Subsea tunnel site selection evaluation: A new evaluation model

Abstract

The foundation of subsea tunnel construction is that the expected benefit of the tunnel is greater than the construction cost. The location of subsea tunnels is the most fundamental factor determining the size of both tunnel revenue and cost. At present, the evaluation model for the site selection of subsea tunnels is mainly based on specific engineering projects, and the universal evaluation model for the subsea tunnels site selection is deficient. In this paper, nine parameters including lithology, geologic structure, rock strength, environmental conditions, economic benefit, construction cost, Minimum leakage method, Coal cutting experience under water method, and Norway experience method are selected as evaluation indexes for the site selection of subsea tunnels. The weight of each index is determined by weight back analysis. An evaluation model for subsea tunnel site selection is established based on weight back analysis method and efficacy coefficient method, and evaluation criteria are divided into four grades: excellent, good, medium, and bad. The evaluation model of subsea tunnel site selection is applied to the Qingdao Jiaozhou Bay subsea tunnel, the Xiamen Xiangan subsea tunnel, and the Seikan subsea tunnel. Results show that the site selection of the Qingdao Jiaozhou Bay subsea tunnel is grade II, the site selection of the Xiamen Xiangan subsea tunnel is grade III and the site selection of the Seikan subsea tunnel is grade IV. This new selection process provides a new method for subsea tunnel site selection and evaluation and also provides some reference for site selection of other types of structures.