability tests were conducted 4.8% slope. experimental results showed designed container could meet actual demand element immersion, without sliding rolling during injection, relationship between pressure approximately parabolic. view specific functions different stages equipment layout determined. installation, discharge technologies designed. This has been successfully applied Tunnel project, supports use these construction.