Health evaluation of shield tunnel lining using combination weighting and finite interval cloud model

To solve the problem of inaccurate and unreasonable health evaluation of shield tunnel lining, a novel health evaluation model of shield tunnel lining based on the combination weighting method and finite interval cloud model is proposed. A health evaluation index system including 6 level-Ⅰ indexes and 15 level-II indexes and evaluation criteria are established for the shield tunnel lining. The weights of evaluation indexes are calculated by the game theory combination weighting method. The finite interval cloud model is used to evaluate the health of shield tunnel lining, which considers the uncertainty of various information within the interval. To verify the applicability of the proposed approach, it was applied to the shield construction section from Bei Chen Station to the Olympic Sports Center Station of Xi'an Metro Line 14. The results show that: (1) The health evaluation grade of shield tunnel lining in Samples 1–3 is level II. The result is in agreement with the actual situation which validates the practicality of the employed methodology. (2) The change in the evaluation index has little influence on the evaluation results, and the evaluation results are level II. The key risk factors were identified as U₃₂, U₃₁, and U₁₂ by sensitivity analysis. Corresponding measures should be taken to ensure the stability of these three indexes and to ensure the safety of shield tunnel operation. Therefore, the proposed approach maximizes the assurance of the rationality of the evaluation results, which can be feasibly used in various applications and can provide guidance for other similar projects.