Research on the classification of life-cycle safety monitoring levels of subsea tunnels

As a traffic engineering project across straits or gulfs, subsea tunnel is one of the oceaneering with great construction difficulties, and the key to the success of subsea tunnel engineering lies in timely and accurate assessment of the structure safety of subsea tunnel engineering construction and life-cycle. Xiang’an Xiamen subsea tunnel is China’s first subsea tunnel which crosses complex formation conditions, engineering accidents such as collapse, sudden inflow of water or mud might occur during tunnel construction and operation. Therefore, the concept of subsea tunnel life-cycle monitoring is proposed aiming at the particularity of subsea tunnels. The variation forms of subsea tunnel mainly include large deformation, collapse, primary support cracking, water leakage, water pressure increase, steel arch corrosion, concrete corrosion, longitudinal differential settlement, etc., and classification of the life-cycle safety monitoring levels of the subsea tunnel is conducted based on risk assessment theory and risk level management benchmark to determine the possible variation forms in the monitoring level segments. The research results will provide reference for the subsea tunnel life-cycle monitoring, disaster warning as well as risk management under construction or to be built at home and abroad.